I originally published a blog post about the safety of soy back in 2014, but as I am still asked about it on a daily basis, I figured it was high time I gave it a revamp and re-posted it.
In the original post, I looked at various anti-nutrients in soy products (including saponins, phytate, enzyme inhibitors and lectins), so if you have concerns about these, please read the 2014 post here. Concerns about lectins in particular in soy products have resurfaced in the past year or so in the media, so please read the previous post if it's something you're interested in knowing more about.
I was motivated to write this post as many clients I see in my clinical practice deliberately avoid soy products, with the most common reason stated for doing so being 'I have heard that soy is bad for hormones'. As such, this post will delve into the science of soy and its effect on sex hormones (estrogen and testosterone).
Firstly, soy products refers to foods made from soybeans, and includes:
Tempeh - this is a product not many people are familiar with - it is a traditional Indonesian food, made by forming whole soy beans into a cake and then fermenting it with a mold
Textured vegetable protein (TVP)
Isolated soy protein powders (found in processed foods such as faux meats)
Does soy contain estrogen?
Soybeans contain a class of compounds known as isoflavones, which are characterised as phytoestrogens (‘phyto’ meaning plant-derived). Many other plant foods also contain isoflavones, including flaxseeds and whole grains, though soy is the most significant dietary source.
The isoflavones in soy (daidzein, genistein and glycitein) are structurally similar - although not identical - to human estrogen, and as such, can bind to estrogen receptors in the body. However, compared with human estrogen, phytoestrogens are known to exert a much weaker effect in the body.
There are also two types of estrogen receptors (ER): ER-alpha and ER-beta, which are found in different tissues in the body. Isoflavones have been shown to be selective in their binding to these receptors, choosing to bind to ER-beta in preference to ER-alpha, and hence are often referred to as selective estrogen receptor modulators (SERMs). This selective binding affinity helps to explain how they can both enhance and inhibit the action of estrogen depending on the tissue type.
Soy consumption and breast cancer
Many people believe that the isoflavones in soy products may increase the risk of breast cancer, however, data from population studies (primarily conducted in Asia, where people regularly consume soy products) actually show that moderate consumption of soy products (1-2 servings per day) may reduce breast cancer risk in women (1).
Recent results by Baglia et al from the Shanghai Women's Study (a cohort of over 70,000 women) found that those who had the highest intake of soy products during childhood and adulthood had a reduced risk of breast cancer (2).
Soy consumption in patients with breast cancer
Moderate consumption of soy products is known to be safe for women with breast cancer and those with a history of breast cancer, and may also reduce the risk of breast cancer recurrence (1).
Soy consumption and men’s health
A 2009 meta-analysis (which pools a number of studies) found that men with the highest intake of soy had a statistically-significant reduction in prostate cancer risk, compared to the men who consumed the least soy (3).
A 2010 review on the topic found that neither isoflavone supplements nor soy products affected total or free testosterone levels, or estrogen levels in men (4).
Excessive consumption of soy products in men and feminising effects
I was able to find two journal articles describing feminising effects relating to excessive soy consumption in men.
The first was a case report of a 60 year old man, who had been habitually consuming three quarts (2,840mL) of soy milk every day, which is just over 11 cups. The man developed gynaecomastia, or growth of breast tissue, which resolved on discontinuation of the soy milk consumption (5).
The second case was a 19 year old vegan man who was consuming large quantities of soy products (>14 serves) on a daily basis, which resulted in hormonal dysfunction, loss of libido, and erectile dysfunction, which resolved following discontinuation of his extremely high soy, vegan diet (6).
How much is safe to have each day?
1 serve of a soy product contains around 7g of protein and 25mg of isoflavones, and is equal to:
100g firm tofu
1 cup soy milk
For reference, the mean (average) soy product consumption in Japan is equal to 1-2 servings per day (30-50mg isoflavones) (7). This level of intake is described as a 'moderate' intake.
In the interest of dietary variety, I would advise against the consumption of more than four servings of soy products per day.
My tips for healthy soy consumption
Choose whole food soy products such as tofu, tempeh, and soy milk made from whole soybeans (rather than from soy protein or soy protein isolate)
Avoid highly-refined soy products such as Textured Vegetable Protein (also known as TVP, which is a product made from defatted soy flour). Choose whole legumes (beans, peas, chickpeas and lentils) as a protein-rich option with main meals instead
Avoid soy protein bars, powders and other products in the interests of eating a whole food, plant-based diet
If you have elevated cholesterol levels, include three servings of soy products daily - this is a well-studied intervention for reducing cholesterol levels
If you'd prefer to be conservative with your soy product intake, don't exceed 1-2 servings per day (known as a 'moderate' intake, and in line with typical intakes in Asian countries such as Japan)
1. Soy Research | American Institute for Cancer Research (AICR) [Internet]. [cited 2018 Feb 28]. Available from: http://www.aicr.org/foods-that-fight-cancer/tab-content/soy-research-1.html?referrer=https://www.google.com/
2. Baglia ML, Zheng W, Li H, Yang G, Gao J, Gao Y-T, et al. The association of soy food consumption with the risk of subtype of breast cancers defined by hormone receptor and HER2 status: Soy intake and breast cancer risk by receptor status. International Journal of Cancer. 2016 Aug 15;139(4):742–8.
3. Yan L, Spitznagel EL. Soy consumption and prostate cancer risk in men: a revisit of a meta-analysis. Am J Clin Nutr. 2009 Apr 1;89(4):1155–63.
4. Messina M. Soybean isoflavone exposure does not have feminizing effects on men: a critical examination of the clinical evidence. Fertil Steril. 2010 May;93(7):2095–104.
5. Martinez J, Lewi J. An Unusual Case of Gynecomastia Associated with Soy Product Consumption. Endocrine Practice. 2008 May 1;14(4):415–8.
The Low FODMAP Diet was designed by a team of researchers at Monash University to help reduce gastrointestinal (gut) symptoms such as bloating, abdominal pain, constipation, and diarrhoea in patients with medically-diagnosed Irritable Bowel Syndrome (IBS).
The Low FODMAP Diet is currently the most effective dietary intervention available for patients with IBS, and has been shown to significantly improve symptoms in 3 in 4 people (1).
What is IBS?
IBS is a very common functional gastrointestinal disorder, affecting around 1 in 7 Australian adults. In fact, it is the most frequently diagnosed condition by gastroenterologists in Australia (2).
The formal criteria for a diagnosis (as per the Rome Foundation (3)) are:
Recurrent abdominal pain on average at least one day per week in the last three months, and is associated with two or more of the following:
1. Related to defaecation (i.e. the abdominal pain can be better or worse after having a bowel movement); and/or
2. Associated with a change in frequency of stool (i.e. passing a bowel movement more or less frequently); and/or
3. Associated with a change in form (i.e. the appearance) of stool
The importance of seeking a definitive diagnosis of IBS
If you are experiencing frequent bouts of abdominal pain, bloating, constipation and/or diarrhoea, the first step is to have blood test through your GP to rule out Coeliac Disease as a potential cause of your symptoms, as the gut symptoms of untreated Coeliac Disease are often mistaken for IBS. Because Coeliac Disease is both relatively common in Australia (approximately 1 in 70 people (4)), and has serious health consequences if left untreated, it’s incredibly important to rule it out as a potential cause of your symptoms. There are two different blood tests requested by GPs to screen patients for Coeliac Disease: an antibody test (the most common, which requires you to be eating gluten daily), and a genetic test, which looks at your genetic susceptibility to developing Coeliac Disease in your lifetime.
Once you have had Coeliac Disease ruled out as a potential cause of your symptoms, the next step is to speak to your GP and/or a gastroenterologist about ruling out other conditions which can mimic the symptoms of IBS, such as Inflammatory Bowel Disease. This may require further blood tests and/or stool tests.
What are dietary FODMAPs?
FODMAPs is an acronym which describes a collection of short-chain carbohydrates (sugars) that are only partially-absorbed in the small intestine, and can be fermented by the resident bacteria in the large intestine. These bacteria produce gases (such as hydrogen and methane) which can cause wind, abdominal bloating, and/or constipation, triggering the sensation of pain in patients with IBS, due to hypersensitivity of the nerve endings found in the gut (known as visceral hypersensitivity). The presence of the dietary FODMAPs in the large bowel can also cause water to enter the bowel, resulting in diarrhoea.
The Low FODMAP Diet Basics
The Low FODMAP Diet is not a 'forever' diet; it is a restrictive elimination diet employed by dietitians to determine whether your usual intake of dietary FODMAPs is triggering your IBS symptoms, achieved by significantly reducing the total load of FODMAPs in your diet for a period of two to six weeks.
If the diet results in a significant improvement in your symptoms, you will be guided through the re-challenge phase (the second phase of the diet), which seeks to determine your individual tolerance to each of the FODMAPs (5).
Why not just stay on a low FODMAP diet indefinitely if it relieves the symptoms of IBS?
The FODMAPs are actually a source of fuel for the good gut bacteria (the bifidobateria and lactobacilli) which produce compounds which have a wide range of health benefits in the body, such as short-chain fatty acids. As such, a healthy diet for gut health should be high in FODMAPs, rather than low in FODMAPs.
What does FODMAPs stand for?
FODMAPs refers to Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols, which is quite a mouthful - thankfully we have such a catchy acronym!
The FODMAPs are categorised as:
Oligosaccharides, which includes:
Fructans (also known as fructo-oligosaccharides, or FOS): found in foods such as wheat, rye, garlic and onion; and
Galactans (also known as galacto-oligosaccharides, or GOS): found in legumes (beans, peas, chickpeas and lentils)
Disaccharides – this refers to the disaccharide lactose, which is of no relevance to vegans, as it is only found in dairy products
Monosaccharides – this refers to foods which contain fructose in excess of glucose, such as apples and pears
Polyols – these are a very common cause of bloating and wind. They are found naturally in certain fruits and vegetables, but also in sugar-free chewing gum, mints, lollies and chocolate. Examples of polyols in plant foods are:
Sorbitol - found in apples and stone fruit (such as apricots, nectarines and peaches)
Mannitol - found in celery and mushrooms
Is the low FODMAP diet suitable for vegans?
As the FODMAPs are found almost exclusively in plant foods (with the exception of lactose in dairy products), the low FODMAP diet is particularly restrictive (although not impossible!) for vegans.
What Can Vegans Eat On A Low FODMAP Diet?
Examples of suitable low FODMAP foods for vegans are:
Drinks: green tea, white tea, black tea, cacao powder, peppermint tea
Low FODMAP Vegan Meal Ideas:
Porridge made with 1/2 cup rolled oats or quinoa with chia, unripe banana, strawberries and low FODMAP non-dairy milk of choice
Spelt sourdough toast with peanut butter and sliced unripe banana
Gluten-free Weet-Bix with low FODMAP non-dairy milk of choice and low FODMAP fruit
Spelt sourdough toast with scrambled firm tofu (with added low FODMAP vegetables, e.g. baby spinach and tomato)
Warm brown rice pudding with low FODMAP non-dairy milk of choice and cinnamon
Berry or unripe banana smoothie with low FODMAP non-dairy milk of choice and chia seeds
Main Meal Ideas:
Rice paper rolls with grilled tofu, rice noodles, carrot, cucumber, coriander and capsicum with a homemade low FODMAP peanut butter and lime juice dressing
Sushi with brown rice, tamari marinated tofu, capsicum, cucumber and carrot
Buckwheat or gluten-free pasta with tinned diced tomatoes (up to 1/2 cup per serve) and low FODMAP vegetables (e.g. grated zucchini, carrot, baby spinach) and either crumbled tofu or 1/2 cup tinned brown lentils/red kidney beans
Fried brown rice or quinoa with tamari-marinated tofu, chives, diced carrot, diced zucchini and spinach
Tofu and low FODMAP vegetable stir-fry (e.g. green beans, capsicum, bok choy, carrot, zucchini) with homemade peanut satay dressing
Grilled marinated tofu or tempeh (in a tamari, ginger, orange juice and maple syrup marinade), served with brown rice or quinoa and steamed low FODMAP vegetables
A serve of low FODMAP fruit
A handful of low FODMAP nuts, e.g. walnuts
A slice of spelt sourdough toast with peanut butter
A smoothie with berries or banana, chia and low FODMAP non-dairy milk of choice
Nutrition Tips for Vegans on a Low FODMAP Diet:
Even though the diet is only short-term, it is still important to ensure you are meeting your nutrient requirements.
My nutrition tips for vegans are:
Include a serving of either firm tofu (150g), tempeh (100g) or allowed legumes (1/2 cup tinned red kidney beans or brown lentils) with at least two meals per day to ensure you are meeting your requirements for protein, iron and zinc
Include at least 2 servings of low FODMAPs fruits and 5 servings of low FODMAPs vegetables daily
To meet the Recommended Dietary Intake for calcium (1000mg for adults between 19 and 50 years), choose non-dairy (soy or almond) milks fortified with at least 300mg calcium per cup, tofu set with calcium salts (listed as ‘E509/E516 on the ingredients list), and calcium-rich vegetables such as bok choy and Chinese cabbage every day
Don’t forget to supplement with vitamin B12, use iodised salt (or take a daily multivitamin, which generally provide 100% of the RDI for iodine), and consider an algal-derived EPA + DHA omega-3 supplement
Is the low FODMAP diet a gluten-free diet?
No, the low FODMAP diet isn’t strictly gluten-free, but it is a mostlywheat-free diet, as wheat is naturally high in FOS. Some gluten-containing foods are allowed on the diet, including rolled oats and spelt sourdough bread. Spelt is a variety of wheat which is naturally lower in FOS than regular wheat or rye, and the FOS content is further reduced by the traditional sourdough fermentation process employed in breadmaking. Only spelt sourdough bread can be included in the diet - not spelt pasta, rolled spelt, or other spelt products.
Should I try probiotics for IBS?
There is some evidence to suggest that probiotic supplementation may be beneficial for people with IBS (7), but Monash University recommend trialling one intervention at a time (i.e. either the Low FODMAP diet or probiotics), so you know what is most beneficial for you.
I can't tolerate any amount of legumes in my diet. What should I do?
The FODMAPs found in legumes (galacto-oligosaccharides or GOS) are unable to be digested by humans, as our bodies don't produce the required enzyme (α-galactosidase) to cleave a specific bond found in between the sugar subunits in these carbohydrates. As such, GOS are known as prebiotic fibres, as they pass through the digestive tract to the large intestine, where they are fermented preferentially by the good gut bacteria (lactobacilii and bifidobacteria).
For people transitioning to vegan diets, the rapid increase in consumption GOS-containing legumes can cause abdominal bloating and wind, however, this usually resolves with regular consumption, as the gut bacteria adapt to breaking down the GOS more efficiently.
One study investigating the increase in flatulence with regular legume consumption (1/2 cup cooked beans per day) found that although one third of participants reported an increase in flatulence by the end of the first week, only 3% were still experiencing significant flatulence by the end of the eight week study (8). Similar findings were found for bloating, with 13% of participants reporting an increase in bloating at the end of the first week, which dropped to only 2% of participants by the end of the study (8).
My advice for vegans who struggle to eat legumes is to include a small amount every single day (or on alternate days if symptoms are severe), alternating legumes with tofu or tempeh at main meals. This may be as little as a tablespoon of homemade hummus (without added garlic) or 1/4 cup cooked legumes with just one meal per day. Including the legumes regularly is imperative to encouraging your gut bacteria to break down the GOS more efficiently.
If you are still struggling with including legumes regularly, a recent study published by researchers at Monash University showed that their may be a benefit to trialling an 300mg α-galactosidase supplement with legume meals (9), which can be purchased online from retailers such as iHerb.com.
What if I my symptoms don't improve on the Low FODMAP Diet?
If you're one of the one in four people with IBS who doesn't experience a significant improvement in your symptoms with the Low FODMAP Diet - don't despair! - there are a number of alternative interventions that may help, such as gut-directed hypnotherapy (practised at the Mind+Gut clinic here in Melbourne), probiotics, medications, or clinically-trialed herbal preparations (such as Iberogast).
Resources for patients with IBS:
I recommend trialing the Low FODMAP Diet under the guidance of an Accredited Practising Dietitian (APD). You can find a local dietitian using the Find an APD search function on the Dietitians Association of Australia website. Select ‘gastrointestinal (bowel and stomach) disorders’ in the area of practice dropdown menu to find a dietitian familiar with the Low FODMAP Diet.
I also recommend purchasing the Monash University Low FODMAP Diet app (available for iPhone and Android) if you are considering trialling the diet. It contains a comprehensive searchable food guide, which makes shopping while on the diet a breeze.
1. Halmos EP, Power VA, Shepherd SJ, Gibson PR, Muir JG. A Diet Low in FODMAPs Reduces Symptoms of Irritable Bowel Syndrome. Gastroenterology. 2014 Jan;146(1):67–75.e5.
2. Marsh A, Eslick EM, Eslick GD. Does a diet low in FODMAPs reduce symptoms associated with functional gastrointestinal disorders? A comprehensive systematic review and meta-analysis. Eur J Nutr. 2016 Apr;55(3):897–906.
3. Schmulson MJ, Drossman DA. What Is New in Rome IV. J Neurogastroenterol Motil. 2017 Apr 30;23(2):151–63.
4. Coeliac Disease - Coeliac Australia [Internet]. [cited 2018 Feb 28]. Available from: https://www.coeliac.org.au/coeliac-disease/
5. Tuck C, Barrett J. Re-challenging FODMAPs: the low FODMAP diet phase two: Re-challenging FODMAPs. J Gastroenterol Hepatol. 2017 Mar;32:11–5.
6. Tuck C, Ly E, Bogatyrev A, Costetsou I, Gibson P, Barrett J, et al. Fermentable short chain carbohydrate (FODMAP) content of common plant-based foods and processed foods suitable for vegetarian- and vegan-based eating patterns. J Hum Nutr Diet [Internet]. 2018 Feb 23 [cited 2018 Feb 26]; Available from: http://doi.wiley.com/10.1111/jhn.12546
7. McKenzie YA, Thompson J, Gulia P, Lomer MCE, (IBS Dietetic Guideline Review Group on behalf of Gastroenterology Specialist Group of the British Dietetic Association). British Dietetic Association systematic review of systematic reviews and evidence-based practice guidelines for the use of probiotics in the management of irritable bowel syndrome in adults (2016 update). Journal of Human Nutrition and Dietetics. 2016 Oct;29(5):576–92.
8. Winham DM, Hutchins AM. Perceptions of flatulence from bean consumption among adults in 3 feeding studies. Nutrition Journal. 2011 Dec;10(1):128.
9. Tuck CJ, Taylor KM, Barrett JS, Gibson PR, Muir JG. Oral α-galactosidase improves gastrointestinal tolerance to a diet high in prebiotic fibre (galacto-oligosaccharides). Journal of Nutrition and Intermediary Metabolism. 2017 Jun;8:71
You may have noticed none of my recipes contain any added refined fats or oils, such as coconut oil or even the 'heart-healthy' olive oil.
After attending the 2014 International Plant-Based Healthcare conference in California, my personal and professional focus has shifted away from 'vegan' diets to whole food, plant-based (WFPB) diets, which are based on minimally-processed foods such as fruits, vegetables, grains, nuts and seeds, and legumes (beans, peas and lentils).
Although I still personally align with the vegan philosophy (as I don't use any animal products in my diet or lifestyle), I encourage my vegan clients to adopt this style of eating for the well-documented health benefits. You can read a little more about this on my WFPB page by clicking here.
The reasons I don't use or recommend oils are simple:
1. Oils aren't whole foods As an example: olives are whole foods, olive oil is not. Olive oil is similar to fruit juice - it is stripped of the beneficial food components such as dietary fibre and water which would ordinarily make it hard to consume very much of. In the same way that it’s easy to drink a large glass of orange juice made from 5 oranges (but very difficult to eat 5 whole oranges!), processed oils are very easy to consume a lot of, compared with their whole food counterparts.
2. Oils add hundreds of calories/kilojoules/energy to meals All oils are highly processed and are the most energy-dense foods on the planet at 3,390kJ/811cals per 100mL, or 678kJ/162cals per 20mL tablespoon. Once of the simplest ways to lose weight without even trying is to eliminate added oils from meals and be vigilant about avoiding oils added to packaged foods (see Recommendation #8 below).
3. Unsaturated plant-derived oils are prone to oxidation When packaged in clear plastic or glass bottles, the unsaturated fatty acids in the oil are prone to oxidation by light and heat, and exposure to oxygen in the air once opened. Although some oils do naturally contain antioxidant compounds, many oils have synthetic antioxidants added to them to slow the process. Consider any high fat fruit, nut or seed in nature - the oils are protected by the plant from light and heat by thick, dark skins (as per avocados) or hard shells or husks (as per nuts and seeds such as walnuts and coconuts) to protect the unstable fats they contain.
4. Oils aren’t a requirement of a healthy diet According to the Australian Dietary Guidelines, fats and oils aren’t included within the core food groups. With a little dietary planning, the essential fatty acids omega-3 and omega-6 can easily be obtained in the recommended amounts from a whole food, plant-based diet.
What about olive oil and the Mediterranean diet?
The health-promoting aspects of the Mediterranean diet actually appear to be the high consumption of fruits, vegetables, legumes, nuts and seeds rather than from the olive oil, which is summed up nicely by Dr. Michael Greger, the plant-based Physician behind NutritionFacts.orghere.
Using olive oil in place of saturated fats (such as butter) has well-studied health benefits, such as reducing bad (LDL) cholesterol and increasing good (HDL) cholesterol, and extra virgin olive oil does contain antioxidants, but my advice on oils is similar to that of red wine: if you’re going to drink, it’s a better choice than other types of alcohol (or oils in this analogy), but I would never encourage someone to start drinking red wine (or adding oil to your food) just to get the benefits of the antioxidants. You can easily obtain an array of powerful antioxidants from fresh fruits, vegetables, legumes, nuts, seeds and grains.
If you're still not convinced and still wish to have oil in your diet: I would advise using high quality, mechanically (not chemically) extracted, cold-pressed oils such as Extra Virgin Olive Oil. Make sure it's grown and produced in Australia (to ensure it is fresh and hasn't travelled far), store it in dark cupboard (away from sunlight and heat), and use within a few months of opening to minimise exposure to oxygen.
My oil-free diet recommendations:
Get your omega-3s from whole food sources such as ground flaxseed, chia and walnuts and consider an algal EPA+DHA supplement to optimise your omega-3 status
Consume whole food sources of fats such as avocados, nuts and seeds (and their butters/pastes) and coconut milk in moderation, particularly if you're trying to lose weight
To replace butter/spread/oil on bread or toast: use tahini (which goes fantastically with Vegemite), nut butter (e.g. almond butter) or a thin spread of avocado
Use avocado, cannellini beans or silken tofu as a creamy base for pesto or salad dressings (just blitz in a food processor or blender)
Sauté food using water or vegetable stock instead of oil
You can use mashed banana or silken tofu to replace oil in certain baked goods
Read labels on packaged foods to minimise or eliminate oils from sneaking into your diet. Aside from all the obvious processed foods containing oils (such as potato crisps), foods that often include adding oils include: UHT soy milk and other plant-based milks, curry pastes, stir-fry sauces, muesli bars, mueslis, ‘air-popped’ popcorn, marinated tofu/tempeh, peanut butter, breads and wraps and whole grain crackers. Start reading those labels!
Many clients I see in my clinical practice deliberately avoid soy, with the most common reasons for doing so being:
‘I have heard soy causes breast cancer’
'Soy contains anti-nutrients'
‘I have a thyroid condition and heard soy is bad for the thyroid’
‘Soy is all genetically-modified’
In order to thoroughly dispel all these myths, I’ve waded through the scientific literature on the subject and will address each of these concerns in turn.
Firstly, soy products include foods made from soybeans, such as soy milk, tempeh, tofu, edamame, soy yoghurt, texture vegetable protein (TVP), isolated soy protein powders (available as protein supplements or in processed foods such as vegetarian sausages), miso paste, soy sauce and tamari.
Does soy contain anti-nutrients?
Anti-nutrients are defined as dietary components that can reduce or inhibit the utilisation of specific nutrients in food. They are naturally-occurring in almost all plant foods, as a defense mechanism against predators. The anti-nutrients in soy including protease (enzyme) inhibitors, saponins, phytates and lectins are increasingly being considered as having numerous health benefits (1), including being protective against cancer (2).
Saponins are a broad range of compounds found in a number of plant foods, including soybeans. The name is derived from their ability to form a soap-like foam in liquids (if you’ve ever rinsed quinoa you’ll now know what the foam is!). As some of the saponins have been shown to be highly-toxic, the entire class of compounds known as saponins have all been ‘mistakenly labeled' as toxic (3).
Lucky for soybeans, the saponins found in soybeans have no reported adverse effects in humans, and have are being extensively researched for their antioxidant properties, cholesterol-lowering effect, attenuating (blunting) the blood glucose response to a meal and anti-cancer potential (3).
Phytic acid (and its salt, phytate) is a storage form of phosphorous and minerals for the growing grain or seed kernel. Phytate is found in cereals, legumes, oilseeds (including soybeans) and nuts, and can bind to and inhibit the absorption of certain minerals including zinc and iron. However, it is only thought that this inhibitory effect can lead to mineral deficiencies under ‘non-varied and non-balanced dietary conditions’ (4).
Furthermore, the inhibitory effect of phytate on iron and zinc absorption can be reduced by adding a good source of vitamin C to your meal (such as tomatoes or red capsicum), and adding a good source of beta-carotene to your meal (such as carrot, pumpkin, sweet potato or kale) (4).
Schlemmer et al recently reviewed the available scientific evidence on dietary phytates and human health and found evidence for a blood glucose lowering effect, antioxidant capacity and anticancer activity, and in light of these findings, noted that terms for phytate such as ‘antinutrient’ should ‘belong to the past’ (4). Another author (Shamsuddin, 2002) went so far as to propose that phytic acid should be considered an ‘essential nutrient (perhaps a vitamin)’ (5).
In summary, in well-balanced diets, the inhibitory effect is relatively low and phytate is increasingly being considered a beneficial component of food.
Many foods contain enzyme inhibitors, including chicken eggs, potatoes and soybeans. The enzyme inhibitors in question in soy are trypsin inhibitors, which block the action of human the digestive enzymes responsible for breaking down proteins into smaller peptides and amino acids (such as trypsin and chymotrypsin). However, as the majority of these enzyme inhibitors are inactivated by soaking soybeans overnight and heat-treating the soybeans (as per the production of soy milk or tofu), or by fermentation (as per tempeh or miso production). As we don’t eat soybeans raw, they are of no significance to human health .
Lectins (also known as haemagglutinins) are widely-distributed in the plant foods, including soybeans (known as soybean agglutinin or SBA). These proteins have been extensively studied since early experiments showed that lab animals (mainly rats) experienced growth problems when fed raw soybeans (6). Further animal studies have shown that lectins from raw soybean withstand digestion in the gastrointestinal tract and can bind to the intestinal epithelium (the cells lining the gastrointestinal tract) and cause a number of adverse effects including increased intestinal permeability (‘leaky gut’) (6). However, studies in animals using raw soy products are of little relevance to human health as the lectins in soy are easily deactivated by 'wet' heat, and hence pose no threat to human health (6)(7).
Does soy contain estrogens?
Soy is rich in a class of phytonutrients known as isoflavones, which are classed as phytoestrogens (‘phyto’ meaning plant-derived). Other plant foods also contain isoflavones, including flaxseeds and whole grains. The isoflavones in soy are structurally similar to human estrogen (a reproductive hormone), but this doesn’t mean that soy products contain estrogen. Isoflavones can bind to estrogen receptors in the body, but they generally exert a much weaker effect than human estrogen, and can have pro- or anti-estrogenic effects in the body.
There are also two types of estrogen receptors (ER), named ER-alpha and ER-beta, which are found in different locations in the body. Isoflavones have been shown to be ‘selective’ in their binding to these receptors, choosing to bind to ER-beta over ER-alpha, and hence are known as selective estrogen receptor modulators (SERMs). This helps to explain how they can both enhance and block the action of estrogen, depending on the tissue type. They can also reduce levels of circulating estrogen by increasing the level of sex hormone binding globulin (SHBG), which binds and inactivates estrogen.
Soy & Breast Cancer
Many people believe that the phytoestrogens in soy products may increase the risk of breast cancer, however, the majority of the evidence suggests that soy consumption is either neutral or protective against breast cancer. A review in 2010 in the Journal of Nutrition found that women who consumed moderate amounts of soy (1-2 servings per day) throughout their life have lower risk of developing breast cancer risk than women who do not consume soy; however, this protective effect may originate from soy intake early in life (in childhood and adolescence). The authors also concluded that soy consumption does not increase the risk of breast cancer recurrence in women who have previously survived breast cancer (8).
Soy & Men’s Health
Soy products may help to prevent prostate cancer in men. A recent meta-analysis (which pools a number of studies) found that men with the highest intake of soy had a statistically-significant reduction in prostate cancer risk, compared to the men who consumed the least soy (9).
A recent review on the topic found that neither isoflavone supplements nor soy products affected total or free testosterone levels, and there was no evidence to suggest that isoflavone exposure affects estrogen levels (10).
There are a handful of published case reports of men suffering from adverse hormonal effects relating to excessive soy consumption, but these men were all consuming very large quantities of soy (in excess of 12 servings per day). The main effects reported were growth of breast tissue (gynecomastia) and reduced libido.
How much is safe to have each day?
The use of soy protein for lowering LDL cholesterol levels has been extensively studied, which has resulted in the recommendation to have 25g of soy protein each day (the equivalent of 2-3 servings). This represents a minimum level of intake to reap the cholesterol-lowering benefits, and could be used as a conservative upper limit of intake if you are still concerned soy.
Dr. Michael Greger (of NutritionFacts.org) recommends an intake of 3-5 servings per day to maximise the health benefits and minimse any risk of harm from excessive consumption (13).
1 serve is equal to:
-100g firm tofu
-½ cup (120g) shelled edamame
-1 cup soy milk
My Tips for Healthy Soy Consumption
When choosing a soy milk, read the label to make sure it’s made from ‘whole soybean’ rather than from ‘soy protein’ or ‘soy protein isolate’
Choose non-GM (genetically-modified) soy if that it is important to you
Avoid isolated soy protein (also known as soy protein isolate) in protein powders and bars, mock meats and textured vegetable protein (TVP)
1. Singh J. Non-Nutritive Bioactive Compounds in Pulses and Their Impact on Human Health: An Overview. Food Nutr Sci. 2012;03(12):1664–72.
2. Mathers JC. Pulses and carcinogenesis: potential for the prevention of colon, breast and other cancers. Br J Nutr. 2002 Dec;88(S3):273.
3. Shi J, Arunasalam K, Yeung D, Kakuda Y, Mittal G, Jiang Y. Saponins from edible legumes: chemistry, processing, and health benefits. J Med Food. 2004;7(1):67–78.
4. Schlemmer U, Frølich W, Prieto RM, Grases F. Phytate in foods and significance for humans: Food sources, intake, processing, bioavailability, protective role and analysis. Mol Nutr Food Res. 2009 Sep;53(S2):S330–75.
5. Shamsuddin AM. Anti-cancer function of phytic acid. Int J Food Sci Technol. 2002 Oct 1;37(7):769–82.
6. Liener IE. Implications of antinutritional components in soybean foods. Crit Rev Food Sci Nutr. 1994 Jan;34(1):31–67.
7. Ma Y, Wang T. Deactivation of Soybean Agglutinin by Enzymatic and Other Physical Treatments. J Agric Food Chem. 2010 Nov 10;58(21):11413–9.
8. Hilakivi-Clarke L, Andrade JE, Helferich W. Is Soy Consumption Good or Bad for the Breast?123. J Nutr. 2010 Dec;140(12):2326S – 2334S.
9. Yan L, Spitznagel EL. Soy consumption and prostate cancer risk in men: a revisit of a meta-analysis. Am J Clin Nutr. 2009 Apr 1;89(4):1155–63.
10. Messina M. Soybean isoflavone exposure does not have feminizing effects on men: a critical examination of the clinical evidence. Fertil Steril. 2010 May;93(7):2095–104.
11. Schaafsma G. The protein digestibility–corrected amino acid score. J Nutr. 2000;130(7):1865S – 1867S.
12. Sathyapalan T, Manuchehri AM, Thatcher NJ, Rigby AS, Chapman T, Kilpatrick ES, et al. The Effect of Soy Phytoestrogen Supplementation on Thyroid Status and Cardiovascular Risk Markers in Patients with Subclinical Hypothyroidism: A Randomized, Double-Blind, Crossover Study. J Clin Endocrinol Metab. 2011 Feb 16;96(5):1442–9.
13. Michael Greger. How much soy is too much? [Internet]. NutritionFacts.org. [cited 2014 Nov 12]. Available from: www.nutritionfacts.org/2013/02/19/how-much-soy-is-too-much/
Ah 'superfoods': an ever-expanding list of foods which promise to hold the key to radiant health and wellbeing, most worth most worth more per kilogram than solid gold. Foods like açaí berries, goji berries, and ... bacon?
Sarah Wilson (well, one of her underlings named Meg Yonson) has decided that bacon is the new superfood. Yeah. Bacon. You heard me. I heard me, and it still sounds just as ridiculous as when I first read the post.
The idea that bacon is a health food - let alone a superfood - is utter rubbish. Not that the word 'superfood' even has a scientific definition, but I think we can safely say that bacon is not on par with the likes of broccoli and blueberries.
Anyway, in common usage, the word 'superfood' seems to be reserved for plant foods, which are naturally jam-packed with vitamins, minerals, phytochemicals and antioxidants, not saturated fat and nitrates, as per cured meat products.
Anyway, let me debunk the following '7 reasons why bacon 'may just be the new acai berry', according to Meg:
1. 'Bacon contains monounsaturated fats. This is the kind of fat that has been shown to lower cholesterol levels.'
→ Yes, a percentage of the fat in bacon is monounsaturated, but a decent percentage is saturated fat, which is known to increase cholesterol levels. You can get your monounsaturated fats (without the dose of saturated fats and cholesterol) in whole plant foods, such as avocados and nuts. Crisis averted.
2. 'It’s high in protein. Providing several grams of protein per serve and all the essential amino acids.'
→ My favourite part of this point is 'several grams of protein per serve'. How many grams would we say 'several' refers to? I'd say it's a step up from 'a couple' (which is obviously two), so my guess is that several is 3g. Well, by this logic, MOST foods contain several grams of protein. But I digress.
ALL plant foods contain 'all the essential amino acids' in varying levels, so there's nothing special about bacon there.
3. 'It curbs your sugar cravings. Thanks to the saturated fats in bacon, it fills you up for longer and stops blood sugar crashes.'
→ This is amazing. Maybe all these sugar cravings that I Quit Sugar devotees are experiencing are relating to not getting enough carbohydrates (glucose) to their brains?
Including low GI sources of carbohydrates such as whole grains, legumes, fruit and vegetables in each meal is the best way to combat sugar cravings.
4. 'It’s good for your brain. Bacon is filled with the nutrient choline, which helps boost brain function and memory.'
→ Choline isn't an essential nutrient in the diet, as we can make it in our body (provided we have are getting enough lysine and methionine).
5. 'Bacon is a natural mood enhancer. And not just because it tastes so damn good! The umami taste of bacon is said to improve mood and satisfaction.'
→ This link is tenuous at best. The taste of umami is found in many plant foods, such as mushrooms, nutritional yeast, sun-dried tomatoes, miso, tamari and sea vegetables. No bacon required - sorry Meg.
6. 'It’s very nutritious compared with other meats. It’s high in B vitamins, iron, magnesium and zinc.'
This is where Meg should have really done her homework, instead of blindly taking information from India's Largest Online Men's Lifestyle magazine, MensXP (I'm serious. She linked to it in the post). A 100g serve of bacon contains a meagre 17mg of magnesium, which is 5% of the RDI for a woman. Not exactly 'good source' material, is it? It also only contains 11% of the RDI for B2 (riboflavin) and 17% of the RDI for niacin.
7. 'It’s high in the mineral selenium. This nutrient is essential to regenerating glutathione, an important antioxidant in your body.'
→ I couldn't find any data on selenium in bacon, but I can tell you that the best dietary source of selenium are brazil nuts, which contain 920mcg selenium per 100g . Just 2 brazil nuts will provide you with 92mcg of selenium, which is 130% of the RDI of 70mcg per day.
Okay, so not much credible information there. Perhaps Meg should have quit health reporting instead of sugar?
So, what do we (i.e. the scientific community) know about bacon?
The cocktail of haem iron, nitrites, heterocyclic amines and saturated fat are believed to contribute to cancerous cell growth in the body. The World Cancer Research Fund advises people to limit or avoid processed meats (such as bacon) altogether.
Am I the only one who thought mushrooms were just chewy little domes of nothingness? I mean, I knew that they must have been good for me, given that they're classed as a vegetable (even though they're technically fungi), but I wouldn't have put much money on them containing anything above and beyond some fibre and a small amount of protein.
How wrong I was!
It turns out that mushrooms are packed with vitamins, minerals, powerful phytonutrients and antioxidants.
Vitamins & Minerals
Just 100g of mushrooms will provide a third of the Recommended Dietary Intake (RDI) for riboflavin (B2) and biotin (B7), and one quarter of the RDI for niacin (B3), panthotenic acid (B5), selenium and copper. Mushrooms are also on par with bananas in their potassium content, at 310mg per 100g serve (compared to 342mg potassium in 100g of banana).
Mushrooms are also the only known plant-based dietary source of vitamin D, as exposing mushrooms to sunlight causes them to produce vitamin D2, in a similar way our bodies make vitamin D from exposure on bare skin (1). Vitamin D-enhanced mushrooms are already on sale in major supermarkets.
Despite not being brightly-coloured like blueberries, tomatoes or grapes, mushrooms have an incredibly high antioxidant capacity, and came in at number five out of 34 in one study of commonly-eaten vegetables in Italy (2). Mushrooms are also the best known food source of the antioxidant compound ergothioneine (3), which researchers in the field of study believe may one day be classified as a vitamin, due to its important role in cellular protection (4).
Are mushrooms a good replacement for meat?
In my opinion, mushrooms aren’t a particularly good replacement for meat, as they’re not particular high in protein (at 3g per 100g raw) and don’t contain appreciable amounts of zinc and iron, whereas meat is a good source of both of these minerals. They’re also very low in energy (103kJ/24 cals per 100g, compared to around 600kJ/143 cals per 100g of raw meat). Substituting meat for mushrooms AND legumes, tofu and tempeh will provide a better nutritional profile, as these foods are all a good source of protein, zinc and iron.
Here are a few ways to include more mushrooms in your diet:
Dice some button mushrooms and add them to scrambled tofu
Add sliced Swiss brown mushrooms to a pumpkin risotto
Add fresh or dried shiitake mushrooms to an Asian-style noodle soup
Add shimeji or enoki mushrooms to an Asian-style stir fry
1. Jasinghe VJ, Perera CO, Barlow PJ. Bioavailability of vitamin D2 from irradiated mushrooms: an in vivo study. Br J Nutr. 2005 Jun;93(06):951.
2. Pellegrini N, Serafini M, Colombi B, Del Rio D, Salvatore S, Bianchi M, et al. Total antioxidant capacity of plant foods, beverages and oils consumed in Italy assessed by three different in vitro assays. J Nutr. 2003;133(9):2812–9.
3. Dubost NJ, Ou B, Beelman RB. Quantification of polyphenols and ergothioneine in cultivated mushrooms and correlation to total antioxidant capacity. Food Chem. 2007;105(2):727–35.
4. Paul BD, Synder SH. The unusual amino acid L-ergothioneine is a physiologic cytoprotectant. Cell Death Differ. 2010 Jul;17(7):1134-40
This post stems from my personal quest to improve the quality of my own sleep. When not confined to a 9-5 job, I tend to indulge my night owl tendencies and stay up late working, at the expense of a decent night’s sleep. I’d also been waking up anywhere from 6am (and feeling rubbish) to midday (and still feeling rubbish). Ah, the freedom of the self-employed.
Anyway, I’ve successfully cleaned up my sleeping act and am happy to report that for the past couple of months I’ve consistently gotten out of bed at 6:30am feeling refreshed and with a clear head. Hurrah! Now I can be one of those insufferable people who go on and on about how beautiful the dawn light is and how great they feel. (But seriously, there is some spectacular light going on and I DO feel much better).
In my practice as dietitian, I always ask people about their sleeping patterns because the quality of your sleep has such an impact on your health and the food choices you make. Chronic sleep deprivation is associated with a range of metabolic derangements, such as decreased glucose (blood sugar) tolerance and insulin sensitivity, and increased hunger and appetite (1). One study showed that after just one night of sleep-restriction (4 hours sleep), subjects ate significantly more calories (22% more) when compared to their well-rested counterparts (2).
The most common sleep-related problems I hear are:
Not getting enough sleep and waking up unrefreshed and feeling tired through the day
Being forced into an irregular sleeping pattern due to working shifts or partying on the weekends
Taking a long time to fall asleep
The following is a list of food and nutrition-related ways to improve the quality of your sleep. Let me know if you've already tried any of the following strategies and had any success by leaving a comment below.
1. Reduce or eliminate caffeine from your diet
Caffeine is a potent central nervous system stimulant found in coffee, black tea, diet Coke, energy drinks and cacao (chocolate). Caffeine has a long half-life - around 5 hours - which means that if you drink coffee throughout the afternoon, there can still be a significant amount of caffeine floating round in your bloodstream when it comes time to go to sleep.
If you find it hard to fall asleep at night and think that caffeine may be a factor, I'd recommend avoiding caffeine after midday or cutting it out of your diet altogether. The amount of caffeine in a cup of coffee is highly variable - instant coffee generally contains less caffeine than espresso-style coffee (approximately 70mg compared to anywhere from 100-200mg per cup), and a cup of tea can also contain anywhere from 25 to 110mg of caffeine per cup, depending on how strongly it is brewed.
To kick the caffeine habit:
Try a coffee replacement: if you're a hardcore coffee addict, switch to roasted dandelion root (often blended with chicory and marketed as a coffee alternative, such as this one), which has a very similar taste to coffee, and makes a top-notch latte.
Go green: if you get your kicks from multiple cups of black tea throughout the day, try switching to green tea, which has slightly less caffeine (at around 30-50mg per cup) but has the same beneficial effects on the brainwaves as black tea, as they come from the same plant (Camelia sinesis).
Go herbal: rooibos is another good option as it's still mentally-stimulating like black tea, yet totally caffeine-free. You could also try any number of the vast array of herbal teas available. I'm currently hooked on cold-steeped hibiscus - it's packed with antioxidants.
2. Try herbal remedies
Herbal teas are a great option to try if you find it difficult to fall asleep at night. Chamomile, lemon balm and passionflower tea have all been shown to help reduce stress and anxiety and promote sleep. Stick to a small (150mL) cup about an hour before you go to bed, as you don't want to be getting up through the night to use the bathroom. Nighttime trips to the bathroom interfere with sleep cycles and affect sleep quality in a big way, so go easy on the fluids before bed!
If you'd like to try a supplemental herbal extract such as valerian, chat to a Naturopath or Herbalist first to make sure it's the right choice for you. Always let your practitioner know if you're taking any medications or other supplements as many herbs can interact with one another and with drugs. Always check with your GP or Obstetrician if you're pregnant or breastfeeding before commencing any herbal therapies - even herbs that are readily accessible to the public may not be safe in pregnancy.
3. Boost the levels of serotonin in your brain with whole plant foods (not supplements!)
Serotonin is a neurotransmitter which can affect our mood, appetite and sleep. Serotonin is converted to melatonin in the brain by the pineal gland, which is a hormone which induces sleep at night. Unfortunately we can't just take a serotonin supplement or eat foods which contain serotonin (such as bananas), as it can't get cross the blood-brain barrier and get into the brain. However, the precursor to serotonin - the amino acid tryptophan - can get into the brain (3). Tryptophan supplements are available, but I always recommend choosing food sources of nutrients rather than relying on supplements.
Tryptophan is found in in high levels in protein-rich foods such as legumes, soy foods, nuts and seeds. Whether the tryptophan in the blood actually gets into the brain depends on a two main factors: the ratio of tryptophan to total protein in the food, and whether carbohydrate is consumed with the protein (4).
Turkey is often thought to be sleep-inducing thanks to its tryptophan content, but this is a myth. Turkey actually contains about the same amount of tryptophan as other meats such as chicken (250mg compared to 230mg per 100g meat), and the tryptophan doesn't actually get into the brain as animal protein contains high levels of other amino acids which compete for transport across the blood-brain barrier (4).
The best way to raise your brain levels of serotonin is to eat plant-based, protein-rich foods such as lentils and legumes, which have a high ratio of tryptophan to total protein and contain carbohydrate, which stimulates insulin release. Insulin causes the uptake of the competing amino acids into the muscle, which allows the tryptophan to get into the brain and convert to serotonin.
Seeds are particularly high in tryptophan - so get into the habit of sprinkling them on your dinner meal (I love pepitas on just about everything) or snacking on them with some fruit after dinner.
4. Ensure you're getting the micronutrients your body needs
Supplemental magnesium is often recommended as a sleep aid, as magnesium acts as a cofactor for an enzyme involved in the synthesis of melatonin in the brain. If you have a magnesium deficiency (because of an inadequate diet), supplemental magnesium may be of use, but I believe in preventing deficiencies in the first place through dietary adequacy rather than recommending supplements. The best dietary sources of magnesium are pepitas (just 30g provides 50% of the RDI for magnesium for a woman), oat bran, rolled oats, tofu, brown rice, chia seeds, soy milk and bananas. If you do choose to take a magnesium supplement, don't take more than 350mg elemental magnesium per day.
Vitamin B12 is involved in the secretion of melatonin in the brain from the pineal gland, and as such, low levels of B12 can interfere with sleep. B12 is only found in animal products and if you follow a plant-based diet, you’ll most likely need to take a supplement (unless you’re having 3 serves per day of fortified foods). You can read more about vitamin B12 in my post here.
Niacin / Vitamin B3:
Niacin is also important in maintaining levels of tryptophan in the body, as if the dietary intake is inadequate, the body will convert tryptophan to niacin. Good sources are whole grain pasta, potatoes and sweet potatoes, almonds, cashews, tahini and tofu.
Vitamin B6 (pyridoxine) is required for the conversion of tryptophan to serotonin in the brain (5). Good sources of B6 are sunflower seeds, pistachio nuts, bok choy, bananas, sweet potatoes and potatoes.
Omega-3 fats are required to convert serotonin to melatonin in the brain, and are another nutrient you need to pay special attention to if you’re plant-based. Good sources of plant-based omega-3 are ground flaxseeds, chia, walnuts, hemp seeds and green leafy vegetables. These foods provide the omega-3 ALA, which is converted to the longer chain forms of omega-3 (DHA and EPA) in the body. As the conversion of ALA to DHA and EPA is known to be quite inefficient in the body, supplemental DHA in the form of algal DHA supplements are also an option.
And one more bonus (not nutrition-related) strategy:
No screens before bed!
TV, computer, laptop and phone screens emit short-wave blue light which can suppress the production of melatonin (the hormone released at night which induces sleep).
To minimise the effect of blue light at night:
Download the program f.lux on your laptop and computer - it blocks blue wavelengths and gives your screen a weird (yet kind of fun) sunset-orange glow.
Ban iPhones from the bedroom. It's particularly detrimental to lie in bed staring at a phone close to your face, as the short distance between the light source and your eyes means you're exposed to a lot of blue light
Get outside when the sun is up to expose your eyes to these blue wavelengths that are found naturally in sunlight - they boost attention, wakefulness and mood, which is what we want through the day (but not at night!)
Happy sleeping! x
1. Spiegel K. Sleep loss: a novel risk factor for insulin resistance and Type 2 diabetes. Journal of Applied Physiology. 2005 Nov 1;99(5):2008–19.
2. Brondel L, Romer MA, Nougues PM, Touyarou P, Davenne D. Acute partial sleep deprivation increases food intake in healthy men. American Journal of Clinical Nutrition. 2010 Jun 1;91(6):1550–9.
3. Young SN. How to increase serotonin in the human brain without drugs. Journal of psychiatry & neuroscience: JPN. 2007;32(6):394.
4. Wurtman RJ, Wurtman JJ, Regan MM, McDermott JM, Tsay RH, Breu JJ. Effects of normal meals rich in carbohydrates or proteins on plasma tryptophan and tyrosine ratios. The American journal of clinical nutrition. 2003;77(1):128–32.
5. Peuhkuri K, Sihvola N, Korpela R. Diet promotes sleep duration and quality. Nutrition Research. 2012 May;32(5):309–19.
We live in a society obsessed with protein consumption. More specifically, we live in a society that regards animal protein as superior to plant-based protein, which is an outdated and incorrect assumption.
When someone finds out I'm vegan, the first question is invariably ‘where do you get your protein?’. I usually reply with ‘from a balanced plant-based diet of whole grains, legumes, fruits, vegetables, nuts, and seeds’, which is almost always met with a quizzical raise of an eyebrow and a grunt which simultaneous means 'fair enough’ and ‘I don’t really believe you, but I don’t dare argue’.
Firstly, let me address the myth that foods are either ‘proteins' or ‘carbohydrates’ (carbs). In nature, it is incredibly rare to find a food that is made up of one single macronutrient, i.e. protein, carbohydrate or fat. Animal foods such as meat, fish and eggs are composed of both protein and fat, whereas dairy products contain all three macronutrients (protein, carbs and fat). Only in processed foods do we find foods composed of a single macronutrient. Oil, for example, only contains fats, and refined sugar only contains sugar (carbs).
All whole plant foods contain a combination of protein, carbohydrate and fat. Protein is ubiquitous in plant foods; even a large potato (which most people would classify as pure carb) contains 4g of protein, and just half a cup of rolled oats contains 5g of protein.
Labelling animal foods such as meat, fish and eggs as ‘a protein’ ignores the fact that they all come packaged with unwanted food components such as saturated fat, cholesterol, and haem iron - all of which are implicated in the progression of chronic diseases such as diabetes and heart disease. For example, red meat is touted as a good source of protein, iron and zinc, but consumption of red meat is also associated with an increased risk of bowel cancers. Plant foods, on the other hand, in addition to being a source of protein are also packed with health-promoting components such as dietary fibre, phytochemicals and antioxidants.
Complete vs Incomplete protein
Proteins are made up of 20 different amino acids, which are the building blocks of proteins. There are 9 essential amino acids which can’t be synthesised in the body, and have to be supplied by our diet. Most plant proteins (but not all) are known as incomplete proteins, as they are lower in (but not devoid of) one or more essential amino acids than what our bodies require. This is of no consequence nutritionally, as the body has a short-term storage pool of essential amino acids which we add to and draw on throughout the course of the day. The discovery of this storage pool debunked the concept of protein combining, which recommended eating plant foods with different amino acid profiles (such as legumes and grains) in the same meal in order to make a complete protein. Eating a wide variety of plant-based foods such as whole grains, legumes, nuts, seeds, fruits and vegetables will ensure you’ll easily meet your amino acid requirements.
So if we know we can get the right type of protein on a plant-based diet (i.e. all the essential amino acids), how do we get enough protein on a plant-based diet?
Let’s start with how much protein the average woman needs, which is approximately 0.75g (the RDI for protein) to 1g per kilogram bodyweight. As the protein in plant foods is less 'digestible' due to their fibre content compared to animal foods (meat and dairy), it is generally recommended that people on plant-based diets aim for the 1g per kilogram bodyweight mark. As an example, a 60kg woman would require 60g of protein per day.
Another way of looking at it is by percentage of energy (kilojoules or calories), which should be around 15%, as a minimum, as protein-rich foods tend to also a good source of the minerals iron and zinc. The Australian government suggest an Acceptable Macronutrient Distribution Range (AMDR) for protein of 15%-25% of energy, which is to ensure requirements for other essential micronutrients (aside from protein) are also met.
If that same 60kg woman was eating around 7,000kJ each day, 15% of the energy as protein equates to 60g of protein (which is in line with the 1g per kilogram bodyweight recommendation).
To translate these recommendations into practice, I recommend that whole grains, fruit and vegetables make up the basis of any plant-based diet (as well as nuts, seeds and good sources of calcium) and that women include 2-3 serves per day (3-4 for men) of any of the following protein-rich plant foods:
125g extra-firm/175g soft firm/250g silken tofu (all provide around 16g of protein)
100g tempeh (18g protein)
3/4 cup cooked legumes (approx. 10g protein), e.g chickpeas, brown lentils, edamame, red kidney beans
Feel free to ask any questions (nutrition-related are preferred) in the comments section below. x L
'Plant-based milk' refers to non-dairy milks which are made from plants, such as almond milk, soy milk, rice milk and oat milk. The market for non-dairy milks is rapidly expanding in Australia and is showing no sign of slowing down - It seems as though every time I'm in the supermarket there's a new product on the shelf.
This is a plant-based nutrition question I’m asked ALL the time, and unfortunately there’s no simple answer - it really depends on your individual nutritional needs, and which you actually like the taste of!
Plant-based milks vary widely in their macronutrient (protein, carb and fat) composition, but also in terms of the micronutrients (vitamins and minerals) they contain.
If you're only having a glass or so or plant-based milk per day, the macronutrient composition won't really affect your daily nutrient intake, however, if you have very specific macronutrient needs (if you're an athlete, for example) or are having more than a glass each day, it's worth making an educated choice about which plant-based milk you're going to drink.
In terms of micronutrients, some are a little higher in certain vitamins than others (e.g. almond and hazelnut milk will contain significant quantities of vitamin E, whereas others won't), and some contain unique health-promoting components (such as beta-glucan in oat milk), but I think the most important micronutrient to focus on in this discussion is the bone-building mineral calcium.
Most Australians get their calcium from dairy products, so people on plant-based diets need to ensure they're getting adequate calcium elsewhere. I've discussed plant-based sources of calcium in an earlier blog post, so I won't go into too much detail here, but I do recall mentioning that plant-based milks which are fortified with calcium can be a very good and convenient source of calcium for people on plant-based diets.
As one cup of cow's milk contains 300mg of calcium, many manufacturers of plant-based milks add calcium to their products to provide 300mg calcium per cup, which makes their milk an excellent alternative to cow's milk (and makes my life as a Dietitian much easier when it comes to making sure people are getting enough calcium). If you don't regularly consume good sources of plant-based calcium such as tofu set with calcium salts, Asian greens, kale and tempeh, then it would be wise to choose a plant-based milk that is fortified with calcium.
You can check this on the nutritional information panel - you're looking for: -300mg calcium per 250mL cup -120mg calcium per 100mL
Here’s a quick run-down of the pros and cons of the most common plant-based milks:
Almond milk is made by extracting the liquid from almonds and leaving behind the almond pulp. It's very easy to make at home, and works out significantly cheaper. All you need is some raw almonds (soaked for 8 hours or overnight), water, a high-speed blender and a nut milk bag (or piece of cheesecloth or muslin).
The issue with commercial almond milks is that most are only 2.5% almonds, which is only about 5 almonds per 250mL glass. No wonder they taste thin and watery! There are higher almond content milks available (such as Pure Harvest's 10% activated almond milk) which are similar in taste to homemade almond milk, but they are more expensive than other almond milks, and much more expensive than homemade. The main issue with almond milks is that they are not usually fortified with 300mg calcium per 250mL glass, as per the soy and rice milks. Many also have added sugar, to make them taste similar to dairy milk (which is quite sweet, at 13g of sugar per 250mL glass), but unsweetened varieties are available if you prefer it.
What to look for: -A high percentage of almonds - the manufacturer has to tell you what percentage the product is by law -No added vegetable oils -Fortified with calcium
In terms of macronutrient composition, soy milk is the closest plant-based milk to cow's milk. It is higher in protein than any other commercially available milk, at around 8g per glass, and contains variable quantities of carbohydrate (sugar) and fat, depending on what the manufacturer has chosen to add to the soy beans.
Soy milks are available in ‘regular', ‘low fat’ and 'fat-free' varieties which refers to the added fat content. The regular varieties have fat added in the form of vegetable oil to bring it up to the same fat content as full-cream cow's milk (3.6% fat, or 9g per cup), whereas the low-fat varieties don't tend to have any fat added, but do still contain a small amount of fat (which is naturally-occurring in soy beans).
What to look for: -No added vegetable oils -In the ingredients list: 'whole soy beans' rather than 'soy protein isolate', or 'isolated soy protein' -Fortified with 300mg calcium per 250mL cup
Rice milks tend to be much higher in carbohydrate than the other plant-based milks (averaging 25-30g carb per 250mL glass, which is equivalent to 2 slices of bread!), but they are a good choice for people with allergies to soy or nuts, or people with food chemical intolerances doing elimination diets. As they are made by breaking down the starch in rice to sugars, they tend to be very high Glycaemic Index (GI), with values between 70 and 90 (as a reference, pure glucose has a value of 100). As a positive, they are usually fortified with 300mg calcium per 250mL cup.
What to look for: -Made from whole brown rice not from rice protein -Fortified with 300mg calcium per 250mL cup
Oat milk is quite a good all-rounder nutritionally, containing more protein than almond milk (at 5g per 250mL cup) but less carbohydrate than rice milk (with around 15-20g carb per 250mL cup). Oat milk also contains the unique soluble fibre beta-glucan, which is clinically-proven to reduce LDL (bad) cholesterol levels. Most oat milks are also fortified with calcium which is a bonus.
What to look for: -Made from 'whole oats' -Fortified with 300mg calcium per 250mL cup
For the other plant-milks, such as nut milks other than almond (cashew, hazelnut, macadamia), grain-based milks (quinoa, spelt), coconut milk formulated for drinking (such as Coco Quench), the same rules as above apply - check how much of the actual ingredient is going into the milk, look for no added oils or sugars and check if they're fortified with calcium.
This is the ingredients list from Australia's Own Almond Milk Blend with Coconut:
Ingredients: Filtered Australian Water, Organic Almond Meal (2.7%), Organic Sugar, Organic Coconut Cream (2%), Salt, Alginate, Guar gum and Locus Bean Gum.
You can see that it's little more than water, a tiny quantity of almond meal and coconut cream and gums holding it all together, and it's a similar story for the Freedom Foods Ancient Grains Quinoa Milk with Chia:
So it turns out I've been storing my fruit and veg all wrong - I'd always kept onions and potatoes together (a big no-no, apparently), always kept cucumber, zucchini and eggplant in the fridge, and never thought to put ginger, chillies, shallots, oranges, lemons or figs in the fridge. Oops.
Storing your fruit and veg correctly means they'll stay fresh for longer, saving you heaps of money and reducing your food waste. All-round win. Most of the issues come from storing at the wrong temperature (i.e. in the fridge when they should be at room temperature), and storing certain fruits and vegetables together, which can cause over-ripening and decay.
Here's where you should be storing your fruit and veg, for optimal freshness and shelf life.
In the FRIDGE:
Ripe stone fruits e.g. plums, peaches, nectarines, apricots
Apples and pears
Ripe Hass avocados
Paw-paw (on a shelf, not in the crisper as they are chill-sensitive)
Bunches of carrots, red radishes and beetroots - removing the leafy tops to make them last much longer than with them attached
Mushrooms, stored in a paper bag
Spring onion (scallions)
Capsicum (bell peppers)
Fresh ginger root
Leafy vegetables, e.g. spinach and kale
At ROOM TEMPERATURE, in a cool place and not in direct sunlight:
Potatoes - store in a dark, cool, well-ventilated cardboard box or paper bag, away from onions
Onions - store in a net or loose in a paper bag or cardboard box, away from potatoes
Cucumber (uncut - move to the fridge when sliced)
Whole melons (e.g. watermelon, cantaloupe or honeydew) move to the fridge when cut
Starfruit - move to the fridge when cut
Unripe stone fruit e.g. plums, apricots and peaches- move to the fridge once ripe
Unripe Hass avocadoes - keep them near bananas to ripen them, then move to the fridge when ripe
Whole pineapple - move to the fridge when cut
Unripe mangoes - move to the fridge once ripe
The principle cause accelerated ripening and decay is ethylene gas, which is produced by the following fruits: apples, apricots, avocados, banana, cantaloupe, kiwi fruits, mangos, melons, nectarines, papayas, peaches, pears, plums and tomatoes. There are many more 'responders' to ethylene gas, which means they will degrade faster than they should just by being in contact with these pesky ethylene producers, and these include: most of the ethylene producers, as well as broccoli, Brussels sprouts, cabbage, carrot, cucumber, cauliflower, eggplant, green beans, leafy greens (such as kale), lettuce, potatoes, peas, spinach, sweet potato and tomatoes.
The takeaway message from the ramble is basically not to store fruit and vegetables together, as fruits tend to be the ethylene producers and vegetables the responders. Savvy?
Also remember to quickly remove any rotting fruit or veg from the others, as the mold can easily transfer to and spoil its neighbours.
In certain cases you can use ethylene gas to your advantage - for example, if you have a very hard, unripe avocado you can place it in a paper bag with a banana (a big producer of ethylene gas) to speed up the ripening process.
Lastly, if you've got too many bananas ripe at the same time, peel a few and pop them in an airtight container in the freezer - they are perfect for making banana 'nice cream' or adding to smoothies.
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