There are toxicological issues associated with production and processing of meat, such as the presence of various toxic contaminants—from dioxins and PCBs to cooked meat carcinogens. Carcinogenesis, the development of cancer, may be the main concern, but there are a number of other toxic responses connected with the consumption of meat products. Lead, for example, can be toxic to the nerves, gastrointestinal tract, bone marrow, and kidneys.
Where is lead found in the food supply? In general terms, the highest levels of lead, as well as arsenic and mercury, are found in fish. Sardines have the most arsenic, but tuna may have sardines beat when it comes to mercury and lead.
The problem is that “fish-consumption advisories related to human health protection do not consider the fish by-products fed to farmed animals,” like farmed fish. If some tilapia are fed tuna by-products, they could bioaccumulate heavy metals and pass them onto us when we eat them. Researchers found the highest levels in frozen sole fillets, averaging above the legal limit for lead.
Lead exposure has been shown to have adverse effects on nearly every organ system in the body. Symptoms of chronic exposure range from memory loss and constipation to impotence and depression. These symptoms present after pretty hefty exposure, though. However, we now know that “[b]lood lead levels in the range currently considered acceptable are associated with increased prevalence of gout and hyperuricemia” (elevated levels of uric acid in the blood). According to the Centers for Disease Control and the World Health Organization, a blood lead level needs to be less than 25 micrograms per deciliter to be “non-elevated.” You’d assume that at values under 25, there’d be no relationship with health outcomes, but even throughout this “acceptable” range, lower lead means lower uric acid levels and lower gout risk. So, even blood lead levels 20 times below the acceptable level can be associated with increased prevalence of gout. “These data suggest that there is no such thing as a ‘safe’ level of exposure to lead.”
Once lead gets into the body, it tends to stay in the body. It builds up in the bones such that it may take 30 years just to get rid of half. The best strategy? Don’t get exposed in the first place.
If lead builds up in bones, though, what about boiling bones for broth? As I discuss in my video Lead Contamination in Bone Broth, we know bones sequester lead, which can then leach from the bones. So, researchers suggested that “the bones of farmyard animals will sequester lead, some of which will then be released into broth during its preparation.” Who eats bone broth? Bone broth consumption is encouraged by many advocates of the paleo diet. Online, you can learn all about purported “benefits” of bone broth, but what they don’t tend to mention is the theoretical risk of lead contamination—or at least it was theoretical until now. Broth made from chicken bones was to have markedly high lead concentrations, up to a ten-fold increase in lead. Researchers concluded, “In view of the dangers of lead consumption to the human body, we recommend that doctors and nutritionists take the risk of lead contamination into consideration when advising patients about bone broth diets.”
But what if you only use bones from organic, free-range chickens? They did use only bones from organic, free-range chickens.
Parkinson’s disease is a movement disorder striking 1 percent of our older population and is the 14th leading cause of death in the United States. While we don’t really know what causes it, we do know that people with a smoking history only appear to have about half the risk. Of course, “[s]moking is hugely damaging to health; any benefit derived from a reduction in risk of Parkinson’s disease is outweighed by the increased risks of cancer and cardiovascular disease,” as well as lung disease, but this shouldn’t stop us from “evaluating tobacco components for possible neuroprotective effects.”
After all, where does nicotine come from? The tobacco plant. Any other plants have nicotine? Well, tobacco is a nightshade plant, so it’s in the same family as tomatoes, potatoes, eggplants, and peppers. And guess what? They all contain nicotine as well.
That’s why you can’t tell if someone’s a smoker just by looking for the presence of nicotine in their toenail clippings, because non-smokers grow out some nicotine into their nails, as well. Nicotine is in our daily diet—but how much? The amount we average in our diet is hundreds of times less than we get from a single cigarette. So, though we’ve known for more than 15 years that there’s nicotine in ketchup, it was dismissed as insignificant. We then learned that even just one or two puffs of a cigarette could saturate half of our brain’s nicotine receptors, so it doesn’t take much. Then, we discovered that just exposure to second-hand smoke may lower the risk of Parkinson’s, and there’s not much nicotine in that. In fact, one would only be exposed to about three micrograms of nicotine working in a smoky restaurant, but that’s on the same order as what one might get eating the food at a non-smoking restaurant. So, the contribution of dietary nicotine intake from simply eating some healthy vegetables may be significant.
Looking at nightshade consumption, in general, researchers may have found a lower risk compared to other vegetables, but different nightshades have different amounts of nicotine. They found none in eggplant, only a little in potatoes, some in tomatoes, but the most in bell peppers. When that was taken into account, a much stronger picture emerged. The researchers found that more peppers meant more protection. And, as we might expect, the effects of eating nicotine-containing foods were mainly evident in nonsmokers, as the nicotine from smoke would presumably blot out any dietary effect.
This could explain why protective associations have been found for Parkinson’s and the consumption of tomatoes, potatoes, and a tomato- and pepper-rich Mediterranean diet. Might nightshade vegetables also help with treating Parkinson’s? Well, results from trials of nicotine gum and patches have been patchy. Perhaps nicotine only helps prevent it in the first place, or could it be that it isn’t the nicotine at all, but, instead, is some other phytochemical in tobacco and the pepper family?
Researchers conclude that their findings will be need to be reproduced to help establish cause and effect before considering dietary interventions to prevent Parkinson’s disease, but when the dietary intervention is to eat more delicious, healthy dishes like stuffed peppers with tomato sauce, I don’t see the reason we have to wait.
The Centers for Disease Control and Prevention recently celebrated the 50-year anniversary of the landmark 1964 Surgeon General’s report on smoking, considered one of the great public health achievements of our time and the first of 30 other such reports from the Surgeon General on smoking. Internal tobacco industry memos, which you can see in my Is Something in Tobacco Protective Against Parkinson’s Disease? video, document their response. Major criticisms of the report include a “[c]avalier treatment of costs of smoking”: The Surgeon General argued that smoking costs the United States billions, but the tobacco industry noted that “smoking saves the country money by increasing the number of people dying soon after retirement,” so we don’t have to pay for Social Security, Medicare, and the like. In fact, the industry argued, if we were truly patriotic, maybe we should encourage smoking to help balance the budget!
The tobacco industry also criticized the Surgeon General for a “[l]ack of balance regarding benefits of smoking,” asserting that “[o]ne has to search pretty hard to find any concession anywhere in the Report that smoking is not all bad.” This is something the tobacco industry liked to bring up when testifying before Congress, saying that health benefits include “the feeling of well-being, satisfaction, and happiness and everything else.” But beyond just all the happiness the Surgeon General was trying to extinguish, he failed to even mention that smokers appear protected against Parkinson’s disease.
“Quite unexpectedly…[m]ore than 50 studies over the last half century consistently demonstrated reduced prevalence of Parkinson’s disease among smokers compared with never-smokers.” Now there are more than five dozen studies.
But smokers are probably dying before they even have a chance to get Parkinson’s, so is that the explanation? No, that didn’t seem to be it. Researchers found a protective effect at all ages. Maybe it’s because smokers tend to be coffee drinkers, and we know coffee consumption alone appears protective. But, no. The protective effect of smoking remained even after carefully controlling for coffee intake. Well, maybe we inherit some propensity to not smoke and to get Parkinson’s. If only we could clone someone to have the same DNA. We can! They’re called identical twins. And still, the relationship remained, suggesting “a true biologic protective effect of cigarette smoking.”
Not so fast. Maybe finding unusually low rates of Parkinson’s among smokers is an example of reverse causation. That is, maybe smoking doesn’t protect against Parkinson’s—maybe Parkinson’s protects against smoking. Could there be something about a Parkinson’s brain that makes it easier to quit? Or perhaps failure to develop a smoking habit in the first place is an early manifestation of the disease.
To put that to the test, researchers studied children exposed to their parents’ smoke. If they grew up to have less Parkinson’s, that would confirm the protective link—and indeed they did. So, smoking really does seem to be protective against Parkinson’s disease, but who cares? How does that help us? “More than 20 million Americans have died as a result of smoking since the first Surgeon General’s report…” Even if we didn’t care about dying from lung cancer and emphysema, even if we only cared about our brain, we still wouldn’t smoke because smoking is a significant risk factor for having a stroke, as well.
Today is #GivingTuesday, kicking off the charitable season with a celebration of giving and philanthropy. To commemorate it this year, we’ve created a limited edition 2019 NutritionFacts.org Staff Recipe Calendar. If your annual wall calendar doesn’t specify when National Kale Day is (first Wednesday of October, duh) then you have the wrong calendar! This year’s recipes include Purple Sweet Potato Burgers (Kristina, Social Media Director), Almond Berry Crunch Bars (Steven, Global Volunteer Director), Curried Chickpea Wraps from my How Not to Die Cookbook, and more…directly from the kitchens of our staff members! The first 200 people to donate $100 or more to keep my 501c3 nonprofit NutritionFacts.org alive and thriving will get a calendar in time for the new year. Don’t wait—we ran out within a few days last year.
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A systematic review of randomized controlled trials of DHA supplementation of pregnant and breastfeeding women failed to find any clear and consistent short- or long-term benefit for psychomotor, mental, visual, or physical development. Perhaps DHA supplementation during pregnancy has no effect because the body wisely protects the growth of the baby’s brain by drawing off of maternal stores of DHA, upregulating maternal DHA synthesis, and preferentially shuttling it to the fetus. But what if moms don’t start out with large maternal stores? In other words, maybe DHA failed to help women who were already getting enough, but perhaps women with very low intakes would benefit from DHA supplementation. My video Should Vegan Women Supplement with DHA During Pregnancy? explores the evidence available to date.
It’s interesting to note that, by 1978, researchers already were suggesting a plant-based diet as the diet of choice in the treatment of our number-one killer, heart disease, but babies breastfed by vegan moms had significantly less DHA in their bloodstreams, presumably because the moms had significantly less DHA in their breast milk.
The question is whether these differences are of any consequence. The growth and development of vegan and vegetarian born children are normal as long as they’re getting their B12, and “[t]here is no evidence that neural or intellectual functions are impaired.” In fact, the two studies we have on kids in vegetarian communities showed they had higher IQs, though that may be because their parents tended to be better educated. However, even though the kids seemed fine, that doesn’t rule out the possibility that there may be some “subtle differences…in visual or neural functioning.”
It would be interesting to compare the function of babies getting vegan breast milk levels versus general population levels. In one of the studies I profile in my video, it shows that vegans hit a level of 14, vegetarians 30, and omnivores 37. Another study compared 0 to 32, 64, and 96, and, though 32 worked better than 0, more than 32 didn’t add anything. This could explain why the general population at 37 doesn’t benefit from additional DHA supplementation. But what about down at 14? Most studies at that level show no advantage over 0, though one study found a benefit supplementing at as low as 5, but that doesn’t help us.
Just because babies breastfed by vegan moms have significantly lower DHA levels in the blood, that doesn’t necessarily mean they have lower levels in their brain, which is where it counts. What we need is a randomized, controlled trial in non-fish-eaters of DHA supplementation. Until then, it’s going to remain uncertain. So, what should pregnant and breastfeeding women who avoid fish do in the meanwhile? Low intake of DHA doesn’t “necessarily equate with fetal DHA inadequacy,” but new data suggest that some infants may not be getting enough and could benefit from their moms supplementing. Given this, I recommend pregnant and breastfeeding women on plant-based diets to follow the consensus guidelines to get about 200mg of preformed DHA from an uncontaminated source, like algae oil, which is probably the best combination for all women given the state of our world to minimize exposure to toxic pollutants such as dioxins, PCBs, and mercury.
One of the reasons breastfed infants may have better cognitive and visual development is because human milk contains long-chain, polyunsaturated fatty acids like the omega-3 DHA, while most available infant formulas do not, based on data I discuss in my video Should Pregnant and Breastfeeding Women Take DHA?. Infants given control formula without DHA didn’t do as well as those given DHA-fortified formula, and neither group did as well as the breastfed infants, who serve as the “gold standard.” This was enough to convince formula manufacturers to start adding DHA to their infant formula starting back in 2002.
The question then became how much to add? Easy, right? Just add the amount that is naturally found in breast milk. However, the DHA level in breast milk is extremely variable depending on what the mom is eating. There are a number of healthy populations who don’t eat any seafood, for example, and they have much lower levels in their milk yet seem fine. So this makes it difficult to determine the optimal amount to add to formula or, for that matter, what to recommend for pregnant and breastfeeding women. “Consensus guidelines recommend that women should aim to consume an average of 200 mg” of DHA daily during pregnancy. “Simply encouraging pregnant women to eat more fish is not so simple, because most fish are to some extent contaminated” with toxic pollutants, such as mercury. (See my video Mercury vs. Omega-3s for Brain Development for more on this.) For most fish, such as tuna, the brain damage caused by the mercury would exceed the benefit from the DHA.
Additionally, some pollutants, like PCBs, can get stuck in our bodies for decades, so it’s not enough to just eat clean during pregnancy.
What about purified fish oil? The methods supplement manufacturers use, like distillation, leave considerable amounts of PCBs and other pollutants in the products, so much so that when taken as directed, salmon, herring, and tuna oils would exceed the tolerable daily intake of toxicity.
Thankfully, one can get the benefits without the risks by getting DHA from algae instead, which is where the fish eventually get it from themselves. So, pregnant and breastfeeding moms can cut out the middle-fish and get DHA directly from the source—at the bottom of the food chain where we don’t have to worry about toxic pollutants.
Until recently, we thought everyone should take these long-chain omega-3s for their heart. However, the balance of evidence is now such that doctors “should not recommend fish oil intake or fish consumption solely for the primary or secondary prevention of CHD,” coronary heart disease. But what about for expectant and breastfeeding mothers? What does the latest science show? Putting all the studies together, it turns out adding DHA to formula does not appear to help infant cognition after all, similar to other recent compilations of evidence that show “no significant benefit.” In fact, at least four meta-analyses, or systematic reviews, have reached a similar conclusion. These were based mostly on the standard series of measurements known as the Bayley Scales for Infant Development. If other tests were used, would there be different results? So far, no. Giving women DHA supplements during pregnancy did not appear to help with other outcomes, like attention span or working memory, either.
Although there may be no significant benefit to infant cognition, what about other things like vision? Six trials have been done to date supplementing pregnant women. Four showed no effect, and the two trials that showed benefit had some problems. So, while we really don’t know at this point, if all the studies so far show either nothing or benefit, why not just take them to err on the side of caution?
There may not be any demonstrable “clear and consistent” benefits, but there are new studies on this coming out all the time. If it’s harmless, maybe women should just take it to be on the safe side? The problem is that it may not be harmless in large doses. In a study in which women were given a whopping 800mg of DHA a day during pregnancy, infant “girls exposed to higher-dose DHA in utero [in the womb] had lower language scores and were more likely to have delayed language development than girls from the control group.”
So, the “absence of clear positive effects and the possible presence of negative effects in the children raise the question whether DHA supplementation is justifiable…” But it was a really large dose, suggesting that there may be “an optimum DHA level below and above which DHA might be detrimental to the developing brain.”