How Not to Die

  In 1997, the Food and Drug Administration called on feed manufacturers to stop using these dioxin-tainted ingredients, stating that “[c]ontinued exposure to elevated dioxin levels in animal feed increases the risk of adverse health effects in animals and to humans consuming animal-derived food products.”35 So did the feed industry clean up their act? Up to a half billion pounds of catfish continued to be churned out of U.S. fish farms every year,36 but it wasn’t until more than a decade later that our government went back and checked for compliance. Researchers from the USDA tested samples of catfish from all over the country and in 2013 reported that 96 percent of tested samples still contained dioxins or dioxin-like compounds. And when they checked the feed used to raise these fish? More than half the samples came back as contaminated.37

  In other words, the feed industry has known for more than two decades that what they were feeding to animals (and, ultimately, to most of us38) may contain dioxins, but apparently, they continue this practice unabated.

  The Institute of Medicine has made suggestions for reducing dioxin exposure, such as trimming fat from meat, including from poultry and fish, and avoiding the recycling of animal fat into gravy.39 Wouldn’t it be more prudent just to trim the amount of animal foods from your diet instead? Researchers have estimated that a plant-based diet could wipe out about 98 percent of your dioxin intake.40

  Smoking and Parkinson’s Disease

  The CDC recently celebrated the fifty-year anniversary of the landmark 1964 surgeon general’s report on smoking, considered one of the great public health achievements of our time.41 It’s interesting to go back and read the reactions of the tobacco industry to such reports. For example, an industry insider argued that contrary to the surgeon general’s argument that smoking costs our nation billions, “smoking saves the country money by increasing the number of people dying soon after retirement.”42 In other words, just think how much we’re saving on Medicare and Social Security thanks to cigarettes.

  The tobacco industry also criticized the surgeon general’s “lack of balance regarding benefits of smoking.”43 As they testified before Congress, these “positive health benefits” include “the feeling of well-being, satisfaction, and happiness and everything else.” Beyond all that happiness the surgeon general was trying to extinguish, the Tobacco Institute argued, “everything else” included protection against Parkinson’s disease.44

  As it happens, quite unexpectedly, more than five dozen studies over the past half century have collectively shown that smoking tobacco is indeed associated with significantly lower incidence of Parkinson’s disease.45 Valiant attempts have failed to explain away these findings. Maybe, public health scientists countered, it’s because smokers are dying off before they get Parkinson’s. No, smoking appears protective at all ages.46 Maybe it’s because smokers drink more coffee, which we know to be protective.47 No, the protective effect remained even after researchers controlled studies for coffee intake.48 Identical-twin studies helped rule out genetic factors in the link.49 Even simply growing up in a home where your parents smoked appears protective when it comes to developing Parkinson’s.50 So was the tobacco industry right? Does it even matter?

  Since the surgeon general’s groundbreaking 1964 report, more than twenty million Americans have died as a result of smoking.51 Even if you didn’t care about dying from lung cancer or emphysema, even if you cared only about protecting your brain, you still shouldn’t smoke, because smoking is a significant risk factor for stroke.52 But what if you could get the benefits of smoking without the risks?

  Maybe you can. The neuroprotective agent in tobacco appears to be nicotine.53 Tobacco is part of the nightshade family, the group of plants that includes tomatoes, potatoes, aubergines, and peppers. It turns out they all contain nicotine, too, but in such trace amounts—hundreds of times less than what’s found in a single cigarette—that the protective potential of vegetables was dismissed as inconsequential.54 But then it was discovered that just one to two puffs of a cigarette can saturate half of your brain’s nicotine receptors.55 Then we learned that even exposure to secondhand smoke may lower the risk of Parkinson’s56 and that the amount of nicotine exposure sitting in a smoky restaurant is on the same order as what you might get from eating a healthy meal in a smoke-free restaurant.57 So might eating lots of nightshade vegetables protect you from Parkinson’s after all?

  Researchers at the University of Washington decided to find out. When they tested for nicotine, they found none in aubergines, just a little in potatoes, some in tomatoes, and more significant amounts in bell peppers. These results were consistent with what researchers found when they studied nearly five hundred newly diagnosed Parkinson’s patients compared to controls. Eating nicotine-rich vegetables, especially peppers, was associated with significantly lower risk of Parkinson’s disease.58 (This effect was found only in the nonsmokers, which makes sense because the flood of nicotine from cigarettes would likely overwhelm any dietary effect.) This study may help explain previous protective associations in terms of Parkinson’s risk that had been tenuously found for tomato and potato consumption, as well as for the nightshade-rich Mediterranean diet.59

  The University of Washington researchers concluded that more research is needed before individuals should consider dietary interventions to prevent Parkinson’s disease, but when that intervention is simply enjoying more healthy dishes like stuffed peppers with tomato sauce, I don’t see a reason why you should have to wait.

  Dairy

  Parkinson’s patients have been found to have elevated levels of an organochlorine pesticide in their bloodstreams, the class of largely banned pesticides that includes DDT.60 Autopsy studies have also found elevated levels of pesticides in the brain tissue of those with Parkinson’s.61 Elevated levels of other pollutants like PCBs were also found in their brains, and the higher certain PCB concentrations, the higher the degree of damage found specifically in the brain region thought to be responsible for the disease, called the substantia nigra.62 As noted earlier, though many of these chemicals were banned decades ago, they may persist in the environment. You can continue to be exposed to them through the consumption of contaminated animal products in your diet, including dairy.63 Indeed, people who eat dairy-free, plant-based diets were found to have significantly lower blood levels of the PCBs implicated in the development of Parkinson’s disease.64

  A meta-analysis of studies involving more than three hundred thousand participants found that overall dairy consumption was associated with significantly increased risk of Parkinson’s disease. They estimated that Parkinson’s risk may increase 17 percent for every daily cup of milk consumed.65 “Contamination of milk with neurotoxins may be of critical importance,” researchers offered by way of explanation.66 For example, neurotoxic chemicals like tetrahydroisoquinoline, a compound used to induce parkinsonism in primates in laboratory studies,67 appears to be found predominantly in cheese.68 The concentrations found were low, but the concern is that they may accumulate over a lifetime of consumption,69 resulting in the elevated levels found in the brains of Parkinson’s patients.70 There have been calls on the dairy industry to require screening of milk for such toxins,71 but they have so far gone unanswered.

  A recent nutrition journal editorial considered the case closed: “The only possible explanation for this effect is the evidence of the contamination of milk by neurotoxins.”72 But there are alternate explanations for the “clear-cut” link between dairy and Parkinson’s.73 For example, pollutant levels wouldn’t explain why Parkinson’s appears more closely tied to the consumption of the milk sugar lactose than to milk fat,74 more closely tied to milk than to butter.75 So maybe the culprit is galactose, the sugar in milk described in chapter 13, blamed for an increased risk of bone fractures, cancer, and death.76 Those with an inability to detoxify the galactose in milk not only suffer damage to their bones but also to their brains.77 This may help explain the link between milk intake and Parkinson’s, as well as the link between m
ilk and another neurodegenerative disease called Huntington’s disease. Indeed, higher consumption of dairy products appears to double the risk of earlier-onset Huntington’s.78

  Another explanation is that milk consumption lowers blood levels of uric acid, an important brain antioxidant79 shown to protect nerve cells against the oxidative stress caused by pesticides.80 Uric acid may slow the progression of Huntington’s81 and Parkinson’s,82 and, most importantly, may lower the risk of getting Parkinson’s in the first place.83 Too much uric acid, however, can crystallize in your joints and cause a painful disease called gout, so uric acid can be thought of as a double-edged sword.84 Too much uric acid is also associated with heart disease and kidney disease; too little, with Alzheimer’s, Huntington’s, Parkinson’s, multiple sclerosis, and stroke.85 Those on dairy-free, plant-based diets appear to hit the sweet spot86 in terms of most optimal uric acid levels for longevity.87

  Milk may not do a body good, at least when it comes to your bones and brain.

  Plant-Based Diets and Pollutants

  As we’ve discussed, organochlorines are a group of chemicals that includes dioxins, PCBs, and such insecticides as DDT. Although most were banned decades ago, they persist in the environment and creep up the food chain into the fat of the animals people eat.

  What if you don’t eat any animal products at all? Researchers have “found that vegans were significantly less polluted than omnivores” when measuring levels of organochlorines in their blood, including a variety of PCBs and one of Monsanto’s long-banned Aroclor compounds.88 This finding is consistent with studies showing higher levels of organochlorine pesticides in the body fat89 and breast milk90 of those who eat meat.

  People eating completely plant-based diets have also been found to have markedly lower levels of dioxins in their bodies91 as well as decreased contamination with PBDEs,92 the flame-retardant chemical pollutants also linked to neurological problems.93 No surprise: The highest levels of flame retardants in the U.S. food supply have been found in fish, though the primary source of intake for most Americans is poultry, followed by processed meat.94 This discovery helps explain the significantly lower levels of PBDEs in the bodies of those eating meat-free diets.95 It appears that the more plant-based foods you eat and the longer you go without eating animal products, the lower your levels fall.96 No regulatory limits have been set for PBDEs in food, but as U.S. Department of Agriculture researchers noted in a survey of flame-retardant chemicals in domestic meat and poultry, “reducing the levels of unnecessary, persistent, toxic compounds in food and your diet is certainly desirable.”97

  Eating healthier can also reduce the concentrations of heavy metals in your body. The levels of mercury in the hair of those eating plant-based diets were found to be up to ten times lower than of those who ate fish.98 Within three months of switching to a plant-based diet, the levels of mercury, lead, and cadmium growing out in your hair appear to drop significantly (but build back up when meat and eggs are added back into the diet).99 Unlike heavy metals, though, some organochlorine pollutants can stick around for decades.100 Any DDT in your KFC may stay with you for the rest of your life.

  Berries

  Dr. James Parkinson, in his original, centuries-old description of the disease that bears his name, described a characteristic feature: “torpid” bowels, or constipation that may precede the diagnosis by many years.101 We’ve since learned that bowel-movement frequency may even be predictive of Parkinson’s. Men with less than daily bowel movements, for instance, were found to be four times more likely to develop the disease years later.102 Reverse causation has been suggested: Maybe constipation didn’t lead to Parkinson’s. Maybe Parkinson’s—even decades before it was diagnosed—led to constipation. This idea was supported by anecdotal evidence suggesting that throughout their lives, many who would go on to develop Parkinson’s reported never feeling very thirsty and, perhaps, decreased water intake contributed to their constipation.103

  Alternatively, given the link between dietary pollutants and Parkinson’s, constipation may be contributing directly to the disease: the longer feces stay in the bowel, the more neurotoxic chemicals in the diet may be absorbed.104 There are now more than one hundred studies linking pesticides to an increased risk for Parkinson’s disease,105 but many of them are based on subjects’ occupational or ambient exposure. Approximately one billion pounds of pesticides are applied annually in the United States,106 and simply living or working in high-spray areas may increase your risk.107 The use of common household pesticides like insect sprays is also associated with significantly increased risk.108

  How exactly do pesticides increase your risk for Parkinson’s? Scientists think they may cause DNA mutations that increase your susceptibility109 or affect the way certain proteins fold in your brain. In order for proteins to function effectively, they have to be the right shape. As you make new proteins in your cells, if they come out folded incorrectly, they are simply recycled, and your body tries again. Certain misfolded proteins, however, can take a shape that your body has difficulty breaking down. Should this glitch happen continuously, the malformed proteins can accumulate and result in the death of the brain’s nerve cells. Misfolded beta amyloid proteins, for example, are implicated in Alzheimer’s disease (see chapter 3); misfolded prion proteins cause mad cow disease, a different malformed protein causes Huntington’s; and misfolded alpha synuclein proteins can lead to Parkinson’s disease.110 In the most comprehensive study of this sort to date, eight out of twelve common pesticides tested were able to trigger the accumulation of alpha synuclein proteins in human nerve cells in a petri dish.111

  As I’ve said, Parkinson’s disease is caused by the die-off of specialized nerve cells in a region of the brain that controls movement. By the time the first symptoms arise, 70 percent of these critical cells may already be dead.112 Pesticides are so good at killing these neurons that scientists often use pesticides in the laboratory to try to re-create Parkinson’s in animals to test new treatments.113

  If pesticides are killing off your brain cells, is there anything you can do to stop the process other than lowering your exposure to them? There are no known drugs that can prevent these misfolded proteins from accumulating, but certain phytonutrients called flavonoids—which are found in fruits and vegetables—may have protective effects. Researchers tested forty-eight different plant compounds able to cross the blood-brain barrier to see if any were able to stop alpha synuclein proteins from clumping together. To their surprise, not only did a variety of flavonoids inhibit these proteins from accumulating but they could also break up existing deposits.114

  This study suggests that by eating healthfully, you can reduce your exposure to pollutants while countering their effects at the same time. And when it comes to countering the effects of pesticides, berries may be particularly useful. In a head-to-head battle between pesticides and berries, researchers found that preincubating nerve cells with a blueberry extract allowed them to better withstand the debilitating effects of a common pesticide.115 But most such studies were performed on cells in a petri dish. Is there any evidence in people that eating berries could make a difference?

  A small study published decades ago suggested that the consumption of blueberries and strawberries might protect against Parkinson’s,116 but the question remained largely unanswered until a Harvard University study of about 130,000 people found that people who eat more berries do indeed appear to have a significantly lower risk of developing the disease.117

  The editorial that accompanied the study in the journal Neurology concluded that more research is necessary, but “until then, an apple a day might be a good idea.”118 Apples did appear protective against Parkinson’s, but only for men. Everyone, however, appeared to benefit from the consumption of blueberries and strawberries, the only berries included in the study.119

  If you do decide to follow my recommendation to eat berries every day, I would advise not serving them with cream. Not only has dairy been shown to block
some of the beneficial effects of berries,120 but, as we saw earlier, dairy products may contain compounds that cause the very damage the berries may be trying to undo.

  Cannibalistic Feed Biomagnification

  If people just eat from the bottom two levels of the food chain, only plants and plant eaters—that is, cows, pigs, and chickens fed grain and soyabeans—why is the American populace so contaminated? Those of you who remember the mad cow disease story may know the answer. In modern agribusiness, there are essentially no more herbivores.

  Millions of tons of slaughterhouse by-products continue to be fed to farm animals in the United States every year.121 Not only have we turned these animals into meat eaters but virtual cannibals as well. When we feed farm animals millions of tons of meat and bonemeal, we’re also feeding them any pollutants this feed may contain. Then, after those animals are slaughtered, their trimmings go to feed the next generation of farm animals, potentially concentrating the pollutant levels higher and higher.122 So we can end up like polar bears or eagles at the top of the food chain and suffer the biomagnified pollutant consequences. When we eat these farmed animals, it’s almost as if we’re also eating every animal they ate.

  The use of slaughterhouse by-products in animal feed can recycle both toxic heavy metals and industrial chemicals back into the food supply. Lead accumulates in animal bones and mercury in animal protein123 (which is why egg whites contain up to twenty times more mercury than do yolks).124 Persistent lipophilic organic pollutants (known as PLOPs125—really!) build up in animal fat. Reducing meat consumption can help reduce exposure, but these contaminants can come back to us in a variety of animal products. “Although a vegetarian lifestyle can lower the body burden of PLOP, MMHg [mercury], and lead,” one toxicologist noted, “such benefits can be undermined by the consumption of contaminated milk and egg products. Farm animals that have been fed contaminated animal products produce contaminated milk and egg products.”126