Lead in Seafood and Wild Game

Most hunters may not be aware of the health risks related to consuming meat from animals shot with lead ammunition.

I’m often asked in lectures whether microwaves are safe. Not if you drop them on your foot! But, otherwise, it matters what you’re putting in them—sweet potatoes and broccoli, or hot pockets and pop tarts? Similarly, when I was exploring the safety of hot sauces in my video Flashback Friday: Lead Contamination in Hot Sauces, given their potential for lead contamination, I had a similar reaction: It matters what you’re putting them on.

When I think about toxic pollutants, the first thing I think of is the aquatic food chain. We know, for example, that giving people a seven-ounce portion of a fish high in mercury, like tuna or swordfish, just once a week, which is about a can and a half of tuna a week, can quadruple mercury levels in the blood within a few months. What about lead?

A dietary intervention with not one but five portions a week significantly increased blood concentrations of toxic metals, including lead. Even though “the background intake of lead was already disturbingly high,” the seafood intake “increased the intake of lead by approximately 25%.” From a public health perspective, it is important to recognize that the amount of seafood researchers used in the study “far exceed[ed] the intake of most populations.”

Lead can also bioaccumulate in other animals, but half of our dietary exposure to lead probably comes from plant foods. Animals shot with lead ammunition, though, may present a special case. I explore this in my video Lead Contamination in Fish and Game.

We know lead is toxic and banned from most household items in developed countries—except for lead ammunition, which “is now likely the greatest, largely unregulated source of lead that is knowingly discharged into the environment in the USA.” But, it is not just discharged into the environment. It’s also discharged into the meat itself. “People generally reject the idea of injecting toxic substances into food, except when it involves hunting wild game.”

Eighty percent of ground venison was found to contain lead, which isn’t surprising given the hundreds of metal fragments that end up in deer carcasses after being shot with standard lead-based rifle bullets—“an impossible number of fragments to pick out by hand, especially because some of these fragments are microscopic.”

As you can see at 2:23 in my video, researchers have shown using x-rays that during penetration, expanding lead core bullets typically release hundreds or thousands of fragments—or even millions or tens of millions of microscopic lead particles per gram. So, one serving could have a billion particles, though they are nanoparticles, extremely tiny, about the size of viruses. 

The only good lead, though, is no lead. Even very low levels of lead exposure can result in brain and nerve damage, yet most hunters may not be aware of health risks related to consuming meat from animals killed with lead ammunition.

Children may be at risk of losing IQ points, which could reduce their future prospects. “Often when I explain to hunters the risk associated with lead exposure, especially when considering their children,” writes a physicians, “their response is, ‘I have been hunting for years and I am fine.’ My response to them is, “but just imagine how smart you could have been.”

Bone broth is another issue, which I cover in Lead Contamination in Bone Broth.


I recently did a deep dive into lead if you’re interested in a comprehensive overview:

In health, 

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Natural Dietary Treatments for Fibroids

The same diet that helps regulate hormones in women may also reduce exposure to endocrine-disrupting pollutants.

Fibroids are the most common benign tumors in women. They can grow to a foot in diameter and affect the majority of women before they hit menopause. Although fibroids tend to be asymptomatic, when symptoms do occur, they tend to manifest as heavy menstrual bleeding—so much so that women may get anemic and experience a lot of pain. So, what can women do? I discuss this in my video The Best Diet for Fibroids.

Up to half go into surgery and get their entire uterus removed. “Although hysterectomy is generally considered a safe operation, complications occur in a significant proportion of patients” and, obviously, you can’t have kids any more. The alternative is a variety of hormone-modulating drugs, which can shrink the fibroids and provide relief, but many of these drugs have significant side effects, like bone loss, so you really don’t want to be taking them for more than a few months. What’s the bottom line? “There is currently no evidence to support the routine use of medical treatment in women with uterine fibroids.” No wonder many women turn to “complementary and alternative treatments…including exercise, diet, herbs, and acupuncture.”

Women who exercise seven or more hours a week do seem to have lower risk of having fibroids than women who exercise less than around 20 minutes a day, but exercise has never been put to the test for treating fibroids. Likewise, to date, there isn’t a single randomized controlled trial of acupuncture for the treatment of fibroids to help guide us. 

In terms of herbs, there are two Asian herbal preparations that show promise—a five-herb combo called Guizhi Fuling and a Malaysian ten-herb formula that contains “secret ingredients” that must not be that secret since they’re just listed in the study, as you can see at 1:50 in my video—and they seemed to work as well as a leading drug. The problem is that traditional Asian herbal remedies may contain a few extra ingredients, like arsenic, mercury, and lead, which have been detected in most of the samples tested from Asian market and health food store shelves, and not just a little. Some, apparently, had really toxic amounts. So, these two Asian herbal preparations “may reduce fibroid size, but there is insufficient evidence to support the efficacy or safety of these treatments.” And, certainly, don’t try to apply caustic herbs internally, as this can lead to scarring, stenosis, and ulceration.

Well, what about diet? In one of the largest studies of diet and fibroids, fibroid tumors were “associated with beef and ham consumption, whereas high intake of green vegetables seems to have a protective effect.” The researchers figured that the “association between levels of estrogen, diet, and breast and endometrial [uterine lining] cancers also may help us understand” why. Indeed, “[f]or breast and endometrial cancers, a direct association with the frequency of consumption of meat and ham was observed…whereas protection was conferred by high intake of vegetables and fruits.” Thus, there may be these shared risk factors between estrogen-responsive malignant tumors, like breast cancer, and estrogen-responsive benign tumors, like fibroids.

We know the presence of fibroids seems to correlate with an increase in the amount of estrogens flowing through your body, for example, and that women eating vegetarian diets have significantly lower levels of excess estrogen. Researchers are using this knowledge to try to explain why there are lower rates of endometrial cancer—that is, lining-of-the-uterus cancer—and possibly breast cancer among vegetarian women, but it could also help explain the fibroid findings. “The incidence of breast cancer among vegetarian American women (Seventh Day Adventists) is 60 to 80 per cent of the incidence among American women in general, and the incidence among women in Africa and Asia is even lower.” Why might vegetarian women have lower estrogen levels? A famous study in the New England Journal of Medicine concluded that it was their “increased fecal output, which leads to increased fecal excretion of estrogen,” resulting in lower blood levels. Double the fecal output, in fact, as you can see at 4:07 in my video.

And, you can put it to the test. Maybe the same reason African-American women have more fibroids is the same reason they have worse breast cancer survival: too much estrogen in their bloodstream due to a less than optimal diet. So, researchers designed a study to see what would happen if they were switched to a more plant-based, higher fiber diet. Compared with the Caucasian women, the African-American women started out with much higher estrogen levels, again helping to explain their increased mortality from breast cancer. But, after they were put on a healthier diet, all of their levels came down, “suggest[ing] that a substantial reduction in breast cancer risk can be achieved” by adopting a diet centered around more whole plant foods. The same also appears to be true for fibroids, especially eating lots of cruciferous vegetables—broccoli, cabbage, and Chinese cabbage—as well as tomatoes and apples.

Women who underwent premature puberty, starting their periods before age 11, may also be at increased risk of fibroids later in life, and we know that higher childhood red meat intake is associated with earlier age of starting one’s period, though total protein and animal protein in general may contribute. For example, girls who eat meat tend to start their periods about six months earlier than vegetarian girls. Those who eat meat analogues like veggie burgers and veggie dogs start their periods nine months later on average, and a similar puberty normalizing influence was found with consumption of whole plants foods, such as beans. 

It could also be the endocrine-disrupting pollutants that build up the food chain. Researchers took samples of internal abdominal fat from women and found there appeared to be a correlation between the presence of fibroids with the levels of a number of PCBs in their fat. So, does that mean fish-eaters have higher risk of fibroids? Researchers did find a small increase in risk associated with the intake of long-chain omega-3 fats, mostly from “dark-meat fish consumption,” by which they meant fish like sardines and salmon. This could be because of “the endocrine-disrupting chemicals commonly shown in fish,” or it could just be a statistical fluke. It would be consistent with the increased risk seen among “sport-fish consumers.” 

Recognizing that diet and endocrine-disrupting persistent organic pollutants have been associated with a variety of gynecologic conditions, including fibroids, researchers looked at consumers of fish fished out of the Great Lakes and found a 20 percent increased risk for every ten years they had been eating the fish. In the most comprehensive study to date, researchers compared pollutant levels in fat samples from women with fibroids to fat liposuctioned out of women without fibroids. They didn’t just find higher levels of PCBs in fibroid sufferers, but also long-banned pesticides, like DDT and hexachlorocyclohexane, PAHs, which are polycyclic aromatic hydrocarbons formed when coal is burned, tobacco is smoked, and meat is grilled, as well as heavy metals, arsenic, cadmium, lead, and mercury. These levels correlated not only to fibroids, but also to seafood consumption or excess body fat. So, the researchers determined that “shedding excess weight and limiting seafood consumption would confer a protective effect” on fibroid tumor development by minimizing exposure to environmental pollutants as much as possible.

Okay, so a plant-based diet may be best, but is there a plant in particular that has been shown to be particularly powerful?

Plant-based compounds with disease-preventive properties, dietary phytochemicals are found in whole grains, fruits, vegetables, beans, split peas, chickpeas, and lentils, herbs, spices, nuts, and certain beverages. As I discuss in my video The Best Food for Fibroids, we know they can help regulate the initiation, promotion, and spread of cancerous tumors, so what about benign tumors like fibroids? Most anti-cancer drugs on the market now were originally derived from plants or plant products, so why not try to use plants to target the inflammation or blood supply of fibroids? Might fibroids be a consequence of chronic inflammation within the body? We know that women with fibroids are more likely to eat more beef and ham, and fewer fruits and green vegetables, but whole plant foods don’t just have anti-inflammatory effects but antioxidant effects as well. “If the generation of free radicals exceeds the protective effects of antioxidants, oxidative damage will occur,” which has been implicated in a variety of disease states, including gynecological conditions such as fibroids. 

If you collect fresh fibroids, as well as normal uterine tissue from hysterectomy surgeries, the fibroid cells have significantly fewer antioxidant enzymes, as you can see at 1:20 in my video, so might antioxidant-rich foods help? Well, if you drip some strawberries onto cells in a petri dish, you can apparently kill of some fibroid tumor cells, while leaving normal uterus cells alone. But, what good does that do us? That’s only relevant if we can show those strawberry compounds get absorbed through our gut and achieve high enough concentrations in uterine tissue. The same with curcumin, the component of the spice turmeric. One of its so-called “miraculous” properties is suppressing the growth of uterine fibroid cells, but, again, that was just in vitro. Yes, an inhibitory effect was found and at concentrations that don’t compromise the growth of normal, regular uterine tissue, but my patients are people, not petri dishes. 

It’s pretty neat to find out what happens to human fibroid cells as you drip higher and higher concentrations of green tea compounds on them in a test tube, as you can see for yourself at 2:19 in my video, but I care less about what happens in vitro or in mice, whether or not they have any clothes on—one study looked at “a nude mice model”—but there were no randomized, controlled clinical studies until 2013. 

Subjects were randomized to green tea extract or placebo for four months. In the placebo group, fibroid volume increased by 24 percent. That’s what fibroids do; they continue to grow. However, those randomized to the green tea group showed a reduction in total fibroid volume—and not just by a little. There was a dramatic decrease, shrinking by almost a third, which is a highly significant difference, as you can see at 3:02 in my video. Okay, but did the women feel any better? Yes, they experienced a dramatic decrease in symptom severity, as well. Month after month, nothing much happened in the placebo group, but those taking the pills that looked the same but happened to contain green tea compounds had consistent improvement and felt lessening symptoms, each month better than the last, as well as an improved health-related quality of life, month after month, that was significantly better than control. What’s more, their blood counts got better too. With all that continued excess blood loss every month, the blood levels kept decreasing in the placebo group, but they reversed in the green tea group. So, anemia also significantly improved, because average blood flow significantly diminished. And, all this—the fibroid shrinkage, less pain, better periods—was achieved with “no adverse effects.” 

So, not only were the results comparable to those for the drugs that are commonly used—again, without the side effects—but the results were also comparable to uterine artery embolization, where they try to cut the blood supply to the fibroid, which is great—unless they accidentally cut the blood supply to the rest of the uterus and cause uterine necrosis, one of many reported major complications. Others include death, not only of the fibroid, but also of the patient, along with other potential complications that may arise from accidentally clogging off non-target arteries. In my book, a side-effect-free solution as good as a more invasive procedure is potentially better than. The researchers conclude that green tea compounds show “promise as a safe and effective therapeutic agent for women with symptomatic UFs [uterine fibroids]. Such a simple, inexpensive, and orally administered therapy can improve women’s health globally.” 

Relatively safe doesn’t mean risk-free, however. Although there were no liver function abnormalities detected, this was a small study. If you give green tea extract pills to a thousand women for a year, like they did in the Minnesota Green Tea Trial for breast cancer, the livers in about 1 in 17 women started to get inflamed and a few became serious. Now, the dose they used in this study was twice that of the fibroid study and it’s not completely clear if the pills were the only cause, but, in general, we should try to avoid extracts and instead get nutrition from foods as grown—or at least from foods as grown that are then dunked in hot water, like green tea. 

The researchers had to use pills in this study, because they wanted it to be a double-blind study and it’s hard to create a placebo tea that looks, smells, and tastes like the real thing. I don’t think we should take green tea extract pills, though. We should drink green tea. The problem is that the dose the researchers used was about 11 cups a day, which would be a lot of caffeine. You could choose decaf, though, and it’s not outside the realm of possibility to drink a couple quarts of tea a day, especially if doing so may shrink your fibroids so much you can keep your uterus. But, for all we know, five cups of tea a day would work or maybe even three cups or one cup. No other dose has been tested, so we just don’t know. But, you can test it in your own life. If you have fibroids, it couldn’t hurt to add a few cups of green tea to your daily diet and see if you start feeling better.

And, for even more on fibroids, see Should Women with Fibroids Avoid Soy? and Talcum Powder and Fibroids.

For more on contaminated herbal products, see Get the Lead Out and Some Ayurvedic Medicine Worse Than Lead Paint Exposure.


I’ve got dozens and dozens of videos on the effects of diet on estrogens, such as:

In health, 

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

What About Coconuts, Coconut Milk, and Coconut Oil MCTs?

Do the medium-chain triglycerides in coconut oil and the fiber in flaked coconut counteract the negative effects on cholesterol and artery function?

Studies of populations who eat a lot of coconuts are “frequently cited” by those who sell coconut oil “as evidence that coconut oil does not have negative effects on cardiovascular health.” For example, there was an apparent absence of stroke and heart disease on the island of Kativa in Papua New Guinea. What were they eating? Their diets centered around tubers, like sweet potatoes, with fruits, greens, nuts, corn, and beans. Although they ate fish a few times a week, they were eating a largely whole food plant-based diet. It’s no wonder they may have had such low rates of artery disease. And, one of the whole foods they were eating was coconut, not coconut oil.

Now, if you go to Pukapuka, even more coconuts are eaten. In fact, as you can see at 0:51 in my video What About Coconuts, Coconut Milk, and Coconut Oil MCTs?, there’s even an island where coconuts make up most of what people eat—and they do get high cholesterol. How can a population eating 87 percent plant-based, with no dairy and only rare consumption of red meat, chicken, and eggs, have cholesterol levels over 200? Well, they’re eating all those coconuts every day. What are their disease rates like? We don’t know. There are no clinical surveys, no epidemiological death data, and no autopsies. Some EKGs were taken, which can sometimes pick up evidence of past heart attacks, but they found few abnormalities. The sample was too small to be a definitive study, though. And, even if they did have low disease rates, they weren’t eating coconut oil—they were eating coconut in its whole form.

Coconut oil proponents pointing to these studies is like the high fructose corn syrup lobby pointing to studies of healthy populations who eat corn on the cob or the sugar industry pointing to studies on fruit consumption and saying you can eat all the refined sugar you want. But fruit has fiber and so do coconuts. Just as adding psyllium fiber (Metamucil) to coconut oil can help blunt the adverse effects on cholesterol, fiber derived from defatted coconut itself can reduce cholesterol levels as much as oat bran. What’s more, the plant protein in coconuts, which is also missing from the oil, may help explain why whole coconuts may not have the same effects on cholesterol. Although coconut fat in the form of powdered coconut milk may not have the same effects on cholesterol as coconut oil, frequent consumption, defined as three or more times a week, has been associated with increased risk of vascular disease, stroke, and heart disease. And, no wonder, as coconut milk may acutely impair artery function as badly as a sausage and egg McMuffin.

Researchers tested three different meals including a Western high-fat meal that “consisted of an Egg McMuffin®, Sausage McMuffin®, 2 hash brown patties and a non-caffeinated beverage (McDonald’s Corporation)” a local high-fat meal, and an “isocaloric low-fat meal.” The study was conducted in Singapore, so the more traditional local high-fat meal was rice cooked in coconut milk and served with anchovies and an egg. These two different high-fat meals were put up against the same amount of calories in an unhealthy low-fat meal of Frosted Flakes, skim milk, and juice. At 3:21 in my video, you can see the artery function—that is, its ability to relax normally—before and after eating each of the three meals. Researchers found that artery function is significantly crippled within hours of consuming the McMuffins and also the local high-fat meal with coconut milk. So, whether the fat is mostly from meat and oil or from coconut milk, the arteries clamped down similarly, whereas that horrible sugary breakfast had no bad effect on artery function. Why? Because as terrible as the Frosted Flakes meal was, it had no saturated fat at all. (It also didn’t have contain any eggs, so that might have helped, too.)

Coconut oil proponents also try to argue that coconut oil has MCTs, medium-chain triglycerides, which are shorter-chain saturated fats that aren’t as bad as the longer-chain saturated fats in meat and dairy. You can’t apply the MCT research to coconut oil, though. Why not? Well, MCT oil is composed of MCTs—about 50 percent of the medium-chain fat caprylic acid and the other 50 percent of the MCT capric acid—whereas those MCTs make up only about 10 percent of coconut oil. Most of coconut oil is the cholesterol-raising, longer-chain saturated fats, lauric and myristic. “It is therefore inaccurate to consider coconut oil to contain either predominantly medium-chain fatty acids or predominantly medium-chain triglycerides. Thus, the evidence on medium-chain triglycerides cannot be extrapolated to coconut oil.”

It’s actually quite “a common misconception” that the saturated fat in coconut oil is comprised of mainly MCTs. Actually, as we discussed, coconut oil is mainly lauric and myristic, both of which have potent bad LDL cholesterol-raising effects. “Coconut oil should therefore not be advised for people who should or want to reduce their risk of CHD,” coronary heart disease, which is the number-one killer of U.S. men and women. The beef industry, for example, loves to argue that beef fat contains stearic acid, a type of saturated fat that doesn’t raise cholesterol. Yes, but it also has palmitic and myristic acids that, like lauric acid, do raise cholesterol, as you can see at 5:12 in my video.

If you compare the effects of different saturated fats, as you can see at 5:29 in my video, stearic acid does have a neutral effect on LDL, but palmitic, myristic, and lauric acids shoot it up—and, frankly, so may MCT oil itself, as it bumps up LDL 15 percent compared to control. Bottom line? “Popular belief”—spread by the coconut oil industry—“holds that coconut oil is healthy, a notion not supported by scientific data.” The science just doesn’t support it.

So, basically, “coconut oil should be viewed no differently” from animal sources of dietary saturated fat. A recent review published in the Journal of the American College of Cardiology put it even more simply in its recommendations for patients. When it comes to coconut oil, “avoid.”

Okay, but doesn’t saturated fat boost HDL, the so-called good cholesterol? Check out Coconut Oil and the Boost in HDL “Good” Cholesterol.


Isn’t coconut oil supposed to be good for Alzheimer’s, though? See my video Does Coconut Oil Cure Alzheimer’s?

If you want to learn more about the original McMuffin artery studies, see The Leaky Gut Theory of Why Animal Products Cause Inflammation.

You may also be interested in Flashback Friday: Coconut Oil and Abdominal Fat.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: