What dietary change can simultaneously help detoxify mercury, lead, and cadmium from the body?
I’ve previously explored the issue of lead contamination in calcium supplements, such as bonemeal, but bone meal isn’t all that can be contaminated. “Substantial quantities of lead have been reported in some over-the-counter calcium supplement preparations,” and testing has revealed continued public health concern over bonemeal. Thankfully, bonemeal isn’t as popular these days, so most of us aren’t likely to get exposed directly to the lead in bonemeal anymore. We may, however, get exposed indirectly through the animals we eat, as I show at 0:31 in my video How to Lower Heavy Metals with Diet.
In the United States, five billion pounds of meat and bonemeal are produced annually as slaughterhouse by-products. What do we do with these millions of tons every year? We feed it back to farm animals, particularly chickens. Now, most of the lead in the bonemeal passes right through the animals into their waste, but we take that waste—that cow, pig, and chicken feces—and feed it right back to the animals once again. So, you can see how the levels of contaminants might build up in their bodies.
You may remember that I’ve talked before about what all this might mean for making something like chicken soup, but the original concern about these kinds of feeding practices, such as feeding cows to pigs, chickens, and even other cows, was about spreading prion diseases, like mad cow. This kind of recycling not only magnifies prions, however; it also magnifies other toxic substances, including lead. So a more plant-based diet may be able to lower lead exposure, and an even more plant-based diet could theoretically lower exposure even more.
What happens when you put it to the test? Should we really expect to find a benefit? As you can see at 1:42 in my video, even though lead is one of the toxins found in meat, half of our dietary exposure probably comes from plant foods. In fact, dietary modeling studies in Europe suggest that vegetarians would be exposed to about the same amount of lead compared to the general population, with the exception of those who eat a lot of wild game, which can have a thousand times more lead than most other foods, as you can see at 2:02 in my video.
A vegetarian diet may even be higher in lead. It’s not what you eat, though; it’s what you absorb. As I’ve discussed previously, researchers found that the uptake of toxic heavy metals from “animal food sources” into human intestinal lining cells may be higher than from vegetable sources. This is why you can have a vegetarian with some of the lowest concentrations of lead and cadmium in their blood, despite having higher concentrations in their diet.
As you can see at 2:41 in my video, there seems to be a tendency towards higher fecal elimination of lead following a change to a vegetarian diet. Researchers found that nine subjects, on average, tripled their elimination of lead, three were unaffected, and four saw their levels drop by about half. The study only lasted a few months, though, and the difference wasn’t statistically significant. So, what would happen in a year? Subjects made the shift to a diet “characterized by large amounts of raw vegetables, fruits, unrefined foods, and whole-meal products [whole grains] and the exclusion of meat, poultry, fish, and eggs” (though it did include fermented dairy, like a type of soured milk). They also cut back on processed foods and junk. Researchers took clippings of their hair before and after the dietary shift and got significant reductions in heavy metals, including cutting their lead level nearly in half. As you can see at 3:28 in my video, within three months of the dietary shift, the mercury, cadmium, and lead that had been oozing from their body into their hair went down and stayed down. How do we know the reduction in toxic heavy metal levels wasn’t just a coincidence? A few years after the study was over, after the participants had gone back to more of their regular diet, their mercury, cadmium, and lead levels shot back up to where they were before.
Researchers found the same with a different group of subjects after two years on a vegetarian diet. The drop in mercury is easy to explain, as it’s presumably due to the drastic drop in fish consumption, and the drop in alcoholic beverages may have contributed to the drop in lead. There also could have been a cadmium-like effect, where the decrease in hair lead content could be due to the dietary shift that resulted in less absorption of lead into the body in the first place.
I have a 16-part series on lead, starting with How the Lead Paint Industry Got Away with It. The series includes videos with specific food recommendations. For example, check out Best Food for Lead Poisoning: Garlic and Yellow Bell Peppers for Male Infertility and Lead Poisoning?.
KEY TAKEAWAYS
- Substantial quantities of lead have been found in some over-the-counter calcium supplements, and there is continued public health concerns over bonemeal. Although bonemeal is not as popular today, we may be getting exposed to lead indirectly through the animals we eat.
- Millions of tons of meat and bonemeal are produced each year in the United States as slaughterhouse by-products and may be fed back to farm animals, particularly chickens. Most of the lead in the bonemeal passes through them into their, but that cow, pig, and chicken feces may then be fed back once again to farm animals. In this way, levels of contaminants may build up in their bodies.
- These kinds of recycled feeding practices, such as feeding cows to pigs, chickens, and even other cows, facilitate the spread of prion diseases, like mad cow, but they also magnify other toxic substances, including lead.
- Lead is a toxin found in meat, but half of our dietary exposure likely comes from plant foods. (Notably, wild game can have a thousand times more lead than most other foods.)
- It’s not what we eat, though; it’s what we absorb, and researchers have found that the uptake of toxic heavy metals from “animal food sources” into our intestinal lining cells may be higher than from vegetable sources, explaining why vegetarians can have some of the lowest concentrations of lead and cadmium in their blood, despite having higher concentrations in their diet.
- After changing to a vegetarian diet, there seems to be a tendency towards higher fecal elimination of lead. Indeed, researchers took clippings of study participants’ hair before and after the dietary shift and found significant reductions in heavy metals, including cutting their lead level nearly in half and lowering the mercury and cadmium in their bodies. A few years after the study concluded and the subjects had gone back to more of their regular diet, their mercury, cadmium, and lead levels elevated back up.
And, these are the videos I mentioned specifically:
In health,
Michael Greger, M.D.
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