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Eating to Block Lead Absorption

Intake of certain nutrients has been associated with lower lead levels in the body. For example, women with higher intake of thiamine, also called vitamin B1, tended to have lower blood lead levels, and the same was found for lead-exposed steel workers—and not just with thiamine, as “content of dietary fiber, iron, or thiamine intake each correlated inversely with blood lead concentrations in workers…” The thinking is that the fiber might glom onto the lead and flush it out of the body, the iron would inhibit the lead absorption, and the thiamine may accelerate lead removal through the bile. So, researchers suggest that eating lots of iron, fiber and especially thiamine-rich foods “may induce rapid removal and excretion of the lead from the tissues.” But thiamine’s never been put to the test by giving it to people to see if their lead levels drop. The closest I could find is a thiamine intervention for lead-intoxicated goats.
 

And much of the fiber data are just from test tube studies. In one, for example, researchers used simulated intestinal conditions, complete with “flasks” of feces, and both soluble and insoluble dietary fiber were able to bind up large amounts of mercury, cadmium, and lead to such an extent that they may have been able to block absorption in the small intestine. But, when our good gut flora then eat the fiber, some of the heavy metals may be re-released down in the colon, so it’s not completely fail safe. And, as with thiamine, there haven’t been controlled human studies.

But where is thiamine found? At 1:47 in my video How to Lower Lead Levels with Diet: Thiamine, Fiber, Iron, Fat, Fasting?, I feature a list of some of the healthiest sources of thiamine-rich foods that also contain fiber, which include highly concentrated, super healthy foods like beans and greens—foods we should all be eating anyway. So, even if thiamine- and fiber-rich foods don’t actually lower lead levels, we’ll still end up healthier.

What happened when iron was put to the test? It failed to improve the cognitive performance of lead-exposed children and failed to improve behavior or ADH symptoms, which is no surprise, because it also failed to bring down lead levels, as did zinc supplementation. It turns out that while iron may limit the absorption of lead, “it may also inhibit excretion of previously absorbed lead” that’s already in your body. What’s more, iron may not even inhibit lead absorption in the first place. That was based on rodent studies, and it turns out we’re not rodents.

We get the same story with zinc. It may have helped to protect rat testicles, but didn’t seem to help human children. “Nevertheless, iron is routinely prescribed in children with lead poisoning.” But, “given the lack of scientific evidence supporting the use of iron [supplementation] in…children with lead poisoning, its routine use should be re-examined.” Though, obviously, supplementation may help if you have an iron deficiency.

High fat intake has been identified as a nutritional condition that makes things worse for lead-exposed children. In fact, dietary fat has been associated with higher lead levels in cross-sectional, snapshot-in-time type studies, and there is a plausible biological mechanism: Dietary fat may boost lead absorption by stimulating extra bile, which in turn may contribute to lead absorption, but you really don’t know until you put it to the test.

In addition to testing iron, researchers also tested fat. They gave a group of intrepid volunteers a cocktail of radioactive lead and then, with a Geiger counter, measured how much radiation the subjects retained in their bodies. Drinking the lead with iron or zinc didn’t change anything, but adding about two teaspoons of vegetable oil boosted lead absorption into the body from about 60 percent up to around 75 percent, as you can see at 4:17 in my video.

The only thing that seemed to help, dropping lead absorption down to about 40 percent, was eating a light meal with the lead drink. What was the meal? Coffee and a donut. I think this is the first donut intervention I’ve ever seen with a positive outcome! Could it have been the coffee? Unlikely, because if anything, coffee drinking has been associated with a tiny increase in blood lead levels. If fat makes things worse, and the one sugar they tried didn’t help, the researchers figured that what made the difference was just eating food—any food—and not taking in lead on an empty stomach. And, indeed, if you repeat the study with a whole meal, lead absorption doesn’t just drop from 60 percent to 40 percent—it drops all the way down to just 4 percent! That’s extraordinary. That means it’s 15 times worse to ingest lead on an empty stomach.

Lead given 12 hours before a meal was absorbed at about 60 percent, so most of it was absorbed. When the same amount of lead was given three hours after a meal and also seven hours after a meal, most of it was absorbed at those times, too. But, if you get some food in your stomach within a few hours of lead exposure, you can suppress the absorption of some or nearly all of the lead you ingested, which you can see at 0:11 in my video How to Lower Lead Levels with Diet: Breakfast, Whole Grains, Milk, Tofu?.

This is why it’s critical to get the lead out of our tap water. Although it’s estimated that most of our lead exposure comes from food, rather than water, it’s not what we eat that matters, but what we absorb. If 90 percent of the lead in food is blocked from absorption by the very fact that it’s in food, 10 to 20 times more lead could be absorbed into your bloodstream simply by consuming the same amount of lead in water drank on an empty stomach.

And, since children empty their stomachs faster than adults because kids “have more rapid gastric emptying times,” the timing of meals may be even more important. With little tummies emptying in as few as two hours after a meal, offering midmorning and midafternoon snacks in addition to breakfast and regular meals may cut down on lead absorption in a contaminated environment. And, of course, we should ensure that children wash their hands prior to eating.

So, do preschoolers who eat breakfast have lower levels of lead in their blood? In the first study of its kind, researchers found that, indeed, children who ate breakfast regularly did appear to have lower lead levels, supporting recommendations to provide regular meals and snacks to young children at risk for lead exposure.

Is there anything in food that’s particularly protective? Researchers tested all sorts of foods to find out, and it turns out the “effect of a meal was probably largely due to its content of calcium and phosphate salts but lead uptake was probably further reduced by phytate which is plentiful in whole cereals,” but if calcium and phosphates are protective, you’d think dairy would work wonders. And, indeed, they started giving milk “to workers to prevent lead exposure” ever since calcium was shown to inhibit lead absorption in rats. But, in humans, there’s something in milk that appeared to increase lead uptake, and it wasn’t the fat because they found the same problem with skim milk.

“For over a century milk was recommended unreservedly to counteract lead poisoning in industry,” but this practice was abandoned in the middle of the last century once we learned that milk’s “overall effect is to promote the absorption of lead from the intestinal tract.” What’s the agent in milk that promotes the absorption of lead from the gut? It may be the milk sugar, lactose, though the “mechanism by which lactose enhances lead absorption is not clear.”

The bottom line? “In the past…milk was used as a prophylactic agent to protect workers in the lead industry. Recent studies, however, suggest that this practice is unjustified and may even be harmful.” So, giving people whole grains may offer greater protection against lead uptake.

However, the most potently calcium and phytate-rich food would be tofu. Isolated soy phytonutrients may have a neuroprotective effect, at least this was the case in petri dish-type studies. As you can see at 3:45 in my video, if you add a little lead to nerve cells, you can kill off about 40 percent of them, but if you then give more and more soy phytonutrients, you can ameliorate some of the damage. This is thought to be an antioxidant effect. If you add lead to nerve cells, you can get a big burst of free radicals, but less and less as you drip on more soy compounds.

Nevertheless, even if this worked outside of a lab, cutting down on the toxic effects of lead is nice, but cutting down on the levels of lead in your body is even better. “Because tofu has high content of both calcium and phytic acid phytate…it is biologically plausible that tofu may inhibit lead absorption and retention, thus reducing blood lead levels.” But you don’t know, until you put it to the test.

Tofu consumption and blood lead levels were determined for about a thousand men and women in China. For every nine or so ounces of tofu consumed a week, there appeared to be about four percent less lead in their bloodstream. Those who ate up to two and a half ounces a day had only half the odds of having elevated lead levels, compared to those eating less than about nine ounces a week. Those consuming nearly four ounces a day appeared to cut their odds by more than 80 percent. This was just a cross-sectional study, or snapshot in time, so it can’t prove cause and effect. What you need is an interventional study where you randomize people into two groups, giving half of them some food to see if it drives down lead levels. I cover this in my video Best Food for Lead Poisoning: Chlorella, Cilantro, Tomatoes, Moringa?.


Where does all this lead exposure come from anyway? Check out the first five videos on this series:

For more about blocking lead absorption, as well as what to eat to help rid yourself of the lead you’ve already built up, see:

Or, even better, don’t get exposed in the first place. Find out more in these videos:

Some of my other videos on lead include:

And what about lead levels in women? See:

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:

 

Discuss

Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.


11 responses to “Eating to Block Lead Absorption

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  1. Wow, that was packed with information!

    Excellent!

    Wow, tofu might be genuinely saving a billion lives in China or something like that.

    Keep the lead out is better than Get the lead out.

  2. I was also wondering if therapeutics might finally show up in the death numbers of COVID.

    It was a holiday weekend, so they probably weren’t reporting them but it was still fabulous to see them listing 286 yesterday after months of over 1,000 deaths per day.

    Weekends sometimes dropped below 1,000 but 286 was exceptionally low.

  3. “So, giving people whole grains may offer greater protection against lead uptake.”

    As long as they aren’t contaminated with aflatoxin. Which is a topic that, remarkably, has never been addressed on NF.org. How about a series on how to avoid aflatoxin?

    1. It’s unsurprising that NF.org has never covered this topic since, according to the CDC,

      ‘To date, no outbreak of human illness caused by aflatoxins has been reported in the United States,’
      https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/aflatoxins

      A friend of mine would never eat wholemeal bread because of fear of aflatoxins. He would only ever eat white bread. He died of colon cancer in his mid-fifties, poor devil. He was a great bloke. I always wondered though if his insistence on eating white bread played a role. The link between protection against colorectal cancer and fibre consumption, especially fibre from whole grains, is fairly widely accepted ….. according to the World Cancer Research Fund

      ‘A high intake of dietary fibre, in particular cereal fibre and whole grains, is associated with a reduced risk of colorectal cancer in a review of prospective cohort studies as part of the Continuous Update Project’
      https://www.wcrf.org/int/latest/our-science-and-policy-partnerships/colorectal-cancer-project

      1. My understanding is that there have been no reported cases of acute poisoning in the US. But there have been recalls. In these cases, the FDA grants a temporary waver to allow the grain to be fed to beef cattle. (The toxin can then be passed on through the meat.) It would be interesting to know if there have ever been any independent tests of contamination levels in grains and corn. The allowable levels in the US are higher than the EU.

        But yes, I agree. Whole grains are among the healthiest foods. I eat a ton of them. Which is precisely why I’m interested. Aflatoxin is a potent liver carcinogen.

  4. I have been listening to the audio of How Not To Diet and I LOVE the audio version.

    I started listening to it way back when but everybody around me was sick, so I ended up reading Bird Flu and other of your books, and people had been picking on the audio version back then and I had started listening and loved it and has suspected that they didn’t like it as a way to protest the new format of the videos and I am even more convinced of that this time through.

    You didn’t read it too fast or with too much inflection at all.

    I went to pause it on Audible and was surprised because I have been listening at 1.5 x and even that sped up version wasn’t too fast.

    Maybe people were listening at the wrong speed.

    Anyway, I said it back then and after listening for hours, you did an EXCELLENT job at reading your book. Almost 24 hours of audiobook. That is so impressive.

    I am only 6 and a half hours in but it is so packed full of information that I just wanted to come back and thank you for all of your hard work.

  5. 90 percent of soy grown in USA is GMO I used to eat a lot soya. Won’t go near it now, and no such think as organic these days, eat it at your peril. Best of health

    1. Yes 90% of US soy is GMO and it’s used for cattle feed, export and possibly to make oils etc.

      As far as I know. all soy sold for human consumption in the US is non-GMO. Check the labels though.

      I only eat non-GMO organic tofu etc myself but I have never seen any evidence that GMO soy is harmful, have you? I just avoid it on the ‘better safe than sorry’ principle.

  6. I was told that years ago, at Trail British Columbia, the site of a lead/zinc smelter, children where given lot’s of milk to drink to remove lead and contaminants from the blood. They later discovered the metals accumulated in the bones. Substantial investments in scrubbers and very tall smoke stacks resulted in a substantial reduction of chemicals in the immediate local environment.

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