How to Lower Lead Levels with Diet: Thiamine, Fiber, Iron, Fat, Fasting?

Michael Greger M.D. FACLM · May 26, 2017 · Volume 36

4.8/5 - (80 votes)

Iron, zinc, oil, and even doughnuts are put to the test to see if they can block lead absorption.

Discuss

Transcript

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

There are certain nutrients whose intake has been associated with lower lead levels in the body. For example, women with higher thiamine intake (vitamin B1 intake) tended to have lower blood lead levels; the same with lead-exposed steel workers. Fiber and iron intake were also associated, to a lesser degree, with lower lead levels in the blood. The thinking is that the fiber might glom onto the lead, and flush it out of the body. And, the iron would inhibit the lead absorption, whereas the thiamine may accelerate lead removal through the bile. Thus, the research suggests that eating lots of iron, fiber, and especially thiamine-rich foods “may induce rapid removal and excretion of…lead from the tissues.” But thiamine’s never been put to the test, where you give people thiamine, and 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 like this, where, under simulated intestinal conditions, complete with flasks of feces, 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 blocked absorption in the small intestine—though when our good gut flora then might eat the fiber, some of the heavy metals may be re-released in the colon. So, it’s not completely fail-safe, and, like thiamine, there haven’t been controlled human studies.

But look, where is thiamine found? Here’s some of the healthiest sources that also contain fiber, concentrated in super-healthy foods like beans and greens that we should all be eating anyway. So, even if thiamine and fiber-rich foods don’t actually lower your lead levels, you’d still end up healthier.

Iron was put to the test, though, and it failed to improve the “cognitive performance” of lead-exposed children, failed to improve “behavior” or ADHD symptoms. No surprise, because it failed to bring down lead levels, as did zinc supplementation. Turns out that while “iron may limit [the] absorption of lead,…it may also inhibit [the] excretion of…lead” that’s already in your body.

And, 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.

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, “[G]iven the lack of scientific evidence supporting the use of [indiscriminate] iron [supplementation] in… children with lead poisoning, its routine use should be reexamined.” Though obviously, if you have an iron deficiency, supplementation may help.

High fat intake has also been identified as something that make things worse for lead-exposed children. Dietary fat was associated with higher lead levels in a cross-sectional, snapshot-in-time study, 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, they also tested fat. They gave a group of intrepid volunteers a cocktail of radioactive lead. Then, with a Geiger counter, they could measure how much radiation they 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% up to around 75%.

The only thing that seemed to help, dropping lead absorption down to about 40%, was eating a light meal with the lead drink. What was the meal? Coffee and a doughnut. I think this is the first doughnut intervention I’ve ever seen with a positive outcome. Could it have been the coffee? Unlikely, as, if anything, coffee drinking has been associated with a tiny increase in blood levels.

If fat makes things worse, and the one sugar they tried didn’t help, they figured that it was just “eating food”—any food—not taking in lead on an empty stomach, that made the difference. And, indeed, if you repeat the study with a whole meal, lead absorption doesn’t just drop from 60% to 40%, but all the way down to just 4%! That’s extraordinary. That means it’s 15 times worse to ingest lead on an empty stomach.

Please consider volunteering to help out on the site.

Sources

Acknowledgements

Icons created by Anand Prahlad, Jon Trillana and Imogen Oh from the Noun Project.

Image credit: Kristina DeMuth. Image has been modified.

Motion graphics by Avocado Video.

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

There are certain nutrients whose intake has been associated with lower lead levels in the body. For example, women with higher thiamine intake (vitamin B1 intake) tended to have lower blood lead levels; the same with lead-exposed steel workers. Fiber and iron intake were also associated, to a lesser degree, with lower lead levels in the blood. The thinking is that the fiber might glom onto the lead, and flush it out of the body. And, the iron would inhibit the lead absorption, whereas the thiamine may accelerate lead removal through the bile. Thus, the research suggests that eating lots of iron, fiber, and especially thiamine-rich foods “may induce rapid removal and excretion of…lead from the tissues.” But thiamine’s never been put to the test, where you give people thiamine, and 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 like this, where, under simulated intestinal conditions, complete with flasks of feces, 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 blocked absorption in the small intestine—though when our good gut flora then might eat the fiber, some of the heavy metals may be re-released in the colon. So, it’s not completely fail-safe, and, like thiamine, there haven’t been controlled human studies.

But look, where is thiamine found? Here’s some of the healthiest sources that also contain fiber, concentrated in super-healthy foods like beans and greens that we should all be eating anyway. So, even if thiamine and fiber-rich foods don’t actually lower your lead levels, you’d still end up healthier.

Iron was put to the test, though, and it failed to improve the “cognitive performance” of lead-exposed children, failed to improve “behavior” or ADHD symptoms. No surprise, because it failed to bring down lead levels, as did zinc supplementation. Turns out that while “iron may limit [the] absorption of lead,…it may also inhibit [the] excretion of…lead” that’s already in your body.

And, 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.

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, “[G]iven the lack of scientific evidence supporting the use of [indiscriminate] iron [supplementation] in… children with lead poisoning, its routine use should be reexamined.” Though obviously, if you have an iron deficiency, supplementation may help.

High fat intake has also been identified as something that make things worse for lead-exposed children. Dietary fat was associated with higher lead levels in a cross-sectional, snapshot-in-time study, 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, they also tested fat. They gave a group of intrepid volunteers a cocktail of radioactive lead. Then, with a Geiger counter, they could measure how much radiation they 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% up to around 75%.

The only thing that seemed to help, dropping lead absorption down to about 40%, was eating a light meal with the lead drink. What was the meal? Coffee and a doughnut. I think this is the first doughnut intervention I’ve ever seen with a positive outcome. Could it have been the coffee? Unlikely, as, if anything, coffee drinking has been associated with a tiny increase in blood levels.

If fat makes things worse, and the one sugar they tried didn’t help, they figured that it was just “eating food”—any food—not taking in lead on an empty stomach, that made the difference. And, indeed, if you repeat the study with a whole meal, lead absorption doesn’t just drop from 60% to 40%, but all the way down to just 4%! That’s extraordinary. That means it’s 15 times worse to ingest lead on an empty stomach.

Please consider volunteering to help out on the site.

Icons created by Anand Prahlad, Jon Trillana and Imogen Oh from the Noun Project.

Image credit: Kristina DeMuth. Image has been modified.

Motion graphics by Avocado Video.

Doctor's Note

This is why it’s critical to “get the lead out” of our tap water, but it’s estimated that most of our lead exposure comes from food, rather than water. It’s not what we eat, however, 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, you could get 10 to 20 times more lead absorbed into your bloodstream consuming the same amount of lead in water you drink on an empty stomach.

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

For more on blocking lead absorption, as well as what to eat to help rid yourself of 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:

If you haven't yet, you can subscribe to our free newsletter. With your subscription, you'll also get notifications for just-released blogs and videos. Check out our information page about our translated resources.

Pin It on Pinterest

Share This