How to Lower Lead Levels with Diet: Breakfast, Whole Grains, Milk, Tofu?

Michael Greger M.D. FACLM · May 29, 2017 · Volume 36

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Getting food into your stomach within a few hours of lead exposure can suppress the absorption of lead by 90 percent or more—but which foods are particularly protective?

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.

The same amount of lead given 12 hours before a meal is absorbed at about 60%; so, most of the lead is absorbed. Three hours after a meal, most lead is absorbed; seven hours after a meal, most lead is absorbed. But, get some food in your stomach within a few hours of lead exposure, and you can suppress the absorption of some, or nearly all, of the lead you ingested.

That’s why it’s critical to “get the lead out” of our tap water. Now, it’s estimated that most of our lead exposure comes from food, rather than water, but it’s not what we eat; it’s what we absorb. If 90% 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 drunk on an empty stomach.

And, since children empty their stomachs faster than adults, meal timing 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 absorption in a contaminated environment, making sure, also, of course, that children are washing 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.

Anything in food that’s particularly protective? Researchers tested all sorts of foods to find out, and it turns out that the meal effect “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 [grains].” Now, if calcium and phosphates are protective, you’d think dairy would work wonders. And, indeed, they started giving milk to lead workers ever since “calcium was shown to inhibit lead absorption in rats.” But, in humans, there’s something in milk that appears to increase lead uptake. It wasn’t the fat, since they found the same problem with skim milk.

“For over a century milk was recommended unreservedly to counteract lead poisoning,” but started to be abandoned in the middle of the last century, once we learned that the “overall effect [of milk may have been to actually] 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 “[t]he mechanism by which lactose enhances lead absorption is not clear.” Bottom line is that while “[i]n the past, milk was used as a prophylactic agent to protect workers in the lead industry. Recent studies…suggest that this practice is unjustified and may even be harmful.” So, maybe giving people whole grains may offer “greater protection against lead uptake,” though the most potently calcium- and phytate-rich food would be tofu.

Isolated soy phytonutrients may have a neuroprotective effect, at least in petri dish-type studies, where, if you add a little lead to nerve cells, you can kill off about 40% of them. But then, if you add 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 get a big burst of free radicals, but less and less as you drip more and more soy compounds. Okay, but 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 [tends to have a] high content of both calcium and [phytate, it’s] 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, and for every nine or so ounces of tofu consumed a week, there appeared to be about 4% less lead in their bloodstream. Compared to those eating less than about nine ounces a week, those that ate up to two and a half ounces a day only had half the odds of having elevated lead levels, and those consuming nearly four ounces a day appeared to cut their odds by more than 80%. Now, this was just a cross-sectional study, a snapshot in time; so, it can’t prove cause and effect. What you’d need is an interventional study where you randomize people into two groups, give half of them some food, and see if it drives lead levels down—which we’ll cover next.

Please consider volunteering to help out on the site.

Sources

Acknowledgements

Icons created by Universal Icons, Gan Khoon Lay and Thomas Helbig from the Noun Project.

Motion graphics by Avocado Video.

Image credit: Unsplash. Image has been modified.

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.

The same amount of lead given 12 hours before a meal is absorbed at about 60%; so, most of the lead is absorbed. Three hours after a meal, most lead is absorbed; seven hours after a meal, most lead is absorbed. But, get some food in your stomach within a few hours of lead exposure, and you can suppress the absorption of some, or nearly all, of the lead you ingested.

That’s why it’s critical to “get the lead out” of our tap water. Now, it’s estimated that most of our lead exposure comes from food, rather than water, but it’s not what we eat; it’s what we absorb. If 90% 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 drunk on an empty stomach.

And, since children empty their stomachs faster than adults, meal timing 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 absorption in a contaminated environment, making sure, also, of course, that children are washing 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.

Anything in food that’s particularly protective? Researchers tested all sorts of foods to find out, and it turns out that the meal effect “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 [grains].” Now, if calcium and phosphates are protective, you’d think dairy would work wonders. And, indeed, they started giving milk to lead workers ever since “calcium was shown to inhibit lead absorption in rats.” But, in humans, there’s something in milk that appears to increase lead uptake. It wasn’t the fat, since they found the same problem with skim milk.

“For over a century milk was recommended unreservedly to counteract lead poisoning,” but started to be abandoned in the middle of the last century, once we learned that the “overall effect [of milk may have been to actually] 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 “[t]he mechanism by which lactose enhances lead absorption is not clear.” Bottom line is that while “[i]n the past, milk was used as a prophylactic agent to protect workers in the lead industry. Recent studies…suggest that this practice is unjustified and may even be harmful.” So, maybe giving people whole grains may offer “greater protection against lead uptake,” though the most potently calcium- and phytate-rich food would be tofu.

Isolated soy phytonutrients may have a neuroprotective effect, at least in petri dish-type studies, where, if you add a little lead to nerve cells, you can kill off about 40% of them. But then, if you add 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 get a big burst of free radicals, but less and less as you drip more and more soy compounds. Okay, but 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 [tends to have a] high content of both calcium and [phytate, it’s] 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, and for every nine or so ounces of tofu consumed a week, there appeared to be about 4% less lead in their bloodstream. Compared to those eating less than about nine ounces a week, those that ate up to two and a half ounces a day only had half the odds of having elevated lead levels, and those consuming nearly four ounces a day appeared to cut their odds by more than 80%. Now, this was just a cross-sectional study, a snapshot in time; so, it can’t prove cause and effect. What you’d need is an interventional study where you randomize people into two groups, give half of them some food, and see if it drives lead levels down—which we’ll cover next.

Please consider volunteering to help out on the site.

Icons created by Universal Icons, Gan Khoon Lay and Thomas Helbig from the Noun Project.

Motion graphics by Avocado Video.

Image credit: Unsplash. Image has been modified.

Doctor's Note

Would any kind of food cut down on lead absorption? Even doughnuts? You’ve got to see it to believe it. Check out my video How to Lower Lead Levels with Diet: Thiamine, Fiber, Iron, Fat, Fasting?.

Next, let’s look into foods that don’t just block absorption, but may actively pull lead from our bodies. See:

Some of my other videos on lead include:

And what about lead levels in women? See:

What exactly are phytates? See:

What about soy and breast cancer? See:

And if you missed any of my background videos on lead, catch up with these:

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