Hello and welcome to Nutrition Facts. I'm your host, Dr. Michael Greger. Today we're going to explore smart nutrition choices based naturally on facts.

Have a history of high blood pressure in your family? How about heart disease, diabetes? There are foods we can eat that may not only help prevent many of these chronic diseases, but even stop them in their tracks.

We recently took a close look at the heavy metal lead on this podcast, an element that can cause a wide range of health problems when humans are exposed to it.

Today we're going to discover some of the positive steps we can take to mediate some of the damage. First up, iron, zinc, oil, and even doughnuts are put to the test to see if they can block lead absorption.

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 levels, the same with lead exposed steel workers.

Fiber and iron intake were also associated with lower lead levels in the body to a lesser degree.

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, they suggest 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 to see if their lead levels drop. The closest I could find is a thiamine intervention for lead intoxicated goats.

Much of the fiber data is just from test tube studies 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 it may be able to block absorption in a small intestine.

Though when our good gut flore then eat the fiber, some of the heavy metals may be re-released down the colon, so it's not completely fail safe, and like thiamine, there haven't been controlled human studies.

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 this 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 were not rodents.

Same story with zinc, it may help to protect rat testicles, but didn't seem to help children.

Nevertheless, iron is routinely prescribed in children with lead poisoning, given the lack of scientific evidence supporting the use of indiscriminate iron supplementation in children with lead poisoning, its routine use should be re-examined.

Though obviously if you have iron deficiency supplementation may help.

High fat intake has been identified as something that may make things worse for lead exposed children.

Dictory fat has been associated with higher lead levels and cross-sectional snapshot in time type studies, and there is a plausible biological mechanism.

Dictory 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 like a Geiger counter they could measure how much radiation they retained in their body.

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%.

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