 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 ingest it. 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 mid-morning and mid-afternoon 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 learn 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 the mechanism by which lactose enhances lead absorption is not clear. Bottom line is that while in 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 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 1,000 men and women in China, and for every 9 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 9 ounces a week, those that ate up to 2.5 ounces a day only had half the odds of having elevated lead levels, and those consuming nearly 4 ounces a day appeared to cut their odds by more than 80%. Now this was just a cross-sectional study 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, give half of them some food, and see if it drives lead levels down, which we'll cover next.