The half-life of lead in the bloodstream is only about a month. In other words, if you feed people lead for about a hundred days to boost up their blood levels, and then you stop giving them lead, the levels in their blood start to drop, such that within about 30 days, their lead levels are cut in half. In another month, they’re cut in half again. So, by around three months, their body is able to remove about 90 percent from their bloodstream. You can see a graphic depicting this at 0:10 in my video The Rise in Blood Lead Levels in Pregnancy and Menopause.
If you’re chronically exposed to lead, however, you can have chronically high lead levels in your blood. More than half a million kids in the United States have concerning high lead levels, and “poor people…in politically disempowered communities of color are most at risk of lead poisoning,” regardless of age.
If you don’t live in those communities and are not constantly exposed to lead, why should you care about dietary strategies to lower the lead level in your own blood, if your body is already so good at it? Even if you do get exposed to lead here and there, about 90 percent of the lead in your blood is gone after just three or four months. Ah, but go where?
More than 90 percent of lead in our body “is stored in our bone where it has a half-life of years to decades,” so instead of it taking a few months to get rid of it, how about a few decades? Indeed, researchers estimate the half-life of the tibia, commonly known as shinbone, to be 48.6 years. So, even if we moved to some other planet and never had any further exposure to external sources of lead, we still have an internal source of lead leaching the toxic heavy metal into our system throughout our life.
Okay, but if it’s mostly just stored in our skeleton, what’s the big deal? Well, if you were to lose bone, all the trapped lead could come flooding back into your system. For example, when we lose weight, we lose bone, which makes a lot of sense. Heavier people have a heavier skeleton with greater bone mineral density. Their body has to maintain stronger bones to carry around all that extra weight. So, if we lose weight, do the levels of lead in our bloodstream go up as our skeleton downsizes? As you can see at 2:14 in my video, the answer, unfortunately, is yes—but only if we lose a lot of weight. If you lose 10 pounds or so, not much happens, but if you lose more than 80 pounds, the lead levels in your blood can rise 250 percent.