Can Vitamin C Supplements Help with Lead Poisoning?

“Even if a nutritional manipulation is proven effective in reducing blood lead levels, reliance on such an intervention places most of the burden for prevention on those most affected and least responsible for the underlying environmental causes of lead toxicity. Nutritional interventions, therefore, must never substitute for efforts to reduce lead exposure to safe levels. On the other hand, when used as an adjunct to environmental measures, some nutritional changes may prove to have benefits beyond any impact on lead toxicity.” For example, consumption of vitamin C-rich foods may help with “blood pressure, blood lipid profiles, and respiratory symptoms,” in addition to perhaps influencing “lead toxicity through an influence on absorption of lead, elimination of lead, transport within the body, tissue binding, or secondary mechanisms of toxicity,” that is, even just helping ameliorate some of the damage. But what is this based on?

In 1939, a remarkable study was published, entitled “Vitamin C treatment in lead poisoning,” in which 17 lead industry workers were given 100 mg of vitamin C a day, the amount found in one or two oranges, and “with practically all of them there was a marked gain in vigor, color of skin, cheerfulness, blood picture, appetite and ability to sleep well.” The 17 workers were chosen because they seemed to be in pretty bad shape and possibly even had scurvy, so it’s no wonder a little vitamin C helped. But vitamin C is an antioxidant, and oxidation is “an important mechanism underlying lead toxicity,” so it’s conceivable that it may have mediated some of the harm. But, the vitamin C didn’t appear to just reduce the damage from the lead—it also reduced the lead itself. As you can see from 1:43 in my video Can Vitamin C Help with Lead Poisoning?, the amount of lead in a painter’s urine over a period of a month after starting 200 mg of vitamin C a day exhibited a five-fold drop, suggesting he was absorbing less of the lead into his body. He was one of three painters researchers tried this on, and evidently all three painters’ levels dropped. The researchers concluded that those “exposed to lead…should be advised to include in their diet plenty of such rich sources of vitamin C as tomatoes (fresh or canned), raw cabbage, oranges or grapefruit, raw spinach (or even cooked, in very little water), raw turnips, green bell peppers, cantaloupe, etc.”

Now, this drop in lead in the subjects’ urine was seen with only three painters, and the study didn’t have a control group of painters who didn’t take vitamin C, so perhaps everyone’s lead levels would have dropped for some other reason or perhaps it was just a coincidence. You don’t know…until you put it to the test.

Those original data were so compelling that others were inspired to try to replicate them. I mean, if it actually worked, if vitamin C could help with lead poisoning, grapefruits could be handed out at the factory door! The earlier study didn’t have a good control group, but the researchers weren’t going to make that same mistake this time. In this study, half of the group got 100 mg of vitamin C a day—not just for a month but for a year—and the other group got nothing. The result? “Careful study of a large group of lead workers failed to reveal any effect of ascorbic acid vitamin C…on the lead concentration in the blood…or urine” (emphasis added). There was no difference in their physical condition and no changes in their blood work, so “no reason has been found for recommending the use of ascorbic acid vitamin C to minimize effects of lead absorption.” What a disappointment. It looked so promising!

Whenever I study a topic, I try to read the research chronologically so I can experience the discoveries as they happened throughout history. At this point, though, I was so tempted to jump to a recent review to see what had happened in the intervening 74 years since that first study was published, but I didn’t want to spoiler alert! myself, so I kept reading the papers sequentially. There were in vitro studies where researchers dripped antioxidants on lead exposed cells and it seemed to help, so they jumped on the cantaloupe bandwagon, too, but these were test tube studies.

The first population study was published in 1999, and, as you can see at 4:02 in my video, researchers did find that those with high vitamin C levels in their blood tended to have lower lead levels. Youths with the highest vitamin C levels had a nearly 90 percent lower prevalence of elevated blood lead levels compared to those with the lowest vitamin C levels. Now, this was a cross-sectional study, just a snapshot in time, so we don’t know if the vitamin C caused a drop in lead or if perhaps the lead caused a drop in vitamin C. Lead is a pro-oxidant, so maybe it ate up the vitamin C. And who has higher vitamin C levels? Those who can afford to have higher vitamin C levels and eat lots of fruits and vegetables. “It is also possible that higher ascorbic acid levels may represent healthier lifestyles or greater socio-economic status.” Indeed, maybe lower vitamin C levels are just a proxy for being poor, and that’s the real reason for higher lead levels.

There are lots of good reasons to be eating more fruits and vegetables, and we should be eating more spinach regardless, but it would be nice to know if vitamin C actually helps with lead poisoning. And, to know that, we need to put it to the test.

Unfortunately, most of the published interventions are not very helpful, with such titles as “Effects of dietary vitamin C supplementation on lead-treated sea cucumbers,….”  And, there is a surprising number of articles on the effects of vitamin C supplementation on mouse testicles. Why? Because lead may impair male fertility. Indeed, lead workers appear to have a reduced likelihood of fathering children, but this may in part be due to oxidative stress. In that case, how about giving an antioxidant, like vitamin C, and putting it to the test(es)? No, I’m not talking about rat testes or suggesting frog testes. Neither am I proposing crab testes. (I didn’t even know crabs had testicles!) Finally, here’s one to discuss: “Clinical relevance of vitamin C among lead-exposed infertile men.” A study of human men, which I will cover in Yellow Bell Peppers for Male Infertility and Lead Poisoning?.

I’m always conflicted about writing these kinds of blogs and producing videos like Can Vitamin C Help with Lead Poisoning?. I can imagine some just want “the answer,” but those with vested and commercial interests often exploit that natural impulse. This is problem with science in general, but perhaps particularly in nutrition. When it comes to something as life-or-death important as what to feed ourselves and our families we shouldn’t just follow someone’s opinions or beliefs on the matter. We should demand to see the science. That’s what I try to do: Present the available data as fairly and even-handedly as possible, and let you make up your own mind. You can imagine how easily someone could cherry-pick just one or two studies and present a distorted but compelling case for or against, in this case, vitamin C supplements. That’s why I feel it’s important to present each study in their historical context. Stay tuned for the thrilling conclusion in Yellow Bell Peppers for Male Infertility & Lead Poisoning?.

 For those of you who are thinking, Why should I care about lead? I don’t eat paint chips or use leaded gasoline. Anyway, what’s the big deal?, check out my full series of lead videos for information on how we got into this mess and some of the ways we can dig ourselves out:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Sparkling or Still Water for Stomach Upset and Constipation?

“Natural bubbling or sparkling mineral waters have been popular for thousands of years,” but manufactured sparkling water was first “‘invented’ in the mid to late 1700s” when a clergyman suspended water over a vat of fermenting beer. “For centuries, carbonated water has been considered capable of relieving gastrointestinal symptoms, including dyspepsia,” or tummy aches. But we didn’t have good data until a study was published in 2002, which I discuss in my video Club Soda for Stomach Pain and Constipation. Twenty-one people with dyspepsia, which was defined in the study as “pain or discomfort located in the upper abdomen” including bloating, nausea, and constipation were randomized to drink one and a half quarts of either carbonated or tap water every day for two weeks.

Carbonated water improved both dyspepsia and constipation compared to tap water. “Drink more water” is a common recommendation for constipation, but researchers didn’t observe a clear benefit of the added tap water. It seems you need to increase fiber and water rather than just water alone, but sparkling water did appear to help on its own. The study used a sparkling mineral water, though, so we can’t tell whether these effects were due to the bubbles or the minerals.

There’s been a concern that carbonated beverages may increase heartburn and GERD, acid reflux disease, but that was based on studies that compared water to Pepsi cola. Soda may put the pepsi in dyspepsia and contribute to heartburn, but so may tea and coffee in those who suffer from heartburn. That may be partly from the cream and sugar, though, since milk is another common contributor to heartburn. Carbonated water alone, though, shouldn’t be a problem.

Similarly, while flavored sparkling drinks can erode our enamel, it’s not the carbonation, but the added juices and acids. Sparkling water alone appears 100 times less erosive than citrus or soda. So, a sparkling mineral water may successfully help treat a stomach ache and constipation without adverse effects, unless you’re the teenage boy who opened a bottle of sparkling wine with his teeth or the nine-year-old boy who tried to do so on a hot day after he’d shaken it up, actions placing them at risk for a pneumatic rupture of the esophagus.

For more on combating acid reflux, see Diet and GERD Acid Reflux Heartburn and Diet and Hiatal Hernia.

Some of my other videos on beverages include:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

What About Canned Fruit?

Food cans used to be soldered with lead compounds—so much so that people living off of canned food may have died from lead poisoning. Thankfully, this is no longer a problem in the United States. Lead contamination was one of the first priorities of the Food and Drug Administration back in 1906, before it was even called the FDA. Newspapers now have online archives going back a century so we can read about landmark historical events like “FDA Proposes Lead-Soldered Cans Be Banned” from way back yonder in…1993. So even though it was a priority in 1906, the ban didn’t actually go into effect until 1995. Evidently it was complicated because lead solder was “grandfathered” in as a “prior-sanctioned” substance.

Now that the lead is gone, though, are canned foods healthy? It depends primarily on what’s in the can. If it’s SPAM or another processed meat product, for instance, I’d probably pass.

What about canned fruit? We know fruits and vegetables in general may help protect us from dying of cardiovascular disease, and, when it comes to preventing strokes, fruit may be even more protective. But whether food processing affects this association was unknown, as I discuss in my video Is Canned Fruit as Healthy? One study found that unprocessed produce, mostly apples and oranges, appeared superior to processed produce. But that study focused mainly orange and apple juice. It’s no surprise whole fruit is better than fruit juice.

What about whole fruit when it is in a can? Dietary guidelines encourage eating all fruit whether it’s fresh, frozen, or canned, but few studies have examined the health benefits of canned fruit…until now. Canned fruit did not seem to enable people to live longer. In fact, moving from fresh or dried fruit to canned fruit might even shorten one’s life. Therefore, perhaps dietary guidelines should stress fresh, frozen, and dried fruit rather than canned.

Why the difference? While there’s no longer lead in cans these days, there is bisphenol A (BPA), the plastics chemical used in the lining of most cans. BPA can leach into the food and might counterbalance some of the fruits’ benefits. Recently, for example, blood levels of this chemical were associated with thickening of the artery linings going up to the brains of young adults. Canned fruit is often packed in syrup, as well, and all that added sugar and the canning process itself may diminish some nutrients, potentially wiping out 20 to 40 percent of the phenolic phytonutrients and about half of the vitamin C.

Maybe one of the reasons citrus appears particularly protective against stroke is its vitamin C content. It appears the more vitamin C in our diet and in our bloodstream, the lower the risk of stroke. And the way to get vitamin C into the bloodstream is to eat a lot of healthy foods, like citrus and tropical fruits, broccoli, and bell peppers. “Therefore, the observed effect of vitamin C on stroke reduction may simply be a proxy for specific foods (eg, fruits and vegetables) that causally lower stroke” risk. How could the researchers tell? Instead of food, they gave people vitamin C pills to see if they worked—and they didn’t.

This might be because citrus fruit have all sorts of other compounds associated with lower stroke risk, proving that the whole is greater than the sum of its parts. You can’t capture Mother Nature in a pill. It’s like the apocryphal beta-carotene story. Dozens of studies showed that people who ate more beta-carotene-rich foods, like greens and sweet potatoes, and therefore had more beta-carotene circulating in their system, had lower cancer risk. What about beta-carotene supplements instead of whole foods? Researchers tried giving beta-carotene pills to people. Not only did they not work, they may have even caused more cancer. I assumed the National Cancer Institute researcher who did this study would conclude the obvious: produce, not pills. But, no. Instead, the researcher questioned whether he should have tried lower dose pills, alpha-carotene pills, pills with other phytochemicals, or maybe multiple combinations. After all, he said, “[i]t is likely that neither the public nor the scientific community will be satisfied with recommendations concerned solely with foods…”

Check out my other videos on the can-lining chemical BPA, including:

Is fresh fruit really that healthy? See:

Is it possible to get too much of a good thing? See How Much Fruit Is Too Much?.

Now that there’s no more lead in the cans, are there any other ways we’re exposed to the toxic heavy metal? I did a whole series on lead, which you can watch. See also:

I close with yet another screed against reductionism. For more on that, see my videos Why Is Nutrition So Commercialized? and Reductionism and the Deficiency Mentality.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: