 mainstream medicine has long had a healthy skepticism of dietary supplements extending to the present day. Enough is enough. But this commentary in the Archives of Internal Medicine argued we may have gone too far as evidenced by our uncritical acceptance of supposed toxicities, the surprisingly angry, scornful tone found in medical texts with words like careless, useless, defensible, wasteful, and insidious, as well as ignoring evidence of possible benefit. To illustrate the uncritical acceptance of bad news about supplements, they discussed the well-known concept that high-dose vitamin C can cause kidney stones. But just because something is well-known in medicine doesn't mean it's necessarily true. They couldn't find a single reported case. We've known that vitamin C is turned into oxalates in the body, and if the level of oxalates in the urine gets too high, kidney stones can form. But even at 4,000 milligrams of vitamin C a day, that's like a couple gallons of orange juice worth, urinary oxalates may not get very high, but there may be rare individuals that have increased capacity for this conversion into oxalates, and so a theoretical risk of kidney stones with high-dose vitamin C supplements was raised in a letter printed in a medical journal back in 1973. OK, but when it's talked about in the medical literature, they make it sound like it's an established phenomenon. Here's a reference to seven citations supposedly suggesting an association between excessive vitamin C intake and the formation of oxalate kidney stones. Let's look at these cited sources. OK, there's the letter about the theoretical risk. That's legit. But this other citation has nothing to do with either vitamin C or kidney stones, and the other five citations are just references to books, which can sometimes be OK if books cite primary research themselves. But instead, there's like this circular logic where the books just cite other books that cite that theoretical risk letter again. So it looks like there's a lot of evidence, but they're all just expressing this opinion with no new data. Now by that time there were actually studies that followed populations of people taking vitamin C supplements and found no increased kidney stone risk among men. And later women, same thing. So you can understand this author's frustration that vitamin C supplements appear to be unfairly villainized. The irony is that now we know that vitamin C supplements do indeed appear to increase kidney stone risk. This population of men was followed further out, and men taking vitamin C supplements did indeed end up with higher risk. Confirmed now in a second study, though also of men, we don't know if women are similarly at risk, though there's now also been a case reported of a child also running into problems. What does doubling of risk mean exactly in this context? That means those taking like 1,000 milligrams a day of vitamin C may have a 1 in 300 chance of getting a kidney stone every year instead of a 1 in 600 chance, which is not an insignificant risk, 1 in 300. Kidney stones can be really painful. So they conclude that, look, since there's no benefits in some risk, better to stay away. But there are benefits. Taking vitamin C just when you get a cold doesn't seem to help, and regular supplement users don't seem to get fewer colds, but when they do get sick, they don't get as sick and get better about 10% faster. And those under extreme physical stress may cut their cold risk in half. So it's really up to each individual to balance the potential common cold benefit with a potential kidney stone risk.