In the January issue of the American Journal of Clinical Nutrition, there was a study on the long-term effects of a high-protein diet.
Over 64 weeks, the researchers found that there was a direct relationship between weight loss and protein intake. The more protein the people ate, the more they tended to lose weight. People that were in the upper third of protein intake (88 grams per day) lost an average of 14 pounds, while people with lower protein intakes lost half that amount.
So, chalk up another point for protein.
In the same journal, Spanish researchers reported vitamin C supplementation (1 gram per day) to interfere with endurance exercise performance. The reason? Endurance exercise causes oxidative stress on the body. This stress is one of the things that causes your body to adapt to the endurance exercise, improving oxygen delivery to your muscles and making the exercise easier. When you take an antioxidant like vitamin C in high doses, you can interfere with this adaptive process.
I'd say we're a bit vitamin C-crazy in our society. People chew on vitamin C tablets like gum. We think vitamin C is a cure-all for a cornucopia of conditions from colds to cancer to Carrottop.
However, it's all a bunch of Crap with a capital C.
Let me give you an example that you can C clearly. We all like to pop tons of vitamin C when we have a cold. This is supposed to make our symptoms better...or make our cold shorter...or something...right?
Nope.
This has been repeatedly studied by a number of scientists. A very nice review of the research on vitamin C and colds can be seen here. In the general population, megadoses of vitamin C do not prevent colds. Vitamin C also doesn't shorten the duration of your cold, or make your cold less severe.
Vitamin C pretty much does nothing for colds.
The only people that vitamin C has been found to benefit are marathon runners, soldiers, people in the arctic, or other situations of extreme physical stress. In these conditions, vitamin C does help prevent colds. Now, I'm talking extreme physical stress here....I'm not talking about that workout that your personal trainer put you through that made you puke.
So why is vitamin C so popular? Probably because of the late Linus Pauling, who was the most famous pusher of vitamin C in the 70's and 80's.
Linus Pauling may have won two Nobel Prizes, but they weren't for his work on vitamin C. Most things that Pauling said about vitamin C were simply wrong. In fact, one study showed that megadoses of vitamin C could actually promote skin cancer.
Don't get me wrong. Vitamin C certainly has health benefits. But there's no benefit to taking doses in gram amounts. In fact, at a dose of 200 milligrams, your blood levels are already saturated, so anything more than 200 mg doses is a waste.