A few comments on Vit C intake: 99% of C is manufactured in China. I would eat nothing made in China. 2. Vit C is metabolized to oxalate which in combination with calcium forms calcium oxalate crystals, the basis of some forms of stones in humans. 3. Vit C is an antioxidant, having other health benefits. 4. Taking massive doses probably leads to an increase in stone incidence in susceptible people. 4. Massive doses of C are simply excreted in the urine, most unmetabolized. 5. Vit C’s effect on fighting the common cold is highly controversial and is probably of negligible benefit. 6. Vit C will prevent scurvy based on both experimental proof and 100% response rate in human clinical trials. In summary, pertaining to this study, Vit C most likely does lead to an increase incidence of kidney stones in susceptible populations of people.
Data supporting the claim that "anti-oxidants" have health benefits is very weak. Data is now emerging that suggests that oxygen and oxygen radicals have health benefits and depleting oxygen radicals is not good.
I give it 3 years for the FDA to nuke all those "anti-oxidant" health claims.