Do not expose foods to air, light or water for prolonged periods. For maximum C content, eat vitamin-C foods raw. The unabsorbed vitamin stays in the small intestine, attracting water until diarrhea results. The average individual will achieve complete saturation at intakes of 250 mg a day. For individuals suffering from recurrent kidney stones or gout, calcium oxalate kidney stones may develop.
Large doses can also alter some laboratory tests.
Other Facts Vitamin C is water-soluble. Iron absorption is enhanced only if 50 mg of vitamin C is consumed at the same meal with iron. Int J Sport Nutr, March 1997. Respiratory infection and vitamin C. High intake of vitamin C may protect against respiratory infection. Vitamin C's response to infection may be the pathway in which it appears to protect against cardiovascular disease as well.