Your built-in dose calculator Q: Is the recommended daily allowance of vitamin C a good daily dose for adults? Dr. Wright: The recommended daily allowances (now called dietary reference intakes, or DRIs) established by los Federales are woefully inadequate for most nutrients, including vitamin C. The current RDA/DRI for adults is 75-90 milligrams per day. However, research shows that many of vitamin C's benefits require much higher doses. For example, in 1992 researchers from UCLA published the results of a 10-year study involving over 11,000 adults between the ages of 25 and 74. They concluded that men who took 800 milligrams of vitamin C daily lived six years longer than men who took only 60 milligrams daily. I generally recommend taking "bowel tolerance" doses of vitamin C. Bowel tolerance is the "copy Nature" concept of vitamin C supplementation originated by Nobel Prize winner Linus Pauling. It means taking as much supplemental vitamin C as your body can absorb. Your gastrointestinal tract lets you know how much you're absorbing, and then how much is too much by producing excess gas. If you don't cut back on the amount you're taking, the excess gas will continue to escalate into diarrhea. Many healthy adults 40 years old or older can take 1 to 2 grams of ascorbic acid twice a day with no excess gas, but when you're "coming down with something," or when you're under significant stress, you can take considerably more. With the flu or very bad colds, many people can take 5 to 10 grams two or three times daily before their bodies tell them they're taking too much. | 
