Can you “C” more benefits by increasing your intake of vitamin C? Absolutely, says Balz Frei, director of the Linus Pauling Institute at Oregon State University and a leading expert in all things vitamin C.
In a new report in Critical Reviews in Food Science and Nutrition, Frei and his colleagues challenge the traditional recommended dietary allowance (RDA) of vitamin C – 75 milligrams for women and 90 milligrams for men – and instead recommend that adults more than double their intake to 200 milligrams per day.
They point out that the RDA of vitamin C has traditionally been based on the prevention of the vitamin C deficiency disease, scurvy. And while we view scurvy as a rare occurrence in modern-day developed countries, numerous studies have found that anywhere from 25% to 33% of Americans are vitamin C deficient, even at the current low RDAs. Among some groups, such as college students and seniors, up to 20% are severely deficient.
Fruit & Vegetable Consumption Falls Short of Goal
And for those of us who do meet the current RDA, that doesn’t mean that we aren’t deficient in vitamin C in amounts that could prove beneficial in preventing chronic diseases.
Current evaluations of vitamins and other nutrients are conducted by medical experts in the same way as pharmaceutical drugs; as a result, the conclusion that there is “no benefit” to increasing the RDA of vitamin C can be faulty. Clinical researchers study micronutrients in Phase III randomized placebo-controlled trials (RCTs), studies designed to assess the safety and efficacy of a drug in lowering disease incident or mortality. But this type of study is not designed to study vitamins and essential nutrients already present in the body and required for normal metabolism, the study authors argue.
One of the main reasons this type of testing is flawed is because it may take years or decades for the effects of micronutrients on chronic disease to appear, and the limited time of short-term clinical studies does not allow for those results to be taken into account.
Instead, Frei and his colleagues cite a number of other studies that suggest that higher vitamin C levels aid in reducing chronic diseases that affect many people across the globe – high blood pressure, chronic inflammation, atherosclerosis and poor immune response which can then lead to heart disease, stroke, and cancer.
What Foods are Rich in Vitamin C?
The study authors also note that laboratory animal studies under controlled conditions and using genetically-identical animals can explain their findings. While critics suggest that the benefits come as a result of better diet, the study researchers point out that rather than fruit and vegetable consumption, some health benefits are more strongly associated to vitamin C plasma levels.
Thus, for very little expense and risk, increased supplementation would provide optimum levels and have potentially dramatic results on overall public health.
“The benefit-to-risk-ratio is very high. A 200 milligram intake of vitamin C on a daily basis poses absolutely no risk, but there is strong evidence it would provide multiple, substantial health benefits,” says Frei.
The Bottom Line
The RDA is defined as the "dietary intake level that is sufficient to meet the nutrient requirements of nearly all healthy individuals in a particular life stage or gender".
Instead of using the RDA, we recommend that patients obtain optimal levels of micronutrients. On a daily basis, obtaining 200-400 mg of vitamin C through dietary and supplemental sources is ideal. However, under times of stress such as following surgery, we recommend a higher level, somewhat closer to 1,000 mg daily.
One of the best ways to obtain vitamin C is by eating fruits & vegetables. Fresh, raw, and ripe fruits and vegetables are the best sources of vitamin C, because cooking and freezing has a detrimental effect on the vitamin C content of food. Citrus fruits, broccoli, strawberries, melon, green pepper, tomatoes, and dark green vegetables are good sources of vitamin C. For more information about which foods are rich in vitamin-C and what types of benefits they offer, see our related article on Vitamin C and Bioflavonoids.
Unless you're eating five to nine servings of fruits and vegetables a day, you'll need to augment your diet with a vitamin C supplement.
Something to keep in mind is that vitamin C is water-soluble, meaning it is not stored in the body and must be replenished each day. Additionally, the body can only absorb a certain amount of this nutrient and then any excess is excreted (our blood becomes saturated with this nutrient at about 200-400 mg per day and concentrations reach a plateau at intakes 1,000-2,500 mg per day).
For this reason, if you’re taking vitamin C in supplement form, you’re better off taking the nutrient in divided doses. For example, VitaMedica’s Multi-Vitamin & Mineral is formulated with 300 mg of vitamin C split equally between the morning (Energy Support) and evening (Bone Support) formulations. Clinical Support Program, which is also divided into a morning and evening supplement, is also formulated in this manner, although the amount of vitamin C is higher (750 mg) to support healing after surgery.
And don’t forget, in addition to the benefits touted by the researchers of this study, vitamin C is a potent antioxidant that helps fight oxidative free-radical damage and aids in the formation of collagen. With both health and anti-aging benefits, increasing vitamin C is a no-brainer.