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Athletes and Vitamin C

By Amanda Turner MS, RD | July 07, 2015

Vitamin C

Vitamin C is a water soluble vitamin that our bodies do not store. Originally vitamin C was known for preventing scurvy, a disease sailors suffered from during long sea voyages. Scurvy causes bleeding tissues, especially of the gums. Vitamin C helped prevent scurvy due to its role in the synthesis of collagen; a protein component in connective tissue within the body. Vitamin C has many other functions within our bodies such as assisting in the synthesis of DNA, bile, neurotransmitters such as serotonin and thyroxine, a hormone that helps to maintain basal metabolic rate and body temperature. Lastly, vitamin C enhances the absorption of iron and is recommended that people with low iron stores consume vitamin C rich foods along with iron sources to help improve absorption.

Perhaps one of the most important functions of vitamin C in athletes is as an antioxidant and immune system enhancer. Exercise increases metabolic function which increases cellular oxidative damage. The benefits of exercise still outweigh the increase of oxidative damage, however, this can be mitigated by increasing antioxidant nutrients, like vitamin C, in the athlete’s daily diet. Other nutrients like vitamin E, selenium and beta carotene (in orange veggies) also help reduce oxidative cellular damage.

Where To Find Vitamin C

The Recommended Daily Intake (RDA) for vitamin C is 90 mg per day for men and 75 mg per day for women. The Tolerable Upper Intake Level (UL) is 2,000 mg per day for adults. Smokers should note that their need for vitamin C increases +35 mg per day compared to nonsmokers. Heat and oxygen destroy vitamin C; therefore fresh fruits and vegetables are the primary sources of vitamin C. Citrus fruits (lemons, limes) are excellent sources of vitamin C. The best way to cook without diminishing the value of vitamin C in the food is by steaming, microwaving, or stir-frying. The following foods are great sources of vitamin C:

Sweet potatoes
Leafy greens
Red and green peppers
1 cup raw green pepper = 120 mg of vitamin C
1 cup fresh strawberries = 100 mg of vitamin C
1 medium orange = 75 mg of vitamin C
8 fl. oz unsweetened grapefruit juice = 95 mg of vitamin C

Vitamin C Supplements

Considering that vitamin C is water soluble, it is difficult to cause toxicity by consuming food sources that contain high amounts of vitamin C. Supplements on the other hand can lead to toxicity by dosing above 2,000 mg per day for a prolonged period of time. Symptoms of vitamin C supplemental toxicity include nausea, diarrhea, nosebleeds, and abdominal cramps. The best way to meet the RDA of vitamin C is by dietary intake (fruits, vegetables) and isn’t necessary to take supplemental forms. Vitamin C deficiency is rare, but can occur. Symptoms of deficiency include bleeding gums, wounds that don’t heal, bone pain and fractures, weakness, and depression.

It is common thought that mega-doses of vitamin C is preventative to illness. Research has shown that supplementing vitamin C when diet is already adequate does not improve sickness rates. However, when an individual notices an initial cold, a slight increase in vitamin C may improve the duration of the illness. Bottom line, eat adequate vitamin C on a regular basis and focus more on high vitamin C foods if you are feeling ill.