|Ambersweet oranges, a new cold-resistant orange variety. USDA photo. Image Number K3644-12. (Photo credit: Wikipedia)|
Vitamin C has been studied for many years. It participates in numerous biochemical reactions, suggesting that vitamin C is important for every body process from bone formation to scar tissue repair. We probably know it best as an immune-system booster, found in over-the-counter cold prevention products. In fact, the vitamin is associated with helping to shorten cold duration and severity in those that are deficient.
But how does the vitamin help with exercise? In a recent study, researchers found that men supplemented with the vitamin increased their physical activity levels by almost 40%. The study first focused on cold symptoms, so perhaps shortening the length of upper respiratory infection symptoms simply helped the men get back on their feet again.
Other research suggests that vitamin C play other important roles as well. Vitamin C may also help those that suffer from exercise-induced asthma. It is estimated that 10% of people are affected by this condition in which short term physical stress leads to coughing, wheezing and shortness of breath. Oral vitamin C may reduce bronchoconstriction caused by exercise by nearly 50%.
Interestingly, blood and plasma levels of vitamin C are diminished in those who exercise, indicating a need for improved intake. While the current Dietary Reference Intakes for vitamin C have been established at 90 mg for men and 75 mg for women, it is suggested that athletes aim for at least 100 mg per day. Some studies suggest that more elite athletes take up to 300 mg/day.
With Vitamin C, though, keep in mind that more is not always better. Doses greater than 1500 milligrams oversaturate the body pool and are excreted in the urine. It is much better to take multiple small doses during the day rather than one large dose. Dietitians often recommend 500 mg twice daily as an adequate amount for repletion of depleted stores.
Most experts recommend getting vitamin C from a diet high in fruits and vegetables (especially citrus fruits) rather than taking supplements. Fresh-squeezed orange juice or fresh-frozen concentrate is a better choice than ready-to-drink orange juice as the fresh juice contains more active vitamin C. Other fruits and vegetables rich in vitamin c include Papaya, Bell Peppers, broccoli, Brussels sprouts, Strawberries, Pineapple, Kiwifruit, Cantaloupe, and Cauliflower.
Johnston CS1, Barkyoumb GM2, Schumacher SS3. Vitamin C supplementation slightly improves physical activity levels and reduces cold incidence in men with marginal vitamin C status: a randomized controlled trial. Nutrients. 2014 Jul 9;6(7):2572-83. doi: 10.3390/nu6072572.
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