Vitamin C

Here are a few things you need to know about vitamin C.

■ Humans are one of the few creatures who cannot make their own vitamin C, and therefore, need to eat some. The only other creatures that cannot make their own vitamin C are primates, guinea pigs, locusts, capybaras, Indian fruit bats, trout, salmon and certain birds.

■ The government recommends adults eat just under 100 mg of vitamin C a day to avoid overt deficiency, but many experts argue that higher levels of intake would be more optimal for most. Those who smoke, are pregnant, have an illness, or who are very physically active require even more vitamin C.

■ Vitamin C is essential for the formation of three very important substances in the body. Oxytocin, aka the “love hormone,” is made with the help of vitamin C. Collagen, which is essential for joints, skin, hair, nails and more, as well as norepinephrine, a hormone made by the adrenals in response to stress, depend on vitamin C for production.

■ The best and most common sources of vitamin C are fruits and vegetables, especially those that are fresh and lightly cooked. Citrus is the most well known of the vitamin C superstars with amounts varying between varieties. Navel oranges and clementines have some of the highest levels of vitamin C by weight (about 70 mg in a medium-sized navel), while the other fresh varieties such as mandarins, tangerines, satsumas and grapefruits have about half that amount.

■ Five servings (about 2½ cups) of a variety of fruits and vegetables should average to about 150 to 200 mg of vitamin C, especially when vitamin C-rich fruits or vegetables are eaten. Some of the best sources of vitamin C are citrus, kiwi, papaya, guava, strawberries, peppers, dark leafy greens and broccoli.

■ Native Americans who lived in cold climates with limited plant foods figured out how to prevent scurvy by eating the adrenal glands and organ meats of animals they hunted. The adrenal gland concentrates vitamin C because it is used there to make norepinephrine. The liver also has a moderate amount of vitamin C.

■ Scurvy is the disease caused by severe deficiency of vitamin C. Scurvy causes unexplained bruising, bleeding gums, joint pain, corkscrew shaped body hairs and lethargy. Many of the symptoms of scurvy are related to vitamin C’s role in collagen formation. Historically, sailors developed scurvy on long voyages before it was discovered that citrus fruit could prevent it. Just 10 mg of vitamin C a day can prevent scurvy.

■ Less severe vitamin C deficiency can result in problems that include frequent illness, osteoporosis, and may even contribute to the development of chronic diseases such cancer, heart disease and diabetes. There is reason to believe suboptimal vitamin C levels can lead to lethargy, lack of focus and emotional apathy because of the relationship between vitamin C and oxytocin, which is a hormone responsible for feelings of emotional connectedness.

■ The jury is still out on the influence of vitamin C and the common cold. There is evidence that extra vitamin C can help decrease incidence of the cold in those who are highly physically active or very stressed, but as for the rest of us, the evidence is mixed. However, taking extra vitamin C upon the development of cold or flu symptoms does seem to help shorten the duration of symptoms, sometimes significantly.

■ Most adults can safely supplement with vitamin C up to 2 grams a day, if desired, with a few special exceptions. Those with hemochromatosis (an iron overload disorder) should not supplement with vitamin C since it will enhance iron absorption. Also, there is some concern that supplementing with vitamin C could exacerbate oxalate-based kidney stones in susceptible individuals.

■ If you’re making smoothies or juicing greens, the vitamin C content is highest if you drink what you make right away. If you need to store your drink in the refrigerator for a while, add something acidic to help stabilize the vitamin C and keep it from being degraded and lost during storage.

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