In our previous article, we delved into the chemical nature of free radicals and antioxidants. Now that we know how they work, we need to know where we can get them in our diet. Antioxidants are naturally occurring and readily available in many fruits, vegetables and grains. In this article, we will be looking at the most prevalent antioxidants and common dietary sources for each. In addition, we will look at the health effects associated with their consumption.

Vitamin C

This is the one people are the most familiar with. Foods that contain high levels of vitamin C include citrus fruits (such as oranges, mandarins, grapefruit and lemons among others), strawberries, tomatoes, broccoli and even potatoes. Vitamin C is considered one of the safest and most effective nutrients. The more we study vitamin C, the better our understanding of its effects on our health becomes. Vitamin C’s effects are wide ranging and include boosting our immune system which protects from cardiovascular disease, prenatal health problems, cancer, stroke, eye diseases, and even skin wrinkles.[1]

Overall, vitamin C is definitely a friend when it comes to consuming antioxidants. First of all, it is readily available all year round. Second, it is a water-soluble vitamin, which means that excess vitamin C will simply be removed by the body with normal waste matter. That being said, do not get too carried away taking vitamin C supplements. As with most vitamins, it has the potential to have some negative side effects if taken in excessive amounts. However, when consumed in food, or in moderate supplementation, there is no danger of overdosing on vitamin C. [2]

Vitamin E

A common fat soluble antioxidant, vitamin E is especially beneficial in its work of counteracting oxidation in the lungs. As one can imagine, the lungs are naturally highly exposed to oxidation because they intake oxygen. White blood cells also rely heavily on vitamin E to help keep the body healthy. Common sources of vitamin E are vegetable oils (such as safflower oil and canola oil), wheat germ, whole-grains, seeds, nuts, and peanuts.

Just like with vitamin C, there is no known negative side-effect to getting “too much” vitamin E as long as it is from natural sources and not from supplements. Studies have shown that vitamin E in isolated supplement forms can actually promote disease rather than prevent it. Although vitamin E occurs naturally in vegetable oils, it is best consumed in raw foods or oils because many nutrients are lost when the oils are fried.

Selenium

Selenium is a trace mineral so the body only needs it in small amounts. Selenium produces enzymes that work together with vitamin E to counteract oxidation. Therefore it is important to get this mineral in one’s diet. It is found in nuts and grains as well as in fruits and vegetables grown in soil rich in selenium. Not all soil is selenium rich, but since fruits and vegetables bought at the grocery store tend to come from all across North America, they should be sufficiently varied to supply the body’s selenium needs.[3]

Selenium appears to be especially important for men’s health because men with sufficient levels of selenium in their bodies are less likely to have prostate cancer than those with low levels of selenium. However, if supplements of selenium are taken in excess it may actually increase the risk of skin cancer. In addition, prolonged side effects of excess intake may include hair loss, diarrhea, and nerve abnormalities. However, as we have seen with the antioxidants found in vitamin C and vitamin E, there is no risk found when selenium is consumed in its natural plant form such as in fruits or vegetables.

Flavonoids

Our next antioxidants are actually phytochemicals, which are biologically active chemical compounds that are found in plants. In the past they were known as vitamin P, but the term has fallen out of use. Flavonoids are antibacterial in nature and may also play a role in cancer prevention. Fortunately, they are easy to obtain as they are found in the largest variation of foods. Some examples of food sources include: berries, celery, chocolate, citrus fruits, olives, onions, oregano, purple grapes, soybeans, vegetables and whole wheat.

Not a whole lot is known yet about the role of phytochemicals in preventing disease or if they have the potential to be toxic when consumed in high concentrations, such as in supplements. There is not even a consensus as to a daily recommend intake of this nutrient. Until recently, phytochemicals were not thought to be very important in maintaining one’s health. However, studies done in several countries indicate that eating diets rich in phytochemicals found in the flavonoid family may result in fewer deaths from cancer, heart disease, and heart attacks.[4]

Beta-Carotene

A precursor to vitamin A that is commonly associated with carrots, beta-carotene is a red-orange colored pigment found in carrots and other foods such as spinach, sweet potatoes, winter squash, and broccoli.[5] Like other antioxidants, beta-carotene has been linked to stronger immune health and a lower risk of cancer and heart disease.

Eating beta-carotene in normal amounts (such as in the form of fruits and vegetables in a daily dietary intake) does not have any negative effect on health. However, very high beta-carotene consumption has the capacity to temporarily turn a person’s skin an orange color. This pigmentation is harmless and is the result of beta-carotene being a fat-soluble vitamin that is therefore stored in the fat located just below the surface of the skin. Additionally, some studies reveal that taking increased amounts (through supplementation) of beta-carotene has the potential to assist cancer growth rather than inhibit it.[6]

Dietary Recommendations

As you can see, there are a large variety of antioxidants found in the environment that are readily accessible for human consumption. This means we should not have any trouble helping our bodies counteract disease causing oxidation.

Overall, dietetic experts recommend consumption of at least 2 cups of fruit and 2.5 cups of vegetables daily.[7] It is best for the health of the body to eat a vast array of fruits and vegetables – we should not limit ourselves to only two or three kinds. Eating a variety of foods not only ensures a well-balanced diet but also protects the body by providing multiple forms of antioxidants.  A good tip is to consume as colorful a diet as possible in order to get the best array of nutrients, antioxidants, and phytochemicals.

When eaten in variety and large enough quantity, antioxidants protect the body from the harmful effects of oxidation. The oxygen in our environment is meant to be healthful to our body, and is not our enemy. As long as we have antioxidants working to counteract any of the negative side-effects that come as a result of our body’s natural functioning. So be sure to eat your fill of antioxidants today!

 

References:

[1] “The Benefits of Vitamin C”. Web MD. http://www.webmd.com/diet/features/the-benefits-of-vitamin-c

[2] Sizer, Frances. Nutrition: Concepts and Controversies. Tenth edition. 2006. Thomson Higher Education. Belmont, CA.

[3] Ibid.

[4] Ibid.

[5] Antioxidants.  American Dietetic Association. http://www.eatright.org/Public/content.aspx?id=6792&terms=antioxidants

[6] Stahl, P. The antioxidant conundrum: Two recent studies point in different directions. American Dietetic Association.Journal of the American Dietetic Association, 100(5), 510-510.

[7] Antioxidants.  American Dietetic Association. http://www.eatright.org/Public/content.aspx?id=6792&terms=antioxidants


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Desiree Kröper

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