Tuesday, May 18, 2010

Nutrition ABCs: Anti-Oxidants

Photo taken from the BC Blueberry Council Website http://www.bcblueberries.com/

I picked up Leslie Beck's revised The Complete A-Z Nutrition Encyclopedia: A Guide to Natural Health last week and have been devouring it since...then I got inspired to finally do a blog post. It has been such a busy year that my goal of one post a week has quickly gotten away from me. But change is on the horizon so I am looking forward to putting a lot more content on here for you all to enjoy!

I thought it would be fun to do my own little encyclopedia on topics that I find I get frequent questions about - so let's start at the beginning!

A is for anti-oxidants...

Anti-oxidants are still a hot topic after all of these years and yet, many of us still don't fully understand them. So what is an anti-oxidant?

Anti-oxidants are substances that are either naturally occurring in our bodies or occur in nature which help to combat oxidative damage to our tissues. Oxidative stress from normal body metabolism, stress, lifestyle choices, intense exercise and more creates free radicals which have the potential to wreak havoc on our cells. Free radicals are unstable molecules that cause damage to our body's proteins, cells and DNA as they attempt to stabilize themselves.

Fortunately, we come equipped with a built in anti-oxidant defense system to mitigate the fallout; however, our internal defenses can be overwhelmed when the oxidative stress is too great. When damage accumulates over time we see the results in chronic disease and the signs and symptoms of aging. This is where dietary anti-oxidants come into play.

Anti-oxidants in food come in many forms...here are a few examples:

- phytochemicals like anthocyanins in blueberries and pomegranate
- vitamins like A, C & E
- minerals like selenium
- enzymes like superoxide dismutase

So how do we evaluate which anti-oxidants are best for us or which foods are the best source of anti-oxidants?

This is a challenge as our knowledge of how anti-oxidants work in the body is still fairly new. Does an anti-oxidant work on its own or does it work best in tandem with another? In the case of vitamins C and E, one "recharges" the other and so they work best together. Is more of an anti-oxidant better? In the case of many, including vitamin C, too much vitamin C can actually act as a pro-oxidant and therefore cause damage instead of preventing it. If we isolate an anti-oxidant from food, does it work the same as when we consume it in food? Maybe...as you can see, nutritional science is still playing catch up with the gifts that nature has provided us.

One method of evaluating the levels of anti-oxidants in foods is their Oxygen Radical Absorbing Capacity, or ORAC. Foods can be measured in terms of their ORAC value per 100 grams of food. Useful in some ways, ORAC values can tell us that spinach is a healthier choice than iceberg lettuce as it has a higher ORAC value or that the lowly prune carries just as much of an anti-oxidant punch as blueberries. But ORAC levels don't tell us how that capacity will translate into supporting our body's anti-oxidant defense system or what kind of anti-oxidants a food contains.

Should you take anti-oxidant supplements?

It depends...in the case of vitamin E, we have learned that supplementing does not appear to have the health benefits we once expected and for certain populations, like smokers, it can actually do more harm than good. However, vitamin E rich foods such as whole grains and raw seeds carry numerous health benefits. Beta carotene supplements may also not be the nutritional star we were hoping. Other anti-oxidants, like Coenzyme Q10 and EGCG from green tea, are well studied and can be beneficial for some.

So what is my best source of anti-oxidants?

Beautiful, natural food! A plant based diet that maximizes fresh fruits and vegetables, intact whole grains, legumes and raw nuts and seeds will provide you with a wide variety of anti-oxidant nutrients for better health. These nutrients will be complexed in synergistic combinations, the way mother nature intended and provide numerous other nutrients such as fibre.

Any foods I should try to eat more of due to their anti-oxidant benefits?

Here is a just a handful of the many plant world superstars...green tea, blueberries, pomegranates, dark leafy greens like kale and spinach, raw nuts and seeds like walnuts, Brazil nuts and pumpkin seeds, citrus fruits, tomatoes, turmeric and fresh green herbs like thyme and basil.

To your health,