Saturday, October 23, 2010

Oxidative Stress Primer

By Tereza Hubkova, M.D.

What about oxidative stress? What is it? In simple words, oxidative stress is the damage done to our cells, tissues, and organs by free oxygen radicals. Free oxygen radicals are chemically-reactive molecules containing oxygen. We know that free oxygen radicals are a byproduct of eating food and breathing oxygen—something we obviously all have to do to stay alive. Breathing less oxygen is not a reasonable option. So, the questions remains, how can we minimize the damage done by free oxygen radicals, and the premature aging that results? There are a couple ways to do this. The most obvious way is likely by cutting down on the calories you eat. Most Americans eat more calories than they need, which explains why we tend to be such a chunky nation.

We know for a fact that restricting caloric intake extends our lifespan. Studies have been performed on several animal species and the theory has been validated many times over.  Where are we going with this? Are we writing a book nearly entirely about food and eating proposing right from the beginning to eat fewer calories? No. That wouldn't get us far.

At this point we’ll simply state that it appears that certain foods mimic the effects of calorie-restricted diets on our health. Yes, you read correctly: certain foods have the same positive effects on our bodies as that of restricting calories. But don’t use this as an excuse to overeat.

What more can you do to minimize the impact of free oxygen radicals? Likely you've heard of antioxidants: berries, green tea, dark chocolate, vitamins E and C? Their job is just that, to catch and neutralize the free oxygen radicals before they can do too much harm to us. That’s one of the many reasons why you should eat eight to ten servings of fruits and vegetables a day.

Another source of oxidative stress is environmental toxins: from cigarette smoke to car exhaust. You may have noticed how much faster smokers seem to age. Next time you see one, look at their skin. Chances are it looks years older than that person’s real age. Worse still, inside their body you would see old and dirty lungs, and an old heart with stiff arteries—all results of increased oxidative stress.

You can have oxidative stress from the pesticides in your food as well. Parkinson’s disease, which is one example of many degenerative diseases of the nervous system, is more common in people who spray pesticides, and among people who drink a lot of conventionally produced milk. The fat in milk is storage for the fat-soluble and oxidative stress promoting chemicals.

That is why, in our kitchen, and within this book, we use mostly organic produce, including organic, hormone-free and antibiotic-free dairy and meats. It is also important to know which foods enhance our body’s ability to get rid of the toxins that have already made their way in.

Oxidative stress is damage caused by free oxygen radicals. These free oxygen radicals are byproduct of energy production by burning the calories we eat using the oxygen we breath. In essence, they are atoms and molecules with unpaired electrons, which makes them very chemically reactive, or aggressive, trying to get rid of their extra electron by passing it like a hot potato to other molecules. This process is very damaging to our cells, proteins, lipids, even DNA, and has been linked to a variety of degenerative diseases, such as atherosclerosis, Parkinson’s disease, heart failure, myocardial infarction, Alzheimer’s dementia, chronic fatigue syndrome, etc.

Other then oxygen and calories eaten, oxidative stress is also affected by environmental pollution, smoking and sunshine. Short term oxidative stress can be actually beneficial, such as when you immune system is killing deadly bacteria and viruses, or short bursts of oxidative stress from exercise. This interesting process is called hormesis (low dose of a substance is beneficial while a high dose of the same substance is harmful or even toxic).

You can minimize the damaging oxidative stress my minimizing the amount of calories you eat (eating just as much calories as your body needs to function, and not more – do not overeat), minimize exposure to toxins (eat mostly organic foods), and learn how boost inactivation and elimination of toxins from your body.

To counteract oxidative stress our body produces variety of antioxidants, which (by accepting the unpaired electron) neutralize the process. However, our internal production of antioxidants is not enough, and we rely heavily on their intake in our diet. This is one of the reasons we recommend you to eat 8-10 servings of fruits and vegetables daily. The ability of various foods to neutralize free oxigen radicals is measured in ORACs.

Food with the highest ORAC (Oxygen radical absorbance capacity) are best able to neutralize your free oxygen radicals, thus minimizing the damage from oxidative stress in your body (thus, literally, slowing down aging).

Here are some foods with their ORAC values per serving size:

wild blueberries (1 cup)…… 13727
red kidney beans (½ cup)…13259
cranberries (1 cup)…8983
artichoke hearts (1 cup, cooked)…7904
prunes (½ cup)…7291
raspberries (1 cup) … 6058
pecans (1 oz)…5095
russet potato (cooked)…4649
galla apple… 3903

In addition to focusing on having plentiful antioxidants, we recommend having a variety of colors on your plate. Each color of a fruit or vegetable represents different phytonutrients, that have additional benefits beyond the ORAC value of that food.

So, let’s look at some of the food antioxidants from yet another angle:

Antioxidant vitamins: vitamins A, C, and E

Vitamin A found in dark green, yellow and orange vegetables and fruits, and is hought to protect them (and thus those who eat them) from sun damage. These are your carrots, squashes, broccoli, sweet potatoes, tomatoes (also containing beneficial lycopene), kale, mangoes, oranges, cantaloupes, peaches and apricots, to name a few.

Vitamin C is found mostly in citrus fruits, parsley, green peppers, broccoli, green leafy vegetables, black currants, berries, cabbage and tomatoes.

Vitamin E is found mostly wheat germ, nuts, seeds, whole grains, green leafy vegetables, kiwi, and fish oils. It is fat soluble thus protecting from oxidative stress mostly lipids, including your cholesterol and brain). The most harmful kind of cholesterol is oxidized small LDL, that means LDL exposed to oxidative stress.

Lutein protects mostly your eyes from oxidative stress (helping to prevent cataracts and macular degeneration, one of the reasons from blindness in this country). Food highest in lutein/zeaxeathain are kale, spinach, garden peas, zucchini, Brussels sprouts, yellow corn, saffron, paprika and kiwi.

Lycopene gives the red color to tomatoes, carrots, watermelons and papaya (but not strawberries or cherries). It is one of the few nutrients, whose ability to be absorbed is greatly increased by cooking it. It may help to reduce some kinds of cancer, particularly prostate cancer.

Flavonoids are present in many berries as well as tea and coffee. Many flavonoids were found to have anti-allergenic, anti-carcinogenic, anti-inflammatory and anti-microbial properties in vitro (in test tube).

THIS SITE DOES NOT PROVIDE ANY MEDICAL ADVICE. Information on this website is provided for informational purposes only and is not intended as a substitute for the advice provided by your physician or other healthcare professional or any information contained on or in any product label or packaging. You should not use the information on this website for diagnosing or treating a health problem or disease, or prescribing any medication or other treatment. You should always speak with your physician or other healthcare professional before taking any medication or nutritional, herbal or homeopathic supplement, or adopting any treatment for a health problem.

No comments:

Post a Comment