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Jul 23, 2012

Antioxidant Balance (part 1 of a 3-part blog series)

A few days ago, I received this question via email from Dagmar in Germany...

“I am looking for the best antioxidant product. Can you help me?”

Here is my reply...

Guten tag Dagmar,

Thanks for your question about antioxidants. When it comes to antioxidant nutrients, it is hard to define a "best" antioxidant because different antioxidants are most effective against different free radicals (the reactive molecules that cause cellular damage).

Before I get into a discussion of specific antioxidant nutrients, let me give you a brief overview of what antioxidants are and why our bodies need them in the right amounts and in the right balance.

What are Antioxidants and Free Radicals?

The term "antioxidant" refers to the activity possessed by numerous vitamins, minerals, and other phytochemicals to serve as protection against the damaging effects of highly reactive molecules known as free radicals. Free radicals have the ability to chemically react with and damage many structures in the body. Particularly susceptible to oxidative damage are the cell membranes of virtually all cells, especially the skin because of its high lipid content and its proximity to ultraviolet rays from the sun.

The free radical theory of aging (and disease) holds that through a gradual accumulation of microscopic damage to our cell membranes, DNA, tissue structures and enzyme systems, we begin to lose function and are predisposed to disease. In certain cases­—such as athletes, people who are outside a lot, smokers, and people who live in areas with high air pollution—oxidative damage may be elevated due to increased production of free radicals during intense activity. Although the body increases its production of its own internal (endogenous) antioxidant enzymes (glutathione peroxidase, catalase, superoxide dismutase), it may be theorized that supplemental levels of dietary (exogenous) antioxidants may be warranted to prevent excessive oxidative damage to muscles, mitochondria, and other tissues.

What is ORAC?

Thousands of studies have clearly documented the beneficial effects of dozens of antioxidant nutrients. Increased dietary intake of antioxidant nutrients, such as vitamins C and E, minerals such as selenium, and various phytonutrients such as açai, grape seed, pine bark, and green tea have all been linked to reduced rates of oxidative damage as well as reduced incidence of chronic diseases such as heart disease and cancer. There is certainly no shortage of nutrients and phytochemicals that possess significant antioxidant activity in the test tube. These test tube measurements of antioxidant potential are often termed “ORAC” measures, which refers to the oxygen radical absorbance capacity. ORAC assays measure the ability of an isolated nutrient to slow the degeneration of a synthetic fluorescent molecule in a test tube. It has no bearing whatsoever on the actual antioxidant benefits of the nutrient in a living system. For example, you could have a compound with very high ORAC values (in the test tube) and very low antioxidant benefits in a human body. Likewise, a nutrient with a “moderate” ORAC score could have profound protective abilities in the body. These differences between the test tube and the human body can be due to a range of factors including the stability of the nutrient, to its digestibility and absorbability, to its transport and delivery to target tissues in the body, and to a host of related factors. Your body is not a test tube, and because no health benefit has ever been associated with ORAC, basing your choice of foods or supplements using claims of ORAC scores is misguided to say the least. As a nutritionist, I prefer to base my recommendations about antioxidant nutrition on actual health benefits observed in human feeding trials—rather than on test tube results that have little bearing on actual human experiences.

At the typically recommended levels, the majority of antioxidants appear to be quite safe. For example, vitamin E, one of the most powerful membrane bound antioxidants also has one of the best safety profiles. Doses of 30–100 IU of natural vitamin E have been linked to significant cardiovascular benefits with no side effects. BUT studies have also linked higher doses of isolated synthetic vitamin E (400–1,000 IU) to worse cardiovascular health—indicating a potential for mega-doses of certain antioxidants to cause oxidation by displacing other beneficial nutrients (vitamin E is actually a “family” of 8 different isomers or types, and our body needs them all).

Vitamin C, another powerful antioxidant, can help to protect and restore the antioxidant activity of vitamin E, and is considered safe up to doses of 500–1,000 mg. Like vitamin E, higher doses of vitamin C are not recommended because of concerns that such levels may cause an "unbalancing" of the oxidative systems and actually promote oxidative damage instead of preventing it. Another popular antioxidant, beta-carotene, is somewhat controversial as a dietary supplement. Although diets high in fruits and vegetables might deliver approximately 10 mg of carotenes daily, these would be a mixture of beta-carotene and other naturally occurring carotenoids. Concern was raised several years ago by studies in which high dose beta-carotene supplements appeared to promote lung cancer in heavy smokers. Those studies provided unbalanced synthetic beta-carotene supplements of 30–60 mg, about 5–10 times the levels that could reasonably be expected in the diet. The moral of the story when it comes to antioxidant nutrition is what I like to call the “Goldilocks” scenario, where both “too little” and “too much” can be unhealthy, but “just right” in terms of amount and balance is associated with optimal health and well-being.

Stay tuned for parts 2 and 3 to the rest of this blog from Dr. Talbott.

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