Review finds marine omega-3s and astaxanthin-like antioxidants effective for heart and eye prevention 11/21/2005
According to a leading analytical firm, the U.S. health care system could save up to $5.6 billion over the next five years if people aged 65 or older consumed supplements or foods rich in omega-3 essential fatty acids, lutein, and zeaxanthin.
This is the second such report performed by the Lewin Group on behalf of a trade association called the Dietary Supplement Education Alliance (DSEA).
A Lewin Group study released in 2004 concluded that long-chain marine omega-3s (EPA and DHA) enjoy good evidence of efficacy in preventing cardiovascular problems.
For the new study, the Lewin Group reviewed existing research on two supplements with regard to their preventive health potential in two different areas:
- The impact of long-chain marine omega-3 fatty acids on coronary heart disease (CHD).
- The combined effects of two carotenoid-class antioxidants—lutein and zeaxanthin—on age-related macular degeneration (AMD). As we will explain in more depth below, lutein and zeaxanthin are very close structural and functional cousins to astaxanthin: a more potent antioxidant that’s abundant in wild salmon, which has displayed strong protective effects on animals’ eyes.
What the study showed
The Lewin Group’s expert analysts estimated that if senior Americans took 1,800 mg of omega-3s per day it would reduce the rate of CHD among adults over 65 and prevent more than 384,000 hospitalizations and physicians' fees, for a five-year savings of $3.1 billion.
They also estimated that the five-year net savings from reduced progression of AMD would total $2.5 billion.
The Food and Drug Administration (FDA) previously granted permission for food and supplement companies to make qualified health claims for use of omega-3 fatty acids to promote heart health, and a proposal to allow a claim for lutein and eye health is under review at the FDA now.
In response to the news, Rep. Chris Cannon (R-Utah) announced the creation of a bipartisan caucus on dietary supplements, which he will co-chair with Rep. Frank Pallone (D-N.J.). Rep. Cannon introduced legislation earlier this year to allow the costs of some dietary supplements to be offset by Flexible Spending Accounts (FSAs) and Health Savings Accounts (HSAs).
Should we believe this study?
Although the Lewin Group enjoys a reputation for expertise relevant to this study, they are consultants paid by an industry that stands to benefit from positive findings, so one must view their conclusions with some skepticism.
The key question is not whether the Lewin Group’s savings estimates are precisely accurate, since that is impossible to know. Instead, it is important to ask whether the premise—that omega-3s, lutein, and zeaxanthin exert substantial preventive health powers—is credible.
And, for our purposes, it is important to ask whether their findings vis a vis lutein and zeaxanthin for eye health apply to ingestion of astaxanthin—a closely related carotenoid-class antioxidant that's abundant in wild salmon.
Omega-3s enjoy ample evidence of efficacy
It is easy to accept the marine omega-3 findings at face value, given the large, fast-growing body of evidence indicating that they improve circulatory health and help prevent heart attacks and strokes.
To view the many articles we’ve written about marine omega-3s and heart health, click here.
Do the lutein-zeaxanthin findings apply to astaxanthin?
Cataracts and AMD result in large part from the cumulative effects of a lifetime of light-induced oxidation of the lens and retinal tissues of the eye, respectively. Both the lens and the retina are exposed continually to light and oxygen, which work together to generate oxygen free radicals.
In cataract formation, free radicals impair crystalline proteins and damage proteolytic enzymes that would normally remove the damaged proteins. In the retina, free radicals oxidize (damage) the membranes of vital photoreceptor cells.
The human body uses its own antioxidants—glutathione peroxidase, superoxide dismutase, catalase, vitamins E and C, and melanin—to prevent oxidation of its eye tissues.
But dietary lutein and zeaxanthin are our key eye-health allies, as they concentrate in the macula, absorb blue light, quench damaging oxygen free radicals, and cannot be made by the body.
The results of population studies suggest that diets high in lutein and zeaxanthin (from spinach, kale, and other leafy green vegetables) reduce the risk of cataracts and AMD. And lutein supplements can increase the macular pigment density in the eye, which may reduce the risk of AMD.
It is the antioxidant power of lutein and zeaxanthin that makes them such valuable allies in the fight to prevent cataracts and age-related macular degeneration (AMD): the two leading causes of vision loss and blindness among the elderly.
All three antioxidants—lutein, zeaxanthin, and the astaxanthin in salmon—belong to a class of carotene-type compounds called hydroxyl-group xanthophylls.
The astaxanthin molecule is very similar to lutein and zeaxanthin, and, like them, it concentrates in eye tissues.
However, astaxanthin is a much stronger antioxidant than lutein or zeaxanthin, and the results of test tube and animal research conducted to date indicate that it holds great promise as a key dietary ally against AMD and cataracts: a role it also performs in salmon.
As yet, there are no human clinical studies testing the preventive powers of astaxanthin against AMD or cataracts, but evidence from rodent studies shows that dietary astaxanthin concentrates in the macula, protects the retina from high intensity light, and ameliorates retinal injuries.
Given these facts, it seems reasonable to hypothesize that dietary astaxanthin could be a valuable ally in the fight to keep our eyes healthy well into old age.
And, since cataracts and AMD develop gradually over many decades, it makes sense to start eating salmon early in life and continue the habit over a lifetime.
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