Q. I don't understand the difference between omega 3 and omega 6 fatty acids. I know we're supposed to increase consumption of the omega 3s. What about omega 6?
A. Omega 3 and omega 6 are types of essential fatty acids — meaning we cannot make them on our own and have to obtain them from our diet. Both are polyunsaturated fatty acids that differ from each other in their chemical structure. In modern diets, there are few sources of omega 3 fatty acids, mainly the fat of cold-water fish, such as salmon, sardines, herring, mackerel, black cod and bluefish. There are two critical omega 3 fatty acids — eicosapentaenoic acid (called EPA) and docosahexaenoic (or DHA) — that the body needs. Vegetarian sources, such as walnuts and flaxseeds, contain a precursor omega 3 (alpha-linolenic acid, called ALA) that the body must convert to EPA and DHA. EPA and DHA are the building blocks for hormones that control immune function, blood clotting, and cell growth as well as components of cell membranes.
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By contrast, sources of omega 6 fatty acids are numerous in modern diets. They are found in seeds and nuts, and the oils extracted from them. Refined vegetable oils, such as soy oil, are used in most of the snack foods, cookies, crackers and sweets in the American diet, as well as in fast food. Soybean oil alone is now so ubiquitous in fast foods and processed foods that an astounding 20 percent of the calories in the American diet are estimated to come from this single source.
The body also constructs hormones from omega 6 fatty acids. In general, hormones derived from the two classes of essential fatty acids have opposite effects. Those from omega 6 fatty acids tend to increase inflammation (an important component of the immune response), blood clotting and cell proliferation, while those from omega 3 fatty acids decrease those functions. Both families of hormones must be in balance to maintain optimum health.
Many nutrition experts believe that before we relied so heavily on processed foods, humans consumed omega 3 and omega 6 fatty acids in roughly equal amounts. But to our great detriment, most North Americans and Europeans now get far too much of the omega 6s and not enough of the omega 3s. This dietary imbalance may explain the rise of such diseases as asthma, coronary heart disease, many forms of cancer, autoimmunity and neurodegenerative diseases, all of which are believed to stem from inflammation in the body. The imbalance between omega 3 and omega 6 fatty acids may also contribute to obesity, depression, dyslexia, hyperactivity and even a tendency toward violence.
Bringing the fats into proper proportion may actually relieve those conditions, according to Joseph Hibbeln, M.D., a psychiatrist at the National Institutes of Health, and perhaps the world's leading authority on the relationship between fat consumption and mental health. At the 2006 Nutrition and Health Conference sponsored by the University of Arizona's College of Medicine and Columbia University's College of Physicians and Surgeons, Dr. Hibbeln cited a study showing that violence in a British prison dropped by 37 percent after omega 3 oils and vitamins were added to the prisoners' diets.
If you follow my Anti-Inflammatory Diet (available on my Web site, www.drweil.com), you should get a healthy ratio of these fatty acids. In general, however, you can cut down on omega 6 levels by reducing consumption of processed and fast foods and polyunsaturated vegetable oils (corn, sunflower, safflower, soy and cottonseed, for example). At home, use extra virgin olive oil for cooking and in salad dressings. Eat more oily fish (or take fish oil supplements), walnuts, freshly ground flaxseeds and omega 3 fortified eggs. Your body and mind will thank you.
HGH: a shortcut to healthy aging?
QWhat is your opinion of human growth hormone?
AHuman growth hormone (HGH) is made by the pituitary gland. It is essential for normal growth in children and maintenance of organs and tissues as we develop. Kids of abnormally short stature who are diagnosed with growth-hormone deficiency can be treated with daily shots of synthetic HGH, which usually enables them to reach a normal adult height. HGH may also be recommended to adults who have developed pituitary deficiency due to various causes.
Beyond that, I know of no legitimate use for HGH. I definitely do not recommend the anti-aging supplements being promoted on the Internet and elsewhere as HGH or HGH releasers. (Real HGH is a prescription drug costing about $20,000 per year. HGH "releasers" are in development, but none are currently available.) HGH does decline with age, but there is no evidence to suggest that injections of growth hormone in otherwise healthy adults will extend life or improve general health.
Some studies show that supplemental HGH does increase muscle mass, but there's a question of whether it significantly improves muscle strength or function. A Stanford University review of clinical studies concluded that the only benefit of taking HGH was a slight increase in muscle mass. The researchers found that risks included significantly more soft tissue swelling and joint pain and carpal tunnel syndrome among the about 500 people who participated in 31 studies the researchers analyzed. The data also suggested an increased risk of diabetes and prediabetes although the association didn't reach statistical significance. The review was published in the Jan. 16, 2007, Annals of Internal Medicine.
I discussed HGH with Randy Horwitz, M.D., Ph.D., medical director of the Program in Integrative Medicine at the University of Arizona. He noted that daily HGH injections are expensive and don't mimic the normal secretion patterns of the hormone.
Dr. Horwitz also warned that there are serious risks associated with using HGH as an anti-aging strategy — joint pain, high blood pressure and even diabetes have been associated with HGH administration and, possibly, an increased risk of prostate cancer. What's more, no studies have looked at the long-term effects of HGH in older adults.
You also should know that claims for so-called HGH "releasers," said to prompt the body to trigger release of HGH by the pituitary, are unsubstantiated. I know of no studies demonstrating that they work as advertised. The only way to get supplemental HGH into the body is with regular, sometimes daily, injections, available only by prescription. Unless you have a legitimate medical need for supplemental HGH, it could do you more harm than good. If your goal is healthy aging, focus on your diet and regular physical and mental exercise. There is no hormonal fountain of youth to replace positive effort.