Medical research points up the protective role of omega-3 fats in combating the onset of cardiovascular disease. Omega-3 fats offer protection against heart disease characterized by irregular heart rhythm, or arrhythmia. Omega-3s also lower the risk of internal blood clotting in coronary arteries, which is the inciting event of most heart attacks. They mitigate several known risk factors, such as high blood pressure, elevated low-density-lipoprotein cholesterol and elevated blood triglycerides. In addition to all that, omega-3 fats produce favorable changes in the lining of blood vessels, or endothelium, and provide anti-inflammatory effects.
You can get omega-3 fats from fish sources or in the precursor form of alpha-linoleic acid, found in flaxseed and other oils, walnuts and some green vegetables. The body converts alpha-linoleic acid into two more active omega-3 fatty acids, EPA and DHA, which are found in fish oil and fatty fish, such as herring, mackerel, salmon and sardines. Fish oil and fatty fish are the preferred sources of omega-3, since the body can convert only about 15 percent of alpha-linoleic acid (ALA) into the more active EPA and DHA forms. Indeed, men don’t convert any ALA into DHA, although women do. So you could say that alpha-linoleic acid acts more like a pro-hormone, although it has some unique properties.
Some studies have linked regular intake of alpha-linoleic acid to increased risk for prostate cancer, a relationship that doesn’t exist with EPA and DHA, both of which show an inverse relationship to the onset of prostate cancer. On the other hand, a new study shows that alpha-linoleic acid initiates a process that results in cancer cells’ self-destruction.1 The studies that found an increased incidence of prostate cancer with ALA were riddled with flaws and inaccuracies, despite being widely quoted. One example is the assertion that red meat is ‘rich in ALA.’ In fact, beef is a poor source of ALA. The study likely confused overall fat intake with ALA-specific intake.
Several studies have linked high-level hostility to a greater risk of cardiovascular disease. The new study reported here involves increased sympathetic hormone output as a result of hostility, which causes your body to secrete extra amounts of stress hormones, such as epinephrine and norepinephrine. Those hormones, known as catecholamines, stimulate the heart and constrict blood vessels, forcing a greater workload on the heart and circulatory system. It’s not difficult to understand how chronic hostility can tax the cardiovascular system. After all, these are the fight-or-flight hormones.
Several studies have shown that omega-3 fatty acids, particularly EPA and DHA, appear to lower hostility levels. A 1996 Japanese study found that subjects who supplemented their diets with fish-oil capsules showed not only lower hostility levels but also a 31 percent drop in plasma norepinephrine levels. DHA is the major polyunsaturated fat found in the brain and makes up about 40 percent of its fat. DHA interacts with brain neurotransmitters that affect behavior, such as serotonin and dopamine.
A recent study examined the intake of various fats and fish in the diet of people between the ages of 18 and 30.2 Researchers found an inverse relationship between levels of hostility and intake of fish, especially fish rich in DHA and EPA omega-3 fats. An omega-6 fatty acid called arachidonic acid showed a weak relationship to increased hostility. It’s a precursor of an eicosanoid called thromboxane A-2, linked at elevated levels to blood-vessel constriction and increased platelet aggregation, which favors internal blood clotting. Arachidonic acid is currently being offered as a food supplement. That makes no sense, since the body easily forms it from omega-6 fats. If anything, most people produce too much arachidonic acid because the ratio of their omega-6 to omega-3 intake is so high.
Noting the evidence pointing to a direct relationship between increased hostility and cardiovascular disease, the authors suggest that one of the primary ways omega-3 fats help prevent cardiovascular disease may be their modulation of hostile behavior. Now get out of here and leave me alone.
1 Vecchinin, A., et al. (2004). Dietary alpha-linoleic acid reduces COX-2 expression and induces apoptosis of hepatoma cells. J Lipid Res. 45:308-16.
2 Iribarren, C., et al. (2004). Dietary intake of n-3, n-6 fatty acids and fish: relationship with hostility in young adults’the CARDIA study. Eur J Clin Nutr. 58:24-31.