from Omega-6 Fat News & Commentary Research News by Evelyn Tribole, MS, RD -
"The balancing act between omega-6 and omega-3 fats is an important detail often missed in the headline research news and even by the scientists themselves! This site/blog focuses on the omega-6 fat issue, by offering brief summaries of recently published studies and an occasional commentary from me. It is written for health professionals and individuals who are interested in the science of omega-6 fats and their impact on health."Background:
"Eating an adequate amount of the right types of omega-3 fats, whether through regular fish consumption or fish oil supplements is only half of the omega health picture. Omega-3 fats provide little benefit when excessive dietary omega-6 fats are eaten. In fact, in 1999 there was enough scientific evidence of adverse harm on eating excess omega-6 fats, that international group of scientists recommended putting a cap on the omega-6 fat in our diets. (Simopoulos et al).
Prior to industrialization, no population has been exposed to the current high levels of omega-6 polyunsaturated fats in westernized diets. (Cordain) Today we eat fat that did not exist 100 years ago, such as cottonseed oil. Humans evolved on a diet with a balanced ratio of omega-6 to omega-3 fats of about 1:1. Today, that ratio in westernized countries is near 17:1. This striking fat imbalance is at the root of many chronic diseases.
Cultures that suddenly increase their omega-6 fat intake experience markedly higher death rates and health problems. When Okinawans tripled their omega-6 fat intake, they experienced a rise in cancer and cardiovascular disease, which Japanese researchers called “excess linoleic acid syndrome” Okuyama). Notably, this syndrome occurred in the presence of consuming fatty fish.
When Israel embraced a high polyunsaturated fat diet (at the expense of saturated fats), they achieved one of the highest omega-6 fat intakes in the world--along with an unexpected high incidence of chronic western diseases, which researchers term the “Israeli paradox” (Dubnov).
The Greenland Inuit Eskimos are famous for their high omega-3 fat diet, but just as importantly, their diet was also low in omega-6 fat. The Lyon Diet Heart study, which popularized the health benefits of a Mediterranean diet, is a diet low in omega-6 fat (De Lorgeril et al).
Excess omega-6 fats interfere with the health benefits of omega-3 fats because they compete for the same enzymes, which are in very limited supply in our body. A high proportion of dietary omega-6 throws our body on the pathogenesis path for many chronic diseases. Chronic excessive production of omega-6 eicosanoids (made from omega-6 fats) is associated with heart attacks, thrombotic stroke, arrhythmia, arthritis, osteoporosis, inflammation, mood disorders, asthma and cancer. (Lands)
I recently gave a talk to physicians, and I began by asking them, “Do you ever prescribe anti-inflammatory medications, such as: aspirin, motrin, naproxen, or COX-2 inhibitors-like Celebrex?” The response was something like, “of course”. But when I asked, what do all of these anti-inflammatory medicines have in common, they were stunned to learn the answer: They work by blocking the effects of excess omega-6 fats in the diet! That’s also one of the key ways omega-3 fats provide a variety health benefits, by blocking the effects of excess omega-6 fat.
Specifically, both anti-inflammatory drugs and DHA/EPA (the type of omega-3 fats found in fish), work by blocking the effects of arachidonic acid. Arachidonic acid is the most potent omega-6 fat, which makes a variety of inflammation compounds. This potent fat is found in animal foods including meats, poultry and eggs. Arachidonic acid is also easily made in our body, from the plant sources of omega-6 fats that we eat, such as soybean oil, cottonseed oil, corn oil.
The omega-6 fat issue is especially important in the USA, because the great majority of Americans do not eat enough of the right kinds of omega-3 fats, EPA and DHA, which are found in fish. American average an intake of 85 milligrams of these omegas, which meets only 13% of the international recommended intake of 650 milligrams per day. Notably, omega-6 fats compete with omega-3 fats, which amplify a negative impact on our health."