Omega-3 fat. Is it what got us here?

Philip J. Goscienski, M.D.

July 2008

Can you imagine human knowledge at a standstill? Our very distant ancestors began using crude stone tools about one million years ago but their creativity ground to a halt soon thereafter. Those implements changed so little over thousands of generations that only a trained scientist can distinguish one period's production from another.

Something happened a little more than 100,000 years ago: tool making took a giant leap forward. Stone- and bone-tipped spears, scalpel-sharp flint knives, fishhooks and harpoons became commonplace among the still-sparse populations of that age. The process probably began about 100,000 years earlier when the fossil record shows that early Homo sapiens added fish and shellfish to his family's diet. Brain size doubled in that period. Compared to the previous million years there was a sudden (in the evolutionary sense) burst of technical creativity whose pace has been accelerating ever since.

Many scientists credit omega-3 fatty acids, primarily the ones known as DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) with these advances. Omega-3 fatty acids are critical to the normal function of every cell in the body. They make up about half the dry weight of the brain and are abundant in the eye. Laboratory animals whose diets are omega-3 deficient have poor brain development. Infants who receive breastmilk (rich in omega-3s) sleep better, have better vision and have better mental abilities than formula-fed infants. In the United States, infant formula does not contain omega-3s.

A torrent of information is pouring from research laboratories in support of the idea that brain function is better among persons whose diet and blood levels are high in omega-3 fatty acids and worse among those with low levels. Separate studies in Finland, Iceland and Japan reveal that persons with a low intake of fish have higher rates of depression and violent behavior. Behavior problems in children, attention-deficit disorder, bipolar disorder, schizophrenia, depression and suicide have joined the list of conditions in which a deficiency of these fatty acids seems to play a role.

The best sources of omega-3 fatty acids are coldwater fish such as wild salmon, sardines, herring and mackerel. Farmed trout and salmon vary in their omega-3 content depending on their feed. Fresh tuna and other large fish are good sources of these nutrients but may also contain mercury and other environmental toxins. The U.S. government advises that pregnant women should avoid those fish, which are at the top of the food chain. Wild game contains small amounts of omega-3s but domestic beef has almost none.

Omega-6 fats that come from vegetable and seed oils are important nutrients but they are already overabundant in the American diet. We should be eating omega-6 and omega-3 fats in roughly equal amounts, as Stone Agers did. In the United States that ratio is 15 to 1 or higher, and may explain the high incidence in our society of autoimmune diseases such as lupus and rheumatoid arthritis.

It's not easy to get enough omega-3s in your diet if you don't eat fish at least a couple of times a week. Flaxseed is one source but grinding fresh seeds is inconvenient and the oil doesn't keep well. Pregnant women, who should limit their intake of large fish such as swordfish or tuna, can take fish oil capsules.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at