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Fish Heads

26 March 2012

Omega-3 fatty acids are increasingly being understood as essential for the healthy function of the human body. The problem is that while we may understand that fact, our intake of omega-3 fatty acids is sadly lacking and the evidence is that this may be ageing our brains before their time.

The real problem in today’s diet is not only lack of omega-3 oils but also an excess of omega-6 fatty acids. Never in the history of humanity have we eaten omega-6 fatty acids in such massive quantities. Corn oil, safflower oil, sunflower oil, cottonseed oil, peanut oil, and soybean oil are ingredients in many processed foods. Omega-3 fats compete in the body with the omega-6 fats. We need to consume a ration of around 4:1 in terms of omega-6:omega-3 but that ratio today may be as high as 20:1. The evidence is that this imbalance is bad news for your brain.

The brain has a huge number of cell membranes, and cell membranes are made out of fat. The effect of omega-3 oils on a cell membrane is very different to the effect of omega-6 oils. An omega-6 oil will tend to make the membrane rigid whereas the omega-3 oil will promote membrane fluidity. DHA is required for transport of protein and signals through the membranes, the formation of synapses, and maintaining the integrity of the neuronal membranes. All of these functions are vital for the optimal functioning of your brain.

Given all of this we would assume that omega-3 levels in your body will relate to how well your brain functions and therefore how it ages. That is what was tested in a new study based on data gathered from the Framingham study.

Since 1948 the good folk of a town called Framingham in Massachusetts have submitted to poking and prodding from medical researchers in the interest of medical science. This data was drawn from the second Framingham study generation (average age 67) and looked for a relationship between red blood cell omega-3 (specifically DHA) levels, scores on cognitive testing, and magnetic resonance images (MRIs) of brain activity.

The reason that red blood cells were examined is that they live about 120 days, so red blood cell membranes have omega-3 levels that correlate to dietary intake over the same amount of time. These levels also correlate with fatty acid concentrations in other tissues, like the heart.

The MRIs were studied to look for measures of brain ageing, such as lower brain volume, hippocampus volume, and white matter volume. Grey matter is the cell bodies, white matter is essentially the wiring or connections between neurons and white matter “hyperintensity” can indicate scarring or other damage. The Framingham participants in the lowest 25 per cent for RBC DHA amount had the oldest-looking brains, with lower total volumes and more white matter hyperintensity.

The cognitive testing investigated memory, reasoning, attention, and executive functioning. RBC DHA levels were continuously and positively associated with three of the four tests (only verbal memory had no association). So the more DHA, the better the results on these tests.

Brain scans also showed signs of less blood supply in the brains of people with the lowest omega-3 levels. This suggests the omega-3s may play a role in promoting general blood vessel health in the brain, similar to how they are thought to help heart health.

All in all, low levels of omega-3 fatty acids were equated to two years of brain ageing.

The researchers took into account various health and lifestyle factors, including age, education and body mass index, to explore whether other differences among the people with low levels of omega-3s could help explain their more rapid brain aging. Yet after controlling for those risk factors, the difference in brain ageing remained so they concluded that omega-3 fatty acids are the likely explanation.

Given the known actions of omega-3 fats in the brain and the findings of this latest study, it would seem reasonable if you want to keep the wheels of your mind lubricated in a youthful fashion then you should cut down on the omega-6 and boost your omega-3. Go on, be a fish head, and be proud if it.