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So the health tide is turning and the ‘all fat is bad’ myth has been exposed. No longer the bad guys, we know that fats are absolutely crucial for health and we also know that there are particularly special types that can deliver extraordinary benefits. Omega 3 fats, the ones you’ll find in oily fish such as tuna, mackerel and salmon, have become the subject of extensive and ongoing research. Not a week goes by without another good reason to include more omega 3s in your diet. They have brain, vision and heart-healthy qualities and more. 

In this article we look back at how omega 3 may have even shaped the history of the human race. And forward to how their notable absence from a typical Western diet may be shaping a future of chronic disease.

The brains of the earliest humans were similar in size to those of chimpanzees, our closest living relatives. The human brain however has tripled in size over nearly 7 million years, and most of this growth has happened in the last 2 million. The average weight of an adult chimpanzee brain is 384g, whilst the average human brain weighs in at over 3 times that, at 1,352g! This increase in brain size and the associated ability to compute, manage and store information like never before, is considered a crucial step in our evolution as human beings. However, it’s still not completely clear why human brains grew so much bigger during this time.

Some fascinating theories have traced the development of our brains to early humans who lived near water sources and so began to eat more fish and marine animals, which are rich sources of omega 3 fatty acids

Scientists including Professor Michael Crawford and Professor Stephen Cunnane have hypothesized that it was the addition of these fatty acid rich foods that supported the growth of a larger brain.

In contrast, those who lived inland and did not have access to omega 3s may have got stuck at a brain capacity that was not much bigger than a chimpanzee for three million years.

That omega 3s propelled forward human evolution by enabling the growth of bigger brains is still the subject of much debate, however it gives some clue as to the ongoing importance of omega 3s for brain health. Omega 3 fats, in particular docosahexaenoic acid (DHA) form an important part of the brain’s structure and are absolutely crucial for baby and child brain development, to support cognitive function at any age and to protect against neurodegenerative diseases and other chronic disease into old age. 

Our bodies cannot make omega 3 fats from scratch and so they must be supplied through the diet. What’s devastating though is how typical Western eating patterns have changed to exclude these crucial fats from our diets.  Omega 3 fats (found in oily fish, nuts and seeds) need to be balanced with omega 6 (found in meat, dairy and vegetable oils). Historically and ideally, the dietary ratio of omega 6: omega 3 would have been 1:1 and yet nowadays, dietary patterns have shifted towards 20:1, with detrimental effects on health.

Not only are people consuming more omega 6 fats and very little omega 3, but the development and infiltration into the food industry, of artificially processed ‘trans’ or ‘hydrogenated’ fats has further pushed omega 3 out of diets. Trans fats are unsaturated fats that have been chemically changed to make them behave and taste more like saturated fats. They enable food manufacturers to advertise a low saturated fat content, yet without losing the taste and palatability that saturated fats undoubtedly offer. The best of both worlds it would seem, unfortunately though, the true picture is much darker than that; trans fats are known to be harmful to health and their widespread use in the processed foods industry is a huge cause for concern.

The take away message is that most people would benefit hugely from getting more omega 3 in their diet. And from a brain health perspective, it’s crucial that this happens from a very young age and right through into old age.  Concerns over high levels of toxic contaminants in oily fish (the richest dietary sources of omega 3) mean that people shouldn’t exceed government recommendations of 4 portions per week. Daily supplementation with a high quality, pure and stable fish oil is generally agreed to be the most effective way to increase omega 3 intake on a widespread scale.

From it’s potentially crucial role in human evolution to today’s known health protective qualities, omega 3 is hugely important. Whether you focus on getting more in your diet, or add in a daily supplement for extra peace of mind, it’s essential that you do something to boost omega 3 in your diet and to encourage little ones and older relatives to do the same.  

Professor Stephen Cunnane - Survival of the Fattest: The Key to Human Brain Evolution (World Scientific 2005), and Human Brain Evolution: Influence of Fresh and Coastal Food Resources (Wiley, 2010).  

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