The grim news, according to a study just published in the British Medical Journal, is that brain function can start to decline at the age of 45. Some of us might suspect that our cognitive function went into decline well before then, but let’s not dwell on that. Cognitive decline is something we all fear, and with good reason. Dementia, such as Alzheimer’s, is on the increase. According to the Alzheimer’s Society, there are now 700,000 people with the condition in the United Kingdom, a figure expected to increase by over 38% over the next 15 years, and by 154% over the next 45 years.
Anyway, on the bright side, there’s always something we can do to help ourselves. The scientists behind the study also stated that looking after your heart is one good way of avoiding dementia, because people with high blood pressure, or who are obese, are at higher risk of developing the condition. It makes sense: both heart disease and dementia are considered to be ‘diseases of civilisation’ – the result of our diet and lifestyles. Interestingly, what links these two conditions, is oily fish, or lack thereof.
A strong association between oily fish and reduced risk of coronary heart disease is well established. Fish – and especially oily fish – is an excellent source of two very important omega-3 fatty acids, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). It is impossible to overstate how crucial these two fatty acids are to human health. They are required for cognitive function, vision, coordination, fertility, immunity and growth.
DHA is the most abundant fatty acid in the brains of mammals, and evidence is also now accumulating to suggest that EPA and DHA may be protective against stroke and dementia, in particular Alzheimer’s.
In the UK the current recommendation for adults for combined EPA and DHA is 450mg daily, the equivalent of about 2 portions of fish a week. Yet it is estimated that in the UK we consume on average only 244mg a day (in Japan, the average intake is estimated to be around 950mg daily) – but only about 27% of the adult population consumes any oil-rich fish at all. This suggests to me that the vast majority of people in the UK are almost certainly severely deficient in these fatty acids. Bearing in mind that, two hundred years ago wild salmon was so abundant it was a staple of the poor, you have to ponder the meaning of progress.
So get some mackerel, sardines, herring, trout, salmon (wild), anchovies and so on down you, as often as. And if you really can’t face the fish, take fish oil supplements on a daily basis.
References
FAO/WHO (2008). Joint FAO/WHO Expert Consultation on Fats and Fatty Acids in Human Nutrition (10 – 14 November 2008, WHO, Geneva). Interim Summary of Conclusions and Dietary Recommendations on Total Fat & Fatty Acids.
Givens, D.I. & Gibbs, R.A. (2008) Current intakes of EPA and DHA in European populations and the potential of animal-derived foods to increase them. Proceedings of the Nutrition Society, 67:273-280.