Mediterranean Diet associated with lower rate of cognitive decline

After years of controversy surrounding the detrimental risks associated with a diet full in fat, there is now a growing consensus that fat is actually our friend rather than foe. Past warnings to keep away from fat, have in fact been severely misguided and as research continues to grow, our understanding of the benefits continue to expand as well. Such benefits include but are not limited to, reducing bad cholesterol levels in blood, in turn lowering risk of cardiovascular disease/stroke and risk factors, supports immune function and assists in managing a heathy weight.

We now know that fat is an importance source of energy, assist in cellular function and for long term health, the consumption of monounsaturated and polyunsaturated fats are essential. Thus, it should come as no surprise that these appealing benefits are highly associated with the consumption of a Mediterranean diet. Such a diet involves foods rich in monounsaturated and polyunsaturated fats including nuts, olives, oil and fish, in conjunction with fruit and vegetable consumption.

It the 1960s, it was revealed that Greece had a lower-then-average risk of heart disease, in comparison to other European countries, despite the Greek diet being high in fat. This prompted researchers to examine the underlying reasons for this major difference.

The findings evidenced the main difference laid in the type of fat countries of Europe were consuming. Greece unlike other countries were not eating high rates of saturated animal fats, that was commonly seen in countries with high rates of heart disease.

So, we know that fat is important in a healthy diet but does it help our brain function?

Yes! Findings have supported that the consumption of fat has a wide range of ‘neuro-enhancing’ effects on the brain as well. Theoretically, this should not come as a surprise. Fat is crucial in the production of the vital walls that protect our cells, more commonly referred to as the cell membranes. Fat is also responsible for the insulation that allows our nerve cells to transmit messages amongst each other, otherwise known as our myelin sheaf. Fat assists the body absorb some vitamins and minerals, required for various brain functions and plays an important role in preventing blood clotting and supporting muscle movement.

Ok, so we know we our body needs fat to run properly, but what has the research found?
A systematic review published in 2012 included 12 studies and examined the effects of a Mediterranean diet on the brain. It concluded that the diet had a significant association with better cognitive function and slower cognitive decline. Interestingly, a negative relationship was found with those that followed a Mediterranean diet more strictly and the risk of developing Alzheimer’s disease. It also noted that a common finding saw anti-inflammatory effects of the good fats involved in the diet and the reduction of oxidative stress, which has been known to play a crucial role in brain ageing.
More recently, a study published in 2017, measured the brain volume of 976 people aged between 73-76 years old in Scotland. It reported a significant lesser amount of brain shrinking occurred in those that followed a Mediterranean diet, in comparison to those that did not, highlight the important role diet plays in long term protection of the brain.

In a study by the Annals of Clinical and Translational Neurology, the consumption of extra-virgin olive oil was shown to protect memory and learning ability. Another significant finding the study documented was the reduced formation of amyloid beta plaques (protein fragments snipped from an amyloid precursor protein) and neurofibrillary tangles (an insoluble twisted fiber) both found in the brain and primary biomarkers of Alzheimer’s Disease.
So, where to from here?
While there will never be a ‘one fits all diet approach’ because of the variation across the human population, the number of people affected by cognitive decline and Alzheimer’s Disease is currently increasing at a high rate and there is currently no cure. The future should focus on lifestyles factors, emphasizing diet and perhaps attempt to gain a deeper understanding into the mechanisms behind the Mediterranean diet that lead to its array of benefits on the brain.

References

Lauretti, E., Iuliano, L., & Praticò, D. (2017). Extra‐virgin olive oil ameliorates cognition and neuropathology of the 3xTg mice: role of autophagy. Annals of clinical and translational neurology, 4(8), 564-574.

Lourida, I., Soni, M., Thompson-Coon, J., Purandare, N., Lang, I. A., Ukoumunne, O. C., & Llewellyn, D. J. (2013). Mediterranean diet, cognitive function, and dementia: a systematic review. Epidemiology, 24(4), 479-489.