We have an ageing population and degenerative neurological diseases like dementia and Alzheimer’s Disease are an increasing concern. Such conditions are marked by progressive deterioration of memory, learning, orientation, language, comprehension, and judgement. There are no effective drugs to treat dementia, so prevention is crucial and evidence based preventative strategies are needed. A recent meta-analysis found that adherence to a Mediterranean eating style improved cognition and reduced the cognitive decline, dementia, and Alzheimer’s Disease that tends to come with age.
The Mediterranean diet is generally considered to be an eating style marked by a high intake of olive oil, vegetables, fruits, nuts, legumes, grains; a moderate intake of chicken and fish; with a lower intake of dairy (cheese and yogurt), red meat, processed meats, and sweets; and wine in moderation. This is the traditional diet eaten by those who lived in southern Italy, Greece, and Spain in the 1960s.
This review looked at 32 papers investigating the link between the Mediterranean diet pattern and cognitive function, cognitive decline, and dementia, with Alzheimer’s disease being the most common form of dementia. The authors found that higher adherence to the Mediterranean diet was associated with better global cognition and verbal ability and a slower rate of global cognitive decline. The Mediterranean diet was also associated with significantly reduced confusion, better performance on the MMSE (the Mini-Mental State Examination) and clock-drawing test, and better reaction time on the Corsi Block Test. The highest adherence to a Mediterranean diet resulted in between a 19 and 69% reduced risk of Alzheimer’s Disease, depending upon the study.
The authors discussed the mechanism by which the Mediterranean diet (MD) might lead to these improvements in cognition and reduced rates of cognitive decline and dementia. The MD has been shown to decrease vascular risk factors, thus increasing blood flow to the brain. Second, because the MD contains lots of antioxidants, like vitamin E, vitamin C, folate, and flavonoids, it reduces oxidative stress to the brain that is associated with cognitive decline. Third, the MD may reduce cognitive decline by reducing inflammation in the brain. The MD has been shown to lower inflammatory markers such as C-Reactive protein in neuritic plaques and neurofibrillary tangles in the brains of patients with Alzheimer’s Disease. Fourth, the MD has been demonstrated to control blood sugar levels and we know that insulin resistance, which comes with imbalanced blood sugar, is associated with increased risk of dementia and Alzheimer’s Disease. In fact, some have called Alzheimer’s Disease Type III Diabetes. My recommendation is to follow a low glycemic version of the Mediterranean diet that includes only limited amounts of grains but emphasizes intake of vegetables, nuts, legumes, fruit, olive oil, chicken and fish, eggs, and Greek yogurt.
Reference:
1. Petersson SD, Philippou E. Mediterranean diet, cognitive function, and dementia: A systemic review of the evidence. Advances in Nutrition. 2016;7:89-904.
