Diet

This Is Your Brain on Olive Oil

The Mediterranean diet promotes brain health and reduces dementia risk.

Posted Nov 24, 2020

IGphotography/iStock
Source: IGphotography/iStock

With the holidays taking a different form this year, many of us are considering what will be on the menu. If we’re watching our weight, we may be devising strategies to avoid or proceed cautiously around high calorie or high fat foods.

Another compelling reason to modify one’s diet? Brain health. Importantly, no single food, vitamin, or nutritional supplement will quickly or magically transform your brain—you can debunk any related claims immediately. However, there now are a number of studies that provide evidence-based perspectives on what nutritional styles are good for the brain and what foods should be avoided or minimized.

In terms of a dietary style with solid scientific evidence related to promoting brain health, nothing comes closer than the Mediterranean diet (MeDi). Essentially, this diet references dietary tendencies among people who live in the Mediterranean region (think Italy, Greece, France, Spain, and the Middle East). The diet is mostly plant-based and consists of lots of fruits and vegetables, beans, nuts, and whole grains. Olive oil is emphasized, particularly for cooking. Fish is a preferred protein source, although chicken or turkey work too. Foods that are de-emphasized include those common in a Western-style diet, such as red meat, high-fat dairy products, and processed items (as a nutritionist might say, “foods that your great grandmother wouldn’t recognize”). Also included in the broader MeDi diet are brain-healthy lifestyle choices such as moderate physical activity, social engagement, and adequate daily rest and nightly sleep. 

As far as the science that connects the MeDi with brain function, a wide variety of nutritional studies reveal the same thing: the MeDi plays a protective role against mild or more troubling cognitive problems. The majority of research shows a significantly reduced risk of mild cognitive impairment (MCI) or Alzheimer’s disease—about a 20% to 40% reduced risk—in those who consistently eat lots of MeDi foods like fish, olive oil, fruits, and vegetables. As another key benefit, there’s a lower risk of stroke and depression in those who follow the MeDi. 

In addition, a higher “dose” of the MeDi is more protective for the brain than a lower one. One large study examined whether increased adherence to the MeDi translated into a lower risk of cognitive problems. Those who were moderately committed to the diet had a mildly reduced risk of dementia, while those with a stronger commitment were 40% less likely to develop Alzheimer’s. This so-called dose-response effect applies to other lifestyle choices such as exercise or intellectual activity; the more you engage in a brain-healthy activity, the more cognitive benefits you receive. 

Why is the MeDi so good for the brain? On a microscopic, molecular level, it’s rich in antioxidants and anti-inflammatory components that reduce the negative effects of what is called oxidative stress—too many potentially toxic free-radical molecules—on the brain. Omega-3 polyunsaturated fatty acids are abundant in this diet; these reduce inflammation, support neuronal functioning, and maintain healthy levels of neurotrophins such as brain-derived neurotrophic factor (BDNF). The diet may also have antithrombotic and antiatherogenic features, which is a fancy way of saying that it reduces the risk of strokes and clogged arteries. In addition, people adhering to the MeDi have denser brain matter in multiple regions—including in the frontal and temporal lobes—and show reduced shrinkage of the brain over time. 

Diets that resemble the MeDi also have important brain-boosting properties. One such diet is the DASH diet (Dietary Approaches to Stop Hypertension), which is essentially a Mediterranean diet with low sodium and low saturated fat. While this dietary style was originally designed to prevent or reduce high blood pressure, it has some brain-related benefits too, including better overall cognitive functioning, quicker thinking speed, and a reduced risk of developing Alzheimer’s disease. Another diet called the MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay) builds on the MeDi and DASH diets and emphasizes berry and green leafy vegetable intake. The MIND diet has been found to have some real advantages: it’s been linked to stronger verbal memory and reduced risk of dementia in middle-aged and older adults. People that adhere strongly to this diet are also able to slow the process of cognitive aging, in the form of having cognitive skills that are about seven years younger than their chronological age would predict. 

Overall, a Mediterranean-style diet (including its cousins, the DASH and MIND diets) is ideal for promoting brain health based on a number of studies. Before, during, and after the holidays, consider reaching for carrots and hummus rather than cookies and chips. Your brain will be grateful.

This post was adapted from The Brain Health Book: Using the Power of Neuroscience to Improve Your Life by John Randolph, Ph.D., published by W.W. Norton & Company, Inc.

References

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Berendsen, A.M. et al. (2018).  Association of long-term adherence to the MIND diet with cognitive function and cognitive decline in American women.  Journal of Nutrition, Health and Aging, 22(2), 222-229.

Morris, M.C. et al. (2015).  MIND diet associated with reduced incidence of Alzheimer’s disease.  Alzheimer’s & Dementia, 11, 1007-1014.

Mosconi, L. et al. (2018).  Lifestyle and vascular risk effects on MRI-based biomarkers of Alzheimer’s disease: A cross-sectional study of middle-aged adults from the broader New York City area.  BMJ Open, 8, e019362.

Psaltopoulou, T. et al. (2013).  Mediterranean diet, stroke, cognitive impairment, and depression: A meta-analysis.  Annals of Neurology, 74, 580-591.

Scarmeas, N. et al. (2009).  Physical activity, diet, and risk of Alzheimer disease.  JAMA, 302(6), 627-637.

Singh, B. et al. (2014).  Association of Mediterranean diet with mild cognitive impairment and Alzheimer’s disease: A systematic review and meta-analysis.  Journal of Alzheimer’s Disease, 39(2), 271-282. 

Wengreen, H. et al. (2013).  Prospective study of Dietary Approaches to Stop Hypertension and Mediterranean-style dietary patterns and age-related cognitive change: The Cache County Study on Memory, Health and Aging.  American Journal of Clinical Nutrition, 98, 1263-1271.

Staubo, S.C. et al. (2017).  Mediterranean diet, micronutrients and macronutrients, and MRI measures of cortical thickness.  Alzheimer’s & Dementia, 13, 168-177.