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Food, Mood and Brainpower

What Should We Be Eating for Brain Health?

What we eat seems to have significant implications for the brain: unhealthy diets may increase risk for conditions such as depression and dementia, while healthy diets may be protective. This issue of Staying Healthy highlights some of the research from the last few years to provide a practical resource for brain-friendly nutrition strategies.

The Basics: Med-Type Diet + Physical Activity

A noteworthy study (1) published in 2009 found that people who follow Mediterranean dietary patterns – that is, a diet high in fruits, vegetables, nuts, whole grains, fish, and unsaturated fat (e.g. olive oil) – are up to 30% less likely to develop depression than those who typically consume meatier, dairy-heavy fare. Olive oil lovers may also be less likely to develop mild mental impairment and Alzheimer’s, particularly when they engage in regular physical activity (2,3).

Berries, Chocolate Fight Oxidative Stress

Polyphenols, namely anthocyanins, found in berries and other red and purple fruits and vegetables may slow cognitive decline through their antioxidant and anti-inflammatory properties. In aging animals, for example, a diet high in strawberry, blueberry, or blackberry extract led to better nerve function and behavior involving learning and memory (4). Recent work suggests that berry extracts might stimulate the process by which cells clear debris, such as proteins linked to mental decline and memory loss (5). Berry anthocyanins may also reduce CVD risk by reducing oxidative stress and favorably effecting the expression of inflammatory genes (6).

Chocolate – the darker the better – seems to help scavenge free radicals and improve functioning of the arteries, likely via the polyphenols it contains. A 2010 study reported that consumption of 6 g of chocolate daily – a standard Hershey bar weighs 43 g – was linked to a 39% lower risk for stroke and heart attack (7).

Fish Oil for Mental Health, Brainpower

In a 2010 study, fish consumption correlated with a lower risk for psychotic symptoms (8). Other work suggests that fish oil may help prevent psychosis in high-risk individuals (9). Another reason to put fish on your menu? Low blood concentrations of the omega-3s are associated with smaller brain volume and poorer performance on mental acuity tests in older people (10). Oily, cold-water fish, such as salmon, herring, and mackerel, have the highest omega-3 levels.

What About Coffee and Alcohol?

Both may play a supportive role, but only when consumed in moderation. And when drinking alcohol, the best bet is to go with red wine.

The world's most widely used stimulant might do more than just wake us up: A 2011 review (11) found that daily coffee drinking cut stroke risk by 17%. Another study (12) reports that women who drink about 2 cups of coffee per day have a 15% decreased risk for depression, compared with those who rarely drink it. Limited alcohol use has been tied to a lower risk for overall and Alzheimer dementia (13), a finding supported by a recent German study (14). Moderate alcohol intake may also protect against cerebrovascular disease, with red wine having the added benefit of providing the antioxidant resveratrol.

Foods to Limit?

Diets rich in high-fat dairy, and fried, refined, and sugary foods have been found to increase the risk for depression (15-18). It's good to keep these foods to a minimum, since saturated fats and refined carbs can have detrimental effects on neurotrophins (nerve cell-protecting proteins), the immune system and oxidative stress – all factors known to play a role in depression.

Go easy on the salt shaker too. Too much salt has long been known to increase blood pressure and stroke risk, but now there is some evidence that high salt intake, as well as diets high in trans or saturated fats, can impair mental processes (19,20).

References

1. Sánchez-Villegas, A et al. Association of the Mediterranean dietary pattern with the incidence of depression. Arch Gen Psychiatry 66:1090-98, 2009.
2. Scarmeas N, et al. Mediterranean diet and mild cognitive impairment. Arch Neurol 66:216-25 2009.
3. Scarmeas N, et al. Physical activity, diet, and risk of Alzheimer disease. JAMA 302:627-37, 2009.
4. Medscape.com. New mechanism for berries' potential brain benefits. http://www.medscape.com/viewarticle/727764.
5. Berry extracts and brain aging: clearance of toxic protein accumulation in brain via induction of autophagy. Program and abstracts of the 240th National Meeting of the American Chemical Society; August 22-26, 2010; Boston, Massachusetts.
6. Basu A, et al. Berries: emerging impact on cardiovascular health. Nutr Rev 68:168-77, 2011.
7. Larsson SC, et al. Chocolate consumption and risk of stroke in women. J Am Coll Cardiol. 58:1828-29, 2011.
8. Hedelin M, et al. Dietary intake of fish, omega-3, omega-6 polyunsaturated fatty acids and vitamin D and the prevalence of psychotic-like symptoms in a cohort of 33000 women from the general population. BMC Psychiatry 10:38, 2010.
9. Amminger GP, et al. Long-chain omega-3 fatty acids for indicated prevention of psychotic disorders: a randomized, placebo-controlled trial. Arch Gen Psychiatry. 67:146-154, 2010.
10. Tan ZS, et al. Red blood cell omega-3 fatty acid levels and markers of accelerated brain aging. Neurology 78:658-64, 2012
11. Larsson SC, et al. Coffee consumption and risk of stroke: a dose-response meta-analysis of prospective studies. Am J Epidemiol 174:993-1001, 2011.
12. Lucas M, et al. Coffee, caffeine, and risk of depression among women. Arch Intern Med 171:1571-78, 2011.
13. Wayerer S, et al. Current alcohol consumption and its relationship to incident dementia Age Ageing 40:456-63, 2011.
14. Peters R, et al. Alcohol, dementia and cognitive decline in the elderly: a systematic review. Age Ageing 37:505-12, 2008.
15. Sanchez-Villegas A, et al. Fast-food and commercial baked goods consumption and the risk of depression. Pub Hlth Nutr 15:424-32, 2012.
16. Jacka F, et al. Association of Western and traditional diets with depression and anxiety in women. Am J Psychiatry 167:305-3, 2010.
17. Jacka FN, et al. A prospective study of diet quality and mental health in adolescents. PLoS One 6:e24805, 2011.
18. Frieden TR and Briss PA. We can reduce dietary sodium, save money, and save lives. Ann Intern Med 152:526-527, W182, 2010.
19. Fiocco AJ, et al. Sodium intake and physical activity impact cognitive maintenance in older adults: the NuAge Study. Neurobiol Aging 33: 829.e21-829.e28, 2012.
20. Parrott MD and Greenwood CE. Dietary influences on cognitive function with aging: from high-fat diets to healthful eating. Ann N Y Acad Sci 1114:389-97, 2007.