[*Anya*]

Diet is inextricably linked to conditions such as heart disease, obesity, and diabetes. However, what we consume also seems to have significant implications for the brain: Unhealthy diets may increase risk for psychiatric and neurologic conditions, such as depression and dementia, whereas healthy diets may be protective. Based primarily on recent Medscape News coverage, the following slideshow collects some of the more prominent investigations on nutrition and the brain into a single resource to aid in counseling your patients.

Make for Malta in Depression, Stroke, and Dementia

A 2009 study published in Archives of General Psychiatry found that people who follow Mediterranean dietary patterns -- that is, a diet high in fruits, vegetables, nuts, whole grains, fish, and unsaturated fat (common in olive and other plan oils) -- are up to 30% less likely to develop depression than those who typically consume meatier, dairy-heavy fare.[1]The olive oil-inclined also show a lower risk for ischemic stroke[2,3] and are less likely to develop mild cognitive impairment and Alzheimer disease, particularly when they engage in higher levels of physical activity.[4,5]

Fat: The Good and the Bad

A study conducted in Spain[6,7] reported that consumption of both polyunsaturated fatty acids (found in nuts, seeds, fish, and leafy green vegetables) and monounsaturated fatty acids (found in olive oil, avocados, and nuts) decreases the risk for depression over time. However, there were clear dose-response relationships between dietary intake of trans fats and depression risk, whereas other data support an association between trans fats and ischemic stroke risk.[8] Trans fats are found extensively in processed foods.

Fish Oil to Fend Off Psychosis?

Thanks to their high levels of polyunsaturated fatty acids, namely omega-3 fatty acids, fish can help fend off numerous diseases of the brain. A 2010 study correlated fish consumption with a lower risk for psychotic symptoms,[10] and concurrent work suggested that fish oil may help prevent psychosis in high-risk individuals.[11] Although data are conflicting, new research shows that the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid are beneficial in depression and postpartum depression, respectively, and other research suggests that omega-3 deficiency may be a risk factor for suicide.[12-16] Oily, cold-water fish, such as salmon, herring, and mackerel, have the highest omega-3 levels.

Berries for Oxidative Stress

Polyphenols, namely anthocyanins, found in berries and other darkly pigmented fruits and vegetables may slow cognitive decline through antioxidant and anti-inflammatory properties. A study in rats from 2010 showed that a diet high in strawberry, blueberry, or blackberry extract leads to a "reversal of age-related deficits in nerve function and behavior involving learning and memory."[17] In vitro work by the same group found that strawberry, blueberry, and acai berry extracts -- albeit in very high concentrations -- can induce autophagy, a means by which cells clear debris, such as proteins linked to mental decline and memory loss.[18] Berry anthocyanins may also reduce cardiovascular disease risk by reducing oxidative stress and attenuating inflammatory gene expression.

What Not to Eat?

Saturated fats and refined carbohydrates have highly detrimental effects on the immune system, oxidative stress, and neurotrophins, all factors that are known to play a role in depression. The study by Akbaraly and colleagues cited previously[22] showed that a diet rich in high-fat dairy foods and fried, refined, and sugary foods significantly increases risk for depression. Similar findings were seen in another study from Spain,[7] showing that intake of such foods as pizza and hamburgers increased the risk for depression over time, and in another study, women with a diet higher in processed foods were more likely to have clinical major depression or dysthymia.[17] Research published last year[37] also showed for the first time that quality of adolescents' diets was linked to mental health: Healthier diets were associated with reduced mental health symptoms and unhealthy diets with increased mental health symptoms over time. Excess salt intake has been long known to increase blood pressure and stroke risk[38,39]; however, recent data also correlate high salt intake, as well as diets high in trans or saturated fats, with impaired cognition.[40,41]

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**Studies and references available if interested. Did not list as there are 41 separate citations!