Feeding the Brain

Consumers are taking the cliché food for thought literally, purchasing an ever-expanding variety of supplements and functional foods targeted at boosting the brains fitness. The field of fueling the brain is so hot that much research has been initiated to further mine it.

Brainy nutrition for kids 

Studies on populations in developing countries have shown protein and energy malnutrition in infancy can produce long-lasting effects on cognition and IQ. Gestation through the first two years of life is a critical period of rapid brain growth and development, during which nutritional deficiencies such as iron, essential fatty acids, iodine, folate, zinc and vitamin B12 can wreak havoc. Nutrition remains important as the brain develops throughout childhood and adolescence. Evidence indicating that skipping breakfast interferes with childrens cognition and learning prompted school breakfast programs. Kids who ate school breakfasts with at least one-fourth of the key nutrients improved their math and reading scores.

Recently, much ado has been made about nutritions role in learning disabilities and behavior. Alternative therapies like elimination diets and vitamin/mineral supplementation for attention deficit hyperactivity disorder (ADHD) have gained popularity, although little scientific evidence backs them up. Studies found that children with various social and learning problems have reduced tissue omega-3 long-chain polyunsaturated fatty acids (PUFAs) in the brain. A study looking at the effect of supplementation with highly unsaturated fatty acids (HUFAs) on children with both learning difficulties and above-average ADHD ratings did find significantly lower scores for cognitive and general behavior problems in the HUFA group than in the placebo group (Progress in Neuro-Psychophamacology and Biological Psychiatry, 2002; 26(2):233-9).

Adult mental performance 

The militarys interest in cognitive performance prompted research that shows caffeine enhances cognitive function in sleep-deprived individuals; the amino acid tyrosine appears to prevent cognitive-performance decline associated with acute stress; and carbohydrate supplementation enhances cognitive performance in soldiers undergoing sustained, intense physical activity.

A heart-healthy diet may help maintain brain function, because high blood cholesterol might cause inflammation of blood vessels around the brain. Maintaining good blood glucose levels may also be important, as elevated blood glucose has a detrimental effect on brain function.

Nutrients for the aging brain 

Health experts have long known that nutritional status influences mental cognition in the elderly, a group that can be vulnerable to vitamin deficiencies and protein-energy malnutrition. Researchers have observed many correlations between biochemical indices of thiamin, riboflavin and iron and cognitive performance in healthy persons over 60 years of age (American Journal of Clinical Nutrition, 1990; 52 (1):93-102).

Neurodegeneration in Alzheimers disease (AD) may have many root causes, including oxidative stress, inflammation and the accumulation of beta-amyloid protein fragments that lead to the degradation of neurons. Antioxidants may offer protection against these conditions.

The USDA Agricultural Research Services reports fruits and vegetables, high in antioxidants, ameliorate age-related declines in cognitive function. A recent study found that transgenic mice receiving pomegranate juice learned water-maze tasks more quickly and had approximately 50% less accumulation of Abeta 42 (an amyloid that is increased in AD) and amyloid deposition in the brain compared with control mice (Neurobiology of Disease, 2006; 24(3): 506-15). Research continues on tea flavonoids for antioxidant and anti-inflammatory activities, which might protect neuronal death.

Populations that consume more fish are less likely to end up with dementia and AD than those that eat little or no fish. One omega-3 fatty acid found in fish, docosahexaenoic acid (DHA), is a critical fatty acid in phospholipids (components of brain cells), and it appears to protect the brain cells from inflammation.

In a study published in the Journal of Neuroscience (2005, 25:3032-3040), researchers looked at the brains of AD-susceptible mice fed diets that were either high or low in DHA. DHA-enriched diets significantly reduced total beta-amyloid deposits by more than 70% compared with low- DHA or control diets.

Curcumin, an antioxidant found in turmeric (used in curry), also appears to reduce the brains level of beta-amyloid. In a study published in the Journal of Biological Chemistry (2005, 280:5892-5901), scientists found that curcumin binds to amyloid beta protein, discouraging it from aggregating into waxy clumps associated with AD. Gingko biloba may have beneficial effects on memory and AD, but studies have varying results.

A large, five-year clinical trial by the National Institutes of Healths National Center for Complementary and Alternative Medicine is underway to help clarify gingko bilobas role in preventing cognitive decline. The study is projected for completion in 2007.

Soy phosphatidylserine (PS) has shown positive results in animal tests on memory and cognition, but human findings are limited. The FDA qualified health claim for PS indicates that very limited and preliminary scientific research suggests that it may reduce the risk of dementia in the elderly.

Further research will clarify how certain nutrients play into brain disorders, from autism to AD. But gathering evidence shows that a balanced diet rich in a variety of plant foods with an emphasis on omega-3-rich fatty fish is smart eating. 

Sharon Palmer is a registered dietitian with years of experience in health-care and foodservice management. She writes about food and nutrition for newspapers, magazines, websites and books. Palmer makes her home in Southern California.