"Evidence indicates that what you eat can affect your grandchildren's brain molecules and synapses," Gómez-Pinilla said. "We are trying to find the molecular basis to explain this."

 

Controlled meal-skipping or intermittent caloric restriction might provide health benefits, he said.

 

Excess calories can reduce the flexibility of synapses and increase the vulnerability of cells to damage by causing the formation of free radicals. Moderate caloric restriction could protect the brain by reducing oxidative damage to cellular proteins, lipids and nucleic acids, Gómez-Pinilla said.

 

The brain is highly susceptible to oxidative damage. Blueberries have been shown to have a strong antioxidant capacity, he noted.

 

In contrast to the healthy effects of diets that are rich in omega-3 fatty acids, diets high in trans fats and saturated fats adversely affect cognition, studies indicate.

 

Junk food and fast food negatively affect the brain's synapses, said Gómez-Pinilla, who eats fast food less often since conducting this research. Brain synapses and several molecules related to learning and memory are adversely affected by unhealthy diets, he said.

 

Emerging research indicates that the effects of diet on the brain, combined with the effects of exercise and a good night's sleep, can strengthen synapses and provide other cognitive benefits, he added.

 

In Okinawa, an island in Japan where people frequently eat fish and exercise, the lifespan is one of the world's longest, and the population has a very low rate of mental disorders, Gómez-Pinilla noted.

 

Folic acid is found in various foods, including spinach, orange juice and yeast. Adequate levels of folic acid are essential for brain function, and folate deficiency can lead to neurological disorders such as depression and cognitive impairment. Folate supplementation, either by itself or in conjunction with other B vitamins, has been shown to be effective in preventing cognitive decline and dementia during aging and enhancing the effects of antidepressants. The results of a recent randomized clinical trial indicate that a three-year folic acid supplementation can help reduce the age-related decline in cognitive function.

 

In patients with major depression and schizophrenia, levels of a signaling molecule known as brain-derived neurotrophic factor, or BDNF, are reduced. Antidepressants elevate BDNF levels, and most treatments for depression and schizophrenia stimulate BDNF. Here, too, omega-3 fatty acids are beneficial, as is the curry spice curcumin, which has been shown to reduce memory deficits in animal models of Alzheimer's disease and brain trauma. BDNF is most abundant in the hippocampus and the hypothalamus — brain areas associated with cognitive and metabolic regulation.

 

The high consumption of curcumin in India may contribute to the low prevalence of Alzheimer's disease on the subcontinent.

 

In humans, a mutation in a BDNF receptor has been linked to obesity and impairments in learning and memory.

 

"BDNF is reduced in the hippocampus, in various cortical areas and in the serum of patients with schizophrenia," Gómez-Pinilla said. "BDNF levels are reduced in the plasma of patients with major depression."

 

Smaller food portions with the appropriate nutrients seem to be beneficial for the brain's molecules, such as BDNF, he said.

 

Gómez-Pinilla showed in 1995 that exercise can have an effect on the brain by elevating levels of BDNF.

 

He noted that while some people have extremely good genes, most of us are not so lucky and need a balanced diet, regular exercise and a good night's sleep.

 

The research was funded by the National Institutes of Health's National Institute of Neurological Disorders and Stroke.