In the July, 2008 issue of the journal Nature Reviews Neuroscience, UCLA professor of neurosurgery and physiological science Fernando Gómez-Pinilla summarizes the latest findings concerning the effects of various foods on the brain, noting that some foods have a drug-like effect. "Food is like a pharmaceutical compound that affects the brain," Dr Gómez-Pinilla stated.
"Diet, exercise and sleep have the potential to alter our brain health and mental function. This raises the exciting possibility that changes in diet are a viable strategy for enhancing cognitive abilities, protecting the brain from damage and counteracting the effects of aging."
In an analysis of over 160 studies, omega-3 fatty acids (EPA, DHA, and ALA) emerged as significant dietary compounds to enhance learning and memory, and prevent mental disorders. "Omega-3 fatty acids are essential for normal brain function,” Dr Gómez-Pinilla observed. “Dietary deficiency of omega-3 fatty acids in humans has been associated with increased risk of several mental disorders, including attention-deficit disorder, dyslexia, dementia, depression, bipolar disorder and schizophrenia. A deficiency of omega-3 fatty acids in rodents results in impaired learning and memory."
Omega-3 polyunsaturated fatty acids are needed for the formation of brain cell membranes, which develop connections called synapses that are important in learning. "Omega-3 fatty acids support synaptic plasticity and seem to positively affect the expression of several molecules related to learning and memory that are found on synapses," Dr Gómez-Pinilla explained.
Dr Gómez-Pinilla noted that increasing the omega-3 fatty acid levels of children’s diets improved school performance and reduced behavioral problems. Omega-3 acids combined with iron, zinc, folic acid and other vitamins have been demonstrated to improve verbal intelligence, learning and memory test scores after six months when given to children between the ages of 6 and 12.
Other research has shown that the nutritional content of one’s diet can have effects on the health, including neurological function, of one’s descendants. "Evidence indicates that what you eat can affect your grandchildren's brain molecules and synapses,” Dr Gómez-Pinilla commented. “We are trying to find the molecular basis to explain this."
He additionally observed that reducing the amount of food we eat can be beneficial. Consuming too many calories can decrease the flexibility of the brain cells’ synapses and increase free radical damage. Although the brain is very susceptible to this damage, foods such as blueberries can help counteract it.
Another important brain nutrient is the B vitamin folic acid. Insufficient folic acid has been linked with depression and cognitive impairment, and supplementation with the vitamin has been demonstrated to be helpful in the prevention of cognitive decline and dementia. Folic acid has also been shown to enhance the effects of antidepressants.
In depressed as well as schizophrenic individuals, brain-derived neurotrophic factor (BDNF), a signaling molecule, is reduced. Omega-3 fatty acids as well as curcumin, a compound that occurs in the spice turmeric, can help elevate BDNF in a manner similar to antidepressant or antischizophrenic drugs. "BDNF is reduced in the hippocampus, in various cortical areas and in the serum of patients with schizophrenia," Dr Gómez-Pinilla stated. "BDNF levels are reduced in the plasma of patients with major depression."
“Understanding the molecular basis of the effects of food on cognition will help us to determine how best to manipulate diet in order to increase the resistance of neurons to insults and promote mental fitness,” Dr Gómez-Pinilla concluded.
The best strategy for treating mild cognitive impairment is to avoid it in the first place. This means getting plenty of exercise and good sleep, eating a healthy diet, keeping body weight down, avoiding diabetes, and taking the right nutritional supplements before you experience any signs of cognitive decline.
In one prospective study, more than 500 participants age 55 or older without clinical symptoms of dementia were evaluated. Their diets were assessed at the onset of the study, and participants were screened for symptoms of dementia an average of two years later. After adjusting for other factors, participants with the highest total fat intake were found to have a significantly elevated relative risk of dementia. An increased risk of dementia was also associated with a high dietary intake of saturated fat and cholesterol. On the other hand, a high intake of fish was associated with a significantly lower risk of dementia (Kalmijn V et al 1997). These findings have been supported in several other studies (Solfrizzi V et al 2005; Solfrizzi V et al 2003; Solfrizzi V et al 1999; Panza F et al 2004; Capurso A et al 2000).
Free radicals are highly unstable molecules that react with other molecules in a damaging process known as oxidation. Areas of the body with high energy output, such as the brain, are particularly vulnerable to damage from free radicals. The body normally defends itself against the harmful effects of free radicals with antioxidants, including superoxide dismutase and glutathione peroxidase, as well as vitamins C and E. Animal studies have suggested that diets high in antioxidants can delay age-related memory loss (Joseph JA et al 1998; Perrig WJ et al 1997).
As people age, systemic inflammation can inflict degenerative effects throughout the body. A primary cause of this destructive cascade is the production of cell-signaling chemicals known as inflammatory cytokines. Along with these dangerous cytokines, imbalances of hormone-like messengers called prostaglandins also contribute to inflammatory processes.
MSM (methylsulfonylmethane or dimethyl sulfone) is a sulfur-containing molecule found in various plants and some body tissues. It is a natural and efficient source of the sulfur that is used by many of the body’s structural molecules.
Taurine is a conditionally essential amino acid produced from cysteine by the body and found abundantly in the body, particularly throughout the excitable tissues of the central nervous system, where it is thought to have a regulating influence. Taurine can promote optimal blood flow to nerves. Taurine appears to have multiple functions and plays an important role in many physiological processes, such as osmoregulation, immunomodulation and bile salt formation.
Recent studies suggested that taurine might be a pertinent candidate for use as a nutritional supplement to protect against oxidative stress. Taurine is also critical for maintaining cardiac health in certain aging individuals. Dietary taurine may help maintain healthy liver function. Taurine, however, is deficient in many diets.