Trevor Ponder Human Memory

Adding a moderate, but not high, amount of walnuts to an otherwise healthy diet may help older individuals improve performance on tasks that require motor and behavioral skills, according to an animal model study by Agricultural Research Service (ARS)-funded scientists. Walnuts contain polyphenols and other antioxidants and essential fatty acids.

The study was conducted by researchers at Tufts University in Boston, Mass.

The aging brain undergoes many changes that can result in altered or impaired neuronal functioning. Such disruption can be attributed in part to alterations in “synaptic plasticity,” or the ability of the connections between neurons to change in strength and function, and also by increased oxidative damage to neural tissue. In aged rodents, these impairments are seen as poor performance on age-sensitive tests of balance, coordination, and “spatial” working memory.

For the study, weight-matched, aged rats were randomly assigned to one of four diet groups. For eight weeks, the rats were fed special chow mixes that contained either 2 percent, 6 percent or 9 percent walnuts-or no walnuts-before undergoing motor and memory tests. For comparison, the 6 percent walnut study diet is equivalent to a human eating 1 ounce, or about 7 to 9 walnuts, a day. That counts as both a 2-ounce equivalent from the “meat and beans group” and 2 teaspoons toward a daily allowance of dietary oil, as described at MyPyramid.gov.

The study found that in aged rats, the diets containing 2 percent or 6 percent walnuts were able to improve age-related motor and cognitive shortfalls, while the 9 percent walnut diet impaired reference memory. Walnuts, eaten in moderation, appear to be among other foods containing polyphenols and bioactive substances that exhibit multiple effects on neural tissue, according to the researchers.

Memory and Food memory food

Zinc deficiency was first described in Egyptian and Iranian adolescents more than 30 years ago and continues to be a common health problem for children living in both developing and developed countries. As many as 70 percent of school-aged children in Thailand and 34 percent of Chinese preschool children may be zinc deficient. Zinc deficiency in the United States is much less common, with studies showing that about 6 percent of girls and 10 percent of boys are zinc deficient. Such deficiency is known to impair immune function and to retard growth in children. But its impact on brain function and mental performance has been demonstrated only recently.

Zinc is known to be essential for brain development and function in animals. When mice, rats and primates are deprived of zinc during critical periods of brain development, they exhibit many behavioral deficits, particularly in memory, activity, aggression and socialization. Recent work has shown that even mild zinc deprivation of pre-adolescent monkeys results in deficits in both memory and attention. Severe zinc deprivation of adult animals has also impaired their behavior.

When adult men were treated with an agent that removes zinc from the body, they experienced more mood swings and deficits in visual perception and verbal memory. In a highly controlled, 6-month study at the Grand Forks Human Nutrition Research Center we found that men with low zinc intakes had faster, but less accurate performance on tasks measuring verbal and nonverbal memory. In another controlled study at our Center, we found that restricted zinc intakes caused men to perform more poorly on 9 of 15 cognitive and psychomotor tasks. On the other hand, taking a 30-milligram (mg) supplement of zinc each day improved visual memory in a study done with women.

The early studies of severely and moderately zinc-deficient adolescents in Egypt and Iran found “mental disturbances” and “mental lethargy” among those children. Subsequent studies of mental performance of children at risk of zinc deficiency have yielded inconsistent results. In Canada and Guatemala, young school children given an extra 10 mg of zinc daily had no significant improvement in mental performance. But a study of more than 1,000 school-aged children in China conducted by the our Center had different results. Those supplemented with 20 mg of zinc daily showed more improvement in hand-eye coordination, attention and reasoning than the children given a supplement containing most of the essential vitamins and minerals except zinc and four other minerals known to interfere with its absorption. This was the first intervention study to demonstrate in children a relationship between zinc intake and cognition and psychomotor function.

More recently, scientists found similar effects with zinc supplementation of school-aged Mexican-American children living in southwest Texas. These findings suggest that zinc supplementation most likely improves attention, reasoning and psychomotor function, such as hand-eye coordination. It appears that we are now beginning to uncover the role of zinc for brain function and mental performance of children, and the results of this detective work clearly will have very important implications for the world’s population with suboptimal zinc intakes and others who are at risk for zinc deficiency. This work also is another example of the important work on mineral nutrition and human health and performance being conducted at Grand Forks Human Nutrition Research Center.

Good sources of zinc are: oysters, beef, pork, liver, dried beans and peas, whole grains, fortified cereals, nuts, milk, cocoa and poultry.

Memory and Food memory food, zinc

Memory and Food memory food