People can easily reach a potentially dangerous level, about five times the recommended dose, by taking vitamins and supplements, nutrition researchers say.

"I think there's something to it," said Dr. John Milner, a nutrition researcher at the National Cancer Institute.

He called for more research on the nutritional needs of older people, who until recently have been relatively neglected by nutrition researchers.

Nutriomics is a new field where traditional nutrition researchers adopt genomics technology such as large scale microarray analysis with food intake.

The discoveries chosen were based on the views of the world's leading nutrition researchers and solid research data.

Medical authorities and nutrition researchers have documented that youngsters who eat nutritious meals every day and lead active lifestyles tend to excel.

Historically, the elderly have been sorely neglected by nutrition researchers.

Dr. Simin Meydani, a nutrition researcher at Tufts, reviewed 161 published reports on the immunological effects of yogurt.

Some, like Dr. Jeffrey Blumberg, a nutrition researcher at Tufts University, take an aggressive public health stance.

Dr. Robert Russell, nutrition researcher at Tufts, suggests 25 micrograms a day of B12, about four times the current recommended amount.