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Photo: Chemist Betty Burri and biologist Terry Neidlinger compare models of tracer beta-carotene and natural beta-carotene. Link to photo information

Read: more details in Agricultural Research.

How Well Do You Convert Beta-Carotene into Vitamin A?

By Marcia Wood
March 23, 2001

Beta-carotene adds attractive colors and nutritional value to many familiar fruits and vegetables. Studies led by Agricultural Research Service chemist Betty J. Burri during the past five years provide new information on the ability of our bodies to absorb beta-carotene and convert it into an essential nutrient, vitamin A.

Burri's findings are important for people who are cutting back on the amount of meat or dairy products--foods that are rich in vitamin A--that they eat. Those individuals need to be sure they are getting an adequate supply of vitamin A from other sources, Burri pointed out. She is with the ARS Western Human Nutrition Research Center in Davis, Calif.

Vitamin A is essential for proper growth and reproduction, as well as for good eyesight.

Burri found new extremes in the amount of time it takes for beta-carotene to be absorbed and converted, and in the amount that is converted. Among the most unexpected results was a statistically significant difference in beta-carotene uptake and conversion by physically similar volunteers.

About half of Burri's 45 volunteers--male and female--didn't take up much beta-carotene at all. And about half of the volunteers didn't form much vitamin A from the beta-carotene they did absorb.

Variation in the way our bodies respond to beta-carotene is likely gene-based, according to Burri. Nutrition scientists might soon be able to use new information coming from human genome researchers to develop customized dietary guidelines that take into account an individual's ability to convert beta-carotene into vitamin A.

The current issue of the ARS monthly journal, Agricultural Research, tells more.

ARS is the U.S. Department of Agriculture's chief scientific research agency.

Scientific contact: Betty J. Burri, ARS Western Human Nutrition Research Center, Davis, Calif; phone (530) 752-4748, fax (530)