What happens when the body cannot process beta carotene?


ISLAMABAD, December 17 (online): Two new studies in mice and humans suggest that some individuals may produce insufficient quantities of vitamin A from the beta carotene in their diets. To compensate, they may need to eat more foods containing vitamin A to maintain good cardiovascular health.
The molecular mechanisms that link beta carotene to lower blood cholesterol levels are poorly understood, however.
Now, two new studies have discovered that the body needs an active version of a certain enzyme to reap the full benefits of beta carotene for cardiovascular health.
The enzyme in question converts beta carotene into vitamin A, which reduces the amount of low-density lipoprotein (LDL) cholesterol produced in the liver.
However, up to 50% of people make a less active form of the enzyme, according to Jaume Amengual, an assistant professor of personalized nutrition at the University of Illinois at Urbana-Champaign who was involved in both studies.
After 10 days on the diet, the mice without the enzyme had more beta carotene in their blood and higher cholesterol levels than the normal mice.
Next, the researchers analyzed DNA and blood samples from 475 healthy young adults aged 18–25. The participants also filled out questionnaires about their diets.
After factoring in the amount of beta carotene and vitamin A in the participants’ diets, the researchers discovered that those with a particular variant of the BCO1 gene had significantly lower cholesterol levels.
This genetic variant produces a more active form of the enzyme that converts more beta carotene into vitamin A.
The authors estimate that people who have one or more copies of this BCO1 gene variant could have a 9% reduction in LDL cholesterol, compared with those who do not. “Although speculative, this decrease may be clinically meaningful if maintained through adulthood,” they write.