When It Comes to Red Cabbage, More Is Better
By Rosalie Marion
February 28, 2008
Plant pigments called anthocyanins
provide fruits and vegetables with beneficial blue, purple and red coloring.
Now Agricultural Research Service (ARS)
scientists are learning more about these compounds and their absorption into
the human blood stream.
Anthocyanins are a group of healthful compounds that fall within the
flavonoid class of plant nutrients. ARS scientists have identified 36
anthocyanins in red cabbage, including eight that had never before been
detected in the cabbage.
The study was conducted at the ARS Beltsville Human Nutrition Research
in Beltsville, Md., where scientists have pioneered methods for identifying
and measuring various phytonutrients in fruits and vegetables. Physiologist
Clevidence, plant physiologist
Britz and research associate
Charron, all with the BHNRC's
Components and Health Laboratory, published the findings in the Journal of Agricultural
and Food Chemistry.
Emerging evidence suggests that anthocyanins may provide cancer protection,
improve brain function and promote heart health. An earlier ARS study showed
that some anthocyanins yield twice the antioxidant power of the same amount of
vitamin C in test tubes, though the amount absorbed by the human body was not
Twelve volunteers consumed three different amounts of cooked red cabbage
along with a full diet of carefully controlled foods. Each volunteer completed
three two-day meal regimens, which included 2/3 cup, 1-1/3 cups, or 2 cups of
red cabbage. The volunteers were capable of absorbing the most anthocyanins
when given the largest serving of cooked cabbage.
Interestingly, the anthocyanins that the researchers identified were not
equally absorbed, as measured by the portion of the ingested compound that
reached the blood stream. Nearly 80 percent of cabbage anthocyanins tested were
"acylated," meaning attached to acyl groups, which made them more
stable and less absorbable. The non-acylated anthocyanins present were at least
four times more bioavailable, or absorbed, than the acylated anthocyanins.
The findings could aid plant breeders in developing varieties with key
anthocyanin structures and amounts.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.