Green tea, taken in a capsule or drunk in a cup, may shave a few points off "bad" cholesterol readings, according to a US study involving more than 1,000 people.

The findings, published in the Journal of the American Dietetic Association, showed that green tea trimmed 5 to 6 points more from people's total cholesterol and "bad" LDL cholesterol levels than dummy capsules or other treatments.

The trials tested either green tea itself or capsules containing green-tea compounds called catechins, which are thought to decrease cholesterol absorption in the gut.

Green tea in a cup was more consistently effective than capsules, though the benefits overall were fairly small, notes senior researcher Olivia Phung, an assistant professor of pharmacy at Western University of Health Sciences in Pomona, California.