A study published in the American Journal of Clinical Nutrition suggests that consuming foods rich in flavonoids—bioactive compounds found in fruits, vegetables, and other plant foods—may help lower body fat. The most common flavonoids include anthocyanins (berries, red grapes), flavan-3-ols (green tea, cocoa), flavonols (onions, kale, broccoli), flavanones (citrus fruit), flavones (parsley, celery), and isoflavones (soybeans, legumes).
The researchers analyzed the diets of 2,734 healthy, female twins, aged 18–83, and calculated their intake of total flavonoids as well as different subclasses of flavonoids. They measured the participants’ body fat using dual-energy X-ray absorptiometry, the same technique used to measure bone density.
The researchers found that the women whose diets contained the most foods rich in flavonoids had significantly lower total body fat and abdominal fat compared to those who consumed the least. That was true even after accounting for physical activity and other diet factors such as caloric intake and total intake of fruit and vegetables. The researchers note that this suggests that the protective effects weren’t related to a regular diet high in fruits and vegetables, but rather a specific component in these foods, such as flavonoids.
In addition, the researchers found that the most protective flavonoids were the anthocyanins and flavones. Consuming the most of these types was tied to a 9% lower abdominal fat. Lower body fat was related to eating an extra 2.6 servings per day of anthocyanin-rich foods and an additional 2.7 daily servings of foods high in flavones.
The researchers also examined the link between flavonoid intake and body fat in participants who were identical twins. They did so to find associations that were independent of genetic factors that may play a role in body fat composition. They found that twins with high intakes of foods plentiful in flavonols and anthocyanins had significantly lower levels of abdominal fat than their siblings who consumed less.
The researchers noted that because the studies measured food intake and body fat at one point in time the results can’t prove cause and effect.