Caffeine may offset some health risks of high fat, sugar diets

Caffeine may offset some of the negative effects of an obesogenic diet by reducing the storage of lipids in fat cells and limiting weight gain and the production of triglycerides, according to a new study published in the Journal of Functional Foods.

Rats that consumed the caffeine extracted from mate tea gained 16 percent less weight and accumulated 22 percent less body fat than rats that consumed decaffeinated mate tea, scientists at the University of Illinois found in a new study. The effects were similar with synthetic caffeine and that extracted from coffee.

Mate tea is an herbal beverage rich in phytochemicals, flavonoids, and amino acids that's consumed as a stimulant by people in southeastern Latin American countries. The amount of caffeine per serving in mate tea ranges from 65-130 milligrams, compared with 30-300 milligrams of caffeine in a cup of brewed coffee, according to the study.

For four weeks, the rats in the study ate a diet that contained 40 percent fat, 45 percent carbohydrate, and 15 percent protein. They also ingested one of the forms of caffeine in an amount equivalent to that of a human who drinks four cups of coffee daily.

At the end of the four-week period, the percentage of lean body mass in the various groups of rats differed significantly. The rats that ingested caffeine from mate tea, coffee, or synthetic sources accumulated less body fat than rats in the other groups.

In the rats, the accumulation of lipids in the adipocytes was significantly associated with greater body weight gain and increased body fat, according to the study. To determine the mechanism of action, the scientists performed cell culture studies in which they exposed adipose cells from mice to synthetic caffeine or the coffee or mate caffeine extracts. They found that regardless of its source, caffeine decreased the accumulation of lipids in adipose cells by 20-41 percent.

The scientists also tracked the expression of several genes associated with obesity and lipid metabolism. These included the fatty acid synthase gene (Fasn), an enzyme compound involved in the synthesis of fatty acids from glucose; and the lipoprotein lipase gene (Lpl), which codes for an enzyme that breaks down triglycerides.

All of the caffeine treatments, regardless of origin, significantly downregulated the expression of both Fasn and Lpl. In the cell cultures, Fasn expression diminished by 31-39 percent, while Lpl expression decreased by 51-69 percent among cells treated with synthetic caffeine or the caffeine from mate tea or coffee. In the rats that consumed the mate tea caffeine, expression of Fasn decreased by 39 percent in their fat tissue and by 37 percent in their livers, the researchers said.

The decreased expression of Fasn and two other genes in the liver evoked lower production of low-density lipoprotein cholesterol and triglycerides in the liver as well, according to the study.