The evidence continues to mount demonstrating that anthocyanins found in various plant foods favorably impact blood lipids, other CVD risk factors, and slow or even help shrink atherosclerotic plaques.
Anthocyanins are water-soluble plant pigments in the flavinoid class. They can appear purple, red, blue, and almost black depending on their concentration and pH. They give eggplants, purple cabbage, purple grapes, cherries, strawberries and blackberries much of their reddish to almost black color. Anthocyanins are also found in large amounts in blue or purple corn, purple potatoes, and black rice, olives, soybeans and sorghum. Smaller amounts of anthocyanins are found in red apples, asparagus, peas, and even bananas have some.
A recent double-blind, randomized crossover trial gave a group of 120 dyslipidemic subjects ages 40-65 either a supplement with 160 mg of anthocyanins derived from bilberries and black currants or a look-alike placebo twice daily for 12 weeks. All subjects were instructed to maintain their current diet and lifestyle. In both groups, compliance was excellent. There were no significant differences between the dietary intake of the two groups and there was no significant change in body weight, blood pressure, triglycerides, or blood glucose. However, the LDL dropped about 14% more in the anthocycanin supplemented group than the control group.
In addition HDL level rose by 13.7% in the anthocyanin group but changed little in the placebo group. The researchers also noted a significant drop in plasma Cholesteryl Ester Transfer Protein (CETP). This may help explain the changes in HDL and LDL cholesterol levels observed as CETP is involved in the exchange of cholesterol from these lipoprotein particles in the blood. In addition higher levels of CETP may slow the removal excess cholesterol from artery walls via a process known as reverse cholesterol transport. So if anthocyanins reduce CETP activity they could speed up the process by which HDL particles remove cholesterol from artery walls and transfer it back to the liver where it can be removed from the body. Indeed this was exactly what these researchers observed when they measured the change in which cholesterol was removed (a.k.a., efflux) from cells in the two groups. Cholesterol efflux was increased by 20% in the anthocyanin supplemented group but increased a mere 0.2% in the control group.
An earlier study using this same anthocyanin supplement used in the above study for just 3 weeks compared it to a placebo in 120 subjects 40-74 years of age and found it inhibited pro-oxidant, proinflammatory transcription factor (NK-kappaB). In this study, the anthocyanins directly inhibited the cascade of inflammatory cytokines by human white blood cells.3 Since increased oxidation of cholesterol and inflammation are involved in the growth and rupture of atherosclerotic plaques this data also suggest that regular consumption of anthocyanin-rich foods may help prevent the build up of atherosclerotic plaques and significantly reduce the risk of cardiovascular disease.
While the research on anthocyanins is encouraging, it is still too soon to be recommending anthocyanin supplements for everyone. The amount of anthocyanins used in these two studies could easily be obtained from eating just one anthocyanin-rich food once a day i.e.: blue corn, 2 ounces of eggplant or red grapes or a few ounces of blueberries, cherries, or raspberries per day. These foods contain not only anthocyanins but lots of other phytochemicals, nutrients, and fiber that may also improve cardiovascular disease risk factors and reduce heart disease and strokes. Plus fruits, vegetables, and whole grains rich in anthocyanins have a modest calorie density and so may aid weight loss. Weight loss also lowers LDL and raises HDL as well as reducing inflammation, insulin resistance, and blood pressure. Such health benefits are far less likely to result from adding anthocyanin supplements or acia berry juice to a typical modern diet full of refined carbohydrates and fatty animal products.
By James J. Kenney, PhD, RD, LD, FACN.
1. Am. J. Clin. Nutr. 2009;90:485-92.
2. J Nutr. 2007;137:1951-4
Stephanie Ronco has been editing for Food and Health Communications since 2011. She graduated from Colorado College magna cum laude with distinction in Comparative Literature. She was elected a member of Phi Beta Kappa in 2008.