Anthocyanins are plant chemicals that belong to the flavonoid group of polyphenols. Anthocyanins are responsible for many of the red, blue and purple colours found in berries and petals. The main source of anthocyanins in the human diet is berries, and it is estimated that around 12 mg per day in Western nations are consumed daily. Anthocyanins are bioavailable, which means they are absorbed and enter circulation and then interact with human tissues.
Flavonoids And Cardiovascular Disease
The Zutphen Elderly Study was one of the first to report on an inverse association between flavonoid intake and cardiovascular risk. Since this time, more studies have corroborated the observation that those who eat more flavonoids are less likely to develop cardiovascular disease. Undoubtedly other flavonoids play a role in this association. However, a large part of this protective effect may be due to the consumption of anthocyanins.
High Density Lipoprotein
Anthocyanins have been studied in relation to their ability to raise levels of high density lipoprotein (HDL). Animal and human studies confirm that high intakes of anthocyanin rich fruit, and anthocyanin supplements, can both raise HDL levels. The HDL particle transports plasma cholesterol from the peripheral tissues to the liver for excretion. Therefore anthocyanins might be beneficial to cardiovascular disease through this lipoprotein modulating effect.
Systemic oxidative stress is now implicated as a cause of cardiovascular disease. This oxidative stress is thought to inhibit the synthesis of nitric oxide within the endothelial lining of arteries, and this prevents the normal dilation relaxation cycle that results from blood flow. As a result blood pressure increases because the elasticity of the arteries deteriorates. Because anthocyanins are effective antioxidants, they may prevent endothelial dysfunction and lower blood pressure.
Anthocyanins: How Much?
The average intake of anthocyanins may be less than 15 mg per day. This level is likely too low to provide protection from cardiovascular disease. Supplements are also a poor source of anthocyanins because far high quantities and a wider variety of anthocyanins can be obtained by eating berries. Eating a handful of berries every day would provide more that the current 12 mg per day intake and is likely enough to confer protective effects against cardiovascular disease.