Effects of Fruit Juice Processing and Human Metabolism on the Functionality of Anthocyanins for Cardiovascular Health (DRINC)

People who consume the highest quantities of fruits and vegetables appear to be more protected against heart disease than those who consume lower quantities. Evidence suggests that this protective effect is in part the result of substances in the fruits and vegetables called polyphenols. In recent years, berries and berry derived juices and wines have been promoted as especially healthy foods as they are high in a particular class of polyphenol called anthocyanins. These anthocyanins are reported to have activities that benefit the heart and blood vessels.

Cardiovascular diseases (CVD) and specifically stiffness of the arteries results from accumulated damage to blood vessel walls. There is a single layer of cells that lines the blood vessels which is sensitive to agents/compounds within the blood. When this layer is damaged as a result of injury or chronic disease, it loses its ability to maintain normal blood vessel function and becomes prone to processes that lead to heart disease. Anthocyanins and anthocyanin containing foods have been shown to have direct protective effects on this cell layer, thus restoring proper function to the blood vessels. However, the anthocyanins in the foods we eat often become altered during standard food processing and storage conditions, an effect that is believed to negatively alter their function relative to those in raw fruits or vegetables. As well, when we eat anthocyanins they become modified by our bodies, resulting in drastic changes to their original form. Previous experiments have used unaltered or original forms of anthocyanins to explore how these compounds affect the cells in our bodies and blood vessels. However, no studies have explored the true activity of anthocyanins as they exist within our bodies, as altered products in our circulatory system resulting from changes during processing and digestion. The effects of these alterations on the disease fighting properties of anthocyanins are currently unknown and could be greater, different or impartial to what we currently perceive.

The aim of the present program of research is to identify the actions of pure anthocyanins relative to their altered products of processing and digestion on CVD risk. In order to determine their functions, we must first identify their forms in the body after we eat them. We will identify changes that occur to anthocyanins (cyanidin-3-glucoside, the most abundant anthocyanin in nature) in common fruit juices on the UK market, during standard processing and storage conditions. We will also feed human participants a pure anthocyanin (cyanidin-3-glucoside) in order to trace its path and alteration through the body. We will then study the effects of the identified compounds on CVD risk by exploring their activities on the cells (cultured-cells) lining our blood vessels.

With this study we hope to prove the usefulness of anthocyanins as a dietary treatment for the prevention of cardiovascular disease, using the relevant compounds found in the body; thus providing informed advice on the health benefits of anthocyanins. The results of this study are also relevant to agricultural industries as levels of anthocyanins in food crops can be easily increased using breeding strategies and pre and post harvest manipulation. This project is particularly relevant to the processed food and beverage industry, as although the alteration of anthocyanins during food processing has generally been considered of negative consequence, the proposed research could establish this as a neutral or potentially beneficial outcome; providing valuable evidence to support the use of fruit juices for the delivery of beneficial components for health. This proposal will also generate findings that may be useful for future studies aimed at investigating the relative activity of other dietary polyphenols, such as those found in coffee, tea, wine or chocolate.