Secondary plant substances

Plant foods (e.g. fruit and vegetables) make up a significant part of the human diet. However, humans only use certain parts of most plants for consumption. The potato tuber, for example, is one of our staple foods, while the fruit of the potato plant is inedible and even poisonous.

In addition to vitamins, minerals and fibre, plants produce secondary plant substances that serve as protection against herbivores, attract pollinating insects or protect against UV light. Secondary plant substances include, for example, polyphenols (such as flavonoids and anthocyanins), carotenoids and alkaloids.

These substances are not harmful to humans in the quantities found in common foods. Due to their positive effects on human health, there is an increasing number of products on the market in which secondary plant substances are enriched. Plant extracts are often produced for this purpose, which are added to foods (fortified foods) or offered in the form of food supplements. The BfRshort forGerman Federal Institute for Risk Assessment assesses whether this results in health risks.

Some secondary plant substances are toxic to the human body even in small quantities (e.g. the alkaloids nicotine and morphine) and are therefore not suitable as food ingredients.