Phytonutrients are bioactive compounds naturally found in plants, with their types and concentrations varying from one plant to another. The most predominant classes include terpenoids, polyphenols, phenolic constituents, alkaloids, carotenoids, phytosterols, saponins, and fibres. These compounds support human health in many ways—by providing antioxidant protection, influencing cell differentiation, supporting DNA repair, aiding detoxification enzymes, encouraging healthy cell turnover, and helping regulate inflammation and proliferation.

Researchers have already identified around 10,000 phytonutrients, though estimates suggest there may be anywhere between 50,000 and 130,000 in total, with many still unknown. For this reason, this section focuses on the major, well-identified families of phytonutrients: terpenes, chlorophylls, polyphenols, organosulfur compounds, alkaloids, and phytosterols. To make these easier to understand, this section also highlights their key compounds, common food sources, and known biological actions. See our diagram below for a visual overview of these families and their subtypes.

For centuries, civilisations around the world have used plant-based foods for health benefits, though only in recent decades has science begun to validate these traditional practices with in vivo studies. As with all nutrition, moderation and variety are key. Eating a wide spectrum of plant-based foods is the safest and most effective way to harness phytonutrients, and when in doubt, it’s always best to consult a qualified professional.