Overview
This lecture covers phytochemicals, which are non-essential plant compounds that may promote human health, their functions, sources, and potential concerns.
What Are Phytochemicals?
- Phytochemicals are chemicals found in plants that may provide health benefits but are not essential nutrients.
- Sources include fruits, vegetables, grains, seeds, nuts, and legumes.
- Major groups of phytochemicals are carotenoids, indoles, lignans, phytoestrogens, stanols, saponins, terpenes, flavonoids, anthocyanidins, and phenolic acids.
Functions and Health Effects
- Many phytochemicals act as antioxidants to protect cells from oxidative damage.
- Some phytochemicals mimic hormones, alter cholesterol absorption, inhibit inflammation, or block enzyme action.
- The combined variety of phytochemicals in whole foods is linked to health benefits.
Examples of Phytochemicals and Their Sources
- Carotenoids: found in yellow-orange fruits and dark green leafy vegetables, may help fight cancer.
- Indoles: present in cruciferous vegetables, may inhibit cancer hormone development and tumor growth.
- Phytoestrogens: in grapes, berries, plums, soy, and garlic, may reduce the risk of osteoporosis, heart disease, and some cancers.
- Stanols: found in grains, nuts, legumes, may lower cholesterol and heart disease risk.
- Saponins: in beans and lentils, may decrease blood lipids and cancer risk.
- Terpenes: in citrus fruits, may slow cancer cell growth and support immunity.
- Flavonoids: present in fruits, vegetables, chocolate, tea, etc., may support immunity and prevent cancer.
- Anthocyanidins: in vibrantly colored produce, may prevent cardiovascular disease and inhibit tumor formation.
- Phenolic acids: found in coffee, fruits, cereals, and herbs, may prevent cell damage and promote anti-inflammatory conditions.
Safety and Supplementation Concerns
- Most health benefits and potential toxicities of phytochemicals are not fully known.
- Supplements containing large amounts of single phytochemicals may disrupt the balance and effectiveness of others.
- Eating a variety of whole plant foods is currently the best approach for gaining the benefits.
Key Terms & Definitions
- Phytochemical — a plant substance not essential for life, which may have health-promoting properties.
- Carotenoid — a type of phytochemical that can also act as a vitamin A precursor.
- Micronutrient — an essential nutrient needed in small amounts, such as vitamins and minerals.
- Antioxidant — a compound that prevents oxidation and protects cells from damage.
Action Items / Next Steps
- Review common food sources of major phytochemicals.
- Emphasize eating a wide variety of plant-based foods for optimal health benefits.
- Avoid excessive supplementation with isolated phytochemicals.