Flavonoids are phytonutrients that are most concentrated in purplish red and brownish plants including berries, red cabbage, red onion, some whole grains,coffee and tea, red wine, and cocoa. They come in many different forms including flavonols and flavones. The health effects of flavonoids primarily stem from their potent antioxidant properties, as they are capable of scavenging free radicals, which play a major role in the onset of many chronic diseases. Regular intake of flavonoid-rich foods has been proven effective in the treatment and prevention of heart disease, cancer, and inflammatory disorders.

Carotenoids are extremely powerful antioxidant compounds that protect the cells, tissues, and organs of the body from free radical damage. Due to their effects on free radicals, carotenoids have been shown to protect against heart disease, high blood pressure and certain forms of cancer, amongst other chronic conditions. Common forms of carotenoids include beta-carotene, alpha-carotene, and lycopene. Plant-based sources of such carotenoids include carrot, sweet potato, tomato, cantaloupe, kale, broccoli, sweet peppers, and other vegetables and fruits that are red, orange, yellow or green in color.

Isothiocyanates are one of the most effective cancer-fighting phytonutrients. They have been shown to reduce cancer risk in organs such as the lung, breast, prostate, and colorectum. Isothiocyanates are largely present in cruciferous vegetables like Brussels sprouts, cauliflower, broccoli, cabbage, and horseradish. They are responsible for the bitter taste of these vegetables and they’re generally released when you chop or chew them. Regularly consuming isothiocyanates-rich foods may greatly hinder cancer development and tumor growth, especially when they’re consumed in raw form (click here for six vegetables and fruits that can effectively fight many types of cancer).

Lignans are specialized estrogen-like phytonutrients (phytoestrogens) that exert beneficial hormonal and antioxidant effects. Due to these effects, regular consumption of foods containing lignans may offer protection against cancers of the breast and prostate, colorectal cancer, and even skin cancer. Of all plant-based foods, flaxseeds and sesame seeds are the richest sources of lignans including secoisolariciresinol, pinoresinol, and lariciresinol. In addition to these foods, substantial quantities of lignans are housed in whole-grains, vegetables, and some fruits (berries and apricots).

Indoles are well-known phytonutrients that are largely present in leafy green and cruciferous vegetables like kale, Brussels sprouts, collard greens, broccoli, and bok choy. Similar to lignans, indoles are classified as phytoestrogens as they exert powerful hormonal effects that greatly protect against cancer. They are also effective antioxidants and free radical scavengers. As everyday dietary choices, foods containing indoles have been proven beneficial in the treatment and prevention of various forms of cancer, especially hormone-linked cancers like breast and ovarian cancer.