How Do Phytochemicals in Your Diet Benefit Your Health
Beneficial phytochemicals — nutrients found in plant foods — appear to be antioxidants, hormone-like compounds, and enzyme-activating sulfur compounds. Including phytochemicals in your diet helps maintain health and reduce your risk of certain illnesses, such as heart disease, and some kinds of cancers.
Antioxidants: These prevent a chemical reaction called oxidation, which enables molecular fragments called free radicals to join together, forming potentially carcinogenic (cancer-causing) compounds in your body.
Antioxidants also slow the normal wear-and-tear on body cells, so a diet rich in fruits, vegetables, grains, and beans seems likely to reduce the risk of heart disease and maybe reduce the risk of some kinds of cancer. For example, consuming lots of lycopene along with just a touch of oil has been linked to a lower risk of prostate cancer.
Hormone-like compounds: Many plants contain compounds that behave like estrogens. Because only animal bodies can produce true hormones, these plant chemicals are called hormone-like compounds or phytoestrogens (plant estrogen).
The three kinds of phytoestrogens are
Isoflavones, in fruits, vegetables, and beans
Lignans, in grains
Coumestans, in sprouts and alfalfa
The most-studied phytoestrogens are the isoflavones known as daidzein and genistein (found in soy), two compounds with a chemical structure similar to estradiol, which is the estrogen produced by mammalian ovaries.
Daidzein and genistein hook onto reproductive tissue (breast, ovary, uterus, prostate) called estrogen receptors Research suggests that consuming isoflavone-rich foods such as soy products may provide post-menopausal women with the benefits of estrogen (stronger bones and relief from hot flashes) without the higher risk of reproductive cancers (of the breast, ovary, or uterus) associated with hormone replacement therapy (HRT).
However, some studies question the safety of phytoestrogen-rich foods for women with hormone-sensitive tumors, and suggest that phytoestrogen may stimulate tumor growth in animals whose ovaries have been removed.
On the other hand, including isoflavone-rich soy foods such as tofu, miso, tempeh, soy milk, soy flour, and soy protein in a healthful diet may reduce total cholesterol, lower LDL and maintain or increase blood levels of HDL.
Enzyme-activating sulfur compounds: Cruciferous vegetables such as broccoli, Brussels sprouts, cauliflower, kale, kohlrabi, mustard seed, radishes, rutabaga, turnips, and watercress — all contain stinky sulfur compounds, such as sulforaphane glucosinolate (SGSD), glucobrassicin, gluconapin, gluconasturtin, neoglucobrassicin, and sinigrin, that rev up your production of enzymes that inactivate and help eliminate carcinogens.
These smelly sulfurs may be one reason why people who eat lots of cruciferous veggies generally have a lower risk of cancer.
Dietary fiber: This special bonus found only in plant foods. You can’t get it from meat or fish or poultry or eggs or dairy foods.
Soluble dietary fiber, such as the pectins in apples and the gums in beans, mops up cholesterol and lowers your risk of heart disease. Insoluble dietary fiber, such as the cellulose in fruit skins, bulks up stool and prevents constipation, moving food more quickly through your gut so there’s less time for food to create substances thought to trigger the growth of cancerous cells.