Fruits and vegetables as well as other whole foods contain the plant chemicals, which protect against heart disease, cancer, other diseases
"Eat your fruits and vegetables" is familiar nutritional advice and was no doubt originally intended to encourage people to eat foods that would meet all of their nutritional needs. Now, the science of nutrition has unearthed even more reasons why that advice is indeed beneficial: phytochemicals. Fruits and vegetables as well as other whole foods like nuts, legumes, and whole grains contain phytochemicals that have the ability to alter body processes and protect against heart disease, cancer, and many other chronic diseases.
The word phytochemical means plant chemical. In fact, the term "phyto" comes from the Greek word for "plant." Phytochemicals are organic, non-nutritive, naturally occurring chemicals found in plant foods. Even though they are non-essential nutrients, meaning they are not needed to sustain life, they may prolong life because of their health promotion properties.
PROTECTING PLANTS AND PEOPLE
Phytochemicals are a plant's way of protecting itself. They help shield tender buds and sprouts from predators, the elements, and pollution. These protective compounds are passed along to us when we eat plant foods.
One of the reasons we may like (or don't like) certain foods is because of the phytochemicals they contain. These various compounds give foods their color, taste, and smell. They put the hot in habaneras, the gusto in garlic, the bitterness in broccoli, and the color in carrots. For example, carotenoids give foods their deep red, dark orange, and yellow color while anthocyanins provide the various shades of red, purple, and blue found in other fruits and vegetables.
Flavonoids are the pigments that are responsible for the many other shades of yellow, orange, and red in foods. Isothiocyanates and indoles are the chemicals in cabbage that give that notorious odor to the kitchen when cabbage is cooked. Capsaicin puts the hot in chili peppers.
HOW PHYTOCHEMICALS HELP THE BODY
Phytochemicals appear to have significant physiological effects in the body. Whether they are acting as antioxidants, mimicking hormones, stimulating enzymes, interfering with DNA replication, destroying bacteria, or binding to cell walls, they seem to work to curb the onset of diseases such as cancer and heart disease. Some phytochemicals work alone, others work in combination, and some seem to work in conjunction with other nutrients in food, such as vitamins.
The more brightly colored the food, the more phytochemicals a food contains, perhaps making the food that much more beneficial. However, less colorful fruits and vegetables, like onions and corn, are also rich in phytochemicals. Eating a wide variety of fruits and vegetables is the best way to achieve all the potential benefits that phytochemicals offer.
There are over 1,000 known phytochemicals and probably many more that are yet to be discovered. The table below shows several types of phytochemicals, their possible beneficial effects, and food sources of each.
The recent research into the potential health benefits of phytochemicals has uncovered numerous possibilities. Anthocyanins and other flavonoids appear to improve vision health. Resveratrol is being studied for the prevention of prostate cancer. The isoflavones in soybeans may reduce inflammation and the risk of heart disease. Lignans have shown promise in reducing the growth of cancerous tumors, particularly in the breast and prostate.
Cranberries contain a diverse composition of phytochemicals, and research shows promise that they may help to limit cancer and other diseases of aging. Phytochemicals in apples were shown to reduce cardiac risk factors in obese rats with metabolic syndrome. Whole grain foods contain a wide variety of unique phytochemicals that are thought to be responsible for the health benefits of whole grain consumption.