Fruits and Vegetables

One of the most important messages of modern nutrition is that a diet rich in fruits and vegetables promotes health while protecting against almost all diseases including cancer, cardiovascular disease (CVD), diabetes mellitus, and several other age-related degenerative disorders. Specifically, the intake of 400–600 grams per day of fruits and vegetables is beneficial. Every dietary plant contains numerous types of antioxidants with different properties. Because oxidative stress is common in chronic degenerative disease, dietary antioxidants may explain the protective effect of fruit and vegetable consumption. Many of these antioxidants cooperate in oxidative stress reduction in plants, so the many different antioxidants may also be needed for the proper protection of animal cells.

In addition to essential nutrients, such as protein, amino acids, vitamins, and minerals, plant foods also contain phytochemicals that have additional health benefits. The term “phytochemical” means any compound of plant origin. Phytochemicals may play a key role in reducing chronic disease risk and include phenolics, flavonoids, and carotenoids. Plant sterols, the minor lipid components of plants, may be beneficial due to their cholesterol-lowering effect. Polyphenols are substances with antioxidant activity, which give some flowers, fruits, and vegetables their color. Tea also contains polyphenols. The flavonoids are polyphenolic compounds that have antitumor properties as well as cardioprotective effects with respect to vascular function and platelet reactivity. Flavonoids are universally present as constituents of flowering plants, especially of food plants. Flavanol-rich, plant-derived foods and beverages include wine, tea, various fruits and berries, and cocoa and cocoa products.

Colored fruits are considered a trait that correlates with nutritional values and health benefits. For example, red foods contain lycopene, the pigment in tomatoes, which may be involved in maintaining prostate health, and has also been linked with a decreased risk of cardiovascular disease. Green foods, such as broccoli, Brussels sprouts and kale, contain glucosinolates, which have also been associated with a decreased risk of cancer. Garlic and other white-green foods in the onion family contain allyl sulfides, which may inhibit cancer cell growth. Bioactive substances in green tea and soybeans have additional health benefits. Individuals are recommended to ingest one serving of each of the seven color groups daily, as part of the five to nine servings of fruits and vegetables per day.

Research has shown that people who consume large amounts of fruits and vegetables have a lower incidence of CVD, stroke and tumors. CVD accounts for almost 50 percent of all deaths in industrialized nations and approximately 70 percent of CVD can be prevented or delayed with dietary choices and lifestyle modifications. Of the tree nuts, walnuts, pecans, and chestnuts have the highest antioxidants. Death attributed to cardiovascular and coronary heart diseases show strong and consistent reductions with increasing nut/peanut butter consumption. Because of their chemical structure, plant polyphenols are able to scavenge free radicals and inactivate other pro-oxidants involved in the etiology of many chronic diseases. Many nutrients and phytochemicals in fruits and vegetables, including fiber, potassium, and folate, could be independently or jointly responsible for the apparent reduction in CVD risk.

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