Sufficient consumption of fruits and vegetables is continuously recommended by dietitians and physicians due to their effectiveness in prevention of cancers, cardiovascular disease and the risk factors such as diabetes, obesity and hypertension. Cardiovascular disease mainly refers to the disorders in heart and blood vessel system (arteries, capillaries, veins). The risk of heart disease can be determined by the type of diet. A diet rich in fruits and vegetables can reduce the risk of heart disease and stroke. High blood pressure is a major risk factor for heart disease and stroke.Eating more fruits and vegetables can have a significant effect on balancing cholesterol level and inhibiting the oxidation of low density lipo-protein (LDL) cholesterol in the body. The progression of postprandial lipemia (refers to the excessive lipids in the blood) that is in positive association with the oxidative changes of lipids results in atherosclerosis. Frequent ingestion of fruits and vegetables substantially contributes to decreasing the development of the postprandial oxidative stress in the body.

Fruits and vegetables are abundant in vitamins, minerals and fibres. They can protect the body against the risk of cancer via exerting antioxidant activity and limiting the cellular damage from free radicals. Research demonstrated that the regular ingestion of specific types of fruits and vegetables can suppress/minimise the occurrence of heart disease and certain types of cancer. The most contributing groups include green leafy vegetables (such as lettuce, spinach, swiss chard and mustard greens); cruciferous vegetables (e.g. broccoli, cauliflower, cabbages, brussels sprouts) and citrus fruits (like oranges, lemons, limes, and grapefruits). The beneficial function of these plants is attributed to the presence of some chemical compositions such as dithiolethiones and glucosinolates from cruciferous vegetables that are able to curtail the growth of cancer cells.

It is important to consume sufficient proportion of different types of fruits and vegetables on a daily basis to maintain health and reduce the incidence of carcinogenic and cardiovascular diseases. A daily intake of at least 400g of vegetables and fruits (excluding starchy tubers such as potatoes) per person is recommended. The National Cancer Institute approves a range of 5 to 9 servings of fruits and vegetables per day. 7 daily servings for young women and 9 daily servings for young men are usually recommended by dietitians. Variety is as critical as the proportion. The healthy diet should include dark-green leafy vegetables, yellow / orange / red fruits and vegetables, cooked tomatoes and also citrus fruits.