The Role of Vegetables in Good Nutrition
“Diversifying consumption to include nutritious fruits, vegetables, and nuts can greatly enhance the quality of predominantly grain-based diets that otherwise are unable to sustain a person in good health.” Dr. Fred Bliss, University of California
Vegetables provide substantial amounts of nutrients important for human health, and are particularly important sources of micronutrients including vitamins (A, B3, and C, and folate), minerals, (calcium, potassium, phosphorus, iron and magnesium), and dietary fiber. More recently, the recognition of nutraceuticals, specific compounds in foods that may prevent disease, has added to the value of vegetables in human diet. Vegetables are thought of primarily as a source of nutrients, but could also be important in supplying calories. Studies using world average yields have shown that carrots produce slightly more edible calories per hectare per day than maize, potatoes, and sweet potatoes, and that cabbage and onions are comparable to wheat and rice. High yields of rice and sugarcane can produce 35 kg of dry matter per hectare per day, while New York research demonstrated that table beets, harvested for both leaves and roots, could produce 42 kg per day. Grains are much less perishable and easier to ship than vegetables, but if locally produced, vegetables can be a good source of total nutrition. Minerals supplied by vegetables are critical for growing children, especially those with a limited diet. Calcium is an essential component of strong bones, but is also important in moving nutrients through cell walls and for proper muscle and nerve function. When calcium in the bloodstream is low, the body removes calcium from the bones to maintain these other functions. Bones then become weak, and growth and development is impaired. Phosphorus often works in combination with calcium for formation of bones, teeth and nerves, and is plentiful in vegetables. Fortunately, phosphorus is commonly found in both plant and animal foods, so deficiency is seldom a problem. Magnesium is also essential for development of bone and muscles as well as insulin secretion and absorption of vitamins and minerals. All these minerals are required in relatively large amounts.