Vegetables are the edible products of herbaceous plants, which are plants with soft stems. Vegetables are grouped according to the edible part of each plant including leaves (e.g., lettuce), stalks (celery), roots (carrot), tubers (potato), bulbs (onion), fruits (tomato), seeds (pea), and flowers (broccoli). Each of these groups contributes to the human diet in its own way. Fleshy roots are high in energy value and good sources of the vitamin B group, seeds are relatively high in carbohydrates and proteins, while leaves, stalks, and fruits are excellent sources of minerals, vitamins, water, and roughage. Vegetables are an important food for the maintenance of health and prevention of disease. Higher intakes of vegetables have been shown to lower the risks of cancer and coronary heart disease.
Vegetables are best consumed fresh in their raw state in order to derive the maximum benefits from their nutrients. While canned and frozen vegetables are often thought to be inferior to fresh vegetables, they are sometimes nutritionally superior to fresh produce because they are usually processed immediately after harvest when nutrient content is at its peak. When cooking vegetables, aluminum utensils should not be used, because aluminum is a soft metal that is affected by food acids and alkalis. Scientific evidence shows that tiny particles of aluminum from foods cooked in aluminum utensils enter the stomach and can injure the sensitive lining of the stomach.
Prices - The monthly average index of fresh vegetable prices received by growers in the U.S. in 2007 rose by +11.4% to a record level of 178.7 from last year's level of 160.5.
Demand - The leading vegetable in terms of U.S. per capita consumption in 2007 was the potato with 126.0 pounds of consumption. Runner-up vegetables were tomatoes (90.3 pounds), lettuce (29.5 pounds), sweet corn (26.3 pounds), and onions (21.9 pounds). Total U.S. per capita vegetable consumption in 2007 rose +2.2% at 438.1 pounds. That is about 23% higher than the 356.2 pounds consumed in 1980.