The noun vegetable usually means an edible plant or part of a plant other than a sweet fruit or seed. This typically means the leaf, stem, or root of a plant.
However, the word is not scientific, and its meaning is largely based on culinary and cultural tradition. Therefore, the application of the word is somewhat arbitrary and subjective. For example, some people consider mushrooms to be vegetables even though they are not plants, while others consider them a separate food category.
Some vegetables can be consumed raw, some may be eaten cooked, and some must be cooked in order to be edible. Vegetables are most often cooked in savory or salty dishes. However, a few vegetables are often used in desserts and other sweet dishes, such as rhubarb pie and carrot cake.
As an adjective, the word vegetable is used in scientific and technical contexts with a different and much broader meaning, namely of “related to plants” in general, edible or not — as in vegetable matter, vegetable kingdom, vegetable origin, etc. The meaning of “vegetable” as “plant grown for food” was not established until the 18th century.
Vegetables are eaten in a variety of ways, as part of main meals and as snacks. The nutritional content of vegetables varies considerably, though generally they contain little protein or fat, and varying proportions of vitamins such as Vitamin A, Vitamin K and Vitamin B6, provitamins, dietary minerals and carbohydrates. Vegetables contain a great variety of other phytochemicals, some of which have been claimed to have antioxidant, antibacterial, antifungal, antiviral and anticarcinogenic properties. Some vegetables also contain fiber important for GI function. Vegetables contain important nutrients necessary for proper Hair and Skin as well. A person who refrains from dairy and meat products, and eats only vegetables is known as a Vegan.
However, vegetables often also contain toxins and antinutrients such as α-solanine, α-chaconine, enzyme inhibitors (of cholinesterase, protease, amylase, etc.), cyanide and cyanide precursors, oxalic acid, and more. Depending on the concentration, such compounds may reduce the edibility, nutritional value, and health benefits of dietary vegetables. Cooking and/or other processing may be necessary to eliminate or reduce them.
Diets containing recommended amounts of fruits and vegetables may help lower the risk of heart diseases and type 2 diabetes. These diets may also protect against some cancers and decrease bone loss. The potassium provided by both fruits and vegetables may help prevent the formation of kidney stones.