The trio of potatoes, onions, and garlic is nutritious as well as delicious. If you avoid greasy french fries and potato chips, potatoes not only are extremely nutritious, but they also have a number of disease-fighting properties.

The same can be said of both onions and garlic. Not only are they packed with vitamins, but they can also help protect you from a number of illnesses and diseases.

Potatoes are part of the nightshade family, which also includes tomatoes, eggplant and peppers. They have been grown in South America for some 4,000 to 7,000 years.

As the "World's Healthiest Foods puts it, potatoes are an "exceptionally healthful, low calorie, high fiber food that offers significant protection against cardiovascular disease and cancer."

Baked, steamed or properly sauteed--but not fried--wild and commercial potatoes offer 60 different phytochemicals and vitamins in their flesh and skin.

In addition to vitamins and minerals, potatoes, and particularly potato skins, are an excellent source of dietary fiber, which helps protect against heart disease and perhaps some forms of cancer.

Scientists at the Institute for Food Research in Britain also have found that potatoes are one of the few plants to contain kukoumines, which help lower blood pressure.

Last, but not least, potatoes are good for dieters. As a food with complex carbohydrates, potatoes make you feel fuller for a longer time. Potatoes also are a low calorie food. One new potato, for example, contains only 26 calories.

Onions, as well as garlic, chives and scallions, are part of the lily family.

The World Health Organization supports the use of onions to treat poor appetite and to prevent hardening of the arteries.

Extracts of onion are used to combat colds, coughs, asthma and bronchitis. Sulfides in onions may lower your blood pressure and your cholesterol. Onions also have anti-clotting properties, another heart-healthy benefit.

Onions can suppress harmful bacteria in the stomach, which may aid in the prevention of digestive disorders.

Used for food and medicine in India for some 5,000 years, garlic releases the chemical allicin when its cloves are chewed, cut or crushed. Allicin, which gives garlic its distinctive smell and taste, is a valuable disease and illness fighter.

Garlic is a good source of vitamins A, B and C, as well as minerals such as selenium, iron and calcium.

Long used as an antibiotic before the advent of penicillin, garlic is also an antibacterial infection fighter. It may help prevent colds as well.

In 1993, scientists in a study in England found that garlic could reduce cholesterol levels for people who took garlic tablets. Blood pressure was reduced as well, which helps prevent strokes and heart disease.

It's hard to go wrong with potatoes, onions and garlic as both sources of good nutrition and helpful disease and illness fighters. And they are low in calories, too.

However, eating an excessive amount of onions or garlic can produce stomach distress, but that is about the only minor drawback to enjoying these three vegetables--aside from the bad breath that comes with onion and garlic consumption.