The ABCs of vitamins

Since you were 6 years old and chewing up your Flintstones tablets, you've probably known you needed vitamins to be healthy.

In general, there are 12 to 13 vitamins and six different minerals that the human body needs to avoid illness and function normally, say medical professionals. Most of what you need should be provided in the foods you eat, although some recommend a daily vitamin to supplement anything you're missing.

But why do we need vitamins and minerals? What exactly do they do for your body, and is there such a thing as too much of them? We've broken the information down into a "vitamin dictionary." From blood cell production to bone strength, you might be surprised at these nutrients' multi-tasking abilities.

Water-soluble vitamins

The body absorbs these vitamins easily and does not store them in large amounts. What you don't need, your kidneys get rid of by flushing them out of your system.

Vitamin B1 (thiamin)

What it does: Converts carbohydrates into energy.

Where you can get it: whole grains and enriched grain products, fortified cereal, pork, liver, lean beef, legumes.

Side effects from overuse: none.

Vitamin B2 (riboflavin)

What it does: Helps the body process protein and produce energy.

Where you can get it: lean beef, pork, liver, legumes, cheese, eggs, milk, nuts, green leafy vegetables, whole grains and enriched grain products.

Side effects from overuse: none.

Vitamin B3 (niacin)

What it does: Helps keep a healthy digestive and nervous system; also helps the body process fats and proteins.

Where you can get it: liver, turkey, tuna, peanuts and peanut butter, fish, yeast, enriched whole-grain products.

Side effects from overuse: Flushed skin, liver damage, upset stomach, stomach ulcers.

Vitamin B5 (pantothenic acid)

What it does: Contributes to normal growth and development; helps the body process nutrients and create red blood cells.

Where you can get it: organ meats, beef, chicken, lobster, milk, eggs, peanuts and peanut butter, peas, beans, lentils, broccoli, yeast, cereal, whole grains.

Side effects from overuse: none.

Vitamin B6 (pyridoxine, pyroxidal, pyridoxamine)

What it does: Helps the body create infection-fighting antibodies, insulin and red blood cells. It also helps the body use protein and fats, helps the blood carry oxygen to body tissues and more.

Where you can get it: organ meats, chicken, pork, fish, whole grains, eggs, peanuts and peanut butter, bananas, carrots, yeast, fortified cereals.

Side effects from overuse: nerve damage, which can cause numbness and pain while walking.

Vitamin B12

What it does: Works with folic acid to make red blood cells and is needed for cell genetic material; also maintains healthy nerve cells and prevents one kind of anemia.

Where you can get it: liver, chicken, eggs, clams, sardines, flounder, herring, milk, blue cheese, fortified cereals.

Side effects from overuse: none.

Vitamin C (ascorbic acid)

What it does: Helps the body absorb iron out of food that comes from plants and form connective tissue like cartilage. It also acts like an antioxidant, which protects the body from free radicals (by-products of metabolism). Also maintains healthy teeth and gums, promotes wound healing and benefits the immune system.

Where you can get it: citrus fruit, strawberries, broccoli, green peppers, spinach, brussels sprouts, tomatoes, potatoes, cabbage.

Side effects from overuse: upset stomach, kidney stones, increased iron absorption, gas.

Vitamin H (biotin)

What it does: Helps the body produce energy and metabolize protein, fats and carbohydrates. It's also good for the nervous system.

Where you can get it: liver, kidney, egg yolks, peas, beans, yeast breads, cereals, nuts, tomatoes

Side effects from overuse: none.

Folic Acid (folate)

What it does: helps the body create new cells and prevents certain birth defects.

Where you can get it: dark leafy vegetables, dry beans and peas, oranges, fortified cereals, legumes, liver, wheat germ, other fortified grain products.

Side effects from overuse: High levels can mask signs of B12 deficiency. High levels can also interfere with some medications.

Note: Many doctors prescribe folic acid for pregnant women to prevent birth defects in their babies.

Fat soluble vitamins

These vitamins are absorbed into your body via bile acid and stored in your body fat. Once stored, the body uses them as needed.

Vitamin A (retinol, retinal, retinolic acid)

What it does: Essential for good vision, bone and tooth growth. Also important for healthy skin, immunity, tissue repair and more. Prevents some infection by keeping skin healthy and works as an antioxidant.

Where you can get it: liver, fish, oil, egg yolks, carrots, sweet potatoes, tomatoes, fortified breakfast cereals, red, yellow and orange fruits and vegetables, and many dark, leafy green vegetables.

Side effects from overuse: birth defects, headaches, nausea, vomiting, blurred vision, liver problems and bone abnormalities.

Vitamin D (calciferol)

What it does: Promotes the body's absorption of calcium and phosphorus for bone and teeth strength. Helps prevent fractures from osteoporosis, as well as benefits the immune system.

Where you can get it: saltwater fish, fortified milk and eggs, fortified cereals. The body also produces vitamin D through exposure to sunlight (a very small amount of sun exposure is needed).

Side effects from overuse: kidney stones or kidney damage, nausea, vomiting, constipation, poor appetite, weakness, weight loss, and heart rhythm problems (usually comes from supplements, not sunlight).

Note: People who do not spend a great deal of time outdoors, such as the elderly, may need to supplement vitamin D in their diets.

Vitamin E (tocopherol)

What it does: works as an antioxidant and helps blood flow. Also helps repair body tissues.

Where you can get it: fish, milk, egg yolks, vegetable oils, nuts, fruits, peas, seeds, wheat germ, leafy green vegetables, broccoli, and fortified cereals.

Side effects from overuse: Low risk, but may interfere with vitamin K action and boost effects of anticoagulants.

Vitamin K

What it does: Important for blood clotting and bone formation.

Where you can get it: cheese, spinach, kale, broccoli, brussels sprouts, parsley, cabbage, tomatoes, plant oils and margarine.

Side effects from overuse: none.

Minerals

Calcium

What it does: Helps build strong bones and teeth. Also helps with blood clotting and muscle and nerve operations.

Where you can get it: salmon, sardines, milk, cheese, yogurt, calcium-set tofu, Chinese cabbage, kale and broccoli.

Side effects from overuse: kidney stones and poor kidney function, calcium deposits in the body's soft tissue and decreased absorption of other minerals.

Iodine

What it does: Part of thyroid hormones that prevents goiter and certain birth defects.

Where you can get it: iodized salt, seafood, kelp.

Side effects from overuse: Higher levels of thyroid-stimulating hormone.

Iron

What it does: Helps the body carry oxygen to various parts of the body. Also needed for energy, supports the immune system and prevents anemia.

Where you can get it: meat, fish, poultry, lentils, beans, fortified breads and cereals.

Side effects from overuse: diarrhea, upset stomach, dark stools, constipation, decrease in absorption of other minerals.

Magnesium

What it does: Helps maintain muscle and nerve operations and sustains a regular heartbeat. Also promotes bone strength and helps produce energy.

Where you can get it: meats, seafood, dairy foods, green leafy vegetables, bran cereal, and nuts.

Side effects from overuse: Diarrhea and cramping.

Note: many American men and women tend to be deficient in magnesium. Some studies suggest there is a correlation between high blood pressure and magnesium deficiency.

Phosphorus

What it does: Promotes healthy bones and helps with energy production.

Where you can get it: dairy products, peas, meat, fish, eggs, some cereals and breads.

Side effects from overuse: can decrease the absorption of calcium.

Zinc

What it does: supports the immune system and helps with wound repair. Also maintains healthy senses (taste and smell), makes digestion easier and contributes to normal reproduction and development.

Where you can get it: red meats, liver, oysters, certain seafood, dairy, eggs, beans, nuts, whole grains, and fortified cereal.

Side effects from overuse: decreased absorption to certain minerals and lowered immune system functioning. Can also reduce the amount of good cholesterol in the body.

Sources: Pat Parteleno, pharmacist and director of experiential education for pharmacy at Ohio Northern University, Dave Hipply, director of pharmacy at Van Wert County Hospital, the U.S. Food and Drug Administration and www.cnn.com.