Essential Vitamins and Minerals

Vitamins and minerals are essential to life—and we mean essential. Without them, we couldn't think or even breathe, much less digest food or walk the dog. But chances are you're not getting enough of the good stuff, and figuring out what you need is tricky business. We uncover the key nutrients young women should consume, plus which you should get from food and what's OK to buy in a bottle.

Vitamin A
Talk about your overachiever: This antioxidant boosts immune systems, improves vision, cuts risk of heart disease, and may slow skin aging. But, warns Michael Holick, Ph.D., M.D., author of The Vitamin D Solution, it can be toxic in large doses, so stick with the right amount.

Recommended daily dosage: 2,300 international units (IU)

Need a supplement? It's best to get A from a beta-carotene source, such as a large carrot or a cup of sliced cantaloupe

B Vitamins
The eight B vitamins help maintain metabolism, muscle tone, and a sharp mind, says Mary Ellen Camire, Ph.D., a nutrition professor at the University of Maine at Orono. Most important for young women is B9 (folic acid), which keeps red blood cells healthy and guards against cancer and birth defects.

Recommended daily folate dosage: 400 micrograms (mcg); 600 mcg if you're pregnant

Need a supplement? Probably not (unless you're pregnant or planning to become pregnant), particularly if you eat grains. Just one cup of most fortified breakfast cereals has all the daily B you need. Other options: whole-grain breads, asparagus, and beans.

Vitamin C
Despite its rep as a cold fighter, C has never been proven to prevent or cure the sniffles. But the antioxidant is believed to boost your immune system and help prevent heart disease, prenatal problems, and eye illnesses. It even helps wounds heal faster and fends off wrinkles.

Recommended daily dosage: 75 milligrams (mg)

Need a supplement? No, as long as you eat citrus fruits and vibrant veggies. A single orange is packed with nearly all of your daily C. So is one red pepper or a cup of broccoli.

Vitamin D
The vitamin du jour, D could be something of a wonder drug. Docs believe it can reduce your risk of breast cancer by as much as 50 percent, and it may offer protection from both ovarian cancer and diabetes. More happiness: D helps calcium absorption and plays a central role in muscle function.

Recommended daily dosage: 1,000 to 2,000 IU

Need a supplement? Most likely. Milk, orange juice, and salmon contain small amounts of D, but nowhere near enough.

Calcium
Two words: strong bones. "Women start losing bone density in their twenties," says Camire. "Calcium is your single best defense, and you should start taking it now." The mineral also helps build strong teeth and nourishes your nervous system.

Recommended daily dosage: 1,000 mg

Need a supplement? Yep. Yogurt, milk, and cheese do pack calcium, but not an ideal amount

Iron
Too little of this mineral can spell anemia (a lack of red blood cells) and a weakened immune system. Iron is also "particularly important for women with heavy periods," says Carol Haggans, R.D., a consultant for the National Institutes of Health.