Fortified foods are all the rage. Here, some expert advice on which to take to the checkout-and which to leave on the shelf.

Foods with Omega-3 Fatty Acids

There are three main types of this polyunsaturated fat-EPA, DHA, and ALA. The first two are found naturally in fish and fish oils. Soybeans, canola oil, walnuts, and flaxseed contain ALA.Now in: Margarine, eggs, milk, cheese, yogurt, waffles, cereal, crackers, and tortilla chips.

What they do: Powerful weapons against heart disease, omega-3 fatty acids help lower blood pressure, control the inflammation inside artery walls that can lead to clogging, and regulate heartbeat. In addition, they're important for brain function, helping to prevent depression.

Should you bite? Most women's diets pack plenty of ALA but just 60 to 175 milligrams of DHA and EPA daily--not nearly enough. Fatty fish is the best way to bump up your intake because it's the most concentrated source of omega-3s in addition to being low in calories, high in protein, and rich in the minerals zinc and selenium. But if you don't eat fish, fortified products are a good substitute.You can also take advantage of these fortified products if you're pregnant or breast-feeding, especially if morning sickness makes fish less appealing than usual. Boosting your intake of EPA and DHA might help prevent pregnancy complications like preterm labor and high blood pressure. Omega-3s may also up the IQ of babies who get it from breast milk.

What to buy: Look for products with added DHA and EPA that you can substitute for other healthy foods in your diet. Eggland's Best omega-3 eggs (52 mg of DHA and EPA combined per egg), Horizon Organic Reduced Fat Milk Plus DHA (32 mg per cup), Breyers Smart yogurt (32 mg DHA per 6-ounce carton), and Omega Farms Monterey Jack Cheese (75 mg of DHA and EPA combined per ounce) all fit the bill. If you see a product boasting several hundred milligrams of omega- 3s, check the label carefully. It's probably made with flax or another source of ALA, and your body won't be able to use more than 1 percent of the omega- 3s from it.

Foods with Phytosterols

Tiny amounts of these plant compounds are found naturally in nuts, oils, and produce.

Now in: Orange juice, cheese, milk, margarine, almonds, cookies, muffins, and yogurt

What they do: Block the absorption of cholesterol in the small intestine.

Should you bite? If your LDL (bad cholesterol) level is 130 milligrams per deciliter or higher, the U.S. government's National Cholesterol Education Program recommends adding 2 grams of phytosterols to your diet daily-an amount that's practically impossible to get from food. (For example, it would take 11?4 cups of corn oil, one of the richest sources.) If your LDL cholesterol is 100 to 129 mg/dL (slightly above an optimal level), talk to your doctor. Pass altogether if you're pregnant or nursing, as researchers haven't determined whether extra sterols are safe during these times. For the same reason, don't give sterol-fortified products to kids.

What to buy: Find one or two items that you can easily swap for foods you're apt to consume daily to avoid eating extra calories. Try Minute Maid Heart Wise orange juice (1 g sterols per cup), Benecol spread (850 mg sterols per tablespoon), Lifetime Low- Fat Cheddar (660 mg per ounce), or Promise Activ Super- Shots (2 g per 3 ounces). For maximum benefit, split the 2 grams you need between breakfast and dinner. That way you'll block the absorption of cholesterol at two meals instead of just one.

Foods with Probiotics

When live, active cultures of beneficial bacteria are added to foods specifically to give them a health boost-not just to ferment the product (as with yogurt)-they're called probiotics.

Now in: Yogurt, frozen yogurt, cereal, bottled smoothies, cheese, energy bars, chocolate, and tea

What they do: Probiotics help stave off urinary tract infections and keep your digestive system happy, helping to reduce and prevent constipation, diarrhea, and bloating. The probiotics may hinder the growth of E. coli in the urinary tract, reducing the risk of infection. Other research suggests probiotics boost the immune system, helping to prevent colds, flu, and other viruses.

Should you bite? Experts say most women could benefit from eating probiotics as a preventive measure. If you're having stomach trouble, that's even more incentive to consume them. Have one to two servings a day.

What to buy: Seek a brand of yogurt that contains cultures beyond the two needed for the fermentation process--Lactobacillus (L.) bulgaricus and Streptococcus thermophilus. Those that have reported stomach-soothing benefits include Bifidus regularis (exclusive to Dannon Activia), L. reuteri (only in Stonyfield Farm yogurts), and L. acidophilus (in Yoplait and several other national brands). New technology means probiotics can be added successfully to shelf-stable products like cereal and energy bars (Kashi Vive cereal and Attune bars are two examples), which are good choices especially if you don't like yogurt. But be wary about claims of cultures in frozen yogurt; probiotics may not survive the freezing process very well.

Foods with Green Tea Extracts

Derived from decaffeinated green tea, these extracts contain powerful antioxidants called catechins.

Now in: Nutrition bars, soft drinks, chocolate, cookies, and ice cream

What they do: These antioxidants fight cancer, heart disease, stroke, and other serious health problems. Japanese researchers found that women who drank three to four cups of green tea a day reduced their risk of dying from any medical cause by 20 percent. Some early studies suggest green tea boosts metabolism, but more research is needed.

Should you bite? No fortified product will give you more catechins than a cup of green tea (50 to 100 mg), and it takes far more than that to reap the benefits. But if fortified products replace less-than-healthy foods you typically eat, they're worth including.

What to buy: Tzu T-Bar (75 to 100 mg of catechins) and Luna Berry Pomegranate Tea Cakes (90 mg of catechins) are healthy alternatives to snacks you may already be munching on.