We all want to improve heart health by lowering our cholesterol and blood pressure, boosting our immunity, and regulating digestion. That’s why so many of us are jumping on the functional food bandwagon.

Generally defined as any food that provides health benefits beyond basic nutrition, functional foods are “just foods that promote healthy body functions, helping the body repair itself and work optimally,” says Christine Gerbstadt, MD, RD, a physician and spokesperson for the American Dietetic Association. “They’re enhancing what food already does.”

Which is why so many of us are filling shopping carts with foods and drinks enriched with everything from omega-3 fatty acids and fiber, to plant sterols and probiotics . Not every functional food ingredient has been scientifically proven to be beneficial, however. That’s why WebMD asked the experts which nutrients they would single out as worthy, who benefits from them, and where in the functional food world each can be found.

6 Top Functional Food Ingredients

Before the health professionals named names, each echoed the sentiment of Susan Moores, a registered dietitian and American Dietetic Association spokesperson. “The most important message is: first lay the foundation of a healthy diet with whole foods, then weave in functional foods.”

Ingredients to look for include:

Calcium in Functional Foods

Instrumental in lowering high blood pressure, helping with regular heart beat, and building strong bones, calcium is also a nutrient most of us aren’t getting enough of, according to the 2005 Dietary Guidelines for Americans. And it’s not just women who need more calcium. Men, too, are also at risk for osteoporosis.

While one of the best ways to get calcium is through foods like milk, cheese, and yogurt, not everyone likes or can tolerate dairy. Here’s where functional foods can play a part, say the pros. Along with eating calcium-rich whole foods like dark, leafy greens, look for fortified orange juice, breads, waffles, and soy milk. And don’t forget to get enough vitamin D, which is vital to calcium’s absorption.

Calcium: how much? Adults and pregnant women between age 19 and 50 should aim for 1,000 mg of calcium daily. Adults over 51 should consume about 1,200 mg. Pregnant women under age 19 need 1,300 mg. Vitamin D is vital for the absorption of calcium, ideas on how to get more vitamin D in your diet follow.

Fiber in Functional Foods

Most of us know fiber aids in digestion, but keeping us regular is just the beginning. This powerhouse nutrient also helps fight disease, and may lower risk for high cholesterol, heart disease, diabetes, and cancer.

With all that going for it, it’s a shame that American men and women aren’t getting enough. Most of us are scraping by on half of the fiber we actually need, says the American Heart Association. How can you get more? Produce and whole grains are prime sources for heart-healthy fiber, while functional foods such as breads, cereals, soymilk, and yogurts can fill in gaps.

Fiber: how much? Most of us get about 15 grams daily, but to fight disease and keep digestion humming, aim for at least 30 grams. But take it slow, adding too much fiber too fast can lead to bloating, gas, and diarrhea.

Omega-3 Fatty Acids in Functional Foods

“I think pretty much everyone could benefit from more omega-3s,” says Elaine Magee, a registered dietitian, and author of Food Synergy. “They’re a smart, polyunsaturated fat, and one of the most powerful nutrients we know of.”

Omega-3 fatty acids not only raise good, HDL cholesterol and lower bad LDL cholesterol, they may also lower your risk of heart attack and strokes. Foods with omega-3s are “the functional foods I think are worth the extra pennies,” says Gerbstadt. At the supermarket, look for whole foods rich in omega-3s like salmon, walnuts and flax, as well as functional foods such as omega-3-rich eggs, breads, milk, soy milk, and cereal.

Omega-3s: how much? Of the three major types of omega-3 fatty acids -- alpha-linolenic (ALA), eicosapentaenoic (EPA) and docosahexaenoic (DHA), the body uses EPA and DHA more readily. The American Heart Association suggests that people with coronary heart disease consume about 1 gram of EPA+DHA omega-3 fatty acids daily. They do not recommend supplements for healthy people; instead, they recommend eating fish twice a week.  

Plant Sterols and Stanols in Functional Foods

“Plant sterol spreads have good science behind them,” says David Grotto, RD, author of 101 Foods That Could Save Your Life, “if you have high cholesterol, they can be a really good thing.” Because they reduce cholesterol in the blood, plant sterols may also reduce your risk of coronary artery disease, a leading cause of death for American men and women.

Plant sterols and stanols are found in small amounts naturally in grains, vegetables, fruits, legumes, nuts, and seeds. It’s difficult to get enough sterols and stanols in whole foods, says Kerry Neville, MS, RD, a registered dietitian. That’s where functional foods may help. If you have high cholesterol, look for plant sterols in margarine, fortified juices, granola bars, among other foods.

Plant sterols: how much?  The National Cholesterol Education Program recommends 2 grams of plant sterols and stanols a day for people with high cholesterol. To get that, look for functional foods containing at least 0.65 grams of plant sterols per serving, suggests the FDA. Note: The American Heart Association does not recommend plant sterols for people with normal or low cholesterol until further research on long-term health effects is done.

Probiotics in Functional Foods

Probiotics are live microorganisms very similar to the beneficial ones you’ve already got living inside your gut. Though still in the early stages of study, encouraging evidence suggests that probiotics may benefit those on antibiotics, with some bowel disorders, diarrhea, or certain infections.

While yogurt is a well-known functional food with probiotics, you can also find them in juices and soy drinks though some foods have far more than others and “each probiotic offers different things,” Magee tells WebMD. “What they do and how they help depends on the probiotic and the person using it. We’re still learning.”

Probiotics: how much? Because their effectiveness is still being studied, few recommendations exist. If you think probiotics may fit into your diet talk to your doctor -- and then read labels carefully.

Vitamin D in Functional Foods

“Vitamin D…is one of those nutrients we just don’t get enough of,” Neville says, “it’s very difficult to get, depending on where you live and the season.

The best way for most of us to get the vitamin D we need is through 10 to 15 minutes of sunshine several times a week. But dark skin, season, and geography can limit how much vitamin D your body is able to make. That’s one reason you can find vitamin D in functional foods like milk, yogurt, and fruit juices.

Vitamin D: how much? Current recommendations for vitamin D are 200 international units (IU) for those under 50, and double that for those age 51 to 70. Vitamin D requirements increase to 600 IU for people over than 70, as older skin is less efficient at making the vitamin.

Functional Foods: Only Part of the Picture

It’s important to remember that functional foods and the nutrients in them won’t win the day if your diet is poor. "The underlying fact in all this is you really need to have a healthy diet,” says Neville.

That means following the basics of a heart-healthy living, including eating lots of good-for-you foods like fruits, veggies, and whole grains, getting plenty of exercise, and maintaining your weight.

“If you don’t have a healthy diet to begin with, adding functional foods isn’t going to make your diet healthy,” Neville sums up. The healthy diet part -- that’s up to you.