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HEART Insight:
doi: 10.1097/01.HEARTI.0000363808.59035.ba
Features: Nutrition Know-Knows

Are Some Foods More Equal Than Others?

Gorman, Rachael Moeller

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Abstract

Fortified Foods: Separating Health From Hype

Walk down any supermarket aisle and you'll find products fortified with a variety of nutrients, their packages emblazoned with slogans like “Heart Healthy!”; “High in Fiber!”; and “Lowers Cholesterol!” These foods may cost more than the same foods without fortification, and with many of us pinching pennies these days, even the most health-conscious consumer has to wonder: Is the extra cost worth it? Can fortified foods really help meet heart-healthy nutrition goals?

It depends. The Food and Drug Administration allows claims that a nutrient prevents disease only when several well-conducted studies — especially randomized, controlled trials, the gold standard in science — support such a health claim. To date, only 12 health claims have been approved, and just three of them are for intake of nutrients associated with reducing heart disease risk — soluble fiber, plant sterols and soy protein. One claim supports lowering intakes of nutrients in the diet — saturated fat and cholesterol — which may reduce the risk of coronary heart disease.

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“ROUGHAGING” IT

When it comes to fortification, fiber — what grandma called “roughage” — is first among equals. There are two types of fiber, soluble and insoluble, and both are important. Insoluble is the stuff that passes right through you, keeping you regular, while soluble fiber slows the movement of food through the digestive tract, helping the body absorb important nutrients.

In 1997, the FDA was persuaded that people who ate 3 grams of soluble fiber from whole oats every day, as part of a diet low in saturated fat, trans fat and cholesterol, were less likely to develop coronary heart disease, because the soluble fiber lowered LDL (“bad”) cholesterol. (Though scientists are not completely sure how it works, they know that soluble fiber encourages the liver to remove more LDL from the blood). Since 1997, the FDA has extended the health claim to include soluble fiber from barley (3 grams per day) and psyllium seed husk (7 grams per day).

Yet emerging evidence suggests that insoluble fiber may also have a role to play in heart health. “Soluble fiber is better studied and has more evidence to back it, but insoluble fiber also may have modest cholesterol-lowering effects,” explains Robert Eckel, M.D., professor at the University of Colorado Denver School of Medicine and past president of the American Heart Association.

If you would like to reduce your cholesterol and plan to eat a fiber-fortified food, check the ingredient list for whole oats, oat bran, barley, barley betafiber, betatrim, oatrim, or psyllium seed husk, so you know the product includes soluble fiber. But don't fret if you're getting insoluble fiber as well – it may help your heart, and also has important benefits for your gastrointestinal tract.

Keep in mind that many cereals, breads and pastas claim to have “added fiber,” but are refined white grains with some fiber added back in. Whole-grain versions of these products (like a large bowl of oatmeal, which provides the LDL-lowering of 3 grams of soluble fiber) are a better source — they still contain antioxidants and other nutrients that are lost during processing. When deciding between costlier fortified foods and whole grain or regular foods, “I would choose the whole grain,” says Eckel.

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FIGHT FIRE WITH FIRE

Small amounts of plant sterols and stanols (also known as “phytosterols” and “phytostanols”) occur naturally in many cereals, fruits, nuts, seeds, vegetables and vegetable oils. Sterols and stanols not only inhibit absorption of dietary cholesterol in the digestive tract to reduce LDL and total cholesterol levels, but they are largely indigestible and the body simply gets rid of them when their work is done.

Unfortunately, fruits and vegetables cannot supply levels of sterols and stanols that are high enough to make an appreciable dent in cholesterol levels so “the only way you can get that is with a fortified food,” says Penny Kris-Etherton, Ph.D., R.D., professor of nutrition at Pennsylvania State University.

Manufacturers have been adding phytosterols and phytostanols to margarine, salad dressing, yogurt, orange juice and other foods. Randomized trials using some of these fortified foods to supply two to three grams of these nutrients daily can decrease LDL cholesterol up to 15 percent in people who have elevated LDL cholesterol levels.

Consuming plant sterols or stanols could help people with high LDL remain on lower doses of statins, says Sridevi Devaraj, Ph.D., Director of Toxicology at the University of California, Davis and the head researcher on a study examining the effects of plant sterols in the diet on LDL cholesterol. Your doctor can advise you on whether you can reach your target cholesterol levels with lower doses of cholesterol-lowering drugs by adding phytosterols and phytostanols to your diet.

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SOY SO-SO

In 1999, the FDA suggested that 25 grams per day of soy protein can reduce the risk of heart disease, but a 2006 review of 22 randomized, controlled trials by the AHA found that soy protein reduced LDL by a ho-hum three percent — and only when soy made up about 50 grams, or about half the usual total daily protein intake. Though soy's health benefit is minimal when it comes to reducing heart disease risk, AHA still recommends this extremely high quality vegetable protein replace some of the saturated fat-packed meat we eat because soy foods are good sources of polyunsaturated fats, fiber, vitamins, and minerals, and are low in saturated fat.

The AHA also advises that you eat two meals of fatty fish (such as salmon or tuna) each week because research suggests that eating fatty fish is associated with lower heart disease risk.

Fatty fish contain the long-chain omega-3 fatty acids DHA and EPA, but scientists have gotten inconsistent results when they gave people fatty acids in pills or in fish oil. The only study to examine the cardiovascular benefits of foods fortified with omega-3s found that eating about a gram of the nutrient a day from a variety of products raised omega-3 levels in the blood and kept inflammation (which is linked to atherosclerosis — hardening of the arteries) in check. However, elevated blood pressure and cholesterol levels were unaffected.

One other thing you should know about omega-3 fortification: Some foods that are high in omega-3s are actually fortified with ALA, another omega-3 fatty acid found in flaxseed and other vegetable sources. But “the evidence for ALA [isn't] strong,” says Kris-Etherton. “There are other nutrients in fish, and it's also a good source of protein,” Kris-Etherton points out. “But if you can't achieve those recommendations by eating fish, I think fortified foods are the next best option.” Just make sure the omega-3 fatty acid comes from fish, not flax.

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IS FOLIC ACID FOLLY?

Based on research suggesting that incidence of spina bifida and other neural tube birth defects could be largely prevented if all women of childbearing age consume 400 micrograms (μg) of folic acid daily, the United States and Canada began adding this B vitamin to enriched breads, flours, corn meals, rice, noodles and other grain products in 1998. Now there is emerging evidence that folic acid may also prevent some forms of congenital heart disease.

Researchers had also noticed that folic acid lowers levels of homocysteine (an amino acid that is thought to be associated with coronary artery disease) in adults, but randomized controlled trials have not shown that folic acid supplementation or fortification can help reduce someone's risk of dying of a heart attack.

Bottom line: Experts agree that it makes more sense to eat whole foods that contain heart-healthy nutrients, rather than processed foods that add them in. “If you have some extra money and you want a cholesterol-lowering effect, I think plant sterols are good, but one of the things you'd get the biggest bang for your buck for is buying fatty fish,” says Kris-Etherton. “And, of course, fruits and vegetables and whole grains, and nuts. Pay attention to the whole diet, not single foods — that's what's really important.” HI

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What's It Gonna Cost You?

The U.S. market for functional foods (with nutrients added to enhance health or reduce risk of disease) is expected to approach $25 billion by 2009. The difference in price between the “regular” and fortified versions of some products is just a few pennies, but in other cases you will pay a hefty premium for the added nutrients:

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© 2009 American Heart Association, Inc.

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