October 2008 Issue

Functional Foods:
Explore the New but Rely on the Tried and True
By Christen C. Cooper, MS, RD
Today’s Dietitian
Vol. 10 No. 10 P. 42

Mother Nature offers a wondrous selection of healthy foods, but research has yet to prove any of them magical. Help erase your clients’ fantastical ideas about new “superfoods” by returning to commonsense advice and reviewing the latest research.

Balance, balance, balance. Dietitians repeat this mantra until they are blue in the face. Yet, when clients leave the office, they are bombarded by infomercials, Internet ads, and store displays that promote individual foods as elixirs for better health. Today, with hundreds of so-called superfoods on the market, even the wariest consumers are lured by promises of higher energy, smoother skin, and longer life.

With knowledge of food science and an understanding of consumer food choices, dietitians can help clients make wise decisions about food by judging the value of individual foods within the total dietary framework. After all, man cannot live on bread (or omega-3s or goji berries) alone. No single food, no matter how “super,” can take the place of the important combination of nutrients from all major food groups. Thus, questions such as “What do you think of mangosteen?” are only relevant in the context of the small contribution such foods make to overall dietary intake. We can help our clients view superfoods from this rational, informed perspective.
Some tests to help clients decide whether a certain food is worth trying include the following:

How Does It Taste?
While flavor may seem trivial, no food is worth eating if it doesn’t taste good. Even if a food carries mind-blowing health claims, clients should remember that there are many healthful foods that offer health benefits and good taste.

Where Was It Grown?
A number of the newest superfoods are whole fruits, fruit juices, and foods containing healthful fats. Consider the food’s energy cost: If it takes a great deal of energy to ship it from where it was grown to where it will be sold but offers little caloric energy or nutritional value, it’s probably not worth its environmental cost. Try to choose a comparable local product, one that is likely to taste fresher and contain less packaging.

How Much Does It Cost?
Here, common sense may be even more important than dietary expertise. Many new superfoods come in juice form, which is supposedly a “concentrated” source of antioxidants. But eating whole fruits and vegetables can provide equivalent antioxidant power and additional benefits—especially fiber, which is usually most plentiful in the skin and seeds of fruits, which are excluded from the juice. If a client’s diet is low in fruits and vegetables, he or she could increase antioxidant intake by increasing the portion of common plant foods instead of investing in a $30 bottle of antioxidant juice. (Swap that açai juice for a pint of fresh strawberries.)

Moreover, companies that market superfoods know that food crazes are temporary, and they hope to earn big profits up front. If a food is expensive and there is little research to support it, leave it on the shelf. Look no further than the sale bin at a health food store if you want to see superfoods that have fallen from grace and now cost one half their original price.

Has It Been Researched?
Dietitians can answer this question when we stay up-to-date on research and have done a basic mental synthesis of key information. A good rule of thumb is to recommend superfoods such as omega-3 fatty acids, antioxidant-rich leafy greens, and, yes, numerous fruits and vegetables that have demonstrated health benefits. And the newer headline makers—goji, mangosteen, and açai—may prove beneficial, but their long-term effects have not been studied.

With nutrigenomics on the horizon, we may one day know that chokeberry, for example, could be helpful to someone with a certain gene but useless for someone without that gene. For now, we must rely on epidemiological studies, which can take a long time to produce meaningful results. It is wise to encourage clients to use caution when choosing new and unfamiliar foods. By thinking before buying, consumers—and not advertisers or vendors—remain the judges of which foods are beneficial and worth buying.

What Value Would It Add to the Overall Diet?
Variety has been an important measurement of diet quality in the United States since 1995 when the Healthy Eating Index helped show that individuals who consume a wide variety of foods, particularly fruits and vegetables, are likely to enjoy good health, according to the USDA’s Center for Nutrition Policy and Promotion. Since the average American diet contains a rather narrow range of whole foods, “new” foods can certainly add some nutrient diversity to the common iceberg lettuce-and-French fry repertoire.

Bear in mind, however, that adding variety doesn’t necessarily mean trying wildly new things. It can mean increasing the intake of familiar foods that were previously consumed in smaller amounts. Variety can also mean making some simple substitutions, such as occasionally swapping olive and canola oils for walnut and peanut oils. Even a slight change in flavors, such as different spices, can wake up the taste buds and add more health benefits.

The New
The following is a quick look at some of the latest, and purportedly “greatest,” whole superfoods that your clients may inquire about:

A fruit that grows on evergreens in Asia, Africa, and the Pacific tropics, mangosteen has a sweetness that makes it great for juices and desserts. Many new superfood products contain mangosteen skin extracts, the part of the plant with the highest antioxidant activity. Early animal studies suggest that a small amount of mangosteen may help lower plasma lipid levels.1 In another study, when it was blended into a skin cream with green and white teas and pomegranate extract, mangosteen appeared to help increase skin smoothness and fight the effects of aging.2

A purple berry native to the Amazon region of Brazil, açai is most commonly eaten as a frozen treat, sometimes mixed with banana and granola. For years, it has been consumed by Brazilians as an “energy” food but has only recently gained worldwide fame. One laboratory study on freeze-dried açai pulp showed that this fruit may have the highest recorded antioxidant power of any food, in part due to its high anthocyanin content.3 Açai is also rich in polyunsaturated fats, which makes it higher in calories than most North American fruits, and contains fiber, vitamin E, calcium, copper, potassium, and magnesium.4 Because it is shipped from abroad, finding whole açai fruit is rare in the United States; it usually comes in juice form, blended with other tropical fruit juices.

This fruit was once eaten by Native Americans, who hailed it for its healing powers. Its taste is tart—and therefore it’s also called tart berry—but it contains a large dose of anthocyanins within its purple skins. Some early studies suggest that it may help prevent cardiovascular disease and inflammation.5

Goji Berry
Often found in dried form and added to granola, trail mix, or cereals, goji berry is a bright reddish-orange Asian fruit. It contains fiber, copper, iron, potassium, riboflavin, and zinc. Cultivated by the Chinese for 2,000 years, goji is related to the tomato, potato, and eggplant and combines many of the nutrients these different foods offer, including beta-carotene, zeaxanthin, and lycopene.4

Another tropical fruit, noni is particularly rich in potassium and vitamin C. Recent animal studies suggest that it may confer antioxidant and immunomodulatory benefits, as well as combat fatigue and offer some protection to the liver.6,7 Also called cheese fruit because of its pungent odor and white color, it adds zing to foods such as granola bars, snack mixes, and fruit juice.4

The Tried and True
This list contains only a sampling of dietary die-hard foods that have withstood the test of time and continue to garner scientists’ interest, but there are a number of other excellent choices that could be included in a longer list, including vegetables of other hues, citrus fruits, teas, wine, and spices such as cinnamon, turmeric, and ginger.

Fish, Flax, and Other Omega-3–Rich Foods
Still No. 1 according to many health authorities, omega-3 fatty acids have a range of well-researched health benefits, including the power to lower heart disease risk, protect against certain types of cancer, and improve cognitive function. Alpha-linolenic acid is the omega-3 found in plant foods. The best sources include canola oil, flaxseed oil, and walnuts, as well as leafy green vegetables. The American Dietetic Association (ADA) recommends a daily serving of at least 1.5 grams, the equivalent of 1 tablespoon of canola or walnut oil or 1/2 tablespoon of ground flaxseed. The ADA and American Heart Association both recommend that healthy individuals consume two 4-ounce servings of fish weekly to get heart disease and stroke-fighting levels of docosahexaenoic acid and eicosapentaenoic acid, the omega-3s found in seafood.

Leafy Green Vegetables
It’s hard to find something unhealthful about greens such as kale, Romaine lettuce, spinach, chard, and bok choy. Scientists still have not pinpointed all of the phytonutrients that give greens such impressive health benefits. But vitamin K and several other known antioxidant vitamins, fiber, and minerals such as calcium and magnesium certainly play important roles in the heart disease- and cancer-fighting power of these stellar plant foods. They are an essential component of the Dietary Approaches to Stop Hypertension Diet and other widely recommended healthful eating plans. (A note of caution: Clients taking anticoagulant medications need to monitor their intake of greens carefully to control vitamin K levels in the blood.)

Whole Grains
Another food category that is hard to defame is whole grains. They provide protein, fiber, vitamin E, polyphenols, B vitamins, and a host of other phytonutrients that help lower the risks of numerous chronic diseases. This helps them easily trump their paler, processed counterparts. Not everyone enjoys the taste of brown vs. white rice or whole grain breads vs. white breads, but most people can warm up to the nutty flavor of whole grains if they give them a fair shake. Needless to say, dozens of products carry whole grain labels, so tell clients to read with caution and buy 100% whole grain foods.

Blueberries, strawberries, blackberries, raspberries—they are winners when it comes to delivering vitamin C, folate, fiber, potassium, and phytochemicals such as anthocyanins. These nutrients have been shown to help prevent cancer and lower cholesterol, as well as keep the heart and brain healthy. Berries are sweet, yet low in calories, and are therefore terrific choices for people with diabetes. They can be eaten as snacks or desserts, used as flavorings or toppings for sweet or savory dishes, or as part of baked goods. Encourage clients to buy them when they are in season or to make a fun activity out of picking local berries.

Not a low-calorie food or an easy one to grow in the backyard, nuts offer high taste, high nutritional content, versatility, and well-researched health benefits. Their fiber, selenium, arginine, polyphenols, and polyunsaturated fats have won them an FDA-approved claim: “Scientific evidence suggests but does not prove that eating 1.5 ounces of most nuts, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease,” according to the International Tree Nut Council’s Web site. Like berries, nuts are an ancient food, enjoyed by humans for millennia. Although they are high in fat and calories, a few nuts go a long way to adding taste to all kinds of entrées, snacks, and desserts.

Delicious, low in fat, and rich in protein, legumes have such numerous merits (eg, fiber, protein, iron, B vitamins) that they easily make the superfood cut. Not only are they heart healthy, but they may benefit the prostate as well. Results from the Multiethnic Cohort Study indicate that men with the highest intakes of legumes enjoyed an 11% lower risk of prostate cancer.

It’s no coincidence that the tried-and-true foods list contains representatives from all major food groups, since they all play a role in a balanced diet. Many of the newest superfoods are fruits and fruit juices and, like other sweet beverages, make a disproportionately large caloric contribution and a rather marginal nutrient contribution to overall intake. These products are often expensive for consumers, and when they are imported, they are environmentally expensive as well. Such products can add interest and a certain amount of variety to the diet but should not be relied on as substitutes for fresh, whole fruits.

While fruit and fruit juices may offer vitamins and minerals in a form preferable to those found in supplements, many of today’s heavily advertised functional foods lack scientific clout. Encourage clients to try foods for the right reasons—because they offer enjoyment, variety, nutritional value, and known health benefits at a price that is fair to consumers and the environment.

— Christen C. Cooper, MS, RD, is a Pleasantville, N.Y.-based freelance health and nutrition writer. She has worked in healthcare consulting in Latin America and the United States and holds a master’s degree in nutrition education from Teachers College, Columbia University.


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2. Hsu J, Skover G, Goldman MP. Evaluating the efficacy in improving facial photodamage with a mixture of topical antioxidants. J Drugs Dermatol. 2007;6(11):1141-1148.

3. Schauss AG, Wu X, Prior RL, et al. Antioxidant capacity and other bioactivities of the freeze-dried Amazonian palm berry, Euterpe oleraceae mart (açai). J Agric Food Chem. 2006;54(22):8604-8610.

4. Welland D. Five new exotic fruits: How ‘super’ good for you are they? Environmental Nutrition. 2008;31(6):2.

5. Goulding M. Stealth health food. Men’s Health. 2008;23(4):42.

6. Ma D, West BJ, Su CX, et al. Evaluation of the ergogenic potential of noni juice. Phytother Res. 2007;21(11):1100-1101.

7. Wang MY, Anderson G, Nowicki D, Jensen J. Hepatic protection by noni fruit juice against CCl(4)-induced chronic liver damage in female SD rats. Plant Foods Hum Nutr. 2008;63(3):141-145.