Do functional foods really work?

Something has happened to food. Stores are dotted with omega-3-enriched eggs, dairy products and juice. On commercials, women gyrate in orgasmic pleasure while eating probiotic yogurt. Newspaper lifestyle articles and scientific studies tell us green tea may help prevent breast cancer, while whole-grain foods may reduce the risk of heart disease.

“Functional foods” — foods that have health-promoting properties beyond their basic nutritional makeup — can be whole foods, such as cholesterol-lowering beans, or dietary components, such as flavonoids (found in berries and chocolate). And they’re big business. According to Agriculture and Agri-Food Canada, functional food industry revenues grew 15 per cent between 2002 and 2004 to $2.9 billion.

Food manufacturers would have us believe functional foods are nature’s elixir, capable of delivering a range of health benefits — from alleviating menopause symptoms to warding off Alzheimer's. What’s real and what’s marketing mumbo-jumbo?

Health Canada regulates what manufacturers can claim on packaged foods and in advertising. For example, “May reduce the risk” of heart disease is allowed on certain products that are low in saturated and trans fats and high in fibre. Stating a food will help prevent breast cancer or boost the immune system, however, is not allowed. Those are the rules as they apply to packaging on the shelves; cyberspace is a different story.

The need for educated consumers

Manufacturer websites tout all kinds of health benefits. A site for a Yogen Früz probiotic frozen yogurt states, among other things, that probiotics can reduce the risk of colon cancer, allowing the consumer to leap to the conclusion that its frozen yogurt could do the same. Gregor Reid, a professor of microbiology at the University of Western Ontario finds this sort of advertising “misleading” and “inappropriate.”

The onus is on us to be educated consumers. Ann McConkey, a dietitian in Winnipeg, says there are many reliable web sites, such as Dietitians of Canada (dietitians.ca) and the Canadian Women’s Health Network (cwhn.ca), that have good information and links to other reputable sites. “The media present so many studies that it’s hard to make good choices,” she says. “On these sites, someone has done the research and summarizes it in a way that’s understandable.” You can also look at scientific studies first-hand on such sites as the U.S. National Library of Medicine's PubMed, though you have to know what you are looking for. “I don’t care about the thousands of studies on the health of rats in the labs of North America,” says Bruce Holub, professor emeritus of nutritional sciences at the University of Guelph (Ont.). “Show me the peer-reviewed human studies: That’s all I care about in terms of delivering information to the public.”

So what are these functional food components? More asked nutritional experts for a primer on four components — psyllium, probiotics, omega-3 fatty acids and soy isoflavones — to better understand what we are being asked to put in our bodies.

Psyllium

What is it? Psyllium is a plant with the highest amount of soluble fibre found in nature. We need two types of fibre in our daily diet — soluble and insoluble. Insoluble fibre, in foods such as wheat bran and fruit skins, speeds up digestion, bulks up stool and helps keep us regular. Soluble fibre, from psyllium, oats, legumes, fruits and vegetables, dissolves in water and becomes gel-like, softening stool and slowing down digestion and the release of carbohydrate energy, which stabilizes blood sugar levels and helps you feel full longer.

Where is it found? Two cereals of the few in Canada enriched with psyllium are Kellogg’s All-Bran Buds and All-Bran Guardian. It’s also the dissolvable powder in the fibre supplement Metamucil.

The claim: When Regis Philbin announces on a commercial for psyllium-enhanced Guardian cereal that a bowl a day will lower cholesterol 10 per cent in four weeks, should we believe him? Yes, says Doug Cook, a dietitian at St. Michael’s Hospital in Toronto. “If you have high cholesterol you should be eating at least 10 grams of soluble fibre a day. You get 3.5 grams in a serving of cereal with psyllium, and that’s more than you get in three apples.”

Soluble fibre has been shown to lower low-density lipoprotein (LDL) cholesterol, the “bad cholesterol” that can lead to heart disease. Louise Lambert-Lagacé, a Montreal clinical dietitian and author of Good Nutrition for a Healthy Menopause, has seen “marvelous” results among her middle-aged female patients in lowering LDL with powdered psyllium. That’s in addition to the benefit that both soluble and insoluble fibre offer in fighting constipation, a bogeyman of midlife, when our gastrointestinal motility starts to slow down.

Should we be concerned that, to make them more palatable, psyllium-enriched cereals have a higher sugar content than other high-fibre brands? Guardian’s 10 grams of sugar in a one-cup serving is hefty compared to four grams in Bran Flakes. But since most people don’t get enough fibre in their diets, Lambert-Lagacé feels the benefits outweigh the disadvantages.

The bottom line: Go for it! Bust out your breakfast bowl. “It’s not going to be harmful, and may be helpful,” says McConkey.

Probiotics

What is it? The World Health Organization defines probiotics as “live microorganisms, which, when administered in adequate amounts, confer a health benefit.”

Where is it found? Probiotic yogurt, milk and soy beverages, and fruit juices can be found in most grocery stores.

The claim: Bacteria come in groups, species and strains. To have probiotic effects a product has to have the right strain for a particular health benefit as well as the right amount of live active bacteria (at least a billion per serving). Though some probiotic products claim this amount, tests have shown that the number of live bacteria diminish the longer some products sit on the shelf. Gregor Reid says Danone’s Activia yogurt is one of the few real probiotic foods marketed in Canada, with good science backing its claims of aiding in regulating the digestive track. “Activia has a strain that produces short-chain fatty acids, which help with regularity.” But according to Reid, who has been researching probiotics for 25 years, you shouldn’t take all probiotic product claims at face value. “Companies are getting clever and starting to write strain numbers on products. But then you look up the strain number and find there are no studies on it.”

The bottom line: Probiotic bacteria do aid in digestive tract health, but make sure you are ingesting the right strains in the optimal amounts.

Omega-3 fatty acids

What is it? Omega-3s are essential fatty acids your body needs. They regulate how cells let in nutrients and keep out toxins. There are three forms of omega-3s. Alpha linolenic acid (ALA) comes from plants like flax and canola; it is considered an essential nutrient because our bodies can't produce it. Eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA), found in fish oils. All three are considered beneficial to reducing risk of heart disease.

Where is it found? You can get omega-3s from flax seed and walnuts, and in fatty fish — salmon, sardines and rainbow trout. Apparently, we Canadians don’t eat enough fish. “Women are under-consuming omega-3,” says Holub. “They are wrongly equating all fish with methyl mercury contamination. That’s why functional foods with omega-3 are becoming very popular.” We are now seeing omega-3-imbued eggs, orange juice, bread, yogurt, milk, and even frozen chicken strips.

The claim: Omega-3s are the darling of the baby boom. They’ve been said to reduce heart disease, lower triglycerides, reduce the inflammation of rheumatoid arthritis, reduce the risk of cancers, and help relieve mild to moderate depression. Most scientific studies use high-dose supplements, but experts say we can get health benefits from foods rich in omega-3s, if we eat enough of them. “The average Canadian woman is consuming 130 mg of EPA/DHA omega-3s a day right now,” says Holub. “For general health, Canadian agencies recommend two fish servings a week, which will give you 300 mg per day, well above the average.” Holub and others believe 500 mg a day should be a reasonable target for a healthy person.

Holub has studied the effects of EPA/DHA omega-3s on triglyceride levels in menopausal women. Triglycerides, or fats that circulate in the blood, are a risk factor for heart disease. He found that midlife women tend to have above-average triglyceride levels, yet not high enough for a drug prescription. But last year, a British research team found that the health benefits of omega-3 fatty acids on cardiovascular disease, stroke and cancer were inconclusive. Holub still feels the evidence for cardiovascular disease is strong, but does agree cancer remains a question mark.

The jury is also out on omega-3s’ beneficial effect on depression — with some studies extolling it and others finding little convincing evidence. Depression is not a one-size-fits-all condition, says Holub. “There are all sorts of categories of depression and you get inconsistencies. Is that due to dose, the group tested or the duration of the study? The poor public’s head is spinning.”

The bottom line: As scientists continue to take a closer look at omega-3s’ health benefits, consumers have food choices to make. When you’re paying a premium for these products, are they worth the price? “I would go for omega-3 eggs if a person doesn’t eat fish three or four times a week,” says Lambert-Lagacé. “But I smile when I see omega-3 in orange juice, because it’s a small amount compared to a can of sardines.” True. When you read that there’s 0.1 grams of marine-based omega-3s in a serving of Tropicana Essentials Omega-3 juice, it doesn’t sound like much. “What if I told you a serving had 100 mg; you might be more interested,” says Holub. “Government regulations say you have to use gram units on this type of packaging and 0.1 looks so small.” If you are going for 300 to 500 mg a day for cardio health and you’re not a fish eater, a glass of juice could help get you there.

Soy isoflavones

What is it? Soybeans are legumes that are considered a complete protein and provide us with ALA omega-3s, iron and calcium. They also provide phytoestrogens (isoflavones are one type of phytoestrogen), which produce estrogen-like effects on the body and are thought to help prevent or treat diseases.

Where is it found? Obviously the most direct source of soy is the soybean. However, given that neither soybeans nor tofu has an overwhelming number of fans, most of us get soy from such products as soymilk, meat substitutes or soy-enriched cereals.

The claim: Since researchers in the U.S. halted the Women’s Health Initiative study on hormone therapy (HT) in 2002 after finding long-term use increased the risk of heart disease and breast cancer, there has been renewed interest in soy, particularly isoflavones. Articles have reported that soy reduces “bad” cholesterol, prevents osteoporosis, eases menopausal symptoms, and even prevents certain cancers. But can 10 mg of soy isoflavones in a 1/2 cup of Nature’s Path Organic Soy Granola cereal make a difference in our health? Lambert-Lagacé thinks not. “A 10 mg serving doesn’t mean much if you’re in midlife and have hot flashes,” she says. “You want 75 to 100 mg of isoflavones [a day] to reduce them.”

Studies have found that the more “real” and less processed the soy foods — like edamame (whole soybeans) and tofu — are, the richer the isoflavone content, offering greater health benefits than those from isolated isoflavones found in supplements and such foods as enriched cereals. “In terms of heart health and lowering cholesterol, we don’t really know which components are helpful,” says McConkey. “Is it the isoflavones or the fibre in soy? I think it’s better to go with whole soy than something with isoflavones added to it.”

The scientific literature is confusing. While some studies show positive benefits of soy isoflavones on hot flashes, heart disease, breast cancer and increased bone mass, others say the evidence is inclusive or flawed. Experts are of two minds when it comes to breast cancer and soy consumption, because of soy’s phytoestrogen component. “Some experts are cautious about women with estrogen-positive receptor breast cancer having soy,” says McConkey. “Others feel three to five servings of soy a week is safe.” The American Cancer Society has suggested to breast cancer survivors to use soy supplements in moderation, and Lambert-Lagacé believes it’s fine to eat whole soy in moderation. “Soy isn’t considered a preventive measure for breast cancer in midlife women, but it won’t trigger the disease.”

Osteoporosis is another area where studies conflict. This may be remedied by a two-year, randomized, double-blind U.S. study that looked at 400 post-menopausal women taking different dosages of soy isoflavone supplements or a placebo. Results aren’t in yet — data analysis began in November 2006 — though preliminary findings look positive.

The bottom line: Lambert-Lagacé believes whole, less processed foods are the ones that give the true health value. “If there’s a choice, opt for the real stuff.” But Holub sees a bright future for functional food components as a low-cost, preventive healthcare model. “I can see walking into a grocery store where a life science grad pricks your finger, gets a cholesterol level and then tells you the cholesterol-lowering foods are in Aisle C.”

This article originally appeared in the September 2007 issue of More