This article was originally published in Maclean’s magazine on October 27, 1997. Partner content is not updated.
Let your food be your medicine and let your medicine be your food
So said the Greek physician Hippocrates, more than 2,000 years before modern science published the first of thousands of studies warning about the potential dangers of red meat, caffeine, white flour and almost everything else on the grocery list. Today, food may seem more a menace than a medicine. Threats of cancer flare on the barbecue. Hints of a heart attack sizzle from the porterhouse. Even broccoli, that nutritional superstar, is tainted with the suspicion of pesticides. Even worse, the experts often cannot agree on what is good and what is bad to eat. And consumers are losing patience. More than half of Canadians are "tired of getting conflicting messages about how they should eat to be healthy," concludes a recent poll by the Canadian Foundation for Dietetic Research. Like many of those surveyed, Robert Rose is trying to improve his diet but finds labels and the "blizzard" of studies confusing. "I can't answer what is right to eat or what is wrong to eat," says the 44-year-old Edmonton engineer. "How is the public supposed to figure that out?"
The nation is hungry for answers to questions about food and nutrition - and not just for weight loss. "People want to know all there is to know," says Vancouver dietitian Patricia Chuey, who fields as many as 100 phone calls after her weekly food spots on BCTV. "We see 30 new clients a week for one-on-one consultations." A personal nutritionist now ranks right up there alongside a personal trainer for the diet conscious with a healthy pocketbook - it costs up to $150 an hour for the right advice.
Less well-heeled consumers are forking out more than a little lunch money on thousands of books and magazines about food and nutrition. Practical, encyclopedic texts like Foods That Harm, Foods That Heal are flying off the shelves as fast as more faddish best-sellers like The Zone: A Dietary Road Map, Eat Right 4 Your Type and Your Body Knows Best. The Internet is cooking too, with thousands of Web sites serving up nutritional tips, menus and recipes. In Truro, N.S., customers at Ryan's IGA can get advice as they shop from dietitian Kate Evans, a full-time employee who handles questions about labels, additives and fat content from the food-perplexed, both men and women. "It's a logical place for a dietitian," says Evans. "There is a lot of misinformation out there."
While suspicion and confusion multiply like mould at the back of the fridge, researchers are busily solving the inner mysteries of fibre, fruits and vegetables. In the past decade, scientists have made major breakthroughs, discovering, in an array of plant foods, powerful drug-like compounds called phytochemicals that help prevent cancer and heart disease, and even slow the aging process. Researchers can now state with a confidence based on hundreds of solid studies that a healthy diet - along with exercise and weight maintenance - could prevent between 30 to 40 per cent of cancer cases. "You may be able to do more with food than you used to think you could," says University of Toronto nutrition specialist David Jenkins, echoing Hippocrates. "You may be able to use it as medicine."
Some, particularly health-conscious baby boomers, are already dosing themselves with lentils, tofu and handfuls of food supplements, eager to enhance their immune systems and energy levels. "There is this hope we can somehow find the fountain of youth in food," says McMaster University food historian Harvey Levenstein, author of The Paradox of Plenty: A Social History of Eating in Modern America. "People want super health," says Susan Barr, a professor of nutrition at the University of British Columbia. "It's an exciting area but there is a lot we still don't know." That does not deter a lot of health seekers from popping copious quantities of beta-carotene, vitamin E, blue green algae and other popular supplements. "Sometimes we have to pull clients back," observes Chuey. "People think if a little is good, a lot is better."
But while some people go overboard, most Canadians are making only half-hearted attempts to improve their diets. Statistics Canada reports that the average person's consumption of red meat has declined nearly 10 per cent over the past two decades. But fat still sticks to most people's diets. During the same period, the intake of cheese - most of it high-fat cheddar - has more than doubled. Canadians drink less milk now and have largely switched to skim, one and two per cent, but they consume 50 per cent more cream than they did two decades ago. Others may be deluding themselves, gorging on low-fat foods. "If they have fat-free cookies," Barr says, "they might eat the whole batch."
Of course, many are simply too busy to eat properly. "There's a time factor," says Rosie Schwartz, cookbook author and consulting dietitian to the Heart and Stroke Foundation. "It's easy to eat right if you are Oprah and have a chef who can cook well." A proper diet takes planning, and more than half the population does not know on any given day what they will have for dinner that night, according to the Canadian Foundation for Dietetic Research. Who takes time to consider Canada's food rules, or even read labels, when they run into a supermarket to buy a few groceries on the way home from work?
In fact, the general principles of good eating are fairly simple, says Dr. Andrew Weil, author of the best-selling 8 Weeks to Optimum Health. "Eat more fruits and vegetables and more whole-grain products. Be careful about saturated fat, reduce the percentage of animal foods in your diet and eat some fish - those are the basics." And while most dietitians are urging people to add one particularly beneficial element - soy foods - to their diet, few are promoting outright vegetarianism. "We do not have to give up dairy products or meat," says Joe Schwarcz, a McGill University chemist and nutrition specialist. But it does mean forgetting about "a 16-oz. steak hanging off the plate." The new rule of thumb: a serving of meat should be no larger than a deck of playing cards.
But it is OK now to eat potato chips. Or a chocolate bar. Or a hotdog. "A few potato chips or a bit of chocolate is not going to ruin your system," says the Heart Foundation's Schwartz. Nor, she adds, will a bit of tofu act as a "magic bullet" and transform anyone's health. "There is no perfect food - it's the whole picture that counts." Of course, it cannot be too big a picture. "Moderation has to be emphasized," says Jenkins. "People still have to maintain body weight."
Some experts, such as McMaster's Levenstein, wonder about the anything-in-moderation approach. "Moderation in wine turns out to be, what, one glass a day?" he says. "C'mon." But eating is not an exact science. "It is frustrating for us as nutritionists because people want black and white answers," says nutritionist Judy Fraser Arsenault of Dalhousie University in Halifax. "But often we are operating in a grey area."
In a field where even a tomato is not necessarily just a tomato, scientists are using biotechnology to give that fruit, and a whole array of plants and animals, new properties. Some are practical changes, like making crops resistant to pests. Others are attempts to add healing properties to foods. Some concerned observers see genetic engineering as only one in a long list of threats to the food supply. In an April report titled A Taste of Canada, the Canadian Environmental Law Association lists pesticides, hormones and antibiotics among contaminants to be found in Canadian food. The widely publicized problems with mad-cow disease in Britain and the E. coli bacterium in the United States only increased doubts about the safety of the food supply.
Should consumers fear what's on their plate? Environmentalists say yes - some toxins, in the long term, could damage human health. Federal and provincial health officials say no - contaminants fall well within established safety guidelines. Most food scientists say they just don't know. There are insufficient data, notes Jenkins - and not enough funding to gather the necessary information.
But nutrition experts generally see no need to panic. "We have a very safe food supply," says dietitian Leslie Beck, host of Foodstuff, a daily show on the Discovery Channel, noting that the meat supply, for example, passes several levels of government inspection. Risk can be reduced. "You can wash fresh produce or buy organic products," she adds. "But, even then, you are still taking somebody's word - ultimately, we have to trust someone." The principles of variety, moderation and balance in Canada's Food Guide also offer protection. "If you eat a few grapes from Chile with whatever chemical, it's most likely not a problem," says Chuey. "If you eat only grapes, you are more likely to have a problem."
But no diet comes with a guarantee. Genetics, exercise, stress, environment and just plain luck all play a role in good health. "By eating a balanced diet we minimize risk," says McGill's Schwarcz. "But it's too simplistic to think that if you just eat right, you'll be OK." Food for thought.
Mother Knows Best
It was thumbs-down for the bubble-gum-flavored broccoli. But the chocolate-flavored carrots, cheese-and-onion-flavored cauliflower and pizza-flavored corn won raves from the five- to 13-year-olds who tested a new line of vegetables for Iceland, a British frozen-food chain, early this year. Chocolate carrots? Crazy, maybe, but the London-based Cancer Research Campaign decided to endorse them after a British survey showed that children were eating hardly any vegetables. "We have manufactured tons of the stuff," said Malcolm Walker, the enthusiastic chairman of Iceland, at last April's launch. But is the Wacky Veg line a success? Possibly not - Iceland was not eager last week to discuss sales figures.
There may be a good reason why children - and many adults - refuse to eat their vegetables. U.S. scientists recently discovered that at least 25 per cent of the population have an inherited trait that causes them to dislike the bitter compounds found in grapefruit, broccoli and many other fruits and vegetables. Their tongues contain more taste buds than regular tasters'. But those so-called supertasters may simply have to get over it. Mom was right, the world's top nutritional scientists agree - people who eat plenty of fruit and vegetables live longer, healthier lives. "Over time, the consumption of 400 g per day [five servings] or more of a variety of vegetables and fruits could, by itself, decrease overall cancer incidence by at least 20 per cent," states a report by an international panel of 15 experts, published this month by the World Cancer Research Fund.
The scientists - who reviewed more than 4,500 research studies - found convincing evidence that diets high in vegetables and/or fruits protect against several cancers, including lung, colon and breast. In thousands of other studies, researchers concluded that plant foods can reduce the risk of coronary heart disease, lower blood pressure and cholesterol, help prevent arthritis, cataracts and diabetes, and slow down the aging process.
Tomatoes are rich in lycopene, a plant chemical that appears to prevent prostate cancer. Pumpkin seed oil is a source of essential fatty acids shown to reduce arthritic inflammation. One by one, researchers are discovering an array of powerful, pharmacologically active compounds - known collectively as phytochemicals - in fruits and vegetables. Each acts in a different way, on a different part of the body, to prevent disease and enhance health. Carotenoids, sulforafane, indoles, phytoestrogens and flavonoids are among the better-known phytochemicals, but there are countless others. "There are so many things in citrus fruits, for example, that we never realized," says Kenneth Carroll, director of the Centre of Human Nutrition at the University of Western Ontario.
Beta-carotene - one of the most celebrated phytochemicals - caused excitement as a popular supplement in the late '80s. Epidemiological studies had shown that people who consumed foods rich in beta-carotene had lower rates of cancer and heart disease. "People were all over the beta-carotene bandwagon, popping pills," recalls McGill University chemist and nutrition specialist Joe Schwarcz. But the hype turned to disappointment after two large studies, in Finland in 1994 and the United States last year, showed not only that beta-carotene supplements did not work, but they actually appeared to increase the risk of lung cancer in some smokers. "It doesn't work on its own," notes Schwarcz. "When you are eating beta-carotene [in foods], you are eating lots of other things too, and that is what is important."
Experts also warn against relying on a single food - no matter how nutritious. "From sweet treats like figs to pungent, robust workhorses like garlic, in all their diverse textures, odors, tastes and in a rainbow of color, the power of these plant foods is in the way the phytochemicals combine," writes Richmond, Mass., author Dr. Stephanie Beling in her recent book, Power Foods. "When they do so, they ignite a synergy of pharmacological activity where the whole is greater than the sum of the parts."
A Place for Supplements
Are food supplements necessary? The answer is a definite maybe. Until recently, experts insisted that diet alone - if it reflected the Canada Food Guide - would provide all the nutrients required by a normal, healthy person. "Anyone who didn't say that was an outcast," says University of Toronto nutrition scientist David Jenkins. "Now, people are saying, 'Well, you might need a bit of extra E, or a bit of [the mineral] selenium.' " Why the turnaround? Researchers are finding that it may be possible to prevent some chronic illnesses, including cancer and heart disease, with higher levels of vitamins, minerals, antioxidants and phytochemicals than are found in a typical diet. The problem is, scientists have not established how much higher, and in large doses some of those elements may be harmful.
Nature's Medicine Chest
Scientists are digging into fruits and vegetables and turning up a treasure trove of phytochemicals - natural plant compounds that work with vitamins, minerals and other nutrients to protect against cancer, heart disease and other chronic illnesses. Some promising findings:
The Ocean's Harvest
Seaweed, a staple of the Japanese diet for hundreds of years, is gaining a reputation in some circles as a super food. Various health-food gurus claim that sea vegetables - including the currently trendy blue green algae supplement - can remove toxic chemicals and heavy metals from the body, boost the immune system and cure cold sores. While noting that there is little evidence to support those claims, mainstream nutritionists do acknowledge that seaweeds are rich in minerals, provide some protein and can contain beta-carotene and vitamin C. There are, in fact, more than 2,000 kinds of sea vegetables, including Nova Scotia dulse, nori and kelp. Some, like the agar-agar added to ice cream as a thickener, are used in food preparation. Most sea vegetables are very high in salt and should be avoided by people on a low-sodium diet.
Surf Versus Turf
It may not be politically correct, but red meat is definitely nutritious. Beef, pork and lamb are excellent sources of high-quality protein. One small serving, barely four ounces of cooked lean beef, provides the daily recommended nutrient intake for vitamin B12, half the required protein and zinc, up to a third of the iron, plus several other nutrients. While spinach, bran and some other plant-based foods contain more total iron, meat provides the blood-boosting element in its much more easily absorbed "heme" form.
But, of course, there is a catch. In fact, there are many catches:
»Red meat is riddled with saturated fat and cholesterol. A 16-oz. T-bone steak has nearly 1,000 calories - more than a third of the recommended daily intake for an active adult male. Meat producers have done their best to exorcise those dietary demons - beef is 50-per-cent leaner and pork at least 23-per-cent leaner than they were a decade ago. Still, even after visible fat is removed, a serving of beef contains significant levels of saturated fat.
»Several studies have linked frequent consumption of meat with an increased risk of colon and other cancers. An analysis of the diets of 88,000 nurses, published in the New England Journal of Medicine, revealed that those who ate meat every day were twice as likely as others to develop colon cancer.
»Highly saturated animal fat can raise blood cholesterol levels and increase the risk of cardiovascular disease. Because organ meats are particularly high in cholesterol, liver has lost its lustre in fighting iron-deficiency anemia.
»Protein promotes the excretion of calcium in urine. There is growing evidence that a large intake of meat can produce a calcium deficiency and possibly contribute to osteoporosis.
»It is important to cook beef, particularly hamburger, thoroughly, since a deadly form of E. coli bacteria may survive in contaminated meat served rare. Undercooked pork may contain parasites. Some health lobbyists are concerned about the approved antibiotics and hormones given to food-producing animals.
On Top of Everything Else, Fish is a Brain Food
Canadians do not eat enough fish. Average consumption is only 16 lb. a year per person, compared with a hefty 55 lb. of chicken and 50 lb. of beef. "We should be eating more fish and less meat," says Toronto dietitian Leslie Beck. What's so special about fish? Omega-3 fatty acids. Fish oil - as well as canola, flaxseed and walnut oils - contain these essential substances that are not produced in the body. "Canadians are eating more fat than we like," says Beck. "But they are not eating enough essential fatty acids."
Fish really is brain food. "Omega-3 fatty acids are needed for the normal development and functioning of the brain," notes Beck. "All cell membranes contain omega-3 fatty acids, but they are especially abundant in the brain where they aid in the transmission of nerve impulses." The results of a five-year study of 939 elderly men, published this summer by Dutch researchers, associated high fish consumption with less decline in brain functions.
When it comes to the heart, the fish story is even bigger. "It is generally agreed that eating fish two to three times a week can reduce the risk of heart disease," notes Beck. The latest in a string of studies showing that fish benefits the heart appeared in the New England Journal of Medicine in April, when U.S. researchers reported results of a study showing that men who consumed at least eight ounces of fish a week - most ate canned tuna - had a 40-per-cent lower risk of a fatal heart attack.
Omega-3 fatty acids also have an anti-inflammatory effect, and one recent study suggests that daily consumption of fish may help alleviate some of the painful symptoms of rheumatoid arthritis. Other preliminary evidence suggests that fish may protect against breast cancer.
Is poultry a healthier choice than beef or pork? Not necessarily. "People are afraid of red meat because of the perception that it is high in fat," says Leslie Beck, a dietitian and host of Foodstuff, a daily nutrition show that runs on the Discovery Channel. "I think that is not always justified." A three-ounce serving of broiled inside round steak has 3.5 g of fat, while the same amount of roasted, skinless chicken breast has 3.2 g. "So the difference is minimal."
A more important consideration, notes Beck, is the iron content of meat. Three ounces of beef will have 2.5 mg of iron, compared with .9 mg in the chicken. "When people cut red meat out of their diet and switch to chicken or fish, they are not getting good sources of what we call heme iron, the most absorbable form," says Beck. Poultry, however, contains more protein and less saturated fat than red meat. And there is evidence that chicken soup can relieve cold symptoms. Researchers speculate that cystine, an amino acid in chicken soup, helps thin mucus, making it easier to expel.
Praising the Humble Soybean
Soy flour, soy oil, soy milk and, of course, the much-maligned tofu are only a few of its guises. But not only is the soybean versatile, it is also a nutritional powerhouse, containing iron, calcium and almost as much protein as beef. In fact, the soybean - a good source of B vitamins, potassium, zinc and other minerals - is the only food that can match meat as a source of amino acids, an essential protein.
But the soybean is prized most for its large cache of isoflavones - plant chemicals that help reduce the effects of the hormone estrogen on the body. Researchers believe the Japanese can attribute their world's-lowest rates of breast and prostate cancer to their low-fat, soy-rich diet. They eat 30 times more soybeans than North Americans, who suffer the world's highest incidence of those cancers.
Researchers also credit soy with combating hypertension, protecting against heart disease, easing the symptoms of menopause and strengthening bones. Numerous studies show that soy lowers blood cholesterol levels. Even better, it targets the artery-clogging "bad" cholesterol without affecting beneficial cholesterol. Evidence that soy's isoflavones offer protection against osteoporosis comes from research at the University of Illinois. Women who ate two ounces of soy protein a day increased the bone density in their spines. Australian researchers also report that a diet rich in soy can reduce the severity - although not the frequency - of menopausal symptoms.
The superbean is not devoid of drawbacks. The iron in soy is not easily absorbed by the body, but that problem may be offset by consuming foods high in vitamin C at the same time. Some soy products - including tempeh, a type of soy curd, and miso, a flavoring paste used in soups - are fermented. Although nutritious, they are high in sodium and contain mould that can provoke an allergic reaction.
Vegetarian Risk and Reward
As a debate flares over vegetarianism, nutritionists are far from unanimous. Studies show that, as a group, vegetarians are less prone to many illnesses that afflict meat-eaters. The list includes heart disease, diabetes, gallstones, kidney stones, osteoporosis and diverticulitis, as well as colon cancer. Seventh Day Adventists, who abstain from meat for religious reasons, have up to 30 per cent lower rates of cancer.
While a vegetarian diet - which is typically low in saturated fat and high in fibre - may account for those favorable results, so far scientists have been unable to prove a definitive link. Other lifestyle factors - abstaining from smoking, coffee and alcohol, for instance - may cause or contribute to the health advantage.
On the other hand, several essential nutrients abundant in meat - including iron, zinc and vitamin B12 - appear only in small amounts or are missing from plant sources. Also, with the exception of soy - which, like meat, provides high quality protein with all of the essential amino acids - no single vegetable, grain or other plant food provides complete protein. Strict vegetarians who avoid dairy products may also have difficulty meeting calcium needs.
A Drink to Health
Milk is good for kids, but grown-ups don't need to drink it, right? Wrong. The important news about milk is that adults, even the elderly, need it as much as children. Nutritionists - and parents - have long understood that milk is a rich source of calcium, essential for building strong teeth and bones. But only recently have scientists discovered that increased consumption of milk and other calcium-rich dairy products can help prevent the severe bone loss that leads to osteoporosis. In August a panel of 30 distinguished scientists - appointed by the Canadian and U.S. governments to review nutritional requirements - recommended a significant increase in daily calcium intake.
Tofu, broccoli and canned salmon (with bones) can help provide some of the 1,000 to 1,300 mg of calcium (the equivalent of three or four glasses of milk) that the experts now recommend as the daily intake for an average, middle-aged adult - up from the 700 to 800 mg recommended until recently. But it is difficult to get enough calcium without milk. (Supplements may be a shortcut, but the mineral is not as easily absorbed from pills as from food.)
Why, then, is there little osteoporosis in Asia, where people drink little milk? "Their diet is vegetable-based," explains McGill nutrition specialist Joe Schwarcz. "In North America we have a high-protein diet, and protein causes excretion of calcium from the body, so it is very hard to fulfil that calcium need from broccoli and soya."
Milk, the single best source of calcium, comes packaged with protein and several other important nutrients. In Canada - where winter days are often too short to allow the body to manufacture adequate vitamin D from sunlight - that vitamin, necessary for the absorption of calcium, is added by law. Skim, one- and two-per-cent milk are also fortified with vitamin A, to compensate for amounts lost when the fat is removed.
The most stunning new finding about milk is that it may help prevent breast cancer. Last year, in the British Journal of Cancer, Finnish researchers published a study of more than 4,000 women over a 25-year period showing a correlation between high consumption of whole milk and low rates of breast cancer. The finding, unsupported by other research, contradicts the long-held belief that dietary fat promotes breast cancer.
Even so, milk has long since lost its reputation as a perfect food - mainly because of the fat. Medical experts recommend cutting back on fatty foods in the diet, particularly those of animal origin, because of their links to heart disease and some cancers.
Somewhat less critical is the great mucus debate. Some doctors and alternative practitioners tell patients to avoid dairy products if they have a cold or suffer from allergies. The reason: anecdotal evidence that milk promotes the formation of mucus and studies showing that asthma sufferers improve when they take dairy products out of their diet. The Dairy Bureau of Canada hotly denies the claim. But the research community is not rushing to settle the matter. "There are more important things to study than mucus," notes Dr. David Jenkins, a nutritional scientist at the University of Toronto.
Dairy Counter Culture
Yogurt is made from milk fermented with health-promoting bacteria. Easier to digest than milk for people with lactose intolerance, yogurt contains similar amounts of calcium, and the yogurt bacterial cultures help prevent some diarrhea, fight infection, boost the immune system and reduce the risk of colon cancer.
Cheese - A Mixed Blessing
Cheese is rich in protein, vitamin B12 and bone-strengthening calcium. A 1 ¾-oz. serving of cheddar, for instance, provides as much calcium as an eight-ounce glass of milk. There is also some evidence that eating cheese at the end of a meal may help prevent cavities. But concerns that some varieties pose a health hazard prompted Health Canada last year to consider banning cheese made from raw (unpasteurized) milk. The proposal was dropped, but Australia, New Zealand and the United States have all outlawed cheeses such as Brie, Parmesan and Quebec's own Oka because potentially deadly micro-organisms can survive the centuries-old manufacturing process.
Pasteurized or not, most cheese is high in salt and artery-clogging saturated fats. One ounce of firm cheese like cheddar or Swiss contains about 120 calories - about 90 of them from fat. More than half of the calories in part-skim mozzarella come from fat. Cream cheese is 90-per-cent fat and contains much less calcium than other cheeses. Cottage cheese, made from skim milk, is low in fat and calories - but it has only half the calcium of milk. Tofu cheese may also be high in fat and sodium.
A Regular Jolt of Java
North Americans are hooked on caffeine, routinely reaching for a quick fix of the drug in coffee, tea, soft drinks, chocolate - even plain water spiked with caffeine, a hot new product sold under several brand names. A caffeine jolt can slough off sleepiness and provide at least a temporary boost in energy and alertness. A recent study by Guelph University researchers in Ontario showed that even a moderate amount of caffeine - the equivalent of one large mug of strong coffee - can pump up an athlete's performance. It may even improve memory. A central nervous system stimulant, caffeine can help alleviate migraine headaches. The amphetamine-like substance also increases the rate at which the body burns calories, but offsetting that potential for weight loss is the fact that it also lowers blood sugar and increases hunger.
But caffeine is addictive. Habitual users of excess amounts develop a tolerance and need to consume large quantities to achieve a stimulant effect. Too much caffeine can cause nervousness, anxiety, panic attacks and palpitations. It can aggravate stress, cause heartburn and indigestion, interfere with sleep and increase the side-effects of certain medications. And withdrawal - even for moderate users - can lead to headaches, fatigue and other symptoms.
Numerous studies have shown that the moderate use of caffeine is not associated with risk of cancer, cysts in the breast or heart disease. But Norwegian scientists raised new doubts recently when they reported a strong link between caffeine and homocysteine - an amino acid that in high concentrations in the blood is known to increase the risk of heart disease. Researchers continue to debate the effects of caffeine on pregnant women and fertility.
Brands vary, but a typical 12-oz. can of cola has about 38 mg of caffeine. Two ounces of baking chocolate has about 70 mg. But North Americans' biggest source of caffeine is coffee and a single cup contains anywhere from 65 to 180 mg of caffeine, depending on how it is brewed. But caffeine is only one of more than 400 chemicals in coffee. And not all of them are harmless. Dutch researchers recently discovered that two compounds found in coffee - known as diterpenes - can increase blood cholesterol by as much as 10 per cent over six months in heavy coffee drinkers. The offending oily droplets, released from coffee beans during the brewing process, are most likely to be present in European-style coffee - prepared in a French press, for example. When coffee is filtered, the diterpenes remain on the paper, and levels are also very low in percolated and instant coffees.
But there are other risks. Coffee is known to increase blood pressure, and evidence is mounting that heavy consumption - five or more cups a day - may lead to heart attacks. As for any connection between coffee and cancer, the research is contradictory.
Black Tea or Green Tea?
Put the kettle on. There is strong evidence that tea may help prevent heart disease, stroke, high blood pressure and certain cancers. Will that be black tea or green? Both contain the bioflavinoids and antioxidants believed to be the protective factors. But researchers are still debating the merits of the beverages, derived from the same plant but processed differently. A recent Australian study showed that black tea (the type most popular in North America) was more effective than green tea (the Asian beverage of choice) in boosting the skin's resistance to the damaging effects of ultraviolet rays and in reducing skin cancers in rats. Still, green tea - used as a tonic in Asia for more than 4,000 years - appears to have the health edge. U.S. researchers report that it contains significant amounts of catechins, a chemical that inhibits cancer growth. Green tea is also a good source of vitamin K, a nutrient needed for normal blood clotting. Both teas contain fluoride and tannin, substances that help protect against tooth decay. Tannin, however, also interferes with the absorption of iron consumed at the same time. And as a diuretic, tea may lead to a loss of potassium.
Herbal teas offer a pleasant, caffeine-free alternative to coffee and tea, but sip carefully - many contain ingredients with medicinal properties that may interfere with prescription drugs or provoke an unexpected reaction. Chamomile, for example, is a mild sedative that may aid digestion and relieve menstrual symptoms. But allergy sufferers beware: it is a member of the ragweed family. Nutmeg, harmless when used as a flavoring, can induce hallucinations when brewed in a strong tea. Anyone taking large amounts of herbal teas should consult a physician.
Drink and Be Merry
Raise a glass to a healthy heart. People who drink wine, beer and hard liquor - in moderation - tend to live longer than heavy drinkers and, surprisingly, even longer than those who do not drink at all. This happy observation - known as the French paradox - has emerged during the past decade as scientists tried to figure out how a population that regularly indulges in rich, fatty foods could have such a remarkably low rate of heart disease. The answer - first reported in 1991 - is surprisingly pleasant. The Beaujoulais that the French quaff with their Brie and pâté de foie gras reduces the ability of blood platelets to form blood clots, the cause of most strokes, and lessens the risk of heart attack.
Too good to be true? In dozens of subsequent studies, scientists around the world have provided consistent confirmation that a moderate intake of red wine offers some protection against cardiovascular disease and stroke. One recent French study even suggests that light or occasional consumption of red wine is associated with a lower risk of senile dementia.
Some scientists speculate that red wine is particularly beneficial because red grapes from which it is made contain an abundance of powerful antioxidants - phytochemicals that protect against cell-damaging free radicals. But other researchers have shown that white wine, beer and liquor are equally beneficial. In one of the latest studies, presented in July at the International Congress of Nutrition in Montreal, French researchers reported that a person who has two to six drinks a week could have up to 79-per-cent less risk of sudden death due to heart attack than an abstainer.
Lost in the din of popping wine corks and crackling ice cubes, however, is the fact that, while the French have healthier hearts, they also have a higher rate of cirrhosis of the liver. But drinking is hardly risk-free. Alcohol is addictive. Too much can damage the heart and - even at moderate levels - it boosts blood pressure, gradually leads to diseases of the liver, pancreas and nervous system, and increases the risk of cancer. The potential benefit, experts point out, also depends on the age of the drinker. There is little evidence to suggest that alcohol reduces the risk of heart disease in men under the age of 40 or women under 45, when that risk is still relatively low.
Does alcohol kill brain cells? A study described in the British Medical Journal last June reported no evidence of brain atrophy or intellectual impairment in neuropsychological tests given to 209 elderly Australian men in a nine-year study, even though 40 per cent had consumed "harmful amounts" of alcohol. But Sue Bondy, a research scientist with the Addiction Research Foundation of Ontario, says that finding flies in the face of a body of research that shows that "alcohol does diminish mental acuity in high doses."
For women, alcohol consumption poses a particular dilemma - the risk of breast cancer may begin at the same level that protects the heart. The evidence is far from conclusive, but some studies suggest that as little as one drink a day may increase the risk of breast cancer by 10 per cent, two drinks by 25 per cent.
Some researchers wonder whether there may be unrelated reasons why teetotallers do not live as long as light drinkers. "It may be," notes David Jenkins, a nutrition scientist at the University of Toronto, "that light drinkers have mastered the art of moderation and have generally healthy habits."
"Stop saying, 'Oh no' to tofu," says McGill nutrition expert Joe Schwarcz. Every little bit helps, but it takes about 25 g of soy per day - slightly more than the amount in a typical veggie burger - to achieve significant health benefits. An ideal diet might aim for 50 g a day. Dozens of new soy products - cookies, bread, muffins, milkshakes, pretzels, ice cream - are finding their way to supermarket shelves. And, no, soy sauce won't do the trick - it contains only traces of the prized protein.
Choose salmon, trout, tuna, sardines, mackerel, herring, bluefish, whitefish and halibut over less fatty fish like sole. "Stay away from swordfish," cautions medical researcher and best-selling author Dr. Andrew Weil. "This is a shame but we have polluted the waters, and the bigger the fish and the higher it is on the food chain, the more it concentrates toxins." And there is no need to avoid shellfish simply because they are high in cholesterol. "Dietary cholesterol has little or no effect on blood cholesterol for most people," says Beck. "What matters is saturated fat." And shrimp has almost no saturated fat.
Don't rush to restock that basement bar. Few health experts are willing to prescribe or even recommend alcohol as a heart disease preventive. As for quenching thirst, nutritionists generally say a healthy diet includes at least eight glasses of water a day. There is grudging agreement that if alcohol is consumed at all, it should be limited to less than two drinks a day for men and one for women (and probably none for women who are pregnant, considering pregnancy or breastfeeding). Binge drinking is extremely harmful - it is not advisable to "save up" and drink seven beers on a Saturday night. Experts also warn that hundreds of medications interact with alcohol, many causing serious damage.
A convenient substitute for alcohol may soon be available in pill form. In February, U.S. researchers reported that capsules made from an alcohol-free powdered extract of red wine is just as effective in preventing arteries from clogging up as a glass of Bordeaux. Medical science may soon manage to wring all the goodness, and the fun, out of the grape.
Maclean's October 27, 1997
Limit daily caffeine intake to two cups of drip coffee or six cups of strong tea. Children should have no more than one cola drink a day, less for those sensitive to caffeine. "If people are drinking coffee, it is a big step up to switch to tea - or at least to some tea," advises nutrition author Dr. Andrew Weil. Better yet, he adds, "Give it up." As for decaffeinated coffee, it is made from stronger coffee beans, and one U.S. study suggests it is more likely than regular coffee to raise levels of LDL cholesterol.
What it boils down to is - eat at least five servings of fruits and vegetables, both raw and cooked, each day. Is a tomato better than a carrot? An apple better than an orange? "Eat a variety," says Carroll. "That way you avoid excesses and deficiencies." Reach for dark green, bright orange and yellow produce - those colors indicate higher concentrations of phytochemicals, and more nutrients.
Whatever their benefits, supplements cannot substitute for a healthy diet. But the elderly, children and haphazard eaters of all ages, say many nutritionists, should consider supplements as a form of insurance.
In a recent Dutch study, elderly men who daily consumed about 26 mg of flavonoids - roughly the amount found in a single apple - suffered half as many heart attacks as those with a low intake of the phytochemical.
Sulforafane, a compound that stimulates the production of enzymes that flush carcinogens from the body, is abundant in broccoli. Sulforafane has been shown to reduce the incidence of breast tumors in mice by up to 60 per cent.
A Queen's University scientist is conducting a large-scale study on allicin, a compound in garlic that may protect against chemical toxins and carcinogens.
A decade-long Dutch study showed that onions help prevent gastric cancer. Indian researchers have found an association between eating onions and a reduced incidence of lung cancer. Onions contain allylic sulfides, compounds that stimulate the body's production of enzymes that eliminate potential carcinogens.
In July, researchers from the University of Western Ontario's Centre of Human Nutrition reported results of a study showing that the flavonoids in orange juice cut the risk of breast cancer in mice by 50 per cent.
Several cancer-fighting compounds - beta-carotene, vitamin C, coumarins, flavonoids, monoterpenes and polyacetylenes - are found in parsley. Chlorophyll, the phytochemical that makes it green, may block the absorption of carcinogens from the digestive tract.
Sweet peppers contain more vitamin C than oranges. Hot peppers, or chilies, which also contain flavonoids, are even more nutritious. Capsaicin, the compound that gives chilies their bite, can ease nasal and sinus congestion and may help prevent blood clots.
The most popular vegetable in Canada is a good source of vitamin C, which helps block the formation of cancer-causing nitrosamines in the body. Potatoes also contain saponins, antioxidants linked to reduced cholesterol and a lower incidence of colorectal and, possibly, breast and prostate cancers. Renowned as a comfort food, potatoes have traces of compounds related to benzodiazepines in prescription tranquilizers.
Rhubarb contains a unique mix of soluble and insoluble fibre that may help prevent heart disease, diabetes and constipation. In a study by researchers at the University of Alberta early this year, a daily dose of rhubarb fibre reduced cholesterol levels by as much as 15 per cent over a four-week period.
Lycopene, the pigment that gives tomatoes their bright red color, appears to be effective in preventing prostate and possibly other cancers. A powerful antioxidant, lycopene promotes heart health and may help prevent diabetes. University of Toronto research has shown that lycopene is more readily absorbed from tomato juice, pizza sauce and other cooked tomato products like ketchup - and when mixed with a small amount of fat.
Most experts say there is room in a healthy diet for red meat - but not much. "The closer we are to a vegetable-based diet, the better off we are," observes McGill University chemist Joe Schwarcz. Limit red meat to two or three small servings a week. Choose lean cuts like round, rump or sirloin and trim visible fat before cooking. Avoid eating fat-laden hamburgers often. Even "lean" ground beef contains 10- to 17-per-cent fat.
Poultry skin, high in saturated fat, should be discarded - before cooking. Avoid prebasted turkeys, often injected with butter or other saturated fats.
Vegetarians should plan meals carefully to meet all the body's nutrient requirements. Combine grains with complementary legumes to form complete proteins - for example, rice with beans or bulgur wheat with chickpeas. Adding foods rich in vitamin C will improve iron absorption. Many nutritionists do not advise a vegetarian diet for young children, teenagers, pregnant women, nursing mothers or the frail elderly.
Switch to skim or one-per-cent milk to benefit from all the nutrients with almost none of the fat. Two-per-cent is healthier than whole milk, but while a glass of skim contains perhaps four calories from fat, the same amount of two-per-cent has 43.
Check the label: to be fully effective, yogurt has to contain active bacterial culture. If it has been heat-treated for long shelf life, the active cultures are no longer present. Avoid sweetened brands - a single serving may contain almost as much sugar as a soft drink. "Frozen yogurt will likely not have the live bacterial cultures," notes dietitian Rosie Schwartz. But, depending on the fat content, it can still be a healthy choice because of its calcium
Limit intake of high-fat cheese. Health Canada advises pregnant women and anyone with a weakened immune system to avoid raw-milk cheese.