Dig into nearly anyone's supermarket shopping cart (with their permission, naturally) and what do you find? Amid the canned corn, Rice Crispies, carrots and cellophane, you're likely to unearth a jug of milk, a carton of yoghurt, and a wedge or two of cheese-- even if the basket belongs to one of North America's more-than 12 million vegetarians.
Thanks to star-spangled industry promotions and decades of government-sponsored nutrition "education" in schools, dairy foods are universally revered as a fundamental food group and the vital building blocks of strong bones and teeth. Understandably, North Americans generally react with disbelief when informed-- even by medical authorities-- that dairy foods are not essential for human health, and that most people on this planet do quite nicely without them.
Even harder to swallow is the news that a solid and growing body of scientific evidence suggests that limiting or eliminating dairy products from the diet may be important to achieving optimal health."What do you mean, 'Dairy foods aren't essential?'"
The dairy industry spends millions of dollars of milk money on high-gloss advertising to convince us that their products are not only wholesome and chic, but downright essential for our health. Essential?
"There is no human requirement for milk from a cow," says Suzanne Havala, RD, author of the American Dietetic Association's "Position Paper on Vegetarian Diets" and several books on nutrition. "The use of milk and its products in our country is strictly a cultural tradition," she notes. "There are millions of people around the world who never consume cow's milk and are none the worse for it."
Dietitians Virginia and Mark Messina, PhD, echo this view in their 1996 book The Vegetarian Way. "Vegetarians who avoid dairy products may seem to be choosing an unusual diet by Western standards, but are actually choosing a typical diet by world standards...The belief that milk is essential in the diet is clearly incorrect."The calcium scoop
But aren't dairy products our only reliable source of precious calcium?, you might ask. You'd certainly think so listening to Lauren Bacall, Christie Brinkley and the other mustachioed celebrities paid handsomely to urge us on to ever greater heights of milk consumption.
Although milk, cheese, yoghurt, butter and the like are not pivotal to our welfare, calcium certainly is. In small amounts in the bloodstream, it plays a critical part in blood clotting, muscle contraction, heartbeat maintenance, and proper nerve function. About 99 percent of calcium (roughly three pounds total) is stored in our bones and teeth, which rely upon the mineral for their strength. When needed, calcium is released from our bones into the blood.
Calcium is calcium, however, whether it's from broccoli or cottage cheese. "There's no best source of calcium," explains Robert Heaney, a professor with the Osteoporosis Research Center at Creighton University School of Medicine. "The sheer quantity of calcium in dairy products certainly makes them attractive sources, but they have no monopoly on calcium. There's no reason in the world why you couldn't get an adequate intake from a vegetable source."
In fact, nutritional anthropologists believe that our earliest ancestors-- who got most of their calcium from wild plant foods-- had higher calcium intake than their milk-quaffing contemporaries. Anthropologists also think that until 10,000 years ago or so, all humans were lactose intolerant.Calcium and bone health: What's the connection?
The dairy industry tirelessly advances the notion that their calcium-rich foods are veritable guarantors of unbreakable bones. Problem is, there is scant support for this assertion in the medical literature. There is no clear scientific evidence that high calcium intakes alone-- even the Recommended Dietary Allowance (RDA) of 800 mgs-- can ensure bone health.
"It might surprise you to know that throughout the world people who consume the most calcium actually have the poorest bone health," say the Messinas. "The idea that dosing yourself with calcium will automatically keep your bones in good shape is just plain wrong."
Indeed, researchers have found that nations with the greatest calcium intake have the highest rates of osteoporosis and hip fracture, and that there are relatively few fractures among populations where calcium levels are not so high. After studying bone fracture rates worldwide, researcher JA Kanis concluded that the differences in fracture rates, "cannot be accounted for by differences in dietary intake of calcium but may relate more to physical activity [which promotes strong bones]." Of course the dairy industry disputes these findings, continuing to insist that every man, woman and child would benefit from drinking at least three glasses of milk a day.
The recipe for healthy bones clearly calls for more than simply ingesting copious amounts of calcium-rich foods. Certainly, calcium intake is keenly important, particularly during childhood, early adulthood and up to the age of 30-35 when our bones achieve their peak mass and stop growing. But retaining the calcium we've stored in our bones appears to be even more vital. This is especially the case in our late 40s or so, when our bones begin to break down faster than they can be rebuilt, alas, an inevitable part of aging. Indeed, research from hundreds of subjects indicates that preventing calcium loss is actually three to four times more important in determining calcium balance-- that is, whether we gain, maintain or lose calcium from our bones-- than is calcium intake. And one of the greatest instigators of calcium loss, it turns out, is a high-protein diet.The protein drain
Protein, and especially protein from animal sources, makes our urine acidic, a condition the body attempts to remedy by drawing calcium, an alkaline mineral, from the bones. Eventually, this calcium is lost, flushed from the body in the urine. What makes this even more alarming is that many North American adults typically eat twice the recommended amount of protein. (The RDA for protein is 50 grams for women and 60 for men.) Researchers who reviewed 16 studies examining the protein-calcium relationship found that when protein intake is above 75 grams per day, more calcium is lost in the urine than is retained in the body. Researchers speculate that this level of protein intake alone could account for the bone loss commonly seen in postmenopausal women!
If you already eat a plant-based diet, you'll be comforted to know that meat-free diets produce less acid than those containing meat, and that vegan diets produce less acid than those including dairy products. According to one recent study, by eliminating animal protein altogether from the diet, people can cut urinary calcium losses in half.
All of which leads Havala and others to conclude that Americans would need less calcium in their diets if they simply ate less protein. But researcher Heaney calls this a moot point, believing that Americans aren't willing to shift substantially away from meaty, high-protein fare. "For most people it is easier to fix the calcium intake component of the problem than to fix the calcium excretory loss problem. An extra serving or two of low-fat or skim milk each day will do the job nicely," Heaney claims.
Pediatrician Charles Attwood, MD, represents an opposing viewpoint. "It seems that milk, with its excessive protein, may be part of the calcium problem instead of a solution."
If, for whatever reason, you include dairy foods in your diet, Havala suggests using only nonfat varieties, and limiting your intake of these to one or two servings a day. Havala also recommends that you avoid 1% or 2% milk and yoghurt because of their high-fat content.Okay, so how much calcium DO I need?
Yet, despite these facts, most medical authorities still recommend that people eating a plant-based diet aim to achieve the RDA. Why? Some believe that the evidence that vegetarians need less dietary calcium is not yet conclusive. Others worry that vegetarians will get the erroneous idea that calcium isn't important.
For most people, the RDA can quite easily be fulfilled by eating a varied diet with at least several servings of calcium-rich foods each day. (See sidebar.) Children, teens and young women should be especially careful to include these foods since their calcium needs are relatively high compared to others. Some people may choose to take supplements as added insurance. Of course one advantage of meeting calcium needs with plant foods is that many are also excellent sources of antioxidants, fiber, folic acid, complex carbohydrates, iron and other important vitamins and minerals you won't find in milk products.
Meeting calcium needs without dairy has gotten a lot easier with the availability of a huge assortment of fortified nondairy "milks" made from soy, rice and nuts. (Not all are fortified, so check the labels carefully.) An 8-ounce glass of fortified soy milk has 2-300 mgs of calcium, compared to the 300 mgs in the same glass of cow's milk. (An 8-ounce glass of fortified orange juice also has about 300 mgs of calcium.) Most health food stores and some grocery stores also stock cheeses, yoghurts and frozen desserts made from rice milk, soy milk and fruit juices. Though these products might not taste exactly like what you're used to, with an open mind and adventurous spirit you may find their distinctive flavors divine.Beyond Bones
While the question of whether dairy foods contribute to or detract from the well- being of our skeletons often occupies center stage, there are additional serious health concerns that might make you wary of dairy.
Such findings prompted breast surgeon Robert Kradjian, MD, in 1993 to review more than 500 medical articles written about milk since 1988. "How would I summarize the articles?," Kradian asks. "First of all, none of the authors spoke of cow's milk as an excellent food, free of side effects. The main focus of the published reports seem to be on intestinal colic, intestinal irritation, intestinal bleeding, and anemia, allergic reactions in infants and children as well as infections such as salmonella... In adults the problems seemed centered more around heart disease and arthritis, allergy, sinusitis, and the more serious questions of leukemia, lymphoma and cancer."Conclusions
1. Dairy foods are not essential for human health
2. All the nutrients dairy foods offer can be obtained from plants foods with the added bonus of protective nutrients unavailable in milk products
3. Plant foods are protective against many diseases, dairy foods elevate the risks of numerous diseases
4. Deciding whether to include them in your diet boils down to personal preference.
5. Debate over dairy has grown more acrimonious in the last decade
6. There are enough studies, experts and opinions to satisfy any number of positions.
7. Only certainty: the more you know about dairy foods, the harder it is to eat them with the assurance that they are doing a body good.