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In the Vegetarian & Vegan News...
   Jeff Nelson | Strong Boned Editorial

Sorting through the Calcium Myths
So far, all the hype about the importance of high calcium intake
to build strong bones seems to be just that -- hype.
Research points in other directions.

The milk industry spends hundreds of millions promoting the notion that high calcium intake is critical to developing strong bones and preventing osteoporosis. On the basis of pure political power, the dairy business has succeeded in getting the USDA to raise the Recommended Daily Allowance (RDA) for calcium, with ringing endorsements that dairy products are optimal calcium sources. With organizations hopping on the pro-calcium bandwagon like the American Dietetic Association and the Osteoporosis Foundation (both of which receive money from the dairy industry), many nutritionists have joined in the scaremongering by exhorting us to "get lots of calcium lest we grow a generation of vegans whose bones crumble!"

Unfortunately, these recommendations are not based on an abundance of credible research, but are simply "well, it can't hurt" and "just to be safe" and "just in case there's any truth to it" recommendations -- coming from those who have bought into dairy industry promotional slogans. There is a decided lack of credible research showing a deficiency in calcium may be to blame for the osteoporosis epidemic currently raging in the Western world.

Exercise, Exercise, Exercise

An interesting study published in this month's Pediatrics, the medical journal of the American Academy of Pediatrics, is entitled "Adult Female Hip Bone Density Reflects Teenage Sports-Exercise Patterns But Not Teenage Calcium Intake." [PEDIATRICS Vol. 106 No. 1 July 2000, pp. 40-44 ]

It is yet another in what is becoming a blizzard of studies showing calcium intake to be less than what the dairy industry and their flacks would like us to believe.

The study tracked 81 girls for six years, from ages 12 to 18. Adolescence is a critical period for bone health because the average woman gains 40 to 60 percent of her skeletal mass during those years. Researchers controlled calcium intake via supplementation, and concluded that "Time-averaged daily calcium intake, which ranged from 500 to 1500 mg/day in this cohort was not associated with hip Bone Minderal Density (BMD) at age 18 years, or with total body bone mineral gain at age 12 through 18 years."


 



In other words, consistent with previous studies none of the girls with "low" calcium intake had any different bone development than girls with high calcium intake. Contrary to the dairy-industry propaganda, getting that extra calcium didn't make a difference.

''We (had) hypothesized that increased calcium intake would result in better adolescent bone gain. Needless to say, we were surprised to find our hypothesis refuted,'' said Tom Lloyd of Pennsylvania State University, co-author of the new study.

Height and weight, not diet or exercise, were found to be the main factors determining total body bone-mineral content in adolescent girls. The study further found that the amount of physical activity engaged in by study participants was a primary determinant in bone mineral density growth; there was a ``biologically important'' link between bone mass at the hip and regular exercise.

Interestingly, the study authors point out, "although increased peak hip (bone mineral density) was related to the cumulative sports-exercise score, it was not related to aerobic capacity... That is, it's not the intensity of the exercise that counts -- it's any exercise that is done on a daily or nearly daily basis," Lloyd noted. "It doesn't mean you have to be on the soccer team or that you have to go out and become a gold medalist in field hockey. It means 25 minutes of walking around the block.''

Lloyd cautioned that these "results apply to white women with an average daily intake of at least 500 milligrams per deciliter (of calcium).'' Since data obtained from the National Health and Nutrition Examination Survey suggest that a quarter of teenage girls "do not get 500 milligrams/deciliter...for this population, increasing calcium intake may be of benefit'' for bone health, Lloyd added.

Or it may not. The chief point is that there is currently no credible research which exists to support the (dairy industry-promoted) assertion that lower calcium intake has any adverse impact on bone growth or health -- and there is research which refutes it.

More Calcium?

The average daily calcium intake for South African blacks is 196 mg whereas the daily calcium intake for African-Americans is more than 1,000 mg. Yet the hip fracture rate for African-Americans compared to South African blacks is NINE TIMES GREATER! [Calif Tissue Int 1992;50:14-18] And those countries with the highest calcium consumption turn out to be the same ones with the highest rates of osteoporosis.

"Beyond weaning age, children and adults of various countries and food cultures subsist on diets differing markedly in their calcium content. These differences in calcium intake . . . have not been demonstrated to have any consequences for nutritional health."
-- Health Canada's Nutrition Recommendations

Simply adding more calcium to one's diet, as though there were some linear relationship between calcium intake and good bone health, is fairly ridiculous -- notwithstanding the clamoring of dairy-funded organizations and even a few vegetarian experts with ties to the soy industry. (Soy milk makers fortify their products with calcium in response to all the calcium hype and to compete with dairy.)

In fact, the National Dairy Council funded a study which ended up returning results showing that the more milk women drank, the more bone loss they experienced. OOPS! [Am J Clin Nutrition 1985;41:254]

Things Go Better with Coke -- Except Bones

Another recent study in the Archives of Pediatrics and Adolescent Medicine demonstrated that teenage girls who drink lots of soda may be more prone to bone fractures and osteoporosis later in life than girls who do not drink large quantities of soft drinks. [Archives of Pediatrics and Adolescent Medicine 2000;154:542-543]

"Adolescence is a crucial time for bone development, and any factors adversely impacting on bone acquisition during adolescence can potentially have long-standing detrimental effects," wrote Dr. Neville H. Golden of Schneider Children's Hospital of Long Island Jewish Medical Center in New Hyde Park, New York, in an editorial accompanying the report.

The investigators found that cola may be particularly detrimental to adolescent girls, possibly due to large amounts of the mineral phosphorus that is found in colas. Previous studies have shown that phosphorus can interfere with the skeleton's ability to absorb calcium.

So Where to Go?

It turns out the same things that protect against heart disease, cancer and a host of other diseases -- can help protect against osteoporosis: limit your animal-protein intake, including red meat, chicken, fish, eggs and cheese, all of which leech calcium from your bones. Cigarettes, salt, caffeine and a sedentary lifestyle are also related to poor bone health. Avoid milk -- and regularly exercise!

Another recent study, this one published in the American Journal of Clinical Nutrition, is called "Dietary influences on bone mass and bone metabolism: further evidence of a positive link between fruit and vegetable consumption and bone health?" [Vol. 71, No. 1, 142-151]

Researchers reported that potassium and magnesium -- key nutrients found in high concentrations in many fruits and vegetables -- may be much more important to bone health than calcium. In the study of 62 randomly-selected healthy women between age 45 and 55, researchers assessed bone health and diet. While, as expected, they found no correlation between the consumption of dairy products and bone health, they discovered a significant correlation between high consumption of fruit and positive BMD reads on the neck. This study was only one in a series conducted by researchers showing fruit and vegetable consumption correlates with healthy bones -- while consumption of dairy products and calcium does not.

Potassium can be found in bananas, prunes, raisins, spinach and white potatoes; magnesium is found in dark-green leafy vegetables, brown rice and black beans.

Research continues to point toward a plant-based diet with little or no dairy products -- and moderate physical activity -- as important for maintaining healthy bones. Weight-lifting can be especially effective in increasing BMD, and studies of people working out with weights have shown dramatic increases in BMD, even in individuals in their 70s and beyond.

For more important and current calcium information, please see PCRM's Preventing and Reversing Osteoporosis

 

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