What is Calcium?
Calcium is a major mineral, necessary for healthy bones and teeth. There are several minerals known to be essential to the human body that must be obtained from food: calcium, magnesium, phosphorus, sodium, chloride and potassium. Minerals make up the skeleton, help control the composition of body fluids and aid the action of many enzymes and other proteins. Our bones contain large amounts of calcium that helps to make them firm and rigid.
The Milk Myth
The advertising barrage surrounding cow's milk would make anyone think it is an absolutely essential and natural product for humans. However, whole cow's milk is only suited to the nutritional needs of calves that double their weight in 47 days and grow to 300 pounds within a year. Human milk, by contrast, is designed by nature to meet the needs of a child during her most rapid growth period. It has only 80 mg. of calcium per cup, compared to the 288 mg. of cow's milk.
In fact, human beings are the only species to drink the milk of another species, and the only species to drink milk beyond infancy. About 90% of the world's adult population lacks the lactase enzyme needed to digest milk properly. Lactase is present in infants for digesting their mother's milk, but levels decline after the age of five years. Adults who lack the enzyme suffer from bloating, cramping, gas and diarrhea if they drink milk.
Even before his death, child-care expert Dr. Benjamin Spock joined several doctors in questioning milk's nutritional value and warned of a possible link to juvenile onset diabetes and allergies. Dr. Frank Oski, director of pediatrics at John Hopkins University and Dr. Neal Barnard, president of the Physicians' Committee for Responsible Medicine. Dr. Oski both supported Dr. Spock stating that cow's milk is overrated as a source of calcium, is often contaminated with traces of antibiotics, can cause allergies and digestive problems and has been linked to juvenile diabetes.
What About Osteoporosis?
Osteoporosis is the major cause of bone fractures in the elderly. It is better prevented than treated and prevention includes an adequate intake of calcium throughout life, but especially in childhood and young adulthood. However, recent studies have shown that diets high in protein, particularly animal protein, and in salt (sodium chloride), actually increase calcium loss and may contribute to the cause of osteoporosis.
The dairy industry spends hundreds of millions of dollars promoting the notion that high calcium intake is critical to developing strong bones and preventing osteoporosis. They have even convinced the USDA to raise the Recommended Daily Allowance for calcium, with ringing endorsements that dairy products are optimal calcium sources. Unfortunately, there is a lack of credible research showing that a deficiency in calcium may be to blame for the osteoporosis epidemic currently raging in the Western world.
Osteoporosis is more common in Westernized countries where calcium intake and consumption of dairy products is high compared to the rest of the world. It is comparatively rare in rural subsistence cultures, even though calcium intakes are much lower. Lifestyle factors such as physical activity, lower protein intake, little alcohol consumption and the rarity of smoking may offer protection to people in these populations.
An interesting study published in the July 2000 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)
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 "Time-averaged daily calcium intake, which ranged from 500 to 1500 mg/day in this cohort was not associated with hip Bone Mineral 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.
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! (California Tissue Institute 1992; 50:14-18) Those countries with the highest calcium consumption turn out to be the same ones with the highest rates of osteoporosis.
The Role of Protein - Animal, Vegetable
A high protein diet, especially derived from animal foods, causes calcium loss in the body. The higher sulfur-to-calcium ratio of meat increases calcium excretion, and a diet rich in meat can cause bone demineralization. A report published in 1988 that compared the amounts of calcium excreted in the urine of 15 subjects showed that the animal-protein diet caused greater loss of bone calcium in the urine (150mg/day) than the all-vegetable protein diet (103mg/day). These findings suggest that diets providing vegetable rather than animal protein may actually protect against bone loss and hence osteoporosis. In one study, adults on a low-protein diet were in calcium balance regardless of whether calcium intake was 500mg, 800mg or 1400mg a day.
Calcium Needs Balance
Calcium needs a balance of potassium and magnesium to work effectively in building bone. 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. Vitamin D, the sunshine vitamin, is also vital for the absorption of calcium and helps prevent it from being lost in the urine.
Good Sources of Calcium
Calcium is abundant in dark leafy greens such as collards, kale, turnip, mustard greens, parsley, watercress and bok choy. Dark leafy greens are far richer in calcium per calorie than is cow's milk. Broccoli, almonds, chickpeas, carob, sea vegetables, dried figs and molasses also provide calcium. Numerous other vegetarian foods, such as tempeh, corn tortillas and oranges make respectable calcium contributions too.
Drinking hard water can provide 200mg of calcium daily but soft water contains almost none.
Tofu is commonly recommended as a good source of calcium, but the amount of calcium depends on the coagulating agent used in the process of making tofu. Calcium sulfate and nigari (magnesium chloride) are two commonly used agents. Tofu prepared with calcium sulfate will contain more calcium than tofu made with nigari. When you realize that there is as much calcium in 4 ounces of firm tofu or 3/4 cup of collard greens as there is in one cup of cow's milk, it is easy to see why people who do not drink cow's milk still have strong bones and teeth.
What To Do?
Although the calcium intake of adult vegans tends to be lower than the optimal recommendation, it is close to the Estimated Average Requirement.
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. Eat a balanced diet and exercise!
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