Prevent bone disorders with adequate calcium, other nutrients

The global number of hip fractures has reached epidemic, or pandemic, proportions. As populations "worldwide gradually age, the global load of hip fractures is expected to treble to over 6 million cases a year by 2050," project Robert Lindsay, MBCHB, Ph.D., F.R.C.P., and Jeri Nieves, Ph.D., of the Helen Hayes Hospital Regional Bone Center in West Haverstraw, N.Y.

In a commentary entitled "Milk and Bones: You Are What You Drink," Lindsay and Nieves refer to a recent study by S. Murphy, et al., which proved the benefits of "high calcium intake on bone mineral density."

In a community-based survey of middle-aged and older women (aged 44 to 77), Murphy and colleagues found that "milk consumption before the age of 25 correlated positively with current bone mineral density."

Calcium is a key skeletal building block

These findings, and results of their own studies, led Lindsay and Nieves to conclude that "although peak bone mass is primarily under genetic control, it seems logical that to achieve adequate skeletal maturation during growth requires a plentiful supply of the building blocks of the skeleton, of which calcium is one of the most important."

The study by Murphy and colleagues evaluated rather low intakes of milk, however, Lindsay and Nieves add.

The maximal calcium intake of someone drinking a 227 ml glass of milk every day comes to only 650 mg/day (with 300 mg from the milk and the rest from non-dairy sources).

This is below "the presumed `threshold' of calcium intake -- that level of intake above which" would satisfy the calcium needs of most people, Lindsay and Nieves explain.

To provide this amount of calcium, they added, "even if adolescents absorb calcium more than [do] adults (and this is disputed), would require an intake of at least 1,500 mg/day."

Vitamin D deficiency is another factor related to reduced bone mass, and is another area that has been investigated by Drs. Nieves and Lindsay in conjunction with researchers from the Multiple Sclerosis Center and Columbia University's College of Physicians and Surgeons.

Since it is known that both multiple sclerosis (MS) and osteoporosis occur more frequently in women than in men, and that "patients with MS may be at increased risk for osteoporosis and pathologic fracture," Nieves, Linday and colleagues measured bone-mineral-density and biochemical indicators in a group of 80 female patients with MS.

It was found that bone-mineral-density "was significantly reduced in female MS patients, which might increase fracture risk," and that "vitamin D deficiency with secondary hyperparathyroidism is prevalent and is probably a significant cause of low bone-mineral-density in this population."

The authors concluded that "vitamin D deficiency in the female MS patient might be safely and inexpensively corrected by the routine use of vitamin D supplements."

In a 1994 study that appeared in the Scandinavian Journal of Rheumatology, calcium and vitamin D levels were evaluated in 143 women with rheumatoid arthritis.

Although calcium levels were normal, "vitamin D levels were significantly below normal in most subjects," especially in the winter months, when sun exposure is less, the authors found. "Rheumatoid arthritic patients have increased bone loss and risk due to osteoporosis," they concluded.

According to Michael F. Holick, M.D., in Frank Murray's The Big Family Guide to All the Minerals (1995), "the major cause of age-related vitamin D deficiency is a decrease in milk consumption [and that] four 8-ounce glasses of milk a day provide [the required] 400 IU of vitamin D" needed to prevent such a deficiency.

Vitamin D needs are higher for older women

Murray quoted USDA/Tufts researcher, Elizabeth A. Krall, Ph.D., as saying that "the Recommended Dietary Allowance for vitamin D [200 IU] may be too low to protect older women from losing bone calcium during the winter months."

She added that an "inadequate intake of vitamin D during the sun-starved days of winter, when the skin produces little or no vitamin D, can mean less calcium for the bones."

"As vitamin D levels dip, another hormone rises to help maintain a constant blood calcium level, probably by borrowing calcium from the bones,' she concluded.

According to Robert M. Giller, M.D., in Murray's Guide, to help prevent osteoporosis, we should all take the following permanent lifestyle steps, in addition to others:

* Increase your intake of healthful foods containing calcium.

* Adopt a regular exercise program.

* Eliminate caffeine, sugar, and alchohol from your diet.

* In addition to your usual supplement program, take 1,200 mg of calcium, 400 mg of magnesium, 2 mg of boron, and a multiple that provides 400 IU of vitamin D.

Prevent three serious conditions

What many of the studies are attempting to determine, of course, are optimal levels of calcium and other nutrients which will prevent such conditions as osteoporosis, osteopenia and osteomalacia.

Osteoporosis: Osteoporosis is a disease "in which bone density declines to the point that there is a significant, and thus clinically important, risk of fracture," Lindsay stated in a review article, entitled "Secondary Prevention of Osteoporosis."

A total reduction in the quantity of bone and atrophy (a wasting away) of the skeletal tissue are typically associated with the full-fledged disease, as well.

Osteopenia: This is a condition associated with a reduction in calcification and in bone mass without other signs of, or risk factors for, full-blown osteoporosis.

Osteomalacia: Stedman's Medical Dictionary defines this as a "disease characterized by a gradual softening and bending of the bones with varying severity of pain, [which] occurs because bones contain osteoid tissue which has failed to calcify due to lack of vitamin D." It used to be called "adult rickets" or "late rickets."

Although different options exist today for both prevention of these bone-density deficiencies and intervention in cases of existing deficiency disease, the "simplest approach is calcium supplementation," Lindsay concludes in his review.

In addition to increasing our calcium levels, a review of the current literature points to the following as essential complements to any calcium-supplementation program: professionally supervised exercise and vitamin D supplementation (usually suggested as 200 to 400 IU/day).

REFERENCES

Gormley, James J. "Osteoporosis Prevention Begins in Childhood," Better Nutrition for Today's Living 57 (8):20, 22, 1995.

Komar, L. "Calcium Homeostasis of An Elderly Population Upon Admission To A Nursing Home," Journal of the American Geriatrics Society 41:1057-1064, 1993.

Kroger, H., et al. "Low Serum Vitamin D Metabolites in Women With Rheumatoid Arthritis," Scandinavian Journal of Rheumatology 22:172-177, 1993.

Lindsay, Robert, MBCHB, Ph.D., F.R.C.P. "Secondary Prevention of Osteoporosis," Physical Medicine and Rehabilitation Clinics of North America 6 (3):629-638, 1995.

Murray, Frank. The Big Family Guide to All the Minerals. New Canaan, Conn.: Keats Publishing, Inc., 1995.

Nieves, Jeri, Ph.D., et al. "High Prevalence of Vitamin D Deficiency and Reduced Bone Mass in Multiple Selerosis," Neurology 44:1687-1692, 1994.

Rosen, Clifford J., M,D., and Leah Rae Donahue, Ph.D. "Insulinlike Growth Factors: Potential Therapeutic Options for Osteoporosis," Trends in Endocrinology and Metabolism 6(7):235-240, 1995.

Rosen, Clifford J., M.D., et al. "Premature, Graying of Hair Is A Risk Marker for Osteopenia," Journal of Clinical Endocrinology and Metabolism 79 (3):854-857.

Spraycar, Marjory, editor. Stedman's Medical Dictionary. 26th edition. Baltimore: Williams & Wilkins, 1995.

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