Dr. Lee, the Healthy Professor

How to maintain bone health and prevent osteoporosis

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More women will die from complications of osteoporosis than from breast cancer, cervical cancer, and heart disease combined according to a paper published in the journal Geriatrics in May 2000. One of every two women over 50 will suffer an osteoporosis-related fracture in her lifetime.

Incredibly, you can do something about it. Exercising, quitting smoking, eating adequate protein and getting adequate calcium increases your chances of beating this formidable opponent.

If you are a woman over forty, you may be starting to worry about bone health. Everyone loses bone as they age. By the time a women is told she has osteoporosis, her gradual loss of bone mass has been progressing for years. Men lose bone too, but only about half as fast as women.

  • Osteoporosis. It's responsible for 25,000 hip fractures every year in Canada and according to the Canadian Osteoporosis Society 25% of these fractures end in death and 50% of the survivors are disabled.
  • 1.5 million Canadians are affected with osteoporosis.
  • 2 million people are at risk for developing osteoporosis.
  • Osteoporosis' cost to health care in excess of $1.3 billion a year.
  • 80% of the population with Osteoporosis are women.
  • 1 in 4 women and 1 in 8 men 50 yrs. and over has osteoporosis related fractures.

While a certain amount of bone loss seems inevitable with the passage of time, the process is not entirely beyond our control. Dietary and lifestyle measures can, to some degree, help maintain bone health. Poor nutrition and other health habits such as smoking, alcohol abuse, and physical inactivity contribute to bone loss.

Exercise, especially through activities like walking that put pressure on the weight-bearing bones, stimulates bone remodeling. Exposure to sunlight is helpful. Sunlight forms vitamin D in the skin, vitamin D in turn increases calcium absorption.

Estrogen protects against bone loss and declining estrogen levels after menopause increase bone resorption. Soy protein isolate contains calcium and has an estrogen-like effect that can assist in slowing bone mineral loss.

The risk of osteoporosis has been associated with heavy caffeine consumption. In 1990 the famous Framingham study found that more than two cups of coffee or four cups of tea a day increased calcium excretion in the urine and the incidence of hip fractures.

Too much phosphorus in the diet favors bone loss by increasing excretion of both calcium and magnesium. Too much refers to “in relation to calcium”. In addition, older women with low blood levels of vitamin B12 had greater bone mineral loss.

To build bone, your body needs a family of nutrients to convert the calcium in your blood into bone crystals. Phosphorus is a major bone-building mineral, but you won't find it in many of the leading calcium supplements. Without phosphorus, you don't have bone building.

Also important are vitamins D and K, magnesium, manganese, zinc, and copper, which we include in just the right amounts. Canadian Osteoporosis Society recommends a calcium intake of at least 1500 mg per day for those over 50 years of age.

The most ignored bone-building nutrient is protein. Most people are not aware that bone is 50% protein and 50% mineral. In fact there are erroneous warnings out there indicating that high protein diets increase the risk of bone mineral loss.

In 1990 the Journal of Nutrition published the proceedings of a symposium on this subject and concluded that there was no evidence to support such an allegation. Although there may be more calcium excretion on higher protein diets (mainly because higher protein foods tend to be higher calcium foods) there is no evidence of bone mineral loss.

The following three studies support the addition of adequate protein in the maintenance of bone mineral density.

Protein Consumption and Bone Mineral Density

California Study

A California study published in 2002. American Journal of Epidemiology investigated the associations of total, animal, and vegetable protein with bone mineral density (BMD) and the association with calcium intake. The diets of a group of 572 women and 388 men aged 55–92 years were studied between 1988 and 1992. Statistical review of the data showed a positive association between animal protein consumption, and BMD.

This association was statistically significant in women. For every 15-g/day increase in animal protein intake, BMD increased at the hip, at the femoral neck (top of leg bone), at the spine and for the total body.

Conversely, a negative association between vegetable protein and BMD was observed in both sexes. Some suggestion of effect modification by calcium was seen in women, with increasing protein consumption appearing to be more beneficial for women with lower calcium intakes, The authors concluded that the study supports a protective role for dietary animal protein in the skeletal health of elderly women.

Nebraska Study

A June, 2003 study at Creighton University investigated the associations of dietary protein intake with baseline bone mineral density (BMD) and the rate of bone loss over 3 years in postmenopausal elderly women. A group of 489 women aged 65–77 years were enrolled in an osteoporosis intervention trial. The results showed that a higher intake of protein was associated with higher BMD.

BMD was significantly higher in the spine (7%), mid-radius (forearm bone) (6%), and total body (5%) in subjects in the highest quartile of protein intake than in those in the lower 2 quartiles. This positive association was seen in women with calcium intakes above 408 mg/d.

The conclusions drawn were that the highest quartile of protein intake (72 g/d) was associated with higher BMD in elderly women at baseline only when the calcium intake exceeded 408 mg/d. This level of calcium intake is well below the RNI so could not be considered a supplemented level.

Tufts University Study

In April 2002, the American Journal of Clinical Nutrition published results of a three-year, randomized, controlled study of 342 healthy men and women, 65 years and older, has demonstrated that with adequate calcium and vitamin D, higher intakes of protein are associated with significant gains in bone mineral density (BMD).

Within a calcium-supplemented group, bone status of the total body and at the hip was proportionate to protein intake. Those with the lowest protein intakes lost bone, whereas those with the highest gained enough bone to make a substantial difference in fracture incidence. They concluded that, calcium without adequate protein failed to protect the skeleton.


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