Dietary calcium is better than supplements at protecting bone health

June 19, 2007

Women who get most of their daily calcium from food have healthier bones than women whose calcium comes mainly from supplemental tablets, say researchers at Washington University School of Medicine in St. Louis. Surprisingly, this is true even though the supplement takers have higher average calcium intake.

Adequate calcium is important to prevent osteoporosis, which affects an estimated 8 million American women and 2 million American men. Another 34 million Americans have low bone mass, placing them at increased risk for osteoporosis. Calcium consumption can help maintain bone density by preventing the body from stealing the calcium it needs from the bones.

The researchers' conclusions about calcium intake, published in the May issue of the American Journal of Clinical Nutrition, came from a study of 183 postmenopausal women. The researchers asked the women to meticulously detail their diet and their calcium supplement intake for a week. "We assumed that this sample represented each woman's typical diet," says senior author Reina Armamento-Villareal, M.D., assistant professor of medicine in the Division of Bone and Mineral Diseases and a bone specialist at Barnes-Jewish Hospital. "In addition to analyzing the volunteers' daily calcium intake, we tested bone mineral density and urinary concentrations of estrogen metabolites."

The researchers found that the women could be divided into three groups: one group, called the "supplement group," got at least 70 percent of their daily calcium from tablets or pills; another, the "diet group," got at least 70 percent of their calcium from dairy products and other foods; and a third, the "diet plus supplement group," consisted of those whose calcium-source percentages fell somewhere in between these ranges.

The "diet group" took in the least calcium, an average of 830 milligrams per day. Yet this group had higher bone density in their spines and hipbones than women in the "supplement group," who consumed about 1,030 milligrams per day. Women in the "diet plus supplement group" tended to have the highest bone mineral density as well as the highest calcium intake at 1,620 milligrams per day.

The hormone estrogen is known to maintain bone mineral density. But the standard form of estrogen is broken down or metabolized in the liver to other forms - some active and some inactive. Urinalysis showed that women in the "diet group" and the "diet plus supplement group" had a higher ratio of active to inactive estrogen metabolites than women in the "supplement group."

"This suggests that dietary calcium is associated with a shift in estrogen metabolism that favors production of active forms of estrogen," says Armamento-Villareal. "Although we're not yet certain what underlies this effect, it could be that nutrients other than calcium cause this shift. It's also known that dairy products, which are a major source of calcium, can contain active estrogenic compounds, and these can influence bone density and the amount of estrogenic metabolites in the urine."

Calcium supplements differ in how well their calcium can be absorbed, and this also could play a role in the study's findings, according to its authors. For example, calcium carbonate tablets need to be taken with a meal so that stomach acid can facilitate absorption, but calcium citrate tablets don't have this limitation. If the study participants taking calcium carbonate weren't conscientious about the timing of their supplements, they might not have received the highest benefit from them.

"Only about 35 percent of the calcium in most supplements ends up being absorbed by the body," Armamento-Villareal says. "Calcium from the diet is generally better absorbed, and this could be another reason that women who got a high percentage of calcium in their food had higher bone densities."

Although dairy foods are excellent sources of calcium, Armamento-Villareal suggests that individuals with dairy sensitivities could consume other calcium-rich food sources such as calcium-fortified orange juice. Dark green leafy vegetables also contain calcium, but it is not as readily absorbed as calcium from dairy sources.

Source: Washington University

Explore further: Obesity may be a factor for fractures

Related Stories

Obesity may be a factor for fractures

October 20, 2017
Does body fat protect you against osteoporosis or make you more vulnerable to fractures? A new study by the University of South Australia hopes to shed light on this question.

Calcium in the prevention of postmenopausal osteoporosis

October 12, 2017
A new clinical guide summarizes the evidence regarding the effects of calcium in reducing the risk of osteoporosis after the menopause.

Hormone therapy may benefit migraine sufferers without increased risk of heart disease

October 11, 2017
Migraine headaches are common among women, but due to various health risks can be challenging to treat in the elderly. While hormone therapy is effective in relieving many menopause symptoms, its safe use in women with migraines ...

It's never too soon to safeguard your bones

August 9, 2017
(HealthDay)—Bone health is literally something you build on throughout your life, not just as a child. And the efforts you put in now will keep bones strong and help prevent the bone-thinning disease osteoporosis later ...

Calcium supplements may not prevent bone loss in women with breast cancer

August 27, 2013
Women undergoing treatment for breast cancer are widely prescribed calcium and vitamin D supplements to prevent and manage osteoporosis, an unwanted side effect of breast cancer therapies. However, new research from Wake ...

New supplement superior to calcium and vitamin D for bone health

November 5, 2014
A new study by a Florida State University researcher reveals that a new dietary supplement is superior to calcium and vitamin D when it comes to bone health.

Recommended for you

Drug therapy from lethal bacteria could reduce kidney transplant rejection

August 3, 2017
An experimental treatment derived from a potentially deadly microorganism may provide lifesaving help for kidney transplant patients, according to an international study led by investigators at Cedars-Sinai.

Exploring the potential of human echolocation

June 25, 2017
People who are visually impaired will often use a cane to feel out their surroundings. With training and practice, people can learn to use the pitch, loudness and timbre of echoes from the cane or other sounds to navigate ...

Team eradicates hepatitis C in 10 patients following lifesaving transplants from infected donors

April 30, 2017
Ten patients at Penn Medicine have been cured of the Hepatitis C virus (HCV) following lifesaving kidney transplants from deceased donors who were infected with the disease. The findings point to new strategies for increasing ...

'bench to bedside to bench': Scientists call for closer basic-clinical collaborations

March 24, 2017
In the era of genome sequencing, it's time to update the old "bench-to-bedside" shorthand for how basic research discoveries inform clinical practice, researchers from The Jackson Laboratory (JAX), National Human Genome Research ...

The ethics of tracking athletes' biometric data

January 18, 2017
(Medical Xpress)—Whether it is a FitBit or a heart rate monitor, biometric technologies have become household devices. Professional sports leagues use some of the most technologically advanced biodata tracking systems to ...

Financial ties between researchers and drug industry linked to positive trial results

January 18, 2017
Financial ties between researchers and companies that make the drugs they are studying are independently associated with positive trial results, suggesting bias in the evidence base, concludes a study published by The BMJ ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.