Study Adds Weight to Link Between Calcium Supplements and Heart Problems

Research: Calcium supplements with or without vitamin D and risk of cardiovascular events: Reanalysis of the Women’s Health Initiative limited access dataset and meta-analysis

Research published in BMJ (British Medical Journal) in April 2011 adds to mounting evidence that calcium supplements increase the risk of cardiovascular events, particularly heart attacks, in older women. The findings suggest that their use in managing osteoporosis should be re-assessed.

Calcium supplements are often prescribed to older (postmenopausal) women to maintain bone health. Sometimes they are combined with vitamin D, but it’s still unclear whether taking calcium supplements, with or without vitamin D, can affect the heart.

The Women’s Health Initiative (WHI) study – a seven-year trial of over 36,000 women – found no cardiovascular effect of taking combined calcium and vitamin D supplements, but the majority of participants were already taking personal calcium supplements, which may have obscured any adverse effects.

So a team of researchers, led by Professor Ian Reid at the University of Auckland, re-analysed the WHI results to provide the best current estimate of the effects of calcium supplements, with or without vitamin D, on the risk of cardiovascular events.

They analysed data from 16,718 women who were not taking personal calcium supplements at the start of the trial and found that those allocated to combined calcium and vitamin D supplements were at an increased risk of cardiovascular events, especially heart attack.

By contrast, in women who were taking personal calcium supplements at the start of the trial, combined calcium and vitamin D supplements did not alter their cardiovascular risk.

The authors suspect that the abrupt change in blood calcium levels after taking a supplement causes the adverse effect, rather than it being related to the total amount of calcium consumed. High blood calcium levels are linked to calcification (hardening) of the arteries, which may also help to explain these results.

Further analyses – adding data from 13 other trials, involving 29,000 people altogether – also found consistent increases in the risk of heart attack and stroke associated with taking calcium supplements, with or without vitamin D, leading the authors to conclude that these data justify a reassessment of the use of calcium supplements in older people.

But in an accompanying editorial, Professors Bo Abrahamsen and Opinder Sahota argue that there is insufficient evidence available to support or refute the association.

Because of study limitations, they say “it is not possible to provide reassurance that calcium supplements given with vitamin D do not cause adverse cardiovascular events or to link them with certainty to increased cardiovascular risk. Clearly further studies are needed and the debate remains ongoing.”

 

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Medical News: Calcium Builds Bones But May Weaken Heart – in Cardiovascular, Myocardial Infarction from MedPage TodayThe findings suggest the use of these supplements in managing osteoporosis should be re-assessed, researchers reported online today in the BMJ. In the new study, researchers analyzed data from 16,718 women who were not taking personal calcium supplements at the start of the trial and found that those allocated to combined calcium and vitamin D supplements were at an increased risk of cardiovascular events, especially MI.

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No Bones About It: Eating Dried Plums Helps Prevent Fractures And Osteoporosis

When it comes to improving bone health in postmenopausal women — and people of all ages, actually — a Florida State University researcher has found a simple, proactive solution to help prevent fractures and osteoporosis: eating dried plums.

Bahram Arjmandi is Florida State's Margaret A. Sitton Professor and chairman of the Department of Nutrition, Food and Exercise Science. Photo: FSU Photography Services

“Over my career, I have tested numerous fruits, including figs, dates, strawberries and raisins, and none of them come anywhere close to having the effect on bone density that dried plums, or prunes, have,” said Bahram H. Arjmandi, Florida State’s Margaret A. Sitton Professor and chairman of the Department of Nutrition, Food and Exercise Sciences in the College of Human Sciences. “All fruits and vegetables have a positive effect on nutrition, but in terms of bone health, this particular food is exceptional.”

Arjmandi and a group of researchers from Florida State and Oklahoma State University tested two groups of postmenopausal women. Over a 12-month period, the first group, consisting of 55 women, was instructed to consume 100 grams of dried plums (about 10 prunes) each day, while the second — a comparative control group of 45 women — was told to consume 100 grams of dried apples. All of the study’s participants also received daily doses of calcium (500 milligrams) and vitamin D (400 international units).

The group that consumed dried plums had significantly higher bone mineral density in the ulna (one of two long bones in the forearm) and spine, in comparison with the group that ate dried apples. This, according to Arjmandi, was due in part to the ability of dried plums to suppress the rate of bone resorption, or the breakdown of bone, which tends to exceed the rate of new bone growth as people age.

The group’s research, “Comparative Effects of Dried Plum and Dried Apple on Bone in Post Menopausal Women,” was published in the British Journal of Nutrition. Arjmandi conducted the research with his graduate students Shirin Hooshmand, Sheau C. Chai and Raz L. Saadat of the College of Human Sciences; Dr. Kenneth Brummel-Smith, Florida State’s Charlotte Edwards Maguire Professor and chairman of the Department of Geriatrics in the College of Medicine; and Oklahoma State University statistics Professor Mark E. Payton.

In the United States, about 8 million women have osteoporosis because of the sudden cessation of ovarian hormone production at the onset of menopause. What’s more, about 2 million men also have osteoporosis.

“In the first five to seven postmenopausal years, women are at risk of losing bone at a rate of 3 to 5 percent per year,” Arjmandi said. “However, osteoporosis is not exclusive to women and, indeed, around the age of 65, men start losing bone with the same rapidity as women.”

Arjmandi encourages people who are interested in maintaining or improving their bone health to take note of the extraordinarily positive effect that dried plums have on bone density.

“Don’t wait until you get a fracture or you are diagnosed with osteoporosis and have to have prescribed medicine,” Arjmandi said. “Do something meaningful and practical beforehand. People could start eating two to three dried plums per day and increase gradually to perhaps six to 10 per day. Prunes can be eaten in all forms and can be included in a variety of recipes.”

 

Low Intake Of Vitamin K1 Linked To High Risk For Hip Fractures

A new study from the University of Bergen in Norway suggests that low intake of vitamin K1 may increase risk of hip fractures in elderly people. A low intake of vitamin K1, but not K2, was associated with an increased risk of hip fractures. Ellen M. Apalset and colleagues studied data from 1569 men and 1238 women 71–75 years of age. They found that elderly people in the lowest quartile of vitamin K1 intake were 57 percent more likely to suffer from hip fractures.

 

Ellen M. Apalset, Clara G. Gjesdal, Geir E. Eide, and Grethe S. Tell
Intake of vitamin K1 and K2 and risk of hip fractures: The Hordaland Health Study
Bone 2011 Aug 2. [Epub ahead of print]


ABSTRACT

Background:
Evidence of the effect of vitamin K on bone health is conflicting. The aim was to investigate the association between intake of vitamins K1 and K2 and subsequent risk of hip fracture in a general population sample, as well as potential effect modification by apolipoprotein E gene (APOE) status by presence of the E4 allele.

Methods:
1569 men and 1238 women 71-75years of age were included in the community-based Hordaland Health Study 1997-1999 in Western Norway. Information on hip fracture was obtained from hospitalizations in the region from enrolment until 31 December 2009. Information on intake of vitamins K1 and K2 collected at baseline was used as potential predictors of hip fracture in Cox proportional hazards regression analyses.

Results:
Participants in the lowest compared to the highest quartile of vitamin K1 intake had increased risk of suffering a hip fracture (hazard ratio (HR)=1.57 [95% CI 1.09, 2.26]). Vitamin K2 intake was not associated with hip fracture. Presence of APOE4-allele did not increase the risk of hip fracture, nor was there any effect modification with vitamin K1 in relation to risk of hip fracture.

Conclusions:
A low intake of vitamin K1, but not K2, was associated with an increased risk of hip fractures.

 

Dietary Calcium Is Better Than Supplements At Protecting Bone Health

Women who get most of their daily calcium from food have healthier bones than women whose calcium comes mainly from supplemental tablets. 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, say researchers at Washington University School of Medicine in St. Louis. The researchers’ conclusions about calcium intake, published in 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.