Do you take calcium and vitamin D to protect your bones? A new study says it doesn't help

If taking more vitamin and mineral supplements is part of your plan for a healthier new year, a new study may prompt you to reconsider.
Researchers who scoured the medical literature for evidence that calcium and vitamin D pills could help prevent bone fractures came up empty.

04 JAN 2018--Their analysis focused on adults older than age 50 who lived on their own (that is, not in a nursing home or other type of residential care facility). Fractures are a serious health concern for this population—previous studies have found that about 40 percent of women in this age group will wind up with at least one "major osteoporotic fracture" at some point in their lives, and that among adults who break a hip, 20 percent died within a year of their injury.
The researchers, led by Dr. Jia-Guo Zhao of Tianjin Hospital in northeastern China, combed through clinical trials, systematic reviews and other reports published in the last decade, since late 2006. They identified 51,145 people who were included in studies assessing the role of calcium and/or vitamin D in preventing bone fractures.
Their findings appear in Tuesday's edition of the Journal of the American Medical Association.
Among the 14 trials that pitted calcium supplements against either a placebo or no treatment, there was no statistically significant relationship between use of the mineral (in pill form) and the risk of suffering a hip fracture. Nor was there any clear link between calcium supplements and fractures involving the spine or other bones.
Even when the researchers accounted for each study participant's gender, past history of bone fractures, the amount of calcium they consumed in their diets and the dose of the calcium pills they took (if they did), there was still no sign that supplements were helpful.
An additional 17 trials examined the role of vitamin D, which helps the body absorb calcium. Once again, they found no statistically significant link between supplement use and hip fracture risk. Ditto for fractures in the spine and elsewhere.
Upon drilling down to certain subgroups, they found that for people who started out with at least 20 nanograms of vitamin D per milliliter of blood, adding more vitamin D through supplements was associated with a greater risk of hip fractures. The same was true for people who took high doses of vitamin D supplements just once a year.
Finally, there were 13 trials involving people who took a combined calcium-vitamin D supplement. As before, there was no statistically significant link between supplement use and the risk for any kind of fracture or combination of fractures. That held up even when accounting for gender, past fractures, supplement dose, dietary calcium or baseline blood levels of vitamin D.
The researchers noted that thousands of people in this final group were participants in the Women's Health Initiative, a long-term study sponsored by the National Heart, Lung and Blood Institute in the U.S. Earlier reports based on data gathered by the Women's Health Initiative found that calcium and vitamin D supplements were associated with a lower risk of fractures, but only for women who took hormone therapy after menopause. To get a clearer picture of the direct link (if any) between supplements and fracture risk, Zhao and his colleagues opted not to include data from women on hormone therapy.
It's still possible that calcium and vitamin D supplements are useful for people who live in nursing homes or other residential facilities, the study authors wrote. Such people are more likely to have osteoporosis, due to a combination of poor diet, less sun exposure (which the body needs to synthesize vitamin D) and other factors.
But for older adults who live on their own, they wrote, the results are clear: "These findings do not support the routine use of these supplements."

More information: Jia-Guo Zhao et al. Association Between Calcium or Vitamin D Supplementation and Fracture Incidence in Community-Dwelling Older Adults, JAMA (2017). DOI: 10.1001/jama.2017.19344

Expert advises against high doses of supplements

05 may 2012-- That vitamin D and calcium you're taking could be causing more harm than good, a new article in the Journal of the National Cancer Institute says.

The paper, co-authored by a professor at the University of Arizona's Mel and Enid Zuckerman College of Public Health, cites evidence that high doses of some supplements increase cancer risk.
"You may not need to take supplements if you have a healthy diet," said article co-author Elizabeth Jacobs, a UA associate professor of epidemiology and a researcher at the Arizona Cancer Center. She cited an old phrase: "The dose makes the poison."
"If you are deficient in nutrients, taking a supplement is probably not going to cause any harm, but if you are already adequate in nutrients, then taking a supplement at a minimum has no benefit and in some cases has been shown to cause harm," Jacobs said.
Jacobs said the authors are not trying to say people who take supplements will get cancer. But she cautions about taking megadoses like 10,000 I.U.s of vitamin D per day, for example.
"A lot of literature has shown that often the people who take dietary supplements need them the least, so they already eat a good diet, they have a lot of nutrients in their diet, they exercise, they don't necessarily need extra nutrients," Jacobs said. "And those are the people who tend to take supplements - they are very health conscious, and that's where the danger is because you are already getting enough of these vitamins or minerals in your diet, and then you are adding more."
The article, titled "Dietary Supplements and Cancer Prevention: Balancing Potential Benefits Against Proven Harms," appeared in the April 25 issue of the Journal of the National Cancer Institute. Its lead author is María Elena Martinez of the University of California-San Diego, who is a former UA College of Public Health epidemiology professor.
"Undoubtedly, use is driven by a common belief that supplements can improve health and protect against disease, and that at worst, they are harmless," the scientists write. "However, the assumption that any dietary supplement is safe under all circumstances and in all quantities is no longer empirically reasonable."
In an email, Martinez stressed that the article is not a study but rather an invited commentary that she hopes will "continue to increase awareness among the scientific community, policymakers and relevant government agencies about the scientific evidence on the topic, especially as it relates to harm related to these products."
Nutritional supplements are an estimated $30 billion-per-year industry.
"If you have too much of anything, that is not a good thing," said Cara Welch, vice president of scientific and regulatory affairs for the Washington, D.C.-based Natural Products Association, a nonprofit group representing natural-products retailers and suppliers. "The article was looking at very high doses in particular populations. It is against the law to market your supplement to treat or prevent cancer - at that point it turns into a drug. There's no way around it. You can't imply you prevent cancer."
Both Martinez and Jacobs say there are certainly people who need supplements, such as women of childbearing age who are considering getting pregnant, people who have been diagnosed with a specific nutrient deficiency like anemia and people with food allergies or intolerances, like lactose intolerance.
Folic acid is recommended for women considering pregnancy, but it is an example of a supplement that could be harmful for people who don't need it, Jacobs said.
"When you are older, folic acid is shaking out to be one of the more worrisome supplements," Jacobs said. "It's not natural. It's completely synthetic folic acid, and so your body is getting this new compound and we're just not as efficient at metabolizing folic acid as folate. So that is some cause for concern."
Jacobs said her personal hope is that the article will inspire better regulation and oversight of the supplement industry.
For most claims made in the labeling of dietary supplements, the law does not require the manufacturer or seller to prove to the government's "satisfaction" that the claim is accurate or truthful before it appears on the product, Food and Drug Administration literature says.
Welch said her organization has a research and education arm that works with companies to ensure "truth in advertising."
And the industry is not regulated in the same way as pharmaceuticals for a reason, she said.
"We're not regulated as drugs because we're not drugs," she said.
Welch said a majority of Americans take supplements like multivitamins and Omega-3 to maintain health. "Unfortunately, the standard U.S. diet doesn't give us all the nutrients we need," she said.
None of the article's five scientist authors takes any supplements, not even the much-heralded vitamin D, Jacobs said.
"Eat a variety of food, exercise, don't smoke - that is superior to taking a supplement," Jacobs said. "You aren't supposed to get the recommended dietary allowance (of nutrients) every day. It rarely happens. You are supposed to just average over time. You just do the best you can. But in the U.S. our problem isn't really under-nutrition, it's over-nutrition."
"You aren't supposed to get the recommended dietary allowance (of nutrients) every day. It rarely happens. You are supposed to just average over time. You just do the best you can. But in the U.S., our problem isn't really under-nutrition, it's over-nutrition."
Read more: http://azstarnet.com/news/science/health-med-fit/ua-expert-advises-against-high-doses-of-supplements/article_c3c3c91d-9939-5387-adea-15bea5184f58.html#ixzz1tsvDO4ej
Provided by University of Arizona

Calcium, vitamin D modulate human energy metabolism

13 march 2012--There is considerable evidence that calcium and vitamin D intake are influential in modulating energy metabolism in humans, according to a study published online March 2 in Obesity Reviews.

Mario J. Soares, M.B.B.S., Ph.D., of Curtin University in Perth, Australia, and associates conducted a literature review of randomized controlled trials (RCTs) to explore the role of calcium and vitamin D in regulating body weight and adiposity.

The researchers found consistent evidence that calcium and vitamin D increase whole body fat oxidation after meals and that calcium induces modest energy loss through increased fecal fat excretion. Equivocal evidence exists for the association with increased diet-induced thermogenesis and lipolysis, suppression of lipogenic enzymes, and decreased hunger ratings or energy/macronutrient intake. A potential improvement in insulin sensitivity has been suggested following vitamin D, which would impact food intake and substrate oxidation, but very few RCTs have explored postprandial routes of action.

"It is our opinion that calcium with or without vitamin D modulates human energy metabolism. The evidence is convincing that calcium increases fat oxidation after a single meal and over several meals of the day," the authors write. "While it is clear that nutrition and public health recommendations demand consistency of observation from a variety of study designs, the inclusion of mechanistic pathways in such investigations is essential in cementing the biological plausibility of the outcomes."

More information: Abstract

Calcium tied to lower cancer risk in older people

By Lindsey Tanner

CHICAGO, 02 mar 2009 --A study in nearly half a million older men and women bolsters evidence that diets rich in calcium may help protect against some cancers. The benefits were mostly associated with foods high in calcium, rather than calcium tablets.

Previous studies have produced conflicting results. The new research involved food questionnaires from participants and a follow-up check of records for cancer cases during the subsequent seven years. This research method is less rigorous than some previous but smaller studies.

But because of its huge size -- 492,810 people and more than 50,000 cancers -- the new study presents powerful evidence favoring the idea that calcium may somehow keep cells from becoming cancerous, said University of North Carolina nutrition expert John Anderson, who was not involved in the study.

The study was run jointly by the National Institutes of Health and AARP. The results appear in Monday's Archives of Internal Medicine.

National Cancer Institute researcher Yikyung Park, the study's lead author, called the results strong but said more studies are needed to confirm the findings.

Duke University nutrition researcher Denise Snyder said the results support the idea that food rather than supplements is the best source for nutrients.

Participants were AARP members aged 50 to 71 who began the study in the mid-1990s. A total of 36,965 men and 16,605 women were later diagnosed with cancer. There were more than 10 different kinds of cancer, the most common being prostate, breast, lung and colorectal.

Compared with people who got little calcium, those who consumed the most had the lowest chances of getting colon cancer. Those in that highest category got on average 1,530 milligrams a day among men and 1,881 milligrams daily among women. The recommended amount for older people is 1,200 milligrams, and getting much more than that didn't result in any greater protection. Adults can get that amount from four cups of milk or calcium-fortified orange juice.

Men who got the most calcium from food were about 30 percent less likely to get cancer of the esophagus, about 20 percent less likely to get head and neck cancer and 16 percent less likely to get colon cancer, when compared to men who got low amounts of calcium.

Among women, those who got the most food-based calcium were 28 percent less likely to get colon cancer than low-calcium women.

In men, calcium supplements only seemed to help protect against colon cancer; for women, supplements meant a lower risk for liver cancer, which is rare.

Some previous studies have linked diets high in calcium with prostate cancer but the current study found no such risk.

Adults who ate the most calcium also tended to be healthier overall than the others.