Vitamin D and Calcium: From the ABC

Reprinted from ABC Health and Well being. Posted 29 November 2019,

Vitamin D and calcium are both essential for building healthy bones.

Vitamin D and calcium supplements are often recommended to curb osteoporosis risk

New review finds the vitamins have little value for people who are not vitamin deficient.

Calcium supplements may even cause harm, and have no place in modern medicine, experts say

Now, research has revealed it might be time to ditch two of our most popular vitamins.

Calcium and vitamin D supplements, often recommended to older Australians to prevent osteoporosis, offer very little benefit to healthy adults.

In fact, calcium supplements may be doing more harm than good.

While the nutrients themselves are important, the researchers found calcium and vitamin D supplements did little to reduce fracture risk or improve bone density in the healthy older adult population.

The use of vitamin D as a "general tonic" in individuals who were not vitamin D deficient (or at risk of becoming deficient) was found to be largely fruitless.

"Just as we would not expect antibiotics given to individuals without an active infection to have beneficial effects, we should not expect supplements of calcium and vitamin D to benefit people who do not have demonstrable deficiency," the study authors wrote.

Calcium and vitamin D supplements are often administered together for the prevention and treatment of osteoporosis, which occurs when bones lose minerals, such as calcium, more quickly than the body can replace them.

Previous research into these supplements has produced conflicting results.

But this latest review, which assessed the overall safety and effectiveness of supplements, suggests the supplementation of calcium has little place in modern medicine.

"When you give extra calcium to otherwise healthy people living in the community, it makes no material difference to the number of fractures that occur," lead author Ian Reid, professor of medicine and endocrinology at the University of Auckland.

"And the main reason for giving extra calcium was a belief that that would make bones stronger."

According to the review article, calcium supplements can cause constipation, bloating and kidney stones, and may increase the risk of heart attack.

"Calcium supplements are frequently associated with gastrointestinal symptoms ... and they have also been reported to double the risk of hospital admissions related to abdominal symptoms," the authors wrote.

Vitamin D supplements, on the other hand, rarely cause adverse health outcomes. But there is evidence that very high levels of vitamin D can increase the risk of falls and fractures.

Either way, supplements were found to generally only have value in people with vitamin deficiencies, and not across the healthy older population — so talk to your doctor before starting or stopping any supplements.

Although the evidence for supplements in osteoporosis treatment is not strong, Professor Reid said there are some circumstances where they should still be used.

"Some of the new drugs that we are currently using in osteoporosis have only been assessed when calcium and vitamin D have been given at the same time, so I think we need to proceed cautiously," he said.

The use of calcium and vitamin D supplements in people at risk of vitamin D deficiency who require antiresorptive therapies is appropriate.

"But the most commonly used drugs ... it does not appear to matter. As long as your vitamin D levels are satisfactory, not giving calcium doesn't make any difference to the efficacy of those drugs," Professor Reid said.

Outside of osteoporosis, there are some conditions, such as osteomalacia — a bone disease in which bones soften and weaken — for which calcium and vitamin D supplements are considered appropriate.

Vitamin D supplementation is also advised for frail older people, and in some cases, people who cover their bodies for religious or cultural reasons, who are at risk of vitamin D deficiency.

Our main source of vit D is from the sun, and the best parts of the day to get your sun exposure and vitamin D dose in summer is the mid-morning or mid-afternoon.

For people with fair skin, five to 15 minutes in the sunshine most days a week should do it if your face and arms are exposed.

For people with very fair skin, it's less than that, and for people with darker skin, it can be a little longer.