Controversy over calcium


In the past decade, a debate has developed over calcium and vitamin D supplements—should everyone older than 50 take them to prevent osteoporosis (weakened, porous bones)? The amount of calcium in our diet, the quantity of vitamin D we make in response to sunlight, and the amount of exercise we get are important factors in preventing bone loss.

Lots of questions…

Can calcium and Vitamin D supplements take the place of a healthy diet and exercise? Can we get enough of these nutrients without supplements? How much is enough? Can too much be dangerous?

Here’s the controversy: several years ago, the US Preventive Services Task force issued a statement saying there was not enough evidence to support a need for calcium supplements in older adults who did not have osteoporosis or vitamin D deficiency.

In December 2017, the Journal of the American Medical Society published an analysis of 33 trials on older adults not living in nursing homes. It found no clear benefit from these supplements.

Another concern with supplements is the large “bolus” of calcium that floods the blood stream after a tablet is taken. Studies suggest that this could increase the risk of heart disease, with some showing up to 30% increased risk in those taking calcium supplements. Recommendations now suggest dividing calcium supplements over the day if they are being taken to avoid a spike in blood calcium. However, the problem is that researchers did not design these studies to look for potential heart problems, so we cannot completely trust these results. We need more research to confirm this.

Vitamin D—more controversy

The official recommended daily amount (or “RDA”) of vitamin D is 400iu per day, but this is the quantity needed to avoid Rickets, a disease of softening of the bones. We now know that we need larger amounts of vitamin D for a healthy immune system. Experts suggest 800 to 1000 iu daily for those who are not making their own vitamin D due to lack of sunlight exposure, but researchers are still trying to decide how much is ideal. If you missed that article, click HERE to link to it.

This week, a new study published in the journal Gut suggests calcium supplements may increase the risk of polyps in the colon after six to 10 years of therapy… and polyps are important “precursors” to colon cancer (meaning: polyps are a stage in the development of cancer). Again, researchers said that more research is needed to confirm their results—being the first study to suggest this connection—but are concerned since millions of people take them.

Supplements versus food

One difference between getting calcium from a supplement rather than food, is that most common supplements contain calcium carbonate. Even when taken with food, this form of calcium is only 20% absorbed. The other 80% remains in the bowel where it causes constipation and, perhaps, also polyps.

Calcium in food, on the other hand, can be much more highly absorbed, especially when you have adequate vitamin D. I have read studies that found as little as 300mg of absorbed calcium a day in the diet can keep bone healthy, compared to 1000 to 1200 mg recommended in supplement form. The difference, however, is likely due to the low level of calcium absorption from tablets.

A broken bone, like a hip or the spine, can devastate the life of an elderly person. And drugs for osteoporosis are expensive, difficult to take and have serious side effects. The best way to prevent osteoporosis and bone fractures is to exercise at least three times a week, don’t smoke, get adequate sunshine (or supplement vitamin D in a northern winter), and eat calcium-rich foods. Examples of these foods are dairy products, vegetables, fish (especially with dissolved bones), mineral water, and even tap water!

If you’re curious about your bone health, you can calculate your risk of a fracture here. (Note: conversion tool on the right to change pounds and inches to kilograms and centimeters)

Find references and read more from Jeannie Collins Beaudin.


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