Many women take a calcium supplement because they feel they ‘should’. Because they’re over 50. Because they fear their bones will crumble if they don’t. Their philosophy seems to be that the more calcium you get into you, the stronger your bones will be. But new research is alerting the world that taking calcium in large doses may be detrimental to your cardiovascular health and increase your risk of having a heart attack or stroke. It’s not just one study, but several, in peer-reviewed journals. The latest “let’s be careful with calcium supplements” warning was published in the August edition of ‘Heart’, volume 98, page 920. Link to the article here
The rising concern with taking calcium tablets stems from the sudden increase in serum (bloodstream) calcium levels that they produce. It seems odd, and the biochemical reason for the connection with cardiovascular problems still isn’t clear – but it’s not so surprising when you consider that calcium is the mineral that helps muscle (including heart muscle) contract.
It’s true that calcium is important for your health. Most of it is stored in bones and teeth, with specialised cells and hormones constantly monitoring and adjusting the level of calcium in your bloodstream. Hormones from the parathyroid gland in your throat regulate blood calcium levels, and specialist bone cells manage the constant rebuilding of bone. Osteoporosis, the reason why some women take calcium, happens when this system becomes dysregulated, and bone building is outstripped by bone re-absorption. Osteoporosis is caused by other factors too, not just calcium intake; including hormones and your body’s pH.
It’s reassuring to read the research advised obtaining calcium from food is safe; most likely because it’s almost impossible to ‘overdose’ on calcium from food. Fat and protein in the calcium rich food helps absorption, and some foods will actually hinder calcium absorption (coffee, tea, cocoa, and vegetables with high levels of phytic acid). That makes almonds and seafood ideal sources of calcium, especially oily fish. Dairy is also a good source of calcium, but too much in your diet can cause other problems, so restrict your dairy intake to two serves per day. Providing you don’t focus too much on any one food or food group, and your digestion is healthy, the calcium is likely to get through.
Your body is very good at regulating how much of a nutrient it absorbs from food. If you’re low on a particular mineral, your body automatically increases the amount of enzymes available to extract that more from your food. But a ‘flood’ of mineral coming through, like what happens when you use a supplement, can overwhelm your body’s natural regulatory processes and cause sudden changes in the mineral mix in your bloodstream.
The most important message from this latest research is that self-prescribing is not a good idea. If you suspect you may be low in calcium, or that you may be in danger of developing osteoporosis, check with your health professional before reaching for a supplement ‘just because you should’.