Why do we need calcium?

Calcium is a key regulator of many of the body’s functions. Brain, muscle and nerve activity all depend on calcium levels remaining constant, so blood concentrations are kept under tight control throughout our lives. Whether we drink milk or not, our levels hardly budge. This is achieved by having an enormous store that can release or absorb large amounts of calcium according to our body’s needs. This store is bone. If calcium in our diet is insufficient to offset normal losses in urine, bone is broken down to retrieve its calcium. Conversely, if calcium intake is increased, bone manufacture occurs and more calcium is deposited as insurance against hard times.

How much calcium do we need?

It is recommended that we all consume more than 1g of calcium per day. Most of us consume far less. Calcium can be obtained from dairy products, as well as seaweed, nuts, seeds, legumes and green leafy vegetables. Many products are also fortified with calcium, including orange juice and soy milk.

The ability to get the most out of the calcium in our diet is critically dependent on our levels of Vitamin D, so most people who take supplements use these in combination. Alternatively, we can grow our greens in the sunshine of our own garden to get both for free. Other simple things we can do to keep calcium in our bones include reducing excessive intake of salt, caffeine and alcohol, thus reducing the loss of calcium into urine. Soluble fiber in our diet can also improve calcium absorption.

What happens if we don’t get enough calcium?

Inadequate calcium intake is associated with an increased risk of osteoporosis, hypertension and some cancers in later life. For those not getting enough calcium in their diet, a range of supplements is available.  These are best taken with food and spread throughout the day, rather than all at once, to get the best absorption. The various supplements contain different amounts of elemental calcium, so we need to be careful to read the label and adjust the dose to achieve 1- 2g per day.

What to look for when supplementing with calcium

Some supplements can cause constipation or bloating, particularly those predominantly comprised of calcium carbonate. As a cheap alternative to supplements, a pinch of finely ground eggshell into meals will also do the trick. Hydroxyapatite is widely marketed as a ‘bone-building’ supplement. It is essentially ground bone. Hydroxyapatite is an excellent source of calcium and a good way to maintain bone mass. It may also contain other chemical elements and toxins that can accumulate in bone, so choose a product that has been fully tested and certified, or is definitively toxin-free.

Last Reviewed 02/Mar/2014

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Dr Merlin Thomas

Professor Merlin Thomas is Professor of Medicine at Melbourne’s Monash University, based in the Department of Diabetes. He is both a physician and a scientist. Merlin has a broader interest in all aspects of preventive medicine and ageing. He has published over 270 articles in many of the worlds’ leading medical journals
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