Calcium

Calcium

Calcium is essential for building and maintaining bone. Almost 99% of the body’s calcium is found in the bones. Calcium combines with other minerals to form hard crystals that give your bones strength and structure.

A small amount of calcium is absorbed into the blood; this calcium is essential for the healthy functioning of the heart, muscles, blood and nerves. Bones act like a calcium bank, if you do not take in enough calcium from your diet, the body will withdraw calcium from your ‘bone bank’ for use in other parts of the body. If your body withdraws more calcium than it deposits, your bone density (bone strength) will gradually decline and you may be at risk of developing osteoporosis.

Calcium requirements

Calcium from food

The best way to get the recommended level of calcium intake for your age is to eat a diet rich in calcium. Calcium content in food varies significantly, so it is important to consume ‘calcium rich’ foods.

Recommended: 3-5 serves of calcium rich food daily (number of serves depends on the level of calcium in each food)

View the following list for calcium content in different foods

Tips for increasing calcium intake

  • Dairy foods contain a high level of calcium which is easily absorbed – include 3 serves per day in your normal diet eg: glass of milk (250 ml), tub of yoghurt (200 g), slice of cheese (40 g). Low fat options contain similar levels of  calcium.
  • Try canned salmon or sardines which contain bones rich in calcium
  • Use yoghurt in soups or salads
  • Add milk or skim milk powder to soups or casseroles
  • Try soy based products and tofu that contain calcium 
  • Include broccoli, mustard cabbage, Bok Choy, silverbeet, cucumber, celery and chick peas in your regular diet
  • Eat more almonds, dried figs and dried apricots
  • Products fortified with calcium (e.g. some breakfast cereals) can help improve your calcium intake

Calcium - do we absorb everything?

Not all the calcium we consume is absorbed. It is normal for a small amount of calcium to be lost and excreted. This is factored into the recommended intake for your age. However other factors can lead to an abnormally low level of calcium absorption and should be discussed with your doctor, for example:

  • Low vitamin D levels
  • Excessive caffeine and alcohol
  • Diets high in phytates (eg: some cereals and brans) or oxalates (eg: spinach, rhubarb)
  • Certain medical conditions (eg: coeliac disease, kidney disease) and certain medicines (eg: prednisone, prednisolone)

Less than half of all Australian adults get their daily recommended intake of calcium.

Calcium Supplements

Osteoporosis Australia recommends you try to obtain the calcium you need from your diet. When this is not possible a supplement may be required. Osteoporosis Australia recommends doses of 500-600 mg per day, supplementation in this range is considered safe and effective. 

The most common supplements are calcium carbonate, calcium citrate or hydroxyapatite. Supplements may take the form of oral tablets (swallowed), effervescent tablets, chewable tablets or soluble powder.

Calcium supplements are usually well tolerated and are sometimes combined with vitamin D supplements (as required). Take supplements as directed and talk to your doctor or pharmacist if you have any queries.

Is calcium enough?

Calcium is just one of the essential ingredients for taking care of your bones. For people diagnosed with osteoporosis (including those who have experienced a fracture) calcium alone is not sufficient to prevent fractures. Osteoporosis treatment is also required, as advised by a doctor. It is common for doctors to prescribe calcium supplementation to accompany treatment.

Calcium factsheet

Author: Osteoporosis Australia Medical & Scientific Advisory Committee
Last updated: 03/09/2015 - 09:43