Along with vitamin D and weight-bearing physical activity, Calcium is an essential mineral for building and maintaining healthy bones. In this article, Clinical Nutritionist Deborah Stone explains how consuming a calcium rich diet can help to prevent osteoporosis and whether taking calcium supplements can help to enhance our dietary calcium intake.

Calcium is a mineral that is really important for building strong, healthy bones. Around 99% of the calcium in our body is stored in our bones, teeth and nails to provide strength and structure. The other 1 % required for a number of metabolic functions such as vascular contraction and dilation, muscle function and nerve transmission.

The Recommended Daily Intake (RDI) in Australia for adults between 19 to 50 years of age is 1000mg/day. This increases to 1300mg/day for either women over 50 years of age or men aged over 70 years.

As calcium is not made in the body it must be absorbed from our food and drink. Therefore, consuming a healthy calcium rich diet is the preferable approach to meeting your RDI.

As we age, calcium is absorbed less effectively from the intestines. Furthermore, as women enter the menopause, estrogen deficiencies can diminish calcium absorption further. However, we can help to enhance calcium absorption by having adequate levels of Vitamin D, magnesium and Vitamin K in our diet. If we eat a diverse variety of fruit and vegetables, nuts, seeds and good quality proteins and have adequate safe sun exposure, we will provide our bodies with sufficient intake of these nutrients.

The most well-known source of calcium is dairy foods such as milk, yoghurt, cottage cheese and hard cheeses. The Australian Government Department of Health recommends that you consume four serves of this type of food every day in order to meet your daily calcium requirements. However, at least 70% of the world’s population is lactose intolerant, to some degree. For this percentage of the population, consumption of dairy foods can result in gastrointestinal discomforts such as bloating, cramping, constipation or diarrhoea. Therefore, it is best to obtain your calcium from a variety of sources.

Foods high in calcium include the following:

Food	Serving	Calcium Serve (milligrams)
Milk, regular	I cup serve 250ml	304
Milk, reduced fat	I cup serve 250ml	367
Regular soy milk	I cup serve 250ml	309
Tofu, firm	I cup serve 250ml	832
Regular Natural yoghurt	200gm tub	386
Cheddar Cheese	1 slice	160
Camembert	1x  25gm wedge	121
Sardines, canned in water	90 grams	486
Red Salmon, canned in water	90 grams	203
Tahini	1 tbsp	66
Almonds	10 almonds	30
Dried figs	3 figs	80
Bok Choy, raw	1 cup	65
Silverbeet, boiled	½ cup	87
Lebanese raw cucumber	1 cup	68
Chickpeas	I cup cooked	90
Boiled	1	21

*Source: Osteoporosis Australia Calcium Fact Sheet 2016/17

The RDI of 1300mg/day can easily be achieved by including a diverse range of calcium rich foods such as nuts, seeds, figs, salmon, sardines, legumes and plenty of leafy greens regularly in your diet. An example of a daily menu is provided below:

Breakfast – Oats cooked with milk/almond or soy milk – you can boost calcium by adding a spoonful of grass-fed butter or organic yoghurt, serve with some walnuts and chopped banana.

Mid-Morning Snack – green smoothie made with green leafy vegetables and fruit.

Lunch – green leafy salad, hummus dip with vegetable sticks or crackers.

Afternoon snack – could include a serve of almonds or piece of fruit or 3 dried figs.

Dinner – red salmon patties with at least 3  serves of vegetables – sweet potatoes, spinach, brussel sprouts, broccoli or cauliflower to name a few.

It is also worth noting that many of our foods might be fortified with calcium. For example, in Australia, breakfast cereals, soy milk, orange juice and chewing gum can all include fortified calcium. Ensure you read the labels on ready-made or processed foods to calculate how much calcium you are consuming per day via these foods.

Calcium Supplements

The question of whether or not we should take supplements to enhance our dietary calcium intake is always a controversial subject.  Many studies have reported adverse effects associated with calcium supplementation, including increased risks of forming kidney stones and developing cardiovascular disease. In contrast, studies exploring the effect of additional calcium provided through dietary changes have reported positive benefits including some protection against heart disease.

The reason for different outcomes between dietary vs supplementary calcium is most likely due to the dosage. Specifically, taking one large dose of calcium within a supplement causes a spike in the calcium levels in the blood. As the body is unable to utilize this surge of calcium all in one go, the calcium is either deposited in arteries or is excreted via our kidneys. In comparison, when we consume calcium via food, it is absorbed at a much slower rate. This slower rate of absorption permits the calcium to reach bones and other cells where it is required to do its job.

Of note, a calcium supplement may be required if it is difficult to consume enough calcium in your diet on a regular basis, for example, if you are lactose intolerant or a vegan.  An ideal supplement would include a dose of no more than 500mg of calcium in an easily digestible citrate form, especially if you have low stomach acid or are taking Proton Pump Inhibitor medicines. Ideally, the calcium supplement should also include magnesium, Vitamin D and Vitamin K to aid absorption.  Please note, if you are taking Bisphosphonates for Osteoporosis, the calcium supplement should be taken at least 2 hours apart.

Calcium is essential for healthy bones but it must be consumed safely. If you are unsure of what intake level is right for you please speak with your GP or relevant Health Professional.