How Much Calcium Does The Body Need? Q&A

There are two times in a woman’s life when calcium needs increase. One is during adolescence, and the other is after menopause. Knowing how much calcium to get from foods or supplements can be confusing, so here are some common questions and answers to help.

Q. How much calcium do I need?

During adolescence, the Recommended Daily Intake (RDI) of calcium jumps from 700 mg for a 4-8 year old female to 1000-1300 mg for the 9-18 year old age group. This increase occurs due to rapid growth and gains in bone mass during the adolescent years.

The RDI for 19-50 year old women is 1000 mg, including during pregnancy and lactation.

After menopause, the RDI  is increased from 1000 mg to 1300 mg/day as oestrogen (a bone protective hormone) declines.

Q. I prefer to get my calcium through foods: what foods do I need to eat to get enough calcium?

Calcium is found in a variety of foods, including vegetables, dairy products, fish and nuts. Although the body needs a lot of calcium per day, the RDI can be met with careful attention to calcium-rich foods. These include:

• Spinach: 50 mg/100 g 
• Sardines (canned): 380 mg/100 g 
• Salmon (canned): 220 mg/100 g 
• Broccoli: 30 mg/100 g 
• Milk (whole milk): 285 mg/250 ml(cup)                           
• Cheese (cheddar): 810 mg/100 g                    
• Yoghurt: 180 mg/100 g

Q. Are dairy foods the best source of calcium?

Although dairy foods are a good source of calcium, they are known for their contribution of saturated fats and relative lack of vitamins, fibre and antioxidants; it’s therefore recommended to get calcium from a variety of foods – not just dairy. Here is a helpful PDF link from Osteoporosis Australia which provides average amounts of calcium in foods: http://www.osteoporosis.org.au/files/general/calcium_content_table.pdf

Q. My health practitioner said that I need to take a calcium supplement, but what is the best one for me?

There are different doses and types of calcium supplements in the market. The amount needed from a supplement should be assessed by a healthcare professional; however, on average, most people will need to supplement with 500-1000 mg of elemental calcium. ‘Elemental calcium’ is the amount of pure calcium joined to another mineral. Common calcium supplements on the market are:

• Calcium carbonate is a popular form of supplemental calcium, as greater amounts of calcium can be attached to the carbonate ion giving a higher amount of elemental calcium per tablet. However, it can be a poorly absorbed form of calcium and is dependant on stomach acidity, with little being absorbed when acidity is low. Therefore, calcium carbonate should be taken with meals when stomach acidity is greater. If you suffer from low acidity, or take antacids, it would be best to take another form of calcium.
• Calcium citrate is one of the better absorbed calcium supplements, dissolving very well even in water. It is a good supplemental calcium for the elderly and those who suffer from low stomach acidity. Not as much elemental calcium fits onto the citrate ion, meaning more tablets will need to be taken to get a therapeutic dose.
• Calcium phosphate is one of the forms of calcium found in bones and teeth.

Q. Is it true there are certain substances which can affect calcium levels?

Yes – there are a number of factors that can contribute to greater losses or poorer absorption of calcium.

• Diuretics, such as coffee, can increase the kidney’s elimination of calcium. Alcohol may reduce the absorption of calcium. It is best to separate the dose by 2 hours.
• Phosphorus, a mineral in soft drinks and in meat, can increase calcium excretion when consumed in excess. 
• Fibre may also bind to calcium in the gastro-intestinal tract. It is recommended to separate calcium supplementation from high-fibre foods by at least 2 hours.

Q. Is it true that calcium supplements can increase cardiovascular risk factors?

Confusion about calcium supplementation has recently emerged, causing many to stop taking calcium supplements. However, the message from Osteoporosis Australia is that there is no need to stop taking calcium supplements as there is still overwhelming evidence to support calcium supplementation in osteoporosis. However, supplementation above RDI’s should be discouraged.

References available on request