How much calcium does the body need? Q&A

Naturopath Jennifer McLennan answers your most common questions about calcium supplementation.

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?

The Australian NHMRC Recommended Daily Intake (RDI) states the following:
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 70 years old the RDI is increased again from to 1300 mg a 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.

As referenced by FSANZ these include:

• Cheese (cheddar): 886 mg/100 g
• Sardines (whole, raw): 725 mg/100 g
• Milk (whole milk): 285 mg/250 ml (cup)
• Kale (cooked) 328 mg/100g
• Salmon (canned): 102 mg/100 g
• Yoghurt: 182 mg/100 g
• Spinach (baby raw): 93mg/100 g
• Broccoli: 26 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, such as bony fish, legumes and certain nuts, fortified soy beverages and breakfast cereals. Calcium may be poorly absorbed from foods rich in oxalic acid (eg spinach, rhubarb, beans) so it is best to restrict your intake if you are concerned about your calcium intake. (reference NHMRC)

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 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 amino acid chelate is a well absorbed form of calcium which is gentle on the stomach. It is a combination of calcium bound to an amino acid to allow for better availability.
• 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, calcium carbonate should be taken with meals when stomach acidity is greater for best absorption. If you suffer from low acidity, or take antacids, it would be best to take another form of calcium.
• 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.

Summary

In summary, your healthcare professional will be able to determine what form of calcium and dosage is best suited to your needs, taking into consideration your diet, lifestyle and any contributing health factors or medication which may be playing a role in calcium uptake.