Check out your Calcium

How much calcium is needed daily?

Calcium is the most abundant and dominant mineral in the body. It is vital for bone health as it assists adequate bone deposition and thus prevents osteoporosis. It also helps with nerve transmission and muscle contraction. Current calcium recommendations for healthy individuals are 1000mg/day for both men and women between the ages of 19 – 50 years. This recommendation increases to 1200mg/ day for women over 50 years and men over 70 years. Most South African’s only manage to consume 500 – 600mg/ day meaning that we are falling short of our recommended daily intake for calcium.

Is supplementation required?

In light of conflicting evidence casting doubt on high dose calcium supplementation (>1000mg/ day) due to its suggested association with cardiovascular disease, consuming calcium-rich foods are recommended to meet your calcium requirements. Only when you are unable to get sufficient calcium from your diet, under teh supervision of a Registered Dietitian, should you consider to supplement to make up the difference. Milk and dairy products are a convenient source of bone healthy vitamins and minerals (calcium, phosphorous and vitamin D) however calcium is also found in other food sources (explained in more detail below).

Just how much Calcium is in foods we eat

When deciding on your preferred source of calcium, you should consider how well calcium is absorbed (the bioavailability of calcium in the food) as well as practical considerations such as the quantity of food you need to consume to ensure an adequate calcium intake.

The absorption of calcium depends on several factors relating to the food in which the calcium is found. While approximately 32% of calcium is absorbed by the body from milk and dairy sources, only 21% is absorbed from almonds (moderate phytate) and only 5% is absorbed from spinach (high phytate). Tri calcium phosphate is commonly used to fortify soy milk. Although this is a good source of calcium in the diet of those avoiding dairy, only 75% of this form of calcium is absorbed when compared to cow’s milk. An alternative calcium source in fortified foods/ beverages is calcium carbonate. This is absorbed more readily, so much so that it is equivalent to cow’s milk.

When comparing the relative calcium availability of milk (32%) to other food sources like broccoli (61%), bok choy (54%), kale (49%) and sweet potato (22%) it is evident that many other foods equal or surpass milk. However, it is not always easy to consume adequate quantities of each of these foods to meet your daily Calcium requirements Although plant foods, such as those described above, have highly available calcium it occurs in much lower quantities compared to dairy products. Thus the following portions need to be consumed to reach a similar amount of calcium as present in a 250mL glass of milk: 2.6 cups broccoli, 2 cups bok choy, 2.2 cups kale and 5.9 cups of sweet potato. Practically it seems easier to consume dairy products, but it is possible to make up your calcium requirement by including other food sources into you re diet.

The calcium content of a variety of food sources:

References:

National Osteoporosis Foundation South Africa. 2012 statement on calcium. http://osteoporosis.org.za.

National Osteoporosis Foundation South Africa. Calcium supplements. http://osteoporosis.org.za.

McCance & Widdowson (2002) The Composition of Foods Sixth summary edition. Cambridge: Royal Society of Chemistry

USDA National Nutrient Database for Standard Reference. https://ndb.nal.usda.gov/ndb/foods

Other references available on request