Tuesday, March 23, 2010

Calcium absorption

Try answering this question (it’s not a trick question):

From which food are we likely to absorb the most calcium per serve?

a. Milk, 200 mL

b. Soy milk (calcium fortified), 200 mL

c. Broccoli, 1 cup cooked

d. Spinach, 1 cup cooked

The answer is (a), but here is the bit I didn’t know. We absorb about 32% of the calcium in milk and around 25% of the calcium in soy milk, yet we absorb 60% of the calcium in broccoli. Despite some strange folk promoting spinach as a calcium source, we absorb only 5% of the calcium in spinach.

Although we absorb a higher percentage of calcium from broccoli, the reason milk wins is because of its high level of calcium in the first place. From the serves given, about 75mg of calcium from milk serve is absorbed, 55mg from soy milk, 24mg from broccoli and only 4mg calcium from a cup of spinach.


John Denton - Denton And Associates said...

Glenn, that's interesting about the milk and calcium. I believed (until now) that calcium absorption from milk was very low. Don't we need magnesium with it to help absorption?

Also, what kind of milk - does skim milk and all those other varieties contain the same level of calcium? We may get the calcium but we also get the fat!
John Denton

Glenn Cardwell said...

Thanks John. I will respond to these comments in my next posting as others asked similar questions. Onya.