Calcium requirements

[tammy]

Received this question via email:

I sure would like to get my daily calcium in whole food form as opposed
to supplements. Off hand would you have any suggestions?

[I have edited this post to just the basic question as the person who originally emailed me did not want it posted. However, without posting the question, we cannot have the answer so I have cut the question down to the basic question that was asked.]

[kmeldrum]

The "calcium question" is often asked in reference to a vegan diet. From my reading on the subject, I've learned that the RDA for calcium is perhaps overstated. This comes from Dr. John McDougall, who cites studies of rural peoples in Asia and Africa who follow a starch based diet, including fruits and vegetables, and whose intake of calcium is much lower than the RDA. In these populations, osteoporosis is virtually unknown. Compare that to populations in the highest calcium (and protein) intake areas, such as Scandanavia (and the US), where osteoporosis runs rampant, and people eat lots of protein. Dr. McDougall's message is that osteoporosis is not caused my calcium deficiency in the diet, but instead is caused by calcium loss due to diet and a few other factors, such as lack of exercise, etc. The main dietary factor in losing calcium from your bones is high protein intake, especially animal protein.

You can find more information on calcium, the need for it, where to get it, and why we lose it on Dr. McDougall's website (drmcdougall.com) and in the writings of Dr. Neal Barnard, President of Physicians Committee for Responsible Medicine (www.pcrm.org). Following is an excerpt from an article in Dr. McDougall's Jan 2003 newsletter.

The Right Diet Will Save Your Bones

Two recent publications clearly demonstrate the effects of diet on bone health (osteoporosis) and kidney stone formation. On the destructive side, research from the University of Chicago looked at the effects of the high protein Atkins diet on calcium balance.1 Data was collected for 2 weeks of the Atkins induction diet and 4 weeks on the maintenance diet. The induction diet contained 164 grams of protein a day and the maintenance 170 grams/day. The Atkins diet produced an acid load, because animal proteins are high in sulfur-containing amino acids, which break down into very potent sulfuric acid.2 Dietary acids must be buffered to prevent an acidic build-up in the body. The bones provide the alkaline materials to neutralize the acids. The end result was a large increase in calcium loss into the urine caused by the breakdown of bone materials. (The calcium balances decreased by 130 mg/day and 90 mg/day, respectively on the two phases of the diet). Markers of bone resorption increased, suggesting loss of bone during this short 6 week trial. Eventually, chronic calcium loss results in osteoporosis. The large amount of calcium in the urine, along with other changes produced by a diet high in animal proteins, is a setup for calcium-based kidney stones. Over 95% of kidney stones in Western societies are made primarily of calcium.

On the constructive side, a study from the University of Applied Sciences in Germany examined vegans (on an all vegetable-foods diet with no animal protein) and found them to be in positive calcium balance – more calcium entered the body than left.3 The balance was a positive 119 mg/day. There were no changes in markers of bone resorption, suggesting the bones were not breaking down. The vegans consumed an average of 843 mg of calcium a day from their foods and calcium-rich mineral water.

These effects of animal protein on bone health are not limited to only 2 weeks as has been claimed by some poorly informed people (such as Robert Atkins claiming that the calcium losing effects of his diet are limited to 2 weeks, on the January 6, 2002 Larry King Live CNN-TV Show), but continues as long as the person’s diet is high in protein.1,4 Therefore, to save your skeleton and prevent kidney stones, you need to follow a (vegan) diet based on starches, vegetables, and fruits....