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Do we need more calcium in order to avoid osteoporosis, the progressive thinning of bones in the elderly?
In the West we are certainly told so. The dairy industry vigorously promotes the suggestion that without its products we face an unpleasant and probably shrunken future.
Yet the data uncovered in China do not support this view. Although most Chinese consume little if any dairy and ingest low amounts of calcium in general, they appear to be at a much lower risk for this potentially disabling disease. Hip fractures, for example, are only about one-fifth of what they are in the West – a striking difference.
Is it because the Chinese are more physically active? Or that they possibly adapt to a low-calcium diet? Or perhaps because they eat far less protein than we do in the West?
We do know that high protein intakes result in calcium loss through the urine. High-protein diets – especially protein of animal foods – can cause the body to excrete more calcium than it gets. For example, a person eating 142 grams of protein a day – which some Americans do – will excrete twice as much calcium in the urine as a person taking in a more moderate 47 grams. Because our bodies need calcium to regulate many different functions, such as the functioning of our muscles and nerves, the deficit caused by too much protein causes the body to withdraw more calcium from our main calcium reserve “banks” – our bones, which become increasingly more fragile as calcium is removed from them.
We are continuing to analyze the Chinese data on this topic; in the meantime, eat plenty of vegetables such as broccoli and collard greens. These super-foods contain a good amount of calcium, without the drawbacks of high protein. One cup of broccoli, for example, contains 178 milligrams of calcium, while 5 dried figs have 135. With a target of perhaps 800 milligrams of plant-derived calcium a day, it’s not difficult to fill your quota. And here’s a plus: vegetables contain boron, a mineral that helps keep calcium in the bones. Milk contains virtually none.
The Cornell-Oxford-China Nutrition project, conducted in mainland China and Taiwan, is a massive survey of over 10,000 families designed to study diet, lifestyle, and disease across the far reaches of rural China. By investigating simultaneously more diseases and more dietary characteristics than any other study to date, the project has generated the most comprehensive database in the world on the multiple causes of disease.