Even though calcium intake is a major factor in bone health, there are many other nutritional and lifestyle aspects involved. Our last article reported that a cup of cooked choy sum contains about the same amount of absorbable calcium as a cup of milk. This data is from a research paper that analyzed hydroponically grown choy sum and the calcium absorption was measured from cooked choy sum which was pureed prior to eating. Locally grown choy sum may or may not be comparable. Also, calcium absorption could be less if you don't chew your food well.
Dietary protein is another interesting factor in bone health.
Protein is part of bone structure and adequate protein intake is important for the maintenance of healthy bones. However, too much protein in the diet can be detrimental since it causes increased losses of calcium in the urine. If someone consuming a high protein diet does not also consume a high amount of calcium, then bone calcium is gradually lost. As a general rule of thumb, a bone-healthy diet should have about 16 milligrams of calcium for each gram of protein. Milk has about 38 milligrams of calcium for each gram of protein.