Researchers have frequently noted that osteoporosis (low bone density) is rare in Japan and other Asian countries where dairy consumption is low, and most common in the west where we have a love affair with cheese, butter and cream. Since calcium is a primary component of both bones and milk, and calcium supplements are routinely prescribed as a treatment for osteoporosis, why should this be so?
One theory of why Asian bones are so much healthier than those of people in the west is that they eat a low acid diet. In Asian cooking, foods that produce little acid in the body such as fruit and vegetables, form a much greater proportion of the diet than meats, cereals and dairy products that break down into acidic by-products.
Although we think of bones as one of the most solid parts of our body, they are actually in a continual process of being broken down and rebuilt. Either breaking down too quickly or building up too slowly is going to have a detrimental effect on bone density. In addition to providing the body’s skeletal foundation, our bones also play a pivotal role in regulating the pH of the blood. If the blood becomes too acid, then calcium is taken from the bones in order restore the acid-alkaline balance. So regardless of how much calcium we are consuming, if our blood becomes too acid, calcium will be lost from the bones and put us at a much greater risk of osteoporosis.
The idea that a low acid (alkaline) diet can lead to good health has been around since the 19th century, when scientists noticed that a more meat-based diet led to more acidic urine. The theory has been more widely explored over the last hundred years and championed by alternative health practitioners as a way of preventing and curing heart disease, cancer, obesity and many other common and severe ailments. It has not been without criticism, however, and conventional medical thinking gives little credence to the theory. The American Institute for Cancer Research has also stated that changing the pH level of the whole body to provide a less acidic environment for cancer cells to flourish is “virtually impossible”.
A paper published in 2001 by the USDA Human Nutrition Research Center on Aging supported the low acid diet in reducing the loss of bone density in older adults, but other studies have not been so positive. Furthermore, the most recent scientific analysis of the current evidence on the metabolic role of acidic ions published in Nutrition Journal in 2009 concluded that an increase in acid-forming foods did not lead to an increase in the loss of calcium or breakdown of bone. In fact, increased acidic metabolites in the form of phosphates actually seemed to reduce calcium loss through urine.
So, although the low-acid diet is still advocated as a way of potentially preventing and slowing the development of osteoporosis, the jury is still out as to whether there is good evidence behind it. Until an acid-osteoporosis connection is definitively established, eating a balanced diet, getting some regular weight-bearing exercise and reducing tobacco and alcohol consumption is the best route to improving bone density.