Q. Why do so few calcium supplements have phosphate? Isn’t phosphate needed for bones?
A. Phosphorus is an essential mineral, just like calcium, magnesium, and several trace minerals. It is always found in the body combined with oxygen, in the form of phosphate, and most of the body’s phosphate is found stored in our bones. However, it is also an important component of our genetic material (DNA and RNA). In cellular fluids it is an essential part of the machinery involved in the production and transfer of energy throughout the body.
The American diet provides generous amounts of phosphate from foods such as meat, eggs, milk products, and grains. These are among the favorite foods of our society. In addition, more phosphate can be found in our soft drinks and cured meat products. In fact, we may get an excess of phosphate in relation to the amount of calcium and other minerals, which is the primary reason it is not often found in supplements.
Good nutrition means more than getting a sufficient amount of each of the essential nutrients. Balance among the nutrients is vital, and each nutrient interacts with all the other nutrients in such a way that an increase in one will modify the requirements of the others. It is well established that an increased phosphate intake will increase calcium requirements. Adults today take in an estimated 1,500 milligrams of phosphorus (4,500 milligrams of phosphate) per day compared with a recommended level of 800 milligrams. Children, adolescents, and pregnant or lactating women require more than 800 milligrams per day, but still less than 1,500 milligrams. Most nutritionists recommend approximately equal amounts of calcium and phosphorus, so this high intake of phosphorus may be one of the reasons why some women today require such large calcium supplements in order to ward off osteoporosis.
High phosphate intake tends to increase the loss of calcium by increasing the calcium content of digestive juices. In addition, an elevated serum phosphate concentration is capable of increasing the deposition of calcium in blood vessels, leading to arteriosclerosis or “hardening of the arteries.” Maintaining calcium and phosphorus intake in a good balance (a ratio of about 1-to-1) can thus improve your chances of a long and comfortable life.
A German pharmacist has recently brought up the possibility of a connection between high dietary phosphate and Attention Deficit Disorder. Hertha Hafer’s research revealed that high phosphate content was the common component in the foods that triggered her son’s hyperactivity. She found a low-phosphate diet was helpful in treating her son and other children with ADD. A diet containing only minimal phosphate led to a marked reduction in the symptoms of ADD and, in many cases, to their eventual disappearance. In a study of 15 children with ADD, whose symptoms had been under control for several months with the low-phosphate diet, capsules of 75 milligrams of phosphate (about the amount in one-sixth of a sausage biscuit) were given to the children. They reacted quite violently with reoccurrence of their ADD symptoms that lasted for days.
A low-phosphate diet does not mean one should avoid all dietary phosphate, since many of the nutrient-dense foods we eat have a high phosphate content. Cutting down on cured meat, carbonated drinks, breads made with baking powder, and other dispensable phosphate sources could be sufficient to keep calcium and phosphate in balance.
This article appears in October 17 • 2003.