Osteoporosis is a common avoidable skeletal condition characterized by low bone mass, and nutritional status is of key importance. Although we typically think of calcium and vitamin D as the important nutrients in prevention, there are any many more to consider.
After the menopause, oestrogen deficiency triggers the activity of the osteoclasts, the cells responsible for bone breakdown. Bone is continuously broken down and re-formed and thus has a on-going requirement for calcium, but also for energy and for other nutrients including phosphorus, copper, manganese, zinc, magnesium, vitamin C and vitamin D.
In addition the rate at which bone breaks down may vary from person to person, and markers of bone formation and resorption (blood tests such as bone ALP and TRAP) are useful to identify “fast” bone losers. In osteopaenic women the 10-year probability of fracture amounted to 26% if bone alkaline phosphatase was elevated vs. only 6% in women with normal enzyme levels.
Vitamin D deficiency, together with poor calcium intake, is a major risk factor for osteoporosis and osteoporotic fracture.
Optimum levels of vitamin A (retinol) are also required for bone metabolism; too much or too little vitamin A is thought to interfere with the action of vitamin D and contribute to the development of osteoporosis.
Phosphorus is required as a component of bone, but whilst dietary calcium deficiency is common, phosphorus deficiency is extremely rare and supplementation is not recommended for healthy individuals as high quantities of this mineral are already consumed in the average diet. In fact, too much phosphate and too little calcium decreases bone mass.
Adequate magnesium levels are required for bones as 55% of body magnesium is found in the bones. Poor magnesium intake can therefore deplete bone magnesium and the magnesium content of cells around the body. Magnesium deficiency can also affect hormone secretion from the parathyroid glands and directly interfere with calcium and phosphate metabolism.
Zinc is also necessary for bone formation. As an enzyme co-factor, zinc is required for bone mineralisation and the development of bone structure. Systemic zinc deficiency reduces the concentration of zinc in bone.
Vitamin K dependent proteins are also involved in the regulation of bone turnover and calcification as well as inhibition of calcification in blood vessels. Sub- optimal vitamin K reserves in bone also lead to reduced bone mineral density.
In summary, measuring serum and bone ALP and TRAP (tartrate-resistant acid phosphatase) can give an idea of the rate of bone loss. Measuring and correcting deficiencies in plasma calcium, inorganic phosphorus, copper, manganese, zinc, vitamin D, vitamin K or red cell magnesium is beneficial in the prevention of osteoporosis.