Calcium is the nutrient most commonly associated with bone health. This is true for the scientist and layman alike. ‘Drink your milk and you will have strong bones’ they say. Of course this is true to a certain extent as calcium is required for the formation of bone tissue. However, although physiologically calcium is required as a structural component of bone, the ability of dietary calcium to affect bone health is limited unless intake is severely deficient.
Calcium has been extensively researched with respect to osteoporosis. Osteoporosis is a bone disease that mainly affects postmenopausal women. Pores appear in the bone and this causes the bones to become brittle and weaken. This then increases the risk of fracture. Theory would suggest that if bone is made of calcium, that dietary calcium would strengthen bone. However, increasing the calcium in the diet is not effective at treating or preventing osteoporosis.
A New Paradigm
Recently the mainstream scientific establishment has shifted its understanding of osteoporosis. It is now believed that the disease forms not from a deficiency of calcium, or a lack of weight bearing exercise, although both these things are needed for healthy bones. Instead the acidification of blood is thought to be responsible for the gradual erosion of the structural strength in the bone, leading ultimately to osteoporosis following the menopause.
Acid Base Balance
Normally the blood is kept within a narrow window around a neutral pH. If too much acid is produced by the body, the associated hydrogen ions must be removed to bring the pH back into normal limits. To do this the body has a number of buffering systems that are present in blood which can mop up the hydrogen ions and thus maintain normal pH. One of these buffers is the minerals in bone including calcium, that can be released to the blood to soak up hydrogen ions.
Western Diet (Again)
So what causes the acidification of the blood that leads to calcium leaching from bone? Well diets high in animals fats such as the Western diet are thought to be a primary cause. When certain proteins are digested, they release amino acids that can form acidic by-products. If the protein component in the diet is too high, and it is not balanced by alkali forming foods, then the blood becomes acidic and chronic leaching of the minerals from bone can occur.
Plant Foods (Again)
Plant foods are able to protect from the acidification of the blood. This is because the potassium, calcium and magnesium in the plant foods are metabolised to alkaline salts which enter the blood and act to raise pH. This spares the need for minerals to be leached from bones to prevent acidification of the blood, and thus is protective of osteoporosis. Diets high in plant foods are therefore protective of the acidifying nature of high protein diets and are protective of osteoporosis.