Zinc can do more to prevent brittle bones than any other nutrient. Collagen tissue is necessary for the deposition of calcium phosphate to form bone. That is, collagen tissue provides the infrastructure for the bone to be formed. It is into this structure that calcium is deposited to form the bone. The presence of collagen is essential for bone strength and density. Without it all the calcium in your diet has nowhere to go and zinc is an essential part of collagen formation.
Collagen holds it all together
Calcium With D
Collagen is the most widespread tissue in the body. It forms the background of all your tissues of all your organs, making them firm and resilient. When the skin starts to wrinkle and loose elasticity you can be sure that your collagen cells are not as active as they used to be.
Each strand of collagen is made up of amino acids and it takes many of these amino acids to make up one strand. The strength of collagen tissue is increased as some of the molecules are strengthened by a biochemical process initiated by vitamin C. This process helps to stabilize the whole collagen structure. If the process does not occur the bones soften. Three single strands of collagen are, initially, twisted around one another, forming a triplet. Three of these triplets are then twisted around each other forming a super cable. Each strand is also bonded to adjacent strands by cross-linking. It is into this collagen structure that calcium phosphate is deposited to form your bones. Bone therefore consists of collagen (an organic protein - live material) and calcium phosphate (an inorganic material).
Collagen ages slowly to be replaced by new collagen tissue. To ensure that this process continues it is important to see that your intake of protein and nutrients are adequate. One of the important nutrients is zinc.
Zinc a critical nutrient
Adequate levels of zinc are necessary to form collagen tissue, unite bone fractures, heal wounds and prevent osteoporosis. For the formation of collagen tissue zinc is essential, other nutrients are also necessary, but zinc is the most important.
It is recommended that you have 12 to 15 mg of zinc a day and that this level be increased during pregnancy.
Food sources of zinc include: meat, chicken, beans, nuts and oysters.
Dietary phytates, which are found in wholegrain cereals and unleavened bread may significantly decrease the absorption of zinc. There is also the possibility that increasing your calcium level inappropriately can interfere with zinc absorption.
Zinc can be taken as a supplement and should be taken as a salt, such as, zinc sulphate, combined with vitamin C. Zinc is best absorbed after eating a protein meal - preferably not breakfast which could contain foods high in dietary phytates.
Zinc, pregnancy and the first stage of osteoporosis
Johns Hospital Medical School estimates that 85 percent of pregnant women throughout the developed world have an intake of zinc that is insufficient for the pregnancy. During pregnancy zinc requirements increase by 50% during the last 15 to 10 weeks. If the mother does not consume sufficient zinc, then zinc in her muscles and bones will be given to the fetus, thus starting the first stage of osteoporosis. (NOTE: the British Medical Association advises that zinc sulphate be avoided or used with caution during pregnancy as safety is not established and it crosses the placenta.)
Calcium and osteoporosis
The reason for the emphasis on the calcium content of bones to prevent osteoporosis, and for the neglect of zinc as the critical nutrient, is that when X-rayed, zinc and collagen are invisible. When osteoporotic bone is X-rayed and compared to normal bone, it appears transparent because you are unable to see the normal amounts of calcium. Medical Practitioners often recommend increased calcium consumption but then neglect to recommend a zinc supplement to help replace the collagen. Unfortunately, without the collagen and zinc the calcium has nowhere to go, which will see the development of the osteoporosis to continue.
Fractures and zinc
There are two stages to the healing of bone:
Initially, after the fracture, an extensive blood clot forms around the ends of the fractured bone. Collagen forming cells invade the blood clot producing a specialized form of collagen which wraps itself around the fracture. Slowly, the bone forming cells move into the collagen tissue, now called a callus. These cells lay down the calcium, giving the bone its strength again.
If the patient is given zinc supplements immediately after the fracture occurs, a large amount of collagen tissue is formed quickly, as the enzymes responsible for laying down the bone callus are activated by zinc. Zinc is not only responsible for rapidly increasing the amount of collagen tissue around the fracture, it is also responsible for activating the bone cells which deposit the calcium into the collagen tissue.
Exercise and zinc
It is paradoxical that physical exercise which is recommended for the prevention and treatment of osteoporosis can also increase it if the person exercising has insufficient nutrients - in particular zinc. People who exercise excessively lose a significant amount of zinc in sweat. The loss of zinc in sweat per hour can exceed by 50% the excretion of zinc in urine in 24 hours.
In America this condition is labelled 'brittle bones, but good body'. In women the condition is also accompanied by amenorrhea (cessation of menstruation) as a zinc deficiency can decrease ovarian activity.
Menopause
In the lead up to menopause the formation of collagen tends to slow down as the activity of the hormones decreases. Beyond menopause a zinc deficiency can be more pronounced with the accelerating loss of collagen and calcium. If the loss of collagen is due to the lack of zinc then calcium excretion can increase.
One of the effects of the reduced estrogen production is an increased excretion of hydroxyproline, an amino acid critical in stabilizing collagen structure. Calcium will do nothing to prevent this occurring. It is therefore important to guard against the rundown of your collagen tissue at menopause. This is achieved by maintaining an adequate intake of nutrients, including zinc.
Zinc is an important (and often underestimated) nutrient for the prevention of osteoporosis. Zinc is often deficient in the diet and in times of added need such as during pregnancy or menopause or when doing a lot of exercising the zinc levels in the body can run low.
References
Bland, J. 1996, Contemporary Nutrition. J & B Associates.
Davies, S. and A. Stewart., 1997, Nutritional Medicine. Pan.
Fitzherbert, J.C. 2002, Osteoporosis: The Missing Zinc. Wellbeing, Issue 87.
Holden, S., Hudson, K., Tilman, J. & D. Wolf, 2003, The Ultimate Guide to Health from Nature. Asrolog Publication.
Pressman, A. and S. Buff, 2000, The Complete Idiot's Guide to Vitamins and Minerals. (2nd Ed.) Alpha Books.
Soothill, R. 1996, The Choice Guide to Vitamins and Minerals. A Choice Book Publication.
Sullivan, K. 2002, Vitamins and Minerals: A Practical Approach to a Health Diet and Safe Supplementation. Harper Collins.