Logo by S. Popis
 
  OSTEOPOROSIS  

Osteoporosis: The Missing Zinc
By J.C. Fitzherbert

Standford University's, Professor Stryer in his world acclaimed text Biochemistry (published by W. H. Freeman and Co, 1995) states "Collagen tissue is essential for the deposition of calcium phosphate to form bone". Meaning, it is collagen tissue that provides the infrastructure of bone. It is onto this structure that calcium is deposited to form bone. It is presence of collagen which is critical for bone strength and density. Without it, all the calcium in your diet has nowhere to go.

Collagen - holding it all together
Collagen tissue is one of the most widespread tissue in your body. It forms the background tissue of all your organs, making them firm and resilient. It is easy to study the state of your own collagen tissue by looking at and feeling your skin. When skin starts to wrinkle and lose elasticity you can be sure that the cells which form your collagen tissue are not as active as they should be. Your hair will also lose its gloss. This is part of the aging process but if you don't take steps to prevent it, it can be permanent.

To make up for the loss of collagen under your skin, it is possible to have injections of collagen. However, it is not possible to inject collagen into your bones. Nor does injected collagen persist. It is only temporary. In your body, collagen turns over slowly. To hold back the aging process, it is necessary to reform and replace collagen as it is lost.

Collagen tissue has a very remarkable structure. After a surgical operation, fibroblasts, the specialised cells around the wound are activated to form collagen, to seal and close the wound. This collagen is so strong that a weight of 10 kilograms is need to break a fibre of collagen 1mm in diameter.

As the ligaments around joints are made up of thousands of strands of collagen, you can appreciate how powerful the force is that holds the joint together. Each strand of collagen is made up of protein structures called amino acids. The most abundant are named proline and glycine. It can take thousands of these amino acids protein structures to form one strand. The strength of collagen tissue is further increased as some of the proline molecules are strengthened by a biochemical process initiated by vitamin C. The proline molecules are changed to hydroxy proline which is very important as it helps to stabilise the whole collagen structure. If the change is not made, the bones soften resulting in the development of scurvy.

Three single strands of collagen are, initially, twisted in spiral fashion around one another, forming a triplet. Three of these triplets are then taken and twisted around each other to form a super cable. Each strand is also bonded to adjacent strands by cross-linking. The combination is called a collagen super-helix.

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 product).

Collagen ages slowly, to be replaced with new collagen tissue. To ensure this process continues it is important to ensure your intake of protein and micronutrients are adequate to reform and replaced the progressively aging collagen.

Zinc - the critical nutrient
It is not possible to heal wounds, unite fractures of bone, form collagen tissue or prevent osteoporosis from developing if your intake of zinc is below minimal requirements. For the formation of collagen tissue, an adequate intake of zinc is essential. Several other micronutrients are also essential but zinc is the most critical.

The recommended daily allowance of zinc is 12-15 mg, the level increasing during pregnancy. Meat and poultry provide the majority of zinc in the Western diet. Other food sources include beans, nuts, and oysters. Dietary phytates, which are found in whole grain cereals and unleavened bread, may significantly decrease the body's absorption of zinc. There is also a 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 simple salt, such as zinc sulphate, combined with vitamin C. Zinc is best absorbed after eating a meat meal, preferably not at breakfast which could contain food with a high fibre content.

Zinc deficiency can occur when zinc intake is inadequate, when there are increased losses of zinc from the body for example during intensive exercise, or when the body's requirement for zinc increases for example during pregnancy. Signs of zinc deficiency include poor appetite, weight loss, delayed healing of wounds, taste abnormalities, and mental lethargy. As body stores of zinc decline, these symptoms worsen and are accompanied by diarrhea, hair loss, recurrent infection, and a form of dermatitis. Zinc deficiency has also been linked to poor growth in childhood.

Pregnancy
A paper from the John Hopkins Medical School estimates that 85 per cent of pregnant women throughout the developed world have an intake of zinc which is insufficient for the pregancy. During pregancy, zinc requirements can increase by 50 per cent during the last 15-20 weeks. If there is not adequate zinc consumed by the mother, zinc from the mother's muscles and bones will be given to the foetus, thus starting the first stage of osteoporosis.

The reason for the emphasis on the calcium content of bones to prevent osteoporosis, and for the neglect of zinc as the critical micronutrient is because when bones are x-rayed, zinc and collagen are invisible. When osteoporotic bones are x-rayed and compared with normal bone, it appears transparent because you are unable to see the normal amounts of calcium. Doctors often recommend increased calcium consumption but neglect to recommend zinc supplementation or meat consumption to replace lost collagen. Unfortunately, without collagen and zinc the calcium has nowhere to go, which may cause the development of osteoporosis to continue.

Fractures
The formation of bone can be understood when studying the healing of a fracture. There are two stages in this process. Initially, after a fracture, an extensive blood clot forms around the ends of the fractured bone. Collagen forming-cells invade the blood clot producing a specialised form of collagen which wraps itself around the fracture site. Slowly, the bone-forming cells move into the collagen tissue, now called callus. These cells lay down calcium in the collagen-type tissue.

If the patient is given zinc supplements immediately after the fracture occurs, a large amount of collagen tissue is form very quickly as the enzymes responsible for laying down the bone callus are activated by zinc. Zinc is not only responsible for rapidly increasing the formation of collagen tissue around the fracture site, it is also responsible for activating the bone cells which deposit the calcium into the collagen tissue.

Exercise Warning
It is paradoxical that physical exercise, which is recommended for the prevention and treatment of osteoporosis, can also increase the development of the condition. People who exercise excessively can lose a significant amount of zinc in sweat. So much so that the loss of zinc in sweat per hour can exceed the excretion of zinc in urine in 24 hours by 50 per cent.

In America, they have colloquially labeled this condition "brittle bones, good body". In women this condition is also often accompanied by amenorrhoea (loss of menstruation) as zinc deficiency can retard ovarian activity.

The early association of physical exercise with osteoporosis becomes evident when the athlete develops stress fractures of bones in the vertebral body or foot.

Menopause
In the lead-up to menopause, the formation of collagen tends to slow down as the activity of the hormonal body reduces. Beyond menopause, zinc deficiency can be more pronounced with the accelerating loss of collagen and calcium. If the loss of collagen tissue is due to zinc deficiency, calcium excretion can increase. This can be further accentuated by the onset of menopause with the reduction of oestrogen production .

One of effects of reduced oestrogen production is an increased excretion of hydroxyproline. This amino acid is critical in stabilising collagen structure. Calcium will do nothing to prevent this event occuring. It is therefore important to guard against the rundown of your collagen tissue at menopause by maximising the production of collagen tissue as early as possible by maintaining an adequate intake of zinc.


| Up | Home | Feedback |
Designs and implementation by S. Popis. All Rights Reserved