Osteoporosis: The Missing Zinc

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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.