THE "CALCIUM" DILEMMA-BONE VS HEART

Women and old people after the age of 60 years are prime candidates for Calcium supplements as they are considered vulnerable to bone related problems that include thin bones, brittle bones, frequent fractures, misshaped bones, osteomalacia and osteoporosis. Normally these supplements are supposed to deliver 500-800 mg Calcium per day. As Calcium is involved in formation and growth of bones, routinely these supplements are prescribed by orthopedists to many people and excess intake is not considered harmful hitherto. While high intake of Calcium is not known to be toxic, what other adverse effect it can have is a matter of conjecture with different reports indicating divergent views. Though a daily intake of 700 mg of Calcium is recommended for sound bone health, most of this requirement comes from every day foods like milk, cheese, yogurt, greens, leafy vegetables and fish with edible bones like sardines. It is believed that many older people do not get enough of this mineral increasing the risk of osteoporosis leading to thin and weak bones which can break easily, Same is true with women also at even younger ages due to hormonal changes during menopause. It is acknowledged that intake of Calcium supplements does increase bone strength but what is doubtful is whether it will really prevent fracture.

According to a recent review of some of the best scientific papers on Calcium in New Zealand, excess intake of this mineral can have other unintended consequences which calls for a re-look at the way Calcium supplements are prescribed in a routine way without realizing the long term consequences. Supplying Calcium over and above the intake through the food route can increase the risk of heart attack and strokes as increased levels of Calcium can affect the heart functions adversely, at least in some people. A study of 12000 people taking Calcium supplements, more than 500 mg per day regularly, has indicated that they faced a 30% increased chance of a heart attack during the period they took the supplement. Treatment of 1000 people with calcium supplements for a period of 5 years is estimated to cause 14 heart attacks, 10 strokes and 13 deaths but can prevent 26 fractures. also alarming is the finding that vulnerability to heart attack increased with higher dosage of Calcium supplement.Though the conclusion of the study is indeed alarming, a more careful analysis of the data indicates that out of the 12000 participants on Calcium supplement only 166 had heart attacks while 130 under the control and how significant this can be is uncertain. But qualitatively it does show the relevance or otherwise, of Calcium supplements in general, especially amongst those with even mild heart disease. As these studies were based on double-blinded controlled trials, there is no doubt about their reliability. Deciding on the risk-benefit aspects of Calcium supplements is indeed a tricky task. While bone fractures are not generally fatal, heart attacks can be and hence the dilemma for the health authorities in taking any decision.

One of the variables that has not been taken into consideration is about the complimentary effect of Vitamin D on the effect of Calcium intake as both of them are prescribed in most of the case because of the involvement of the former in bone development. Calciferol ( Vitamin D) is a critical vitamin formed under the skin from precursors already present in the body through exposure to Ultra Violet rays in the wave length range 270-300 nm and its bio-active form Calcitriol is known to reduce inflammation. Now that a shadow of doubt has been cast on the safety of Calcium supplements, it is necessary that these findings are validated through more thorough scientific studies to arrive at a reliable conclusion.

V.H.POTTY
http://vhpotty.blogspot.com/
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'SUNNY' BABIES-REACHING FOR THE MOON!

Sun rays are always shunned, especially in western countries due to their potential to cause skin cancer by too much exposure. Sun is also avoided in tropical countries especially during summer to avoid sun-strokes and consequent fatality. But limited exposure to sun is necessary if humans have to make vitamin D in their body from the precursor 7-dedydrocholesterol present under the skin. Whether it is due to sun rays alone or because of its role in making vitamin D, the amazing finding that pregnant women tend to deliver taller babies during summer compared to those born during winter, is some thing to be examined for confirmation through scientific studies. But the very fact that they found summer born babies, half centimeter taller with wider bodies, is worth probing further. The role of sun light in the formation of Vitamin D3 is well known, the Ultraviolet B rays responsible for the conversion. Vitamin D3 has many functions like promoting bone formation, strengthening of the skeleton, strengthening immune system by promoting phagocytes, helping kidneys re-absorb nutrients, anti-tumor activity etc.

In a cohort study lasting 18 years in UK involving 14000 women and 7000 children of age less than 10 years, a definitive conclusion was drawn regarding the advantages of a few minutes exposure to sun in delivering babies with longer and wider bones. The height growth rate was 2-2.5 times higher in children of mothers who had exposure to sun in the 3rd trimester during the months of March to May, than others who did not had this advantage. In some other studies in countries in Africa and South America, it was consistently found that 65-75% of children born during dry seasons with bright sunlight available in plenty had maximum growth spurt compared to those born during rainy seasons.

The linkage between sunlight and Vitamin D3 formation being undisputed, it is thought that the seasonal variations in the availability of the required UV rays from the sun and the consequence fluctuations in D3 formation, could explain the phenomenon of increased growth during sunny season. Vitamin D3 has critical role in remodeling of skeleton and mineralization of bone tissues. The endocrine system and the hormones involved in growth regulation are influenced by the D3 concentration in the blood. This is confirmed by the findings that use of sun lamps during winter enabled children to gain heights as much as 1.5 cm. Such children had extra 5 inches of bone, because of increased periosteal growth, compared to their counterparts with insignificant exposure to light. Children from 6 months to 4 years can benefit maximum by extra supplementation with Vitamin D3. But such supplementation may be necessary only if adequate exposure to sun cannot be achieved, especially in areas where sunshine is limited.

What is intriguing in all these studies is whether sunshine has really an important role to play in height growth because of the complex metabolic regulatory matrix that works in humans governing the longitudinal and periosteal bone development. If such is the case most of the children born in tropical countries should be taller than those in temperate and cold climates which in reality does not happen. When USA was the most predominant economic power till a few years ago, their population were taller significantly compared to those in Europe. To day newer generation in Netherlands, Norway, Japan and other modern industrial nations boasts of men, a good 1"-2" taller than an average American. Obviously affluence, healthy foods, good physical work out and other favorable developments in the living environment have brought about this significant change. Many factors like gene inheritance, food consumption and others may have more critical influence on height growth than sunlight alone. But Vitamin D3 definitely plays an important role in bone mass development which is reflected more by the thickness or width of the bones.

V.H.POTTY
http://vhpotty.blogspot.com/