The Sunshine Vitamin

As research continues to shed new light, scientists are realizing that vitamin D has many critical functions in the body. It works more like a hormone rather than a vitamin and affects the performance of almost every cell of the body. 

1.      We all know that vitamin D is critical in maintaining adequate amounts of calcium and phosphorus in bones and teeth. In simple words it helps keep bones and teeth strong and protects against osteoporosis and dental caries. However we need vitamin D for many other roles. 

2.      It is important in the regulation of the immune system. It produces anti - bacterial and anti- viral substances and helps fight infections like common cold and influenza. 

3.      It helps to keep the brain functioning normally in later life and prevents mental illnesses like dementia, Alzheimer's disease, schizophrenia and depression. 

4.      Vitamin D helps maintain ideal body weight. Those with vitamin D deficiency are likely to be obese and fail at attempts to reduce body weight via diet and exercise. 

5.      It plays a role in preventing inflammatory disorders like Rheumatoid Arthritis (multiple joint pains), inflammatory bowel disease, psoriasis and eczema. 

6.      It reduces the frequency and severity of asthma and allows for speedy recovery from tuberculosis. 

7.      It reduces the risk of heart attacks and protects against high blood pressure and diabetes. 

8.      Vitamin D has recently been shown to be critical for a normal pregnancy. It prevents pregnancy related illnesses, reduces risk for premature deliveries and reduces infertility. 

9.      It reduces risk of all types of cancer. 

What are the daily requirements of this valuable vitamin? Most authorities recommend around 600 IU of vitamin D daily. Infants less than one year old need 400 IU and adults above 70 years of age need 800 IU.

Now that we realise the critical benefits of vitamin D, we must find out how to get it! Unfortunately getting vitamin D from diet alone is an uphill task. Few foodstuffs are a good source of vitamin D. Vitamin D rich foods include beef liver, egg yolk, certain types of cheese and certain types of fish. One egg gives approximately 40 IU of vitamin D. Unfortified milk (milk is fortified with vitamin D in America and European countries as a government initiative) is a poor source of vitamin D. 

Sunlight is an additional source of vitamin D. It is important as dietary sources of vitamin D are few. Ideally we should get 90% of our daily vitamin D requirement from sunlight. UV rays in sunlight convert a type of cholesterol found in the skin to vitamin D. Modern lifestyle has limited our exposure to the sun. There are many variables that affect the ability of the skin to produce vitamin D. As a result it is difficult to recommend how much sunlight is enough. Most authorities recommend between 5 to 30 minutes of sun exposure to your unprotected face, arms, legs or back between 11 am and 3 pm two to three times a week.  Early morning or late evening sunlight does not work as UV rays are not able to penetrate the atmosphere. Ability to produce vitamin D also depends on the colour of the skin. Fair skin people need less sunlight than darker ones in whom melanin (skin pigment) restricts entry to UV rays. Exposure to sunlight should be direct as UV rays are restricted by glass (window panes) and sunscreen. Weather conditions, cloud cover, pollution and clothing also affect vitamin D production in the skin. At the same time too much sun exposure is detrimental.

Certain groups of people are at higher risk for vitamin D deficiency. These include pregnant and breast feeding women, children between 6 months and 5 years, persons older than 65 and persons who keep their skin covered or stay indoors (don't get enough exposure to sunlight). At risk individuals need to discuss with their doctor and get vitamin D supplements. In America and some European countries, milk and fruit drinks are fortified with vitamin D.

Few sources of vitamin D in diet coupled with poor exposure to sunlight and lack of fortified foodstuffs (especially in India and Asia) makes huge sections of the population at risk for vitamin D deficiency. Everyone should get their blood levels of vitamin D tested. If deficient, appropriate changes must be made in lifestyle to increase exposure to sunlight. If that is not possible, vitamin D supplements are necessary.

Vitamin D deficiency is a modern and very real epidemic that has silently contributed to increase rates of osteoporotic fractures, heart attacks, influenza, rheumatoid arthritis, cancer and premature births! The general public needs to become aware of this hidden deficiency and take immediate corrective measures! 

Bone Mineral Density

 A common myth among patients is that all bone related or orthopaedic problems are related to a lack of calcium. Daily, I see patients who are taking calcium supplements on their own accord. People especially women feel that they need to take calcium beyond a certain age, or taking calcium will prevent orthopaedic problems in the future. Usually it is a friend or family member that has scared a person into taking calcium supplements. 

It is wrong to attribute all bone problems to calcium. Often the source of musculoskeletal pain is a joint! There are many joints in the body. Everyone is familiar with the large joints like the hip or knee and small joints like the ones found in the hand and foot. There are also lesser known joints like the facet joints found in the spine (neck and back). Inflammation of the joint is known as arthritis. Arthritis has little to do with the lack of calcium. Therefore taking calcium will not reduce joint pain! 

So if lack of calcium does not cause joint pain, then what does a lack of calcium do? A decrease in the calcium content of bones is typically called osteoporosis (different from osteo-arthritis) There are other disorders of calcium like osteomalacia and rickets but these are rare. Osteoporosis affects women after menopause. It is the lack of female hormones (estrogen and progesterone) that leads to osteoporosis. Osteoporosis also affects men but at a later age and less commonly. Osteoporosis is a silent disease. That means that it causes very few or no symptoms. Many patients of osteoporosis will not know that they are suffering from it! This is similar to medical illnesses like diabetes and hypertension (high BP). Time and again the first symptom of osteoporosis is a fracture of the hip or a vertebra (spine fracture). Rarely osteoporosis may cause bone or muscle pain or tenderness (pain on pressing the bone). 

If osteoporosis is a silent disease, how do doctors and patients diagnose it? Like diabetes early diagnosis of osteoporosis is critical as treatment can reduce fracture risk. Earlier it was difficult to diagnose osteoporosis. Doctors would get some idea of bone strength by looking at x-rays of the patient. However x-rays are a crude test as they show osteoporosis only in the advanced stages. By then it is too late! Measuring the blood calcium levels gives no indication of the strength of bones or the level of calcium in the bones. Nowadays technology has improved. A DEXA scan is currently the gold standard for measuring bone mineral density (BMD). DEXA scan checks the density in the lower back and hip which are the critical areas. DEXA scan is a computerised X-ray based test. Ultrasound of the wrist or heel can also be done. Ultrasound is popular as it is portable (used frequently in patient camps) and cheaper. But ultrasound is less accurate and the wrist and heel density may differ from the density in the back and hip. I do not recommend treatment decisions to be made on ultrasound based bone density results. Does everybody need to do a DEXA scan? The answer is NO! The World Health Organisation (WHO) recommends BMD testing in all postmenopausal women above 65 years of age. In post menopausal women less than 65 and premenopausal women, density testing is required only if they have certain medical risk factors (ask your doctor). There is no need for healthy premenopausal women to do a DEXA scan or other BMD testing. BMD testing is also not recommended for healthy men with no risk factors. 

To conclude, I advice my readers to be smart about calcium supplements. Taking unnecessary supplements in the hope of reducing pain is a waste of money. At the same time one should be alert about osteoporosis. Timely BMD testing by DEXA scan is the key. If osteoporosis is diagnosed by a DEXA scan, then treatment with supplements is imperative.
BMD measurements have today become essential for fracture prevention and osteoporosis treatment, but due care is needed in utilising this asset.

osteoporosis ..... beyond calcium.

The North American menopause society has published new guidelines for the management of post menopausal osteoporosis.

There is much more to management of osteoporosis than calcium and vitamin D. Osteoporosis is a major health problem and some working knowledge about it is essential.

Do you need to get tested for osteoporosis ? I have answered that question in my previous post.

First lets enumerate the non pharmacological methods

• A balanced diet with adequate calcium and vit D intake.

• Adequate exercise.

• Smoking cessation.

• Avoidance of excessive alcohol intake.

• Fall prevention.

Drug treatment of osteoporosis is recommended for all postmenopausal women

• who have had an osteoporotic vertebral fracture.

• who have bone mineral density values consistent with osteoporosis (ie, T-score worse than or equal to -2.5).

• who have a T-score from -2.0 to -2.5 plus at least one of the following risk factors for fracture: thinness, history of fragility fracture (other than skull, facial bone, ankle, finger, and toe) since menopause, and history of hip fracture in a parent.

The first line drugs for treating post menopausal osteoporosis are the bisphosphonates. These drugs act by decreasing osteoclast activity. Osteoclasts are the cells that absorb or remove bone. Thus these drugs decrease bone turnover and help maintain bone mass.

The effectiveness of these drugs to reduce fracture rates have been well documented.
They have been shown to increase BMD by 6%-8% at the spine and by 3%-6% at the hip over a three-year period. Both vertebral and nonvertebral fractures were reduced by approximately 50% over this period of treatment. The bisphosphonates commonly used are alendronate, etidronate and residronate.

The most important precaution is to take the drug on an empty stomach. This is because food interferes with its absorption. One should not eat anything for half an hour after taking the drug.

The second important precaution is to take the drug with a glass full of water. The drug is known to cause esophageal irritation so a glass of water is necessary to wash down the drug.

A good advantage is that many of these drugs can be taken only once or twice a week. Alendronate for instance can be taken once a week as a single tablet of 70mg.

One serious complication that has been reported is that of jaw necrosis. There was approximately a 7% incidence in cancer patients treated with bisphosphonates for 3 to 4 years. However the incidence in patients treated with osteoporosis is very low.

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Bone mineral density

Early diagnosis and treatment of osteoporosis can reduce fracture risk. RadiologyInfo has an excellent page on bone densitometry and DEXA scans for osteoporosis. A dexa scan is currently the gold standard for measuring bone mineral density (BMD). There is growing interest in quantitative ultrasound as an alternative, but it still needs to go a long way to prove itself. Other less widely used techniques are peripheral quantitative computed tomography, quantitative magnetic resonance (QMR) and magnetic resonance microscopy.

The WHO recommendations for who to test for BMD are
for women -

1. In postmenopausal women if there is x ray evidence of demineralisation, evidence of vertebral fracture/deformity or if steroid therapy for more than 3 months is contemplated.

2. In all postmenopausal women above 65 years of age.

3. In postmenopausal women below 65 years of age if they have risk factors like maternal history of fragility fractures, low body weight or medical conditions associated with bone loss like premature menopause, hyperparathyroidism, hyperthyroidism, chronic renal failure, chronic liver disease, malabsorption or use of anti convulsants.

4. In premenopausal women who have medical conditions associated with bone loss listed above.

5. In healthy premenopausal women, BMD testing is not indicated.

for men -

1. BMD testing is definitely indicated in the presence of vertebral deformity, fragility fracture, hypogonadism or chronic steroid therapy.

2. BMD is less definitely indicated in case of alcohol abuse, low weight, x ray evidence of demineralisation or medical conditions associated with bone loss listed above.

3. BMD testing is not recommended for healthy men with no risk factors.

BMD testing is not for everyone. Consider getting it done only if you fall in one of the above categories. Potential harms of DEXA are radiation and cost. Bone mineral density should be measured only to assist in making a clinical management choice.

Besides DEXA quality matters. BMD measurement is not a simple procedure & errors can lead to therapeutic decisions that can harm patients.

BMD measurements have today become essential for fracture prevention and osteoporosis treatment, but due care is needed in utilising this asset.