Vitamin D had been gaining a reputation as a ”wonder supplement.” Studies have suggested it can help bone and heart health, ease mild depression, and lower the risk of cancer. Others have suggested it might help people with fibromyalgia, multiple sclerosis, and other chronic diseases.
Now comes a different finding. Researchers who looked at dozens of studies say that vitamin D supplements do not lower the risks of heart attacks, strokes, cancer, or fractures by more than 15% in generally healthy people. This was true whether or not the supplements included calcium.
Bottom line: For most healthy adults, vitamin D supplements are not worth it, the researchers say in The Lancet Diabetes & Endocrinology.
Not everyone agrees, and the debate is far from done. Here, two experts address the most common questions about vitamin D supplements.
Are vitamin D supplements losing their luster?
“I believe so,” says Doug Campos-Outcalt, MD, of the University of Arizona College of Medicine, Phoenix. He recently wrote a review of vitamin D for The Journal of Family Practice.
Evidence shows that vitamin D helps bone health, he says. But early studies that show vitamin D may help in other areas, such as heart health and cancer prevention, are not convincing.
“Information on the health benefits of vitamin D is difficult to sort out,” he writes in the review. He cites a report from the Institute of Medicine, an independent organization that provides health advice. The institute looked at studies of vitamin D to protect against cancer, heart disease, diabetes, and autoimmune diseases such as lupus. Except for bone health, it found no evidence that vitamin D helped with any other diseases.
Robert R. Recker, MD, director of osteoporosis research at Creighton University School of Medicine in Nebraska, disagrees. He cites research finding vitamin D lowers the risks of colon, breast, and other cancers, and improves how the immune system works.
On the other hand, other experts say low vitamin D levels may be a result of illness, not the cause.
What do we know for sure about vitamin D?
What it does: Experts agree on the basics. Vitamin D helps the body absorb calcium, and that is good for bone health. Vitamin D also helps reduce inflammation in our cells. Inflammation can trigger disease.
What are the main areas of disagreement about Vitamin D?
How much is needed: At the center of the debate is how much vitamin D is enough. “We need more vitamin D than what we are getting [from diet and sun exposure],” Recker says. “What is not agreed upon is how much more.”
The Institute of Medicine recommends that most Americans need no more than 600 international units (IU) of vitamin D a day. People 71 and older may need 800 IU, it says. This level is enough for bone health, it says.
Vitamin D is found in some foods, including fatty fish like salmon and tuna, beef liver, fortified dairy products, cheese, and egg yolks. Except for those, getting enough vitamin D from your diet isn’t easy. As examples, a 3-ounce serving of salmon provides 447 IU, and 3 ounces of tuna fish offer 154 IU.
Meanwhile, our skin makes vitamin D when exposed to natural sunlight. This helps vitamin D levels in our blood. But Recker says only people who live at the equator get a large amount of D from sunlight.
Testing: Experts disagree on whether healthy people need routine testing to detect low vitamin D blood levels.
How much is enough: Experts also disagree on how much vitamin D we need in our blood to be healthy.
Which groups of people might benefit more from higher levels of D?
Older adults who are frail, Campos-Outcalt says. Getting 800 IU a day may help them prevent falls and fractures.
Recker says older people who are healthy can also benefit from the higher levels, ”because the skin loses the ability to make vitamin D” as people age. Some older people also stay indoors more as they age, he says.
Other people may also need to pay close attention to vitamin D in their foods. Among them are people on corticosteroids and other medications that can affect bone health, Recker says.
What are the potential harms of excess vitamin D supplements?
Very high doses of vitamin D can cause extremely high levels of calcium in your blood, which can lead to heart rhythm problems, kidney stones and damage, and severe muscle weakness. This calcium excess usually happens if you take 40,000 IU per day for a couple of months or longer, or take a very large one-time dose.
A new study has revealed that exposing skin to sunlight may help to reduce blood pressure and thus cut the risk of heart attack and stroke.
Research carried out at the Universities of Southampton and Edinburgh showed that sunlight alters levels of the small messenger molecule, nitric oxide (NO) in the skin and blood, reducing blood pressure.
Martin Feelisch, Professor of Experimental Medicine and Integrative Biology at the University of Southampton, said: “NO along with its breakdown products, known to be abundant in skin, is involved in the regulation of blood pressure. When exposed to sunlight, small amounts of NO are transferred from the skin to the circulation, lowering blood vessel tone; as blood pressure drops, so does the risk of heart attack and stroke.
While limiting sunlight exposure is important to prevent skin cancer, the authors of the study, including Dr Richard Weller of the University of Edinburgh, suggested that minimising exposure may be disadvantageous by increasing the risk of prevalent conditions related to cardiovascular disease.
The results suggested that UVA exposure dilates blood vessels, significantly lowers blood pressure, and alters NO metabolite levels in the circulation, without changing vitamin D levels.
Further experiments indicated that pre-formed stores of NO in the upper skin layers are involved in mediating these effects.
The study was published in the Journal of Investigative Dermatology.
MUMBAI: Runny noses and stomach flu aren’t the only ills associated with overcast skies. The absence of sunlight hits production of Vitamin D in the body, adversely affecting blood pressure. A recent study in London by an Indian-born researcher has proved beyond doubt that the lower the vitamin level, the higher the BP.
Vitamin D is synthesized when the sun’s ultraviolet rays fall on the skin. But the high melanin pigment in the Indian skin deters it. So, even a hot and sunny India has high levels of deficiency. Some studies say every second Indian is affected, others peg it higher at eight out of every 10 Indians. The deficiency is worrying as it’s linked to a range of diseases — from bone problems to cancer.
Researcher Vimal Karani’s work from University College London only conclusively proves that low Vitamin D levels can send blood pressure soaring. Karani looked at 35 studies, covering 1.5 lakh people across Europe and North America, and found people with high concentrations of 25-hydroxyvitamin D (25(OH)D) had lower blood pressure and, therefore, a reduced risk of hypertension. A prehormone, 25-hydroxyvitamin D or calcidiol, is produced in the liver when Vitamin D3 is synthesized (a blood test to determine its levels is also an indicator of Vit D levels).
The study found that for every 10% increase in 25(OH)D concentrations, the risk of developing hypertension decreased by 8.1%.
In India, where every fifth grown-up has hypertension, the study has severe implications. Dr Siddharth N Shah, editor-in-chief of JAPI (Journal of the Association of the Physicians of India), said, “The association of lower levels of Vitamin D and high blood pressure can, in part, be associated with increasing number of hypertensives in India.” Delhi-based endocrinologist Dr Anoop Misra, though, pointed out that hypertension has a strong hereditary component. “We know that salt, smoking, obesity and heredity are the causes for hypertension. We can at best consider Vitamin D deficiency as a fifth contributor,” he said.
The theories about Vitamin D deficiency and its various implications have gained importance in the past decade. One reason could be easy availability of diagnostic tests. “When we started offering the test about 15 years back, we would get 5 to 10 cases a month,” said Dr Vipla Puri from Hinduja Hospital, Mahim. Now her laboratory performs 1,500 tests a month.
Why the sudden focus on Vitamin D? Endocrinologist Dr Shashank Joshi from Lilavati Hospital, who has done several studies on both hypertension and Vitamin D deficiency, said, “There are over 200 Vitamin D receptors in the body. Previously, we thought that Vitamin D only affected skeletal aspects of the body.” It is only now that the world is learning that it is connected to the body’s entire metabolism. “Vitamin D has a link with metabolism of glucose, maintenance of blood pressure as well as acceleration of heart diseases,” Joshi said.
Vitamin D levels dictate outcomes of ICUs as well. A study done by Dr HemantThacker in Jaslok Hospital, Peddar Road, showed that patients with lower levels of Vitamin D were more susceptible to infections than patients who had better levels.
Dr Thacker blames the smog-filled environment in cities for poor Vitamin D levels. “It is true we don’t get adequate exposure to sunlight because we travel in cars and buses and don’t come out even during weekends. Children these days watch TV instead of playing football in the grounds, but Vitamin D deficiency isn’t only about paucity of sunlight.” The quality of sunlight plays an important role too.
“A part of the ultraviolet radiation that is needed by the body to make Vitamin D, is filtered out by the smog. This is a leading cause for deficiency,” Dr Thacker said.
Experts say a way of tackling this widespread deficiency would be to chart out a public health policy. “The government should look at solutions like fortifying milk with vitamin D as is done in the US and Europe,” said Dr Joshi.
Indian bones are conventionally weaker, deformed and more osteoporosis-prone compared to Americans or Britons, say leading knee replacement surgeons who participated in a knowledge-sharing exercise here on replacement surgeries.
The exercise also threw up insights about how Africa could also emerge as a major resource pool for tapping patients in India’s quest for medical tourism.
Speaking to us on the sidelines of the event, Erik Zeegan, a leading Las Vegas-based orthopaedic surgeon, said that knee replacement surgeries in India tended to be a lot different from those in the US owing to the more deformities of the bones found in the sub-continent.
“The deformities here are significant. The knees are more worn out. We do not see such deformities in the US,” Zeegan said, adding that knee sizes of patients in the US also tended to be larger than those found here.
One of the reasons for this, according to Ameya Velingker, a Goa-based specialist, is that Indian patients tend to take their osteo-arthritic knees to the very terminal stages before choosing the surgical option to overcome a bad knee situation.
One of the reasons why over 700,000 knee replacement surgeries are conducted in the US every year as compared to 70,000 in India, is because the procedure is considered a natural extension of knee treatment there, Velingkar said.
“In India, a lot of people still give it a lot of thought because of a few failed cases of knee replacement surgeries which have happened because of bad medical advice,” Velingker said, adding that there were instances in the past when knee replacement surgery was relatively new and doctors in some cases recommended the surgery even when it was not required.
He further said that a distinct lack of a physical regimen in India had largely contributed to the “bad bones” phenomenon here.
“Indian bones are of poor quality, plus lack of exercise further deteriorates their growth in most cases in India,” Velingker said, adding that the more the exercise the better the quality of bones.
Obsession with fitness in Western countries has resulted in better quality and denser bones there, he said.
“Most people hit the gym or go running in the West which ensures that they have much better bones than most of us,” he said.
Giving a practical example, Velingkar said that while one surgical saw blade suffices for three to four knee replacement surgeries for Indian patients, the scenario was much different when it comes to operating upon patients from Britain.
“For UK patients I need to use one new saw every time,” he said.
Velingker said that Europe and North America apart, Africa was emerging as a great potential market to tap patients for knee replacement surgeries.
“There is a lot of potential to get patients from countries like Nigeria and Kenya. The medical facilities available there are poor and the governments in these countries facilitate treatment abroad,” he said, adding that a bilateral approach with these African nations could help India’s medical tourism.
He also pointed out that knee replacement surgery in India cost around Rs.2 lakh ($3,400) as compared to the Rs.9-10 lakh which is required for a similar surgery in the US.
Many people drink green tea because of the purported health benefits. Some studies have suggested the antioxidants in the beverage could play a role in lowering cholesterol, preventing diabetes, and even mitigating the effects of dementia.
But a new report from the independent lab ConsumerLab.com shows not all green teas are created equal, says The New York Times Well blog. Bottled varieties of green tea can contain more sugar than antioxidants, and while actual green tea leaves can contain a large amount of antioxidants, they can also contain lead and other environmental contaminants.
ConsumerLabs.com tested a variety of bottled green tea drinks as well as green tea brewed from leaves. The loose-leaf tea contained the highest levels of antioxidants like epigallocatechin gallate (ECGC), which has been tentatively connected to health benefits like weight loss and cancer prevention, the Times says. But some bottled teas like Snapple’s Diet Green Tea contained almost no ECGC at all. One bottled brand, Honest Tea, contained only about 60 percent of the advertised 190 milligrams of antioxidants, and had almost the same amount of caffeine as a cup of coffee and half the amount of sugar in a can of soda, the Times adds.
The report also found that, although the teas brewed from loose leaves have a higher concentration of ECGC and other antioxidants, some of them also contain lead. Finding lead in a plant is not surprising, as plants absorb any elements in the ground around them. But green tea plants are “known to absorb lead at a higher rate than other plants from the environment, and lead also can build up on the surface of the leaves,” ConsumerLabs.com president Tod Cooperman told the Times.
It’s likely the tea leaves that tested positive for lead came from China, which is known to have a problem with industrial pollution, Cooperman added. Tea brands that source their leaves from Japan had less of a lead problem, the Times says. Decaffeination also removes lead from leaves, so decaffeinated green tea leaf blends are likely to have less lead in them.
Fortunately, the lead tends to stay in the leaves throughout the brewing process, the Times says, so the health concerns are minimal. Tea bags tend to filter out the lead, keeping it with the leaf instead of letting it leech into the hot water. “So it’s fine as long as you’re not eating the leaves,” Cooperman told the Times.
Vitamin D ‘helps beat symptoms of asthma’: Supplements could soon be used as treatment alongside other drugs
Vitamin D has the potential to significantly cut the symptoms of sufferers.
Scientists at King’s College London made the discovery.
The ‘sunshine’ vitamin resulted in lower levels of a natural chemical in the body that aggravates symptoms in asthma patients
Vitamin D could help asthma patients breathe more easily, claim British researchers.
Scientists at King’s College London have discovered vitamin D has the potential to significantly cut the symptoms of sufferers. They say it may one day be prescribed as a treatment alongside conventional steroids, but reducing the need for medication. A new study found the ‘sunshine’ vitamin resulted in lower levels of a natural chemical in the body that aggravates symptoms in asthma patients and cuts the effectiveness of steroids. More than five million Britons suffer asthma, including 1.4 million children, and the disease causes 1,400 deaths each year. Asthma is an inflammatory disease of the airways, causing them to constrict and resulting in attacks of breathlessness and wheezing which can be fatal.
Severe asthma is currently treated with steroid tablets which can have harmful side effects. Many sufferers have a steroid resistant variation of the condition making it even more difficult to treat and putting them at greater risk of hospitalisation from severe, even life-threatening, asthma attacks. In a study funded by Asthma UK charity, a team of scientists at King’s identified a mechanism through which Vitamin D can reduce asthma symptoms, providing a potential target for future treatments. IL -17A is a natural chemical which helps to defend the body against infection, but is known to exacerbate asthma and reduce responsiveness to steroids when produced in larger amounts.
The team examined the production of IL-17A and levels of the chemical in cells from 18 steroid resistant asthma patients and 10 patients who responded to steroids, as well as a control group of 10 healthy people. Results showed that patients with asthma had much higher levels of IL-17A than those without asthma and patients with steroid resistant asthma expressed the highest levels of IL-17A. Further tests showed that while steroids were unable to lower the production of IL-17A in cells from patients with asthma, vitamin D significantly cut the production of IL-17A in cells from all patients studied. The results demonstrate that vitamin D could potentially provide an effective add-on treatment for all asthma sufferers, reducing the amount of steroid-based medicines prescribed. There is growing evidence that vitamin D deficiency may be responsible for triggering a range of diseases, including several cancers. The body makes most of its vitamin D from sunlight, although oily fish is a good dietary source. Professor Catherine Hawrylowicz from the Medical Research Council & Asthma UK Centre in Allergic Mechanisms of Asthma at King’s, who led the study, said the findings were ‘very exciting’.
She said ‘They show that Vitamin D could one day be used not only to treat people with steroid resistant asthma but also to reduce the doses of steroids in other asthma patients, reducing the risk of harmful side effects. ‘The results are so positive that we are testing this in a clinical trial in steroid resistant asthma patients to further research the possibilities of vitamin D as a potential treatment.’ The study is published in the Journal of Allergy and Clinical Immunology. Malayka Rahman, Research Analysis and Communications Officer at Asthma UK, said: ‘For the majority of people with asthma, current available medicines are an effective way of managing the condition but we know that they don’t work for everyone, which is why research into new treatments is vital. ‘We also know that many people with asthma have concerns about the side effects of their medicines so if vitamin D is shown to reduce the amount of medicines required, this would have an enormous impact on people’s quality of life. We look forward to the results of the clinical trial.’
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