New research has once again placed optimum vitamin Dintake at much higher than the current recommended amount.
The study of 138 subjects suggested a daily dose of 3800 IU for those with adequate blood vitamin D levels, and 5000 IU each day for those who are vitamin D deficient.
The current recommended intakes for vitamin D are as low as 200 IU daily for those aged 19-50, and go only as high as 600 IU daily for those over the age of 70.
Sources: American Journal of Clinical Nutrition June 2008; 87(6):1952-1958 (Free Full-Text Report)
Want to live longer? Make sure that you expose yourself to sunlight in moderation daily, for a new study has revealed that vitamin D, which is produced in the body in course of the exposure, cuts down mortality rates.
Previous studies have indicated that it might offer a variety of other health benefits, including protecting against cancer, peripheral artery disease and tuberculosis.
Now, a team at Graz University in Austria has found that the “sunshine vitamin” helps the body absorb calcium and facilitates growth of bones, which in turn do have a positive impact on death rates.
“This is the first association study that shows vitamin D affects mortality regardless of the (primary) reason for death,” the daily telegraph quoted lead researcher Harald Dobnig as saying.
Vitamin D is also found in milk and in fatty fish like salmon, but many people do not get enough of it. A lack of it can lead to rickets in children and osteoporosis in adults.
The list of benefits conferred by Vitamin D has just got longer. It also keeps the heart fit as a fiddle, besides developing strong bones, healthy immune system and protection against cancer, according to new research.
In studies on rats, Robert U Simpson and his team at the University of Michigan have reported the first concrete evidence that treatment with activated vitamin D can protect against heart failure.
Treatment with activated vitamin D prevented heart muscle cells from growing bigger – called hypertrophy – in which the heart becomes enlarged and overworked, sometimes leading to heart failure.
They also prevented heart muscle cells from the over-stimulation and increased contractions associated with the progression of heart failure.
Heart failure is a progressive, disabling condition in which the heart becomes enlarged as it is forced to work harder and harder, even for routine daily activities.
Many heart patients or those with poorly controlled high blood pressure go on to experience a form of heart failure called congestive heart failure, in which the heart’s inability to pump blood around the body causes weakness and fluid build-up in lungs and limbs.
Many people with heart failure, who tend to be older, have been found to be deficient in vitamin D.
“Heart failure will progress despite the best medications,” said Simpson. “We think vitamin D retards that progression and protects the heart.”
Simpson and colleagues have explored vitamin D’s effects on heart muscle and the cardiovascular system for more than 20 years.
Way back in 1987, when Simpson showed the link between vitamin D and heart health, the idea seemed far-fetched and research funding was scarce. Now, a number of studies worldwide attest to the vitamin D-heart health link.
The findings of the study are being published in the forthcoming issue of the Journal of Cardiovascular Pharmacology.
US researchers have discovered that Vitamin D protects not just against rickets, osteomalacia and osteoporosis but also against heart diseases, cancer, diabetes and other ailments.
CLICK & SEE
Medical researchers are homing in on a new wonder drug that can significantly reduce the risk of heart disease, cancer, diabetes and many other diseases — sunshine.
A recent study found that men who are deficient in the “sunshine vitamin”, vitamin D, have more than double the normal risk of suffering a heart attack. Another study last week found that low levels of vitamin D increase the risk of diabetes, and a study last month linked deficiencies to an increased risk of dying from breast cancer.
The new findings join a growing body of evidence indicating that an adequate level of the vitamin, which most people can get from 20 daily minutes in the sun, is crucial to maintaining good health.
Not every scientist agrees, and there is controversy about what should be considered an adequate level of vitamin D in the blood. But sentiment gradually is shifting toward a higher intake.
“We don’t have a cause-and-effect relationship here yet,” said biochemist Hector DeLuca of the University of Wisconsin, in the US, to prove that higher doses of vitamin D prevent these diseases. DeLuca was the first to demonstrate how the vitamin interacts with the endocrine system, which manages the body’s hormonal balance.
But the links are so suggestive “that we have to pay attention to keeping blood levels up where they will protect,” he said. Until the protective effect is proved, he added, “what’s wrong with keeping an adequate level of vitamin D in the blood in case it is?”
Until recently, vitamin D was viewed primarily as a protective agent against diseases of the bone, such as rickets, osteomalacia and osteoporosis. Recommendations for the vitamin are based on preventing these disorders and call for a relatively small intake — a minimum of 400 international units (IUs) per day and perhaps twice that for elderly people, who don’t get outdoors much.
The vitamin is produced from natural precursors in the body by exposing skin to ultraviolet B in sunlight. Caucasian sunbathers can get 20,000 IUs in 20 minutes at noon in summer. But any additional exposure simply damages the skin.
Darker skinned people need three to five times the exposure to produce the same amount. Sunblock interferes with production by screening out ultraviolet light.
The primary sources of vitamin D in the diet are milk, which is fortified to yield about 100 IUs per glass, and oily fishes, which have a high content. To have an adequate intake, most people must take supplements or spend more time in the sun — a recommendation that dermatologists generally oppose because of the risk of skin cancer.
Current guidelines call for blood levels of about 30 nanograms per millilitre. By that definition, perhaps 10 per cent to 15 per cent of the white US population and 50 per cent of the black population is deficient in summer, with levels rising in winter when there is less sunlight.
Many researchers now say we should be striving for average blood levels of 50 to 60 nanograms per millilitre, at which level the bulk of the US population would be considered deficient.
Most researchers in the field take supplements of at least 1,500 IUs per day. Most recommend taking no more than 4,000 IUs because of potential toxicity.
Experts attribute the vitamin D deficiency, in part, to modern lifestyles. Video games and computers have brought children indoors, minimising their exposure to sunlight. Fear of cancer and increasing use of sunblock also might have contributed.
In the new analysis, Dr Edward Giovannucci of the Harvard School of Public Health and his colleagues studied 18,225 men enrolled in the Health Professionals Follow-Up study, a subgroup of a much larger ongoing study. The men submitted blood samples when they enrolled in the study, mostly in 1993 to 1995, and the samples were stored.
In 10 years of follow up, the team identified 454 men who had a nonfatal or fatal heart attack. They matched these men with about 900 other study members who did not have an attack, then measured vitamin D levels at study entry.
They reported in the current issue of the Archives of Internal Medicine that men with blood levels below 15 nanograms per millilitre had two and a half times the risk of having an attack or dying. When they controlled for all other possible factors, such as hypertension, obesity and high lipid levels, the risk was still twice as high as it was for the controls.
Men with levels between 15 and 29 nanograms per millilitre also had an increased risk. Unfortunately, Giovannucci said, there were not enough men in the group with levels above 35 nanograms per millilitre to determine whether higher levels are more protective.
The findings are “not out of left field”, he said. Many epidemiological studies have found a lower rate of heart attacks at higher latitudes, at lower altitudes and in winter — all of which correlates to decreased exposure to sunshine.
“They certainly have made the link between diabetes and cardiovascular disease,” said Dr Mason Weiss, a cardiologist at Centinela Hospital Medical Centre in Inglewood, California, who was not involved in the study. “Now the research must be on what the mechanism is.”
Giovannucci speculated that several mechanisms could be responsible for the observation. Previous studies have suggested that low vitamin D levels lead to a build-up of calcium in atherosclerotic plaques on the walls of arteries, increasing the risk of heart attacks.
It also could affect blood pressure or the functioning of heart muscles, making them more susceptible to arrhythmia.
“We obviously need to understand the mechanism better,” Giovannucci said. “But that requires randomised trials, which is a big undertaking.”
Weiss joined the chorus of researchers calling for changes in federal guidelines to reflect the new data.
“The next time they review the daily requirements, they should look at all these articles,” he said. Increasing the recommended intake of vitamin D “could have a significant health benefit,” he said, and would be a very cost-effective change.
Pregnant or breastfeeding women have been urged to boost their vitamin D intake amid warnings that cases of rickets in children are increasing.
………….Most pregnant women should take vitamin D, say experts
Rickets is a bone disease mainly caused by a lack of the vitamin. It can lead to deformities, stunted growth and general ill-health.
Some minority ethnic groups in the UK, including Asians, are particularly at risk, says the Department of Health.
Doctors want pregnant women to take more vitamin D during winter months.
It is made by the skin in response to sunlight, but can also be found in certain foods.
Officials are urging women to check if they are eligible for free supplements from their GP or health visitor under the government’s Healthy Start scheme.
It provides vitamin D-rich milk and fresh fruit and vegetables as well as supplements for those on benefits or women who are under the age of 18 years old and pregnant.
Ultraviolet light
Common at the start of the last century, rickets was thought to be eradicated in the 1950s because of better nutrition.
But research suggests the incidence of rickets could be as high as one in 100 children among Asian, Afro-Caribbean and Middle Eastern ethnic minority groups.
Dark-skinned people do not absorb as much sunlight through the skin and may also wear clothing that limits exposure to the sun for cultural reasons.
Most people in the UK should get enough vitamin D from sunlight – it only takes 15 minutes of sun exposure to the arms, head and shoulders each day during the summer months to make enough vitamin D for good health.
But in winter months at latitudes of 52 degrees north (above Birmingham), there is no ultraviolet light of the appropriate wavelength for the body to make vitamin D in the skin, research shows.
There have been several reports of a “resurgence” of rickets in recent years.
In June 2007, doctors in Dundee said they had seen several cases and warned that guidelines on vitamin D for pregnant women were being ignored.
Free supplements
Health Minister Dawn Primarolo said the Healthy Start scheme was designed to improve the health of the most vulnerable families.
“We encourage people who are eligible to take advantage of the free vitamins, to minimise the risk of developing vitamin D deficiency and other conditions.
“We particularly encourage women who are pregnant or breastfeeding to take vitamin D, to protect the health and wellbeing of their baby and help them get the best possible start in life.”
She added that children under the age of four may also benefit from a supplement containing 10 micrograms of vitamin D.
Dr Colin Michie, a paediatrician at Ealing Hospital, says the biggest problem is maternal shortage of vitamin D.
“Mothers and babies are simply not getting enough of this important vitamin.
“If a pregnant or breastfeeding woman is lacking in vitamin D, the baby will also have low vitamin D and calcium levels which can lead babies to develop seizures in the first months of life.”
