The study, sponsored by the Public Health Agency of Canada, began in 2008. It originally focused on the role that the vitamin plays in severe seasonal influenza in general, but PHAC recently announced that the study will now be adapted to include the N1H1 or Swine flu virus.

The study will build on existing research that started in the 1940s, looking for an association between D vitamin levels and serious seasonal influenza. Decades of early studies and a growing body of epidemiological evidence indicate that low levels of the vitamin are definitely correlated with susceptibility to flu viruses.

PHEA said the current study will probably be continued through three flu seasons in order to collect sufficient sample data. Ultimately, the goal is to see if the vitamin can be used to mitigate severe seasonal influenza, the PHEA announcement said.

The N1H1 virus, which is a substrain of a virus commonly found in pigs, is transmitted from person to person in the same way that other flu viruses are transmitted. Symptoms of the N1H1 virus are also the same as symptoms of other flu strains and include headache, coughing, chills, fever, muscle pain, weakness, and general discomfort.

In most cases the virus is relatively mild, but as with all seasonal flu strains, the very young, the very old, and people with underlying heath conditions can be very much at risk.

The global outbreak of N1H1 virus began in Mexico in April, 2009 and spread rapidly. In June the World Health Organization declared the outbreak to be a pandemic. The virus spread through the southern hemisphere with unprecedented speed, and at the same time cases were confirmed throughout the US and other countries.

The virus has been confirmed in every state in the US. On September 3 the CDC reported more than 9,000 people hospitalized because of the virus, and said a total of 583 deaths were attributed to the flu virus in the US.

Concerns remain that a variation of the virus will recirculate through the world during the upcoming flu season. In late August the WHO predicted a huge increase of cases worldwide throughout the remainder of 2009 and well into 2010. According to the WHO some countries could see the number of cases double every few days until the peak period of transmission has passed.

Medical research shows that maintaining high levels of D vitamin is one of the best things people can do to help fight off colds and flu. It plays a major role in supporting immune function and is known to be an effective agent against inflammation, which is typically caused by flu and other respiratory viruses. By helping modulate the body’s response to respiratory viruses, it helps prevent dangerous and even fatal buildup of fluid in the lungs.

Though as yet there is no clinical evidence that supplemental D vitamin can be considered a flu preventative or treatment, there is ample evidence that it is an excellent immune support. Low levels of the vitamin are associated with higher incidence of a wide range of serious illnesses, including respiratory infections. In addition, numerous studies have shown that people with high levels of the vitamin appear to be less likely to contract flu and other respiratory viruses.

Long recognized as important to bone health and strength, D vitamin has recently been identified as key to immune support and crucial to almost all aspects of health. Deficiency has been recognized as a global health problem, and has been implicated as a factor in a host of illnesses and disorders including cancer, heart disease, hypertension, diabetes, osteoarthritis and osteoporosis. In addition, low levels of the vitamin have been associated with depression, chronic pain, birth defects, and periodontal disease.

Because sun exposure is necessary to stimulate the body’s production of the vitamin, some researchers speculate that the indoor lifestyle and weaker UV rays of winter weather make the traditional cold and flu season even more of challenge. There are relatively few dietary sources of the vitamin, so without adequate sun exposure deficiency is very common.

The Food and Nutrition Board at the Institute of Medicine of The National Academies, responsible for establishing Recommended Dietary Allowances of various nutrients, set an RDA of 200 mgs of D vitamin per day. That recommendation has been questioned as being insufficient, and in 2008 the American Association of Pediatrics announced a new recommendation that literally doubled the existing RDA to 400 IU per day. The AAP recommends that supplementation begin in the first two days after birth.

Hip fracture is one of the most common and most serious age-related health threats. There are about 1.6 million hip fractures worldwide each year, with 75% of the fractures happening to women over 50. Hip fracture leaves about 40% of its victims unable to walk independently, and can create profound loss of function.

In addition to causing chronic pain, reduced mobility, and increased dependence, hip fractures can actually be deadly. According to data from the International Osteoporosis Foundation, hip fracture increases the mortality rate as much as 24% in the first year, with a greater risk of dying for as long as five years after the fracture.

Known risk factors for hip fracture include low body weight, advanced age, and a diet that doesn’t provide enough calcium. But new research is indicating that without enough vitamin D, women are actually at 70% greater risk.

One of the latest studies, conducted by the University of Pittsburgh, monitored 800 women between the ages of 50 and 79 for nine years. The results showed that risk for hip fracture grew incrementally as blood levels of D vitamin dropped, to the point that women with the lowest levels of the vitamin had a 70% increased risk for hip fracture.

The association between low levels of the vitamin and hip fracture risk may be stronger for older women than younger women, the researchers noted. It is believed that vitamin D is tied most closely to hip fractures that occur because of pre-existing frailty, which is more commonly found among women over 50.

The recommended daily dose of vitamin D is 200 IU for people up to age 50, 400 IU for people aged 51 to 70, and 600 IU for people over age 70. Many experts disagree, citing this recommended dosage as far too low with some suggesting up to 1000 IU daily for both infants and adults.

Vitamin D has long been recognized for its importance to bone strength, but a growing body of medical evidence indicates that it plays a crucial role in many aspects of health. Though it is the only vitamin that the body can produce, deficiency is alarmingly common. As many as three fourths of the adults and teens in the US are believed to have inadequate levels, and D vitamin deficiency has been identified as a growing health problem all over the world.

Exposure to the sun triggers the skin to manufacture the vitamin, but the body’s ability to produce it declines with age. There are relatively few natural food sources of it, and most people get the majority of the vitamin by drinking fortified milk.

Crucial to bone, muscle development in adolescent girls
Recent research by the University of Manchester, UK screened 99 girls between 12 and 14 years of age. 75% of the girls had demonstrably low blood levels of D vitamin, though none of the girls showed symptoms of deficiency.

The researchers then tested the girls’ muscle strength and force. The girls who were not deficient scored significantly higher in the strength and force tests than those who were deficient, leading the research team to conclude that the link between deficiency and relative weakness definitely merits further study. The study data highlights the importance of the vitamin to muscle function in adolescent girls, they said, adding that there could be implications for long-term bone development.

Levels particularly important during pregnancy
Studies show that inadequate levels of D vitamin during pregnancy could have a negative impact on many aspects of pregnancy, from increasing the risk of pre-eclampsia to decreasing the length of gestation, birth weight, and odds for good fetal bone development.

It is also believed that sufficiency of the vitamin during pregnancy can actually lower the child’s risk of many health problems and diseases later in life.

One of the most important nutrients for women during and after menopause
The hormonal swings of menopause, together with an increasingly indoor-oriented lifestyle and the aging body’s decreased ability to manufacture D vitamin, makes deficiency among older women common. This is particularly dangerous, experts say, because low levels of the vitamin significantly increase the risk of osteoporosis, osteomalasia, and hip fractures.

In addition, deficiency has been related to an increased risk of several types of cancer, including breast cancer, as well as a higher incidence of heart disease, multiple sclerosis, asthma, and diabetes.

Helps prevent hip and other bone fractures One of D vitamin’s primary functions is to regulate the body’s absorption of calcium, making it a key player in the prevention of bone softening diseases such as osteoporosis and osteomalasia. A 2009 study by the University of Pittsburgh determined that low levels of the vitamin can increase post-menopausal women’s risk of hip fracture by as much as 70%.

May help protect against many forms of cancer, including breast cancer A 2008 study by the German Cancer Research Center, which monitored almost 2,800 post-menopausal women, concluded that women with very low blood levels of the vitamin had a significantly higher risk of developing breast cancer than those with adequate levels.

In addition, the American Journal of Clinical Nutrition reports that a four-year clinical trial involving 1,179 healthy post-menopausal women showed that improving calcium and vitamin D nutritional status substantially reduced all-cancer risk in postmenopausal women.

Deficiencies linked to bacterial infections in pregnant women Another University of Pittsburgh study indicated that there was a strong correlation between low levels of the vitamin and the incidence of bacterial vaginosis in the more than 460 pregnant women participating in the research. Bacterial vaginosis is one of the primary causes of premature delivery and fetal death.

A total of 41 percent of the study participants were diagnosed with bacterial vaginosis, and 93 percent of the women with the infection had insufficient levels of the vitamin. It was further observed that as blood levels of the vitamin rose, the incidence of infection decreased.

May help prevent and treat depression It is known that the vitamin plays a key role in a number of neurological and hormonal processes, and feelings of depression are identified as one of the symptoms of D vitamin deficiency. This connection may be of increasing importance to older women, because the body’s ability to manufacture D vitamin decreases as we age.

The importance of the vitamin to mood was established in a 2008 study by the University of Amsterdam, which showed that older people with low levels of the vitamin were more likely to be depressed. The researchers said that while additional study is warranted to determine whether low levels of the vitamin were the cause of depression or a side effect of it, they observed that the correlation between low D vitamin levels and depression were unmistakable.

Boosts energy and improves physical performance Feelings of fatigue are among the symptoms of D vitamin deficiency, and recent research by the Wake Forest University School of Medicine pinpoints the importance of sufficient levels of the vitamin for improving performance among older people.

The study analyzed data from 976 people aged 65 and older. The study found that physical performance, which included factors such as walking speed, grip strength, and ability to rise from a sitting position to standing, was 10 percent lower among participants with deficient blood levels of the vitamin.

Long recognized as important to the prevention of bone diseases, D vitamin builds and protects bone health and strength by regulating the amount of calcium our bones receive.

Deficiency of this crucial vitamin has been identified as a cause of severe and disabling diseases such as rickets, osteoporosis, and osteomalasia. But recent research is showing that low levels of the vitamin could be behind simpler problems like body aches and muscle pains as well.

A recent study by the University of Minnesota’s Community Health Care Center measured the D vitamin levels of 150 people being treated for persistent, unexplained body aches and pains. The results showed that 93 percent of the patients had seriously low levels of the vitamin. These results echo those of many other studies that have shown a direct correlation between otherwise unexplained body aches and vitamin D deficiency.

In addition, emerging research indicates that supplementation can actually resolve many cases in which patients are virtually immobilized by persistent, unexplained body pain. A Saudi Arabian project involving 299 patients with chronic low back pain used D vitamin supplementation for a period of three months, which resulted in clinical improvement in every case.

These findings could be particularly important for older people, who are both generally more subject to chronic body aches and more prone to deficiency of vitamin D. Exposure to the sun triggers the body to manufacture vitamin D, but older people, particularly those who live in cold climates, tend to have significantly less sun exposure than the general population. This problem is compounded by the fact that the body’s ability to synthesize the vitamin decreases with age.

Other factors that influence the body’s ability to produce the vitamin include weight and skin color; heavier people and those with darker skin have more difficulty producing sufficient amounts and are at higher risk of vitamin D deficiency.

Since there are relatively few dietary sources of the vitamin, sun exposure and fortified milk are both important to keeping blood levels of it sufficient. The current recommendations for D vitamin are 400 IU per day for both children and adults, and 600 IU per day for people over 70 years of age.

The European Male Aging Study, which focused on more than 3300 men between 40 and 80 years old, showed that low levels of the vitamin are definitely associated with slower mental processing, reduced cognitive function, and concentration problems.

The study authors, reporting their results in the Journal of Neurology, Neurosurgery & Psychiatry, said that while high levels of the vitamin correlated with high scores on cognitive function tests, more clinical tests are needed to fully interpret their findings.

Though the study clearly demonstrated the correlation between D vitamin levels and cognitive function/processing speed, the findings stopped short of identifying the vitamin as a treatment for aging brains. Instead, the researchers noted that the association could be simply a “risk marker”, indicating a risk for cognitive decline.

The study concluded that in light of the findings and the fact that vitamin D deficiency is common among older adults, more research is warranted to determine whether Vitamin D supplements could aid in minimizing age-related cognitive decline.

The European study is the latest of many research projects to investigate the association between levels of D vitamin - often referred to as the sunshine vitamin because sun exposure triggers its production in the body - and brain health.

The vitamin is known to play a significant role in brain biochemistry. Nuclear receptors for the vitamin exist in the brain, and it is involved in the biosynthesis of neurotrophins, protiens responsible for neuron growth and development. Because neurotrophins can also repair damaged neurons, some believe they have potential for use in reversing age-related brain disorders including Alzheimer’s Disease. Tests on the effectiveness of vitamin D supplements in Alzheimer’s treatment are ongoing.

In addition, recent studies have revealed that insufficient levels of the vitamin are strongly correlated with incidence of depression.

The University of Toronto study focused on a group of 40 patients diagnosed with relapsing-remitting MS. Part of the group was given a typical 1000 IU dose of the vitamin, while part was given escalating dosages over six months to a maximum of 40,000 IU per day. The dosage was then gradually reduced over the following six months, averaging out to a daily dosage of 14,000 IU over the entire year.

During the 12 months of the study only 16 percent of those receiving the higher dosage experienced relapses, while 40 percent those receiving the lower dosage experienced relapses. In addition, a comparison of relapse rate before and during the study determined that the high-dosage group experienced 41 percent fewer relapses during the study, while the low dosage group experienced 17 percent fewer relapses during the study.

No side effects related to the high dosage of the vitamin were observed.

How the vitamin D/MS connection works
The study’s authors said it is believed that the vitamin works to prevent relapses by suppressing inappropriate autoimmune responses. In typical cases of MS, important immune system cells called T lymphocytes or T cells direct the immune system to attack the protective sheaths around the brain cells. The study showed that T cell activity dropped markedly among the study participants taking high dosages of the vitamin. No similar drop in T cell activity was observed in the group taking lower dosages.

Though the results of this and other studies definitely point to vitamin D as a possible treatment for MS, researchers note that more clinical trials are required and people should confer with their physicians to determine whether supplements of the vitamin might be beneficial.

Though experts have voiced a variety of opinions on this question, the general consensus seems to be a cautious and qualified yes - it’s theoretically possible, but depending on how the tanning bed is calibrated, it may be unlikely. Some skin specialists say limited exposure to the sun itself is the best choice, while others advocate avoiding artificial and natural sun alike and depending on food and supplements to maintain adequate levels of the vitamin.

Exposure to the sun triggers the body to produce Vitamin D, which is often referred to as the sunshine vitamin. Long recognized for its importance to bone health and strength, it has recently been proven to play an important role in a host of aspects of both physical and mental health.

Low levels of the vitamin have been associated with a number of serious diseases including cardio-vascular disease, multiple sclerosis, asthma, Alzheimer’s disease, and several forms of cancer. Recent research has also shown that insufficient levels of the vitamin are clearly correlated with mental health issues, including depression and cognitive impairment in the elderly.

Since few foods contain vitamin D, sun exposure is traditionally an important part of avoiding deficiency. But when hectic schedules, cloudy skies, or winter weather make spending time in the sun a challenge, a few minutes in a tanning salon may seem like a good substitute. But many experts warn that while the rays from a tanning bed could stimulate the production of the vitamin, exposure to the sun itself is safer.

Sunlight - both natural and artificial - contains two types of ultraviolet rays. UVB rays, which are shorter and penetrate only the surface layers of the skin, are the ones that trigger the synthesis of the vitamin. UVA rays are longer and penetrate deeper layers of the skin, and are responsible for the deep golden tans that most tanning salon patrons desire.

As little as 20 minutes of exposure to UVB rays can maintain sufficient levels of D vitamin, but prolonged exposure can quickily lead to sunburns. In order to enhance tanning and reduce the potential for burning, tanning beds are often calibrated to emit primarily UVA rays. This also significantly reduces the amount of vitamin D that this type of exposure that salon tanning can provide.

The argument over whether the benefits of sun exposure outweigh it’s potential for creating problems has been going on for more than a decade. Pointing to the possibility of skin cancer, some dermatologists urge people to actively avoid sun exposure and get their D vitamin from foods and supplements. At the same time, other skin specialists say that the body is equipped to handle moderate sun exposure.

The answer to that question is exactly what ongoing research projects are seeking. Studies done all over the world over the past decade have firmly established that incidence of MS, a debilitating neurodegenerative disease that affects more than 350,000 people in the US, is definitely associated with deficiency of the vitamin.

Vitamin D/MS Link Firmly Established By Decades of Research
Most MS patients have low blood levels of the vitamin, and analysis of The Nurses Study, a massive study of more than 90,000 US women over several years, showed that women with low levels of the vitamin were about 50% more likely to develop the disease.

Geographically-based research has demonstrated that MS is more prevalent in areas geographically farthest from the equator, where people have less exposure to the sun to trigger the body to manufacture vitamin D. Incidence of the disease is below average in tropical areas which provide maximum opportunity for sun exposure.

Animal, Genetic Studies Show Treatment Potential
But though the link between the two has been firmly established, research is still investigating whether supplemental amounts of the vitamin can actually be an effective treatment for MS. Animal studies by the University of Wisconsin showed encouraging results; mice who had been given supplements of the vitamin showed no disability whatsoever after experimental encephalomyelitis, a disease similar to MS which is typically used in animal studies, was induced.

The same study also showed that giving supplements of the vitamin to mice that already had the disease both halted the progress of the disease and limited its severity.

Most recently, a Canadian study has discovered a direct interaction between D vitamin and a genetic variant known to increase the risk of MS. The study results suggest that deficiency of the vitamin effects this variant, which in turn alters the body’s immune processes and may trigger the development of brain and spinal cord problems typical of MS.

Clinical Trials Underway
Ongoing clinical trials of oral supplementation in MS patients are already in phase II and the results are expected to provide insight on how well supplementation works as treatment and how much supplementation is required. But many medical experts agree that until these factors and the long-term effects of supplementation are better understood, the best option for MS patients is to confer with their health care providers about their levels of the vitamin.

A blood test can show whether there are sufficient levels of the vitamin in the blood. In cases where levels are deficient, the patient and care provider can work together to determine a supplementation strategy.