Most of us know that vitamin D is essential for bone strength, especially for the elderly who are prone to falls. But as Go Vita explains this amazing vitamin actually has a whole host of other health benefits.
Why Vitamin D Is Important
Although we have known for several decades that vitamin D is important for calcium absorption, its more extensive role in the body had not been identified until recently. Scientists have now determined that most organs in the body respond to vitamin D, and researchers are discovering that many illnesses and conditions, ranging from autism and the common cold to cancer and chronic pain, are associated with low levels of vitamin D.
Factors Affecting Vitamin D Production
- Time of day
- Air pollution
- Cloud cover
- Sun block and protective clothing
- Skin pigment – the darker the skin, the less vitamin D produced
- Age – elderly people produce less vitamin D
- Weight – people who are overweight produce less vitamin D
The Cancer Link
The results of a study, led by vitamin D expert and Adjunct Professor at the University of California Dr Cedric Garland, projected that women who have vitamin D levels above 52 nanogram/ml have a 50 per cent less risk of developing breast cancer than women with levels below 13 nanogram/ml. This is because vitamin D excels in its ability to rein in rogue cells. Instead of continuing to multiply, vitamin D helps cells that are turning cancerous to die. Vitamin D also prevents the growth of blood vessels that feed these tumours, thus halting their spread. The presence of vitamin D helps to protect healthy cells from cancer, helps to repair cells that may be mutating, and helps to slow the growth of cancer cells that may be present.
Like breast tissue, the prostate also has receptor sites for vitamin D. According to one study, men with prostate cancer who were given 2,000 IU of vitamin D daily for 21 months had up to a 50 per cent reduction in prostate specific antigen (PSA) levels, linked with a lower incidence of prostate cancer.
According to Dr Garland, if the worldwide vitamin D deficiency was corrected, “The first thing we’d see would be a reduction in the incidence of type 2 diabetes by 80 per cent. The next thing we’d see is a reduction by 75 per cent of all invasive cancers combined, a similar reduction in colon and breast cancer, and probably a 25 per cent reduction in ovarian cancer.”
High blood pressure, the most common precursor to heart disease, improves when patients are exposed to UVB rays, since vitamin D relaxes the blood vessels and reduces blood pressure. It’s not surprising then that vitamin D levels in patients with congestive heart failure are 50 per cent lower than those with healthy hearts.
Muscle, Joint And Bone Pain
Dr Soram Khalsa, author of The Vitamin D Revolution, recommends that any patient who experiences unexplained muscle, joint or bone pain should be checked for vitamin D deficiency. A 2003 study found that of 360 patients with lower back pain of unknown cause, 83 per cent had abnormally low levels of vitamin D. After supplementation 95 per cent of patients reported improvement in their back pain.
Blood sugar levels
An Australian study found that sun avoidance could be increasing the risk of type 2 diabetes because lower levels of vitamin D in the blood may be associated with higher blood glucose levels.
Since there are vitamin D receptor sites throughout the body, it makes sense that there are also receptor sites in the brain. Low levels of vitamin D have been linked to an increased risk for depression and schizophrenia, and one doctor, John Cannell, has been developing a theory that links vitamin D deficiency to the rising incidence of autism in children.
Given that the best source of vitamin D is the sun, and Australia is one of the sunniest countries on earth, most of us believe that a daily multi will provide all the vitamin D we need. Yet, according to the Medical Journal of Australia, nearly a third of men and women have mild to moderate vitamin D deficiency.
The Sunshine Paradox
The ‘Slip Slop Slap’ anti-skin cancer message has been so effective over the past 25 years that many of us now are not receiving enough vitamin D through daily sun exposure. Despite the fact that spending 30 minutes in the midday summer sun may produce up to 20,000 IU of vitamin D, it can be a very complex business ensuring that adequate vitamin D is produced by the body while avoiding skin damage: UVA rays don’t prompt your body to produce vitamin D but cause premature ageing and wrinkles; UVB rays also cause skin damage, and only launch the production of vitamin D if they are within a certain wavelength (see box).
Unfortunately, there are simply not enough foods that naturally contain amounts of vitamin D to raise your blood levels to an optimum level. For example, you would need to drink a 250 ml glass of milk 10 times a day to obtain 1000 IU of vitamin D! A study of healthy people in Boston, Massachusetts, demonstrated that despite drinking milk, eating salmon and taking a multivitamin, 32 per cent were still found to be deficient in vitamin D.
The consensus of all vitamin D researchers is that the only reliable way to evaluate vitamin D levels is the 25-hydroxyvitamin D (25D) test, a blood test that is available through your doctor.
They also agree that an optimum normal blood level should be between 30 to 40 ng/ml or higher, however this number is likely to increase as new research emerges.
The recommended daily intake of vitamin D is largely based on the minimum required to prevent rickets – a disease rarely seen today! The current RDI is 1000 IU, but this is likely to increase. If the average person takes 1000 IU a day, this will generally result in a 10 ng/ml increase of their serum vitamin D levels after 3 to 4 months. However, factors such as weight, age and skin colour need to be taken into consideration.
Who Is At Risk?
Consider supplementing if you spend a lot of time indoors or frequently wear clothing that covers up your whole body. Breastfeeding mums should also be aware that human breast milk contains as little as 20 IU of vitamin D per litre.
Many healthcare professionals are now routinely checking vitamin D levels in all their patients due to the widespread nature of this deficiency. Given some of the ground breaking research that is emerging on Vitamin D, it seems a wise idea to have blood levels checked and to add a vitamin D capsule to your daily supplement regime.
Adapted from Go Magazine March 2010