On Thursday (19th June) the American Medical Association (AMA), the largest doctors organisation in the USA, voted at their Annual Meeting to urge the Food and Drug Administration to re-examine the recommendations for vitamin D intake in light of new scientific evidence.

Those of you who have been reading my posts will know that I have mentioned vitamin D a couple of times already with respect to prevention of many diseases including cancer and heart disease.  This year alone there have been over 100 papers, articles or studies released which show how important this ‘sunshine vitamin’ is for our optimal health and wellbeing.  There is an almost constant stream of new scientific findings showing benefit.

The AMA are concerned because the American Reference Intake Values for Vitamin D were established back in 1997.  I hope that here in the UK we follow suit soon and re-examine our recommended intake too.  Ours was set back in the early 1990s!  Current research strongly suggests that we need more of this important vitamin than previously thought.

On Friday (20th June) a study(1) was published in the Journal of Clinical Oncology, I wanted to mention it here because it did not look at vitamin D with regards disease prevention.  The study looked at vitamin D and survival after cancer.  It has been previously shown that individuals with higher levels of vitamin D in their blood are less at risk of contracting colorectal cancer.  This present study found that among patients affected by colorectal cancer a higher pre-diagnosis vitamin D level was associated with a significant improvement in overall survival.  The authors of the study say that a trial is being planned in which colon cancer patients will take vitamin D along with post-surgery chemotherapy to assess whether there are any benefits with supplementation.

Just as I was about to finish this post a very interesting piece of peer-reviewed clinical research came to light(2) that was published in Pain Treatment Topics a few days ago.  The paper looked at vitamin D in relation to ‘pain’ and found that:

“Inadequacies of vitamin D have been linked to chronic musculoskeletal pain of various types, muscle weakness or fatigue, fibromyalgia syndrome, rheumatic disorders, osteoarthritis, hyperesthesia, migraine headaches, and other complaints. It also has been implicated in the mood disturbances of chronic fatigue syndrome and seasonal affective disorder.  Current best evidence demonstrates that supplemental vitamin D can help to resolve or alleviate chronic pain and fatigue syndromes in many patients who have been unresponsive to other therapies.”

There are downloadable documents on the Pain Treatment Topics website which provide detailed background information and recommendations.  There is a Full report and a Patient brochure available.  If you are suffering from any of the mentioned conditions you may wish to discuss this evidence with your doctor to see if Vitamin D supplementation could be useful to you.

Many of us find that spending some time in the sunshine is very healing for the mind and helps to reduce perceived stress-levels too.  It really does seem like the sun is important for the health of the body too!

(1)Ng K et al.  2008.  Circulating 25-Hydroxyvitamin D Levels and Survival in Patients With Colorectal Cancer.  Journal of Clinical Oncology.  26(18):2984-2991
(2) Stewart B. Leavitt, MA, PhD, Pain Treatment Topics, June 2008.  Vitamin D – A Neglected 'Analgesic' for Chronic Musculoskeletal Pain.  An Evidence-Based Review & Clinical Practice Guidance

Written by Ani Kowal

On the 30th May  I wrote about the importance of Vitamin D for health and concentrated mainly on the link to cancer prevention.

Yesterday a study was published in the Archives of Internal Medicine(1) which adds to the growing body of research that links low vitamin D levels to poorer heart health.

This particular study involved a group of 18225 middle aged and older men (aged 40-75 years).  The men were free of diagnosed heart disease at the initial blood collection.  They were then followed for 10 years and in this time 454 developed heart attacks (which were either fatal or non fatal).  The study scientists then compared the blood levels of vitamin D in those men who had suffered a heart attack to a group of 900 similar men (matched for certain factors such as age and smoking status) who had not.  The results showed that men with low blood levels of vitamin D were at increased risk of heart attack compared to men with sufficient levels.  Even men with intermediate blood levels of vitamin D were at increased risk of heart attack.

The findings are significant as the scientists adjusted the results to exclude a whole host of other possible confounding factors such as family history of heart attack, weight (Body Mass Index), alcohol consumption, physical activity levels, history of diabetes, blood pressure, ethnicity, omega 3 fatty acid intake and cholesterol levels.  Even when these factors were taken into account the men with low vitamin D levels were twice as likely to experience a heart attack than those with high vitamin D levels.

The authors of the study conclude that “Low levels of 25(OHD) [vitamin D] are associated with a higher risk of myocardial infarction [heart attack] in a graded manner, even after controlling for factors known to be associated with coronary artery disease”

Previous studies have linked low vitamin D levels to atherosclerosis (hardening of the arteries), congestive heart failure and high blood pressure.  As I mentioned in my previous post on vitamin D many of us in the UK may not have adequate levels of vitamin D in our blood.  A supplement of 12mcg/d (around 500iu) could be useful to those who rarely get out in the sunlight or during the autumn and winter months.

It is not entirely understood why vitamin D is so important for the health of the heart.  There are indications that vitamin D acts to reduce the production of pro-inflammatory chemicals (cytokines) which are linked to heart disease and may even increase the production of anti-inflammatory chemicals which are protective.  Vitamin D may also have an effect on certain hormones which play an important role in the regulation of blood pressure. 

(1)Giovannucci E et al.  2008.  25-Hydroxyvitamin D and risk of myocardial infarction in men: a prospective study.  Arch Intern Med.  168:1181-1187

Written by Ani Kowal

Vitamin D appears to be receiving a lot of attention in the scientific and medical press at present with well over 20 studies due for publication in June alone and many, many more already published in 2008.  In fact, as I started to research for this post the current issue of The Proceedings of The Nutrition Society arrived through my letterbox (Volume 67 No.2) and two of the featured papers covered the importance of vitamin D (one in relation to cancer and one in relation to the treatment and prevention of osteoporosis).

Vitamin D is called the sunshine vitamin, though technically vitamin D is a hormone, as it is produced in the body when the skin is exposed to the UVB rays in sunlight.  In theory spending just 10-15 minutes in the sun everyday should supply all the vitamin D that we need.  However, many of us do not get enough sun on our skin to generate adequate amounts of vitamin D especially in the autumn and winter months.  A recent analysis(1) found that there is a global widespread insufficiency of this vital nutrient and there is evidence from the National Diet and Nutrition Surveys (NDNS) which suggests that in the UK vitamin D deficiency is a real problem (2,3,4,5).  The problem is made worse in the older generations since, as we age our bodies find it increasingly difficult to manufacture vitamin D.

This does not make for good news since vitamin D is vital for our health.  Not just the health of our bones and teeth but a for our hearts (the vitamin may protect against atherosclerosis, heart attack and high blood pressure), our digestive systems, the immune system (there is increasing evidence to show that vitamin D is important in the prevention of cancer), blood sugar control (and the prevention of type I and type II diabetes and insulin resistance), muscles, brain (deficiency is linked to depression and mood), fertility and skin health.  Quite a list!

I would like to write a bit more about the link between vitamin D and cancer.  We are constantly told by the media to avoid the sun as it increases our risk of a certain type of skin cancer called ‘malignant melanoma’.  However evidence is now mounting to suggest that insufficient sunlight exposure and low vitamin D levels actually increase the risk of several types of internal cancers such as breast, prostate, colon, bladder, kidney, lung, pancreas and ovary (to name but a few) (6,7).  Just as I was finishing this post a study was published (8) which looked at UVB exposure, vitamin D levels and breast cancer risk across 107 countries.  The authors of the study found that higher blood vitamin D levels were associated with lower rates of breast cancer and UVB exposure had a protective effect on the risk of breast cancer (these effects were independent of potential confounding factors such as fertility rate, overweight, alcohol intake, animal energy intake).  Vitamin D seems to have many cancer protective properties;  it can prevent cells from multiplying and can also specifically induce the death of cancer cells. 

It certainly seems that the sun is very important for our optimal health and wellbeing!

It is essential to be safe in the sun and avoid getting burned and baked, malignant melanoma is a particularly nasty skin cancer.  However , the risk of this type of skin cancer is relatively low in comparison to other forms of cancers and staying out of the sun completely will probably do more harm than good with regard to health and overall cancer risk.  For more interesting information about the benefits of sunlight for health please visit the Sunlight Nutrition And Health Research Centre, the information there is well presented and backed up by significant amounts of good evidence.

The UV in sunlight is believed to be our main source of vitamin D with only small amounts being found in food sources such as oily fish (mackerel, salmon and sardines)and eggs.  Recently, however, there has been mass debate about whether UV exposure in the UK is sufficient to keep vitamin D levels optimal for health.  I mentioned earlier that most of us in the UK are falling short of recommended levels.  If you rarely get out into the sun you may wish to consider a vitamin D supplement which provides around 12mcg/day (around 500iu).  Such a supplement may be particularly useful during the autumn and winter months.

(1) Hagenau T et al.  2008.  Global vitamin D levels in relation to age, gender, skin pigmentation and latitude: an ecologic meta-regression analysis.  Osteoporosis International May [E publication ahead of print]
(2) Finch S et at.  1998.  National Diet and Nutrition Survey of People aged 65 Years and Over.  London: H. M. Sationery Office.
(3) Gregory L et al.  2000.  National Diet and Nutrition Survey of People aged 4-18 years. Vol 1.  Report of the Diet and Nutrition Survey.  London:  The Stationery Office
(4) Henderson L et al.  2002.  National Diet and Nutrition Survey: Adults Aged 19-64 years.  Vol 1: Types and Quantities of Foods Consumed.  London: The Stationery Office
(5) Hypponen E & Power C.  2007.  Hypovitaminosis D in British adults age 45y: nationwide cohort study of dietary and lifestyle predictors.  Am J Clin Nutr.  85:860-888.
(6) Grant WB.  2002.  An estimate of premature cancer mortality in the U.S. due to inadequate doses of solar ultraviolet-B radiation.  Cancer.  94:1867-1875
(7) Grant WB & Garland CF.  2006.  The association of solar ultraviolet B (UVB) with reducing risk of cancer: multifactorial ecologic analysis of geographic variation in age-adjusted cancer mortality rates.  Anticancer Research.  26:2687-2699
(8) Mohr SB et al.  2008.  Relationship between low ultraviolet B irradiance and higher breast cancer risk in 107 countries.  Breast J.  14:255-60

Written by Ani Kowal