Doctor Andrea Furlan explains what Vitamin D does in the body, what are the sources to obtain Vitamin D and how much should a person take of Vitamin D supplements. She also explains that it is important not to take too much Vitamin D because it can be toxic.
Patients with lupus are more likely to have metabolic syndrome and insulin resistance – both factors linked to heart disease – if they have lower vitamin D levels, a new study reveals.
Researchers believe that boosting vitamin D levels may improve control of these cardiovascular risk factors, as well as improving long-term outcomes for patients with systemic lupus erythematosus (SLE).
Given that photosensitivity is a key feature of SLE, the scientists say that a combination of avoiding the sun, using high-factor sunblock and living in more northerly countries may contribute to lower levels of vitamin D in lupus patients. Patients with more severe disease also had lower vitamin D levels.
An international research team, led by experts at the University of Birmingham and University of Manchester, studied vitamin D levels in 1,163 SLE patients across 33 centres in 11 countries (UK, USA, Canada, Spain, The Netherlands, Sweden, Iceland, Switzerland, Turkey, South Korea and Mexico), publishing its findings in Rheumatology.
Report co-author Dr John A Reynolds, Clinical Senior Lecturer in Rheumatology at the University of Birmingham, commented: “Our results suggest that co-existing physiological abnormalities may contribute to long-term cardiovascular risk early on in SLE.
“We found a link between lower levels of vitamin D and metabolic syndrome and insulin resistance. Further studies could confirm whether restoring vitamin D levels helps to reduce these cardiovascular risk factors and improve quality of life for patients with lupus.”
Lupus is an uncommon incurable immune system illness, more common in women, where the immune system is overactive, causing inflammation anywhere in the body. Untreated, the condition threatens irreversible damage to major organs including kidneys, heart, lungs and brain.
Metabolic syndrome is a combination of diabetes, high blood pressure (hypertension), abnormal cholesterol levels, and obesity. People with metabolic syndrome are at greater risk of getting coronary heart disease, stroke and other conditions affecting the blood vessels.
The researchers note that patients with SLE have an excess cardiovascular risk, up to 50 times that seen in people without the condition – this cannot be attributed to traditional cardiovascular risk factors, such as high blood pressure or smoking, alone.
The mechanisms underlying the association between high blood pressure and low vitamin D in SLE are not clear, but researchers believe they may be linked to impact of vitamin D deficiency on the renin-angiotensin hormone system, which regulates blood pressure, fluid and electrolyte balance, as well as systemic vascular resistance.
“This is the largest-ever study examining associations between vitamin D levels and metabolic syndrome in SLE; it also has the advantage of being an international cohort with diverse racial and ethnic backgrounds – generating results that will be applicable across many settings,” commented Dr. Reynolds.
Vitamin D gel capsules. from Michele Blackwell
Genetically determined vitamin D levels do not have a large effect on risk of type 1 diabetes in Europeans, according to a study published 25th February 2021 in the open-access journal PLOS Medicine by Despoina Manousaki from the CHU Sainte Justine and the University of Montreal, Canada and colleagues.
Type 1 diabetes is a relatively common autoimmune disease that inflicts substantial lifelong illness and significant economic burden. Its incidence is increasing worldwide, and there are no known interventions that can be used to prevent the disease. Vitamin D deficiency has been associated with type 1 diabetes in observational studies, but evidence of a causal effect from randomized controlled trials is lacking. In the new study, the researchers used a Mendelian randomization design to test whether genetically decreased vitamin D levels increase risk of type 1 diabetes. Mendelian randomization is a method of using measured variation in disease-related genes to examine the causal effect of an exposure on a disease. The two-sample Mendelian randomization study involved a vitamin D genome-wide association study (GWAS) including 443,734 Europeans, and a type 1 diabetes GWAS including 9,358 cases and 15,705 controls.
The results do not support a large effect of vitamin D levels on risk of type 1 diabetes (odds ratio: 1.09, 95% confidence interval: 0.86-1.40, p=0.48). However, smaller effects may exist, and the results may not be applicable to non-European populations. The findings suggest that the previous epidemiological associations between vitamin D and type 1 diabetes could be due to confounding factors, such as latitude and exposure to sunlight. According to Dr Manousaki: “Our findings do not support a large effect of vitamin D levels on type 1 diabetes, but there may be smaller effects which we could not detect. Until further evidence from large RCTs, we cannot suggest the use of vitamin D supplements as a strategy to prevent type 1 diabetes in individuals at risk, for instance siblings or offspring of people with type 1 diabetes”.
In recent years, three meta-analyses of clinical studies have come to the conclusion that vitamin D supplementation was associated with a reduction in the mortality rate from cancer of around 13 percent. Scientists at the German Cancer Research Center (DKFZ) have now transferred these results to the situation in Germany and calculated: If all Germans over the age of 50 were to take vitamin D supplements, up to 30,000 cancer deaths per year could possibly be avoided and more than 300,000 years of life could be gained – in addition, health care costs could be saved.
For several years now, scientists have been investigating the influence of an adequate supply of vitamin D on the prognosis of numerous diseases. The focus is particularly on inflammatory diseases, diabetes, respiratory diseases and cancer.
Three meta-analyses of large clinical studies have been published in recent years on the question of how vitamin D supply affects cancer mortality rates. The studies* came to the same conclusion: cancer mortality is reduced by around 13 percent with vitamin D supplementation – across all cancers. Only methodologically high-quality randomized trials from all parts of the world were included in the meta-analyses. Exactly what biological mechanisms might underlie this is not yet clear.
“In many countries around the world, the age-adjusted rate of cancer mortality has fortunately declined over the past decade,” says Hermann Brenner, an epidemiologist at the German Cancer Research Center (DKFZ). “However, given the often considerable costs of many new cancer drugs, this success has often come at a high price. Vitamin D, on the other hand, is comparatively inexpensive in the usual daily doses.”
Vitamin D deficiency is common in the elderly population and especially among cancer patients. Brenner and colleagues now calculated what costs would be incurred by vitamin D supplementation of the entire population of Germany from the age of 50. They contrasted this sum with the potential savings for cancer therapies, which are often associated with costs in the range of several 10,000 euros, particularly in the case of advanced cancers during the last months of patients’ lives.
The scientists based this calculation on a daily administration of 1,000 international units of vitamin D at a cost of 25 euros per person per year. In 2016, approximately 36 million people over the age of 50 lived in Germany, resulting in annual supplementation costs of 900 million euros.
The researchers took the cost of cancer treatment from the scientific literature, assuming mean additional treatment costs of €40,000 for the last year of life. A 13 percent reduction in cancer mortality in Germany corresponded to approximately 30,000 fewer cancer-related deaths per year, the treatment costs of which amounted to €1.154 billion in the model calculation. Compared with the costs of vitamin supplementation, this model calculates an annual saving of €254 million.
The researchers determined the number of years of life lost at the time of cancer death using data from the German Federal Statistical Office. Brenner considers the costs and effort of a routine determination of the individual vitamin D level to be dispensable, since an overdose is not to be feared with a supplementation of 1000 international units. Such a prior testing had not been made in the clinical trials either.
“In view of the potentially significant positive effects on cancer mortality – additionally combined with a possible cost saving – we should look for new ways to reduce the widespread vitamin D deficiency in the elderly population in Germany. In some countries, foods have even been enriched with vitamin D for many years – for example, in Finland, where cancer mortality rates are about 20 percent lower than in Germany. Not to mention that there is mounting evidence of other positive health effects of adequate vitamin D supply, such as in lung disease mortality rates,” says Brenner, adding, “Finally, we consider vitamin D supplementation so safe that we even recommend it for newborn babies to develop healthy bones.”
To improve one’s vitamin D levels at absolutely no cost, DKFZ’s Cancer Information Service recommends spending time outdoors in the sunshine, two to three times a week for about twelve minutes. Face, hands and parts of arms and legs should be uncovered and without sunscreen for this period of time.