Is Vitamin D the answer to auto-immune diseases?

Vitamin D is the buzzword in nutrition and medicine at the moment. The more research we do, the more important vitamin D becomes.  The latest emphasis on vitamin D suggests that it may be able to provide a "miracle cure" for up to 18 auto-immune diseases  ranging from multiple sclerosis, diabetes, coeliac disease, asthma, and autism, to schizophrenia(Gillie, 2014).  

Sources of vitamin D

On the one hand, the human body is capable of manufacturing this vitamin which has been reclassified as a steroid hormone because "the vitamin can be produced in the body, has specific target tissues, and does not have to be supplied in the diet" (Mahan et al, 2012). Lowly and much maligned cholesterol in our bodies is transformed into the active form of vitamin D when the human skin is exposed to the ultraviolet light in sunlight.

At first glance, South Africans should surely not have a problem with manufacturing vitamin D thanks to our usually brilliant sunshine (the Northern regions of the country have not actually seen much of this sunshine for the past few weeks!). But there are a variety of factors that can limit exposure of the skin to sunlight.

Read: Why Sunshine Vitamin D is crucial

Factors that prevent vitamin D production

The advent of sunblock products which are intended to protect us against developing skin cancer, may exacerbate the problem of inadequate vitamin D production.

The amount of melanin in the skin is also a decisive factor which determines how much vitamin D can be produced when the skin is exposed to sunlight. Darker skins which contain more melanin, may require longer exposure periods to produce adequate amounts of vitamin D.

Clothing that covers the entire body, particularly in infants and young children and religious observances, can also prevent the people from obtaining the benefits of vitamin D production (Mahan et al, 2012).

Many factors in our modern lifestyles predispose us to avoid sunlight. So if you wear sunblock faithfully, never venture into the sunshine, spend your days sitting in the office rather than working outside and play computer games or sit in front of the TV instead of playing sport in the sun, then you may well suffer from a vitamin D deficiency  because of inadequate exposure of your skin to sunlight.

Food sources
On the other hand, certain foods including cod liver oil, vitamin D-fortified foods such as milk and diary products in countries like the USA, and fatty fish (salmon, mackerel and tuna fish), are good dietary sources of vitamin D.

At the moment, there is no government regulation that makes it compulsory to add vitamin D to milk and dairy products or any other foods in South Africa.

Some foods such as margarines do contain some added vitamin D on a voluntary basis. I have just checked on a tub of soft margarine in my fridge where it states that a 20 g portion (1 heaped tablespoon), will provide me with 2 microgram of vitamin D, which represents 15% of the Nutrient Reference Value suggested for adults, namely 11 microgram of vitamin D/day.

Read: Vitamin D - your key to optimal health

Vitamin D and asthma

One of the autoimmune diseases that is being investigated in relation to vitamin D, is asthma.

Researchers have been postulating that asthma, an auto-immune disease, is linked to low levels of vitamin D (Gupta et al, 2012). 

A study , called the Vitamin D Antenatal Asthma Reduction Trial (VDAART), to determine if a higher vitamin D intake or status during pregnancy or at birth is protective against asthma and allergies, is being carried out in the United States in three centres (Boston, St. Louis and California).

Pregnant women are either given 110 microgram or 10 microgram of vitamin D per day starting at weeks 10-18 of their pregnancy and continuing for the rest of the pregnancies. Medical records are being kept to determine if any adverse events, which may be related to the additional vitamin D intake, occurred during these pregnancies.

After birth, the offspring are now being monitored up to their 3rd birthdays to determine if this supplementation has had any effect on the development of asthma and allergies in the infants.

A secondary goal of VDAART is to investigate if the higher intake of vitamin D was able to prevent pregnancy complications such as preeclampsia, preterm births and gestational diabetes (Litonjua et al, 2014).

While we await publication of the results of this study, pregnant womenshould discuss their vitamin D levels with their doctors and if necessary have their vitamin D levels tested to determine if they are deficient or not. Sitting in the sun for short periods every day may also be beneficial and even relaxing.

Read: Your 10 point action plan to manage your asthma

Vitamin D and depression

Depression is one of the most prevalent conditions affecting modern society. A research team under Dr Michael Berk from the IMPACT Strategic Research Centre, Deakin University, in Geelong Australia, has attempted to analyse the question: "So depression is an inflammatory disease, but where does the inflammation come from?"

In their insightful review, Dr Berk and his coauthors (2013), reiterate that it is now known that depression is linked to a chronic low-grade inflammatory reaction and can be classified as an auto-immune disease.

The problem is that at present it has not been determined what causes the inflammatory reaction and the activation of so-called "cell-mediated immunity". They list the following possible precipitating factors: psychological and social stressors, dietary deficiencies, physical inactivity, obesity, smoking, changes in the permeability of the gut, atopic reactions, tooth decay, sleep and vitamin D deficiency.

If we just concentrate on the last factor, namely vitamin D deficiency, then Dr Berk and his team (2013), are of the opinion that because so many people in western populations have low levels of vitamin D, it can nowadays be classified as the "most prevalent deficiency state"- this is indeed a scary notion.

Evidence that vitamin D plays a role in depression includes the findings that vitamin D receptors in the brain influence circadian rhythms and sleep, the production of glucocorticoids, growth of neurons, as well as cell growth in the developing brain before and after birth.

If vitamin D may help to prevent depression, then vitamin D, which is also noted for its pivotal role in controlling the inflammatory response which is another newly identified promoter of depression, ensuring adequate levels of vitamin D may well be essential to stem the tide of psychological conditions affecting mankind in this millennium.

Conditions which require further investigation because they may also benefit from increasing vitamin D production or intake, are schizophrenia, and post-traumatic stress disorder (Berk et al, 2013).

Read: Could you suffer from depression?


Although vitamin D is the topic of extensive research and more and more illnesses ae being linked to vitamin D deficiencies of varying severity, this does not mean that you should either rush out and lie in the sun all day or consume bottles of supplemental vitamin D.  

As is so often the case, while the correct intake/production of vitamin D is highly beneficial, excessive doses can reach toxic levels and you may induce a condition called hypervitaminosis D.

This condition is characterised by raised calcium and phosphorus levels in the blood (hypercalcaemia and hyperphosphataemia), which can in turn lead to calcification of soft tissues such as the kidney, lungs, heart and even the membrane of the ear leading to deafness.Headache and nausea in adults and digestive upsets, fragile bones and retarded growth in infants, are warning symptoms of vitamin D overdose (Mahan et al, 2012).

If you suspect that you may be deficient in vitamin D then please ask your medical doctor to send you for blood tests to check if this is the case. The doctor will prescribe vitamin D supplements for you if you should have a deficiency and he/she will also explain how the supplements should be take (e.g. 1 tablet per week). Stick to whatever dose the doctor prescribes to avoid hypervitaminosis D.

(References: Berk M et al, (2013). So depression is an inflammatory disease, but where does the inflammation come from? BMC Medicine, Vol 11:200;  Gillie O (2014). Sunlight could be miracle cure. The Times, 12 March 2014. First published in The Daily Telegraph; Gupta A (2012). Vitamin D and asthma in children. Paediatric Respiratory Rev, 13(4):236-43; Litonjua AA et al (2014). The Vitamin D Antenatal Asthma Reduction Trial (VDAART): Rationale, design and methods. Contemp Clin Trials. 2014, March7; Mahan KL (2012). Krause’s Food & the Nutrition Care Process. 13th Ed., Elsevier, USA)

Read more:
10 facts about autoimmune diseases
Salt may trigger autoimmune diseases
The wow about Vitamin D
Sunshine good for MS patients

(Photo of healthy family from Shutterstock)

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