Too Much Vitamin D During Pregnancy Can Cause Food Allergies

Pregnant women should avoid taking vitamin D supplements. Substitution appears to raise the risk of children developing a food allergy after birth. 

This was the conclusion drawn from a new survey carried out by the Helmholtz Centre for Environmental Research and the Martin Luther University in Halle-Wittenberg in Germany. (Credit: André Kuenzelmann/UFZ)

Vitamin D has always had a good reputation: it strengthens bones, protects against infections particularly during the cold winter months and aids the nervous and muscular systems.

Especially in the prevention and treatment of rickets, it has been given to babies and infants around the world for around 50 years.

However, recent scientific investigations are increasingly questioning the positive aspect of the "bone vitamin."

At the end of the 1990's, for the first time people's attention was drawn to a link between high vitamin D levels and the development of allergies.

To pursue the problem, together with Prof. Gabriele Stangl's group from the Institute of Agricultural and Nutritional Sciences at the Martin-Luther University in Halle-Wittenberg, Dr. Kristin Weiße from the Helmholtz Centre for Environmental Research in Leipzig devoted herself to the following task: can it be proved that there is a correlation between the concentration of vitamin D in the blood of expectant mothers and in cord blood of the babies?

The researchers from the UFZ in Leipzig were furthermore interested in the association between vitamin D levels during pregnancy and at birth, the immune status and allergic diseases of the children later in life. Or, in other words: does the vitamin D level of pregnant women affect the allergy risk of their children?

To investigate the question, Dr. Kristin Weiße's team from Leipzig used samples from the LiNA cohort that the Helmholtz Centre for Environmental Research (UFZ) had established together with the St. Georg municipal clinic between 2006 and 2008 headed by Dr. Irina Lehmann.

In total, it was possible to include 622 mothers and their 629 children in the long-term study "Lifestyle and environmental factors and their impact on the newborn allergy risk."

The level of vitamin D was tested in the blood of the pregnant mothers and also in the cord blood of the children born. In addition to this, questionnaires were used to assess the occurrence of food allergies during the first two years of the children's lives.

The result was clear: in cases where expectant mothers were found to have a low vitamin D level in the blood, the occurrence of food allergies among their two-year old children was rarer than in cases where expectant mothers had a high vitamin D blood level.

In reverse, this means that a high vitamin D level in pregnant women is associated with a higher risk of their children to develop a food allergy during infancy.

Furthermore, those children were found to have a high level of the specific immunoglobulin E to food allergens such as egg white, milk protein, wheat flour, peanuts or soya beans.

The UFZ scientists also got evidence fot the mechanism that could link vitamin D and food allergies. Dr. Gunda Herberth -- also from the Department of Environmental Immunology at the UFZ -- took a closer look at the immune response of the affected children and analysed regulatory T-cells in cord blood in particular.

The cells are capable of preventing the immune system from overreacting to allergens, with the result that they protect against allergies. The UFZ researchers know from earlier analyses that the allergy risk increases in cases where too few regulatory T-cells are present in cord blood.

The interesting result of the current research project: the higher the level of vitamin D found in the blood of mothers and children, the fewer regulatory T-cells could be detected.

The correlation could mean that vitamin D suppresses the development of regulatory T-cells and thus increases the risk of allergy.

Apart from diet, Dr. Kristin Weiße explained that the level of vitamin D is mainly affected by conditions such as season, exposure to the sun and the amount of time spent outdoors -- these factors were also taken into account in the current risk analyses of vitamin D and food allergy.

Even though the occurrence of food allergies is undoubtedly affected by many other factors than just the vitamin D level, it is still important to take this aspect into consideration.

The UFZ researchers would rather advise pregnant women not to take vitamin D supplements. "Based on our information, an excess of vitamin D can increase the risk of children developing a food allergy in the first two years of their life."

Journal Reference: K. Weisse, S. Winkler, F. Hirche, G. Herberth, D. Hinz, M. Bauer, S. Röder, U. Rolle-Kampczyk, M. von Bergen, S. Olek, U. Sack, T. Richter, U. Diez, M. Borte, G. I. Stangl, I. Lehmann. Maternal and newborn vitamin D status and its impact on food allergy development in the German LINA cohort study. Allergy, 2013; 68 (2): 220 DOI: 10.1111/all.12081

Aberdeen Scientists claim artificial light is key to treating Multiple Sclerosis

Aberdeen scientists have found that artificial sunlight can have a “striking effect” in helping treat sufferers of diseases such as multiple sclerosis.

Researchers from Aberdeen University studied patients in the north of Scotland – which has the highest rate of MS in the UK - who were being treated during winter with artificial UV (ultraviolet)-B light therapy for skin diseases caused by their immune systems acting inappropriately.

The research - published in the Journal of Allergy and Clinical Immunology – shows how UV-B light boosts vitamin D, as well as cells in our body that are responsible for regulating or balancing the immune system. Vitamin D is made in our bodies by UV-B light from the sun.

Some studies have suggested a link between vitamin D deficiency and autoimmune diseases such as MS.

This possible link might also explain the increasing prevalence of autoimmune disease among those living far from the equator, where there are lower levels of winter sun.

Autoimmune diseases - like MS and type 1 diabetes - are diseases where the immune system mistakenly attacks the body’s own tissues or harmless substances that enter the body.

Dr Anthony Ormerod, clinical reader in dermatology at the university, said: “Our study shows that UV-B light, which mimics sunshine, can have a striking effect on the immune system of patients.

“We found that UV-B light boosted the production of vitamin D, and of regulatory T cells, which play an important role keeping our immune systems in check.

“Our findings have important implications for future interventions including the recommendations for healthy lifestyle and a possible role for phototherapy and/or vitamin D supplementation in the prevention or treatment of autoimmune and inflammatory diseases.

“While too much exposure to sunlight is harmful and increases skin cancer risk, these results suggest that subjects in our study would have some benefits from small amounts equivalent to summer exposure in the winter but more work needs to determine the role of sunlight and the role of supplementing the diet with vitamin D.”

Dr Helen Macdonald, senior lecturer in nutrition and translational musculoskeletal research at the university and chair of the National Osteoporosis Society Nutrition and Lifestyle forum, said: “There are risks associated with high levels of both therapies, so it is important that we get the balance right.

“We would also want to stress that we are not advocating sun bed use since this is not the same type of radiation produced by sun beds which already have well-documented health risks.

“The average dose of UV light that the volunteers received was the equivalent to sunlight exposure in Aberdeen over spring and summer and further work is required to determine if lower doses are effective.”

Professor Mark Vickers, chair in applied medicine at the university, added: “Ours is the first study to demonstrate in patients a cause and effect between UV light, vitamin D and systemic immune function in people.”