Low vitamin D linked to food allergies

4 March 2013

A lack of vitamin D increases the likelihood of food allergy in infants, according to new research by the Institute. 

Researchers found infants who are vitamin D insufficient were three times more likely to have a food allergy. Those with vitamin D insufficiency were also more likely to have multiple than single food allergies, with the odds increasing to ten times more likely among those with two or more food allergies. Researchers found no link with lack of vitamin D and eczema. 

Interestingly, the study showed the link was only evident for infants with vitamin D insufficiency with Australian-born parents, but not for infants of parents who were born overseas.  Researchers hypothesise the different effect of vitamin D on food allergy depending on the parents' country of birth may be related to skin colour or other genetic, epigenetic or environmental reasons.

The study, which was published in theJournal of Allergy and Clinical Immunology, involved 5,276 12-month old infants.  Infants underwent a skin prick test to common allergic foods including egg white, peanut, and sesame and an oral food challenge to confirm allergy.  Researchers then examined the blood of 780 infants within the study, and measured their serum level of vitamin D.

The findings are consistent with previous research undertaken by the Institute which linked the prevalence of food allergies to the latitude gradients for where people lived. The research showed the further people lived from the equator, the more likely they were to have food allergy, with children residing in Australia's most southerly state having twice the odds of peanut allergy at age four or five and three times the odds of egg allergy than those in northern states. 

Lead researcher, Professor Katie Allen said the rising prevalence of vitamin D insufficiency over the last 20 years has paralleled the rise in food allergy.

"Food allergy is on the rise, and Australia has some of the highest reported prevalence in the world with more than 10% of infants having food allergy.  There has also been a rise in vitamin D insufficiency, with up to 30% of Melbourne pregnant mothers now vitamin D insufficient."

"This study provides the first direct evidence that vitamin D sufficiency may be an important protective factor for food allergy in the first year of life.  This adds supporting evidence for medical correction of low vitamin D levels."

"Also, Australia is one of the few developed countries where routine food fortification with vitamin D does not occur, so this may be another possibility to address the rise of food allergy."

Co-lead researcher, Dr Jennifer Koplin said the next step for researchers is to understand at what stage vitamin D is important in determining who goes on to become food allergic.

"From this study we know vitamin D plays a role in food allergy but what is unknown is at what stage vitamin D is most important.  The next step is to understand whether vitamin D influences food allergy maternally, during pregnancy or whether it's the infants themselves in the first year of life."

This research was done in collaboration with the University of Melbourne.