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.