If you suffer from food allergies, consider your rank in the family birth order. According to a study out of Japan, firstborn siblings are more likely to suffer from food allergies than their younger brothers and sisters.
In a survey of more than 13,000 children ages 7 to 15, food allergies were prevalent in four percent of firstborn children, 3.5 percent of second-born children, and 2.6 percent in subsequent siblings.
Firstborns were also more likely to suffer from symptoms like an itchy, running nose and inflammation of the eyelids than their younger siblings.
The findings likewise suggest that food allergies may have a prenatal origin, as food allergies decreased significantly as birth order increased.
In a study published last November, researchers found that mothers who consume peanuts during their pregnancy could be putting their babies at increased risk of a peanut allergy. The study, published in the Journal of Allergy and Clinical Immunology, evaluated 503 infants across the US, ages three to 15 months, with milk or egg allergies or with severe eczema -- all factors associated with an increased peanut allergy.
A total of 140 infants showed strong sensitivity to peanut-based blood tests, and the consumption of peanuts during pregnancy was a significant predictor.
While previous studies have found links between general childhood allergies and birth order, the Japanese researchers say theirs is the first to show a link between specific food allergies and sibling birth order.
In an interview with MyHealthNewsDaily, study researcher Takashi Kusunoki of the Shiga Medical Center for Children in Shiga, Japan, postulated that younger siblings may be spared from food allergies because the mother's immune system in the womb changes with multiple pregnancies.
Kusunoki also hypothesized that younger children develop stronger immune systems than their older siblings because more children in the house means more germs. That means younger siblings may be exposed to more pathogens at an earlier age.
The study was presented during the 2011 Annual Meeting of the American Academy of Allergy, Asthma & Immunology in San Francisco earlier this week.
The abstract for the study can be found at http://annualmeeting.aaaai.org/, and is No. 525.
To prevent younger children from developing the same food allergies as the firstborn, one study recommends eliminating the offending food from the mother's diet from the third trimester on, and continuing the ban until the child is two years old.
According to researchers from the Royal Prince Alfred Hospital in Australia, seven out of ten babies born to mothers who took avoidance measures had no food allergies, compared to 45 percent of babies whose mothers took no precautions.
Pediatricians recommend eliminating the offending food from both the mother's diet and the household environment.
Breastfeeding has also been shown to protect children against the development of allergies.