Vitamins and the Risk for Asthma and Allergies

Parents who are concerned about a recent study linking the use of vitamins to increased risk for asthma and allergies in their children should continue to follow their doctors' advice when it comes to dietary supplements, say the study authors and a Medical College of Wisconsin allergist. The study, published in the journal Pediatrics earlier this year, raised a bit of a media stir when it concluded that there could be a connection between multivitamins and higher rates of asthma and allergies.

"Asthma and allergy prevalence is rising, but there are a number of other things that are also rising," said Asriani M. Chiu, MD, Medical College Assistant Professor of Pediatrics (Allergy/Immunology). "There are so many other factors and variables involved that I think it is too hard to say that it is one in particular, such as giving vitamins. There's another hypothesis that suggests vaccinations. There's another hypothesis talking about just how 'clean' our environment has become, called the hygiene hypothesis."

By analyzing data from more than 8,000 infants, the Pediatrics study found that African-American children given vitamins in their first six months were about 30% more likely than white children to develop asthma.

Among all infants who were just fed formula, white and black, it was found that those given vitamins were just under 70% more likely to develop food allergies than those who had no extra vitamins in their diet. The study also reported that the risk for food allergies, but not for asthma, was increased in all children using vitamins at age 3 whether or not they were breast-fed or formula-fed.

Experts Urge Caution
Joshua Milner, clinical fellow at the National Institute of Allergy and Infectious Disease at the National Institutes of Health and a co-author of the study, told the Milwaukee Journal Sentinel in July that if parents have not been specifically told by doctors to give vitamins to their children "then they need to ask their doctor or dietitian if they really should be using them." Dr. Milner noted that the study was very preliminary and should not be used as the sole basis for changing a child's diet in general.

"I completely agree with that," said Dr. Chiu. "The study is also interesting in that it reminds us, from the standpoint of health care providers, about what many people think of as 'all natural' vitamins and supplements. It really forces us to delve into the history and make sure we pick out what supplements people think are all natural and 'safe,' knowing that there can be potentially some problem down the line and that we have to make sure that it's appropriate for that particular individual.

"It is very difficult to tease out those particular aspects and say, 'well, the prevalence of asthma and allergy are rising as the use of vitamins may be rising.' This study looked at a specific population, African-Americans, breast-fed infants, and so again there are many variables because we also know that African-Americans already have a higher general prevalence of asthma and allergies. It's still debatable whether that's due to socio-economic variables and/or even genetic and cultural differences.

"In my mind looking at this study, there are too many other things involved to say whether there's a direct correlation between giving vitamins and asthma and allergy."

Risk Factors and Advice for Parents
Parents should learn about other risk factors for allergy and asthma in their children, Dr. Chiu said, and take what steps they can to minimize them. "Again there are many variables, but there are certain risk factors that make the individual more likely to retain the diagnosis of having asthma or allergies. Those risk factors include a family history, and you can't change your genetics or family history. A family history of asthma and allergies makes you more likely to have asthma and allergies than the general population.

"If you have your own history of eczema (an inflammatory skin condition) or hay fever symptoms, those are other risk factors. And the timing of certain viral infections, whether a child gets them at two months or six months or two years of age, can make a difference as to whether a child is at risk for asthma or not.

Dr. Chiu said that if a child is a high-risk individual, decreasing exposure to certain things in their environment could be helpful. "One of the controversial things is exposure to pets," she said. "Does it mean that you can have two dogs but not have cats? That's still a controversial area, but in high risk individuals, I think our clinic's experience leads us to say that if you can decrease the amount of allergens that those children are exposed to on a daily basis, like pets, dust mite, molds, or irritants like cigarette smoke, that probably will be better in the long run."

Other studies have sent mixed messages about the relationship of specific vitamins to asthma and allergies, added Dr. Chiu. "My advice would be that if your doctor prescribed vitamins and it was appropriate for the child to be on them, don't just stop the vitamins. Talk it over with your physician and then make it an informed choice. If the child's primary care provider said the vitamins are needed for some reason, that's also going to play a big role in their development, growth, and other long-term chronic issues."

Dan Ullrich
HealthLink Contributing Writer

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.