Antihistamine use could be a cause of obesity 

A study from Yale University examined the records of 867 adults who took part in a government health survey in 2005 and 2006 in which all participants had their weight and height measured, as well as their blood sugar.

On average, antihistamine users had a high enough body mass index for them to be classed as obese, compared with non-users who were classes as moderately overweight. When the researchers accounted for participants' age and sex, antihistamine use was linked to a 55% increase in the odds of being overweight although not to higher odds of elevated blood sugar, insulin or cholesterol. Among the 268 antihistamine users, 45% were overweight, versus 30% of the 599 study participants not on the medications.

However, the findings do not prove that antihistamines are the cause of the extra pounds, merely that there appears to be an association between two variables – in this case, antihistamine use and body weight. It is possible that some other factor explains the link but, given the number of people who take antihistamines to control their allergies (an estimated 50 million Americans have allergies, and anywhere from 35–50% of them use antihistamines), it is important that the connection be further studied.

Histamine is a chemical produced in the body that is best known for its role in promoting the inflammation associated with allergic responses; blocking histamine is a good thing when it comes to relieving hay fever symptoms, for instance. But cells throughout the brain have receptors for histamine, and the chemical appears to have a hand in a number of physiological functions, including appetite control and calorie burning so, in theory, antihistamines could contribute to overeating and slower fat breakdown.

From Obesity.

First published in August 2010

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