by Amy Spangler
February 27, 2007

Compare the following headline that accompanied a news report of a recent study, Maternal Diet in Late Pregnancy Affects Children’s Risk for Eczema, with the actual title of the research article, Maternal diet during pregnancy in relation to eczema and allergic sensitization in the offspring at 2 y of age.

The news report goes on to describe a study published in the February issue of the American Journal of Clinical Nutrition, in which children born to women who consume allergenic (citrus fruit) foods and foods rich in n-6 polyunsaturated fatty acids (margarine and vegetable oils) during the last four weeks of pregnancy, were reported to have a greater risk of allergic disease at 2 years of age. While children born to women who consume foods rich in n-3 polyunsaturated fatty acids (fish) were reported to have less risk of allergic disease at the same age.

Sounds like a scientific breakthrough—but wait! The study apparently had a few limitations: possible misclassification of dietary exposure, lack of data on usual serving sizes, inability to rule out that the reported associations were modified by the diet of the children during the first 2 years of life, inability to evaluate the health effect of each single food, possible reverse causation if atopic mothers altered their diet during pregnancy to avoid known food allergens, and insufficient power to identify more specific associations between single foods and specific food sensitization.

The authors concluded, “Currently, no recommendations are being made to mothers to modify their diets to prevent allergies in their children because of insufficient evidence of a beneficial effect.”

Lesson learned: Read the beginning, the middle, and the end.