Nut Consumption in Pregnancy May Increase Asthma Risk in Child

Women who eat nut products such as peanut butter daily throughout pregnancy may significantly increase their children's risk of developing asthma symptoms, according to a Dutch cohort study.

At 8 years of age, children whose mothers reported daily consumption of nut products were at significantly increased risk for steroid use (odds ratio 1.62), dyspnea (OR 1.58), and wheeze (OR 1.42), compared with children of women who reported only rarely (no more than three times per month) eating nut products. The data were adjusted for factors such as parental atopy, maternal smoking in pregnancy, and breast-feeding. The associations were independent of the children's diets.

The investigators stressed that these findings should be replicated in other studies “before influencing dietary advice given to pregnant women” (Am. J. Respir. Crit. Care Med.;177:1-8).

Previous research on the effectiveness of maternal dietary allergen avoidance during pregnancy in prevention of childhood allergic disease has been “inconclusive,” wrote Saskia M. Willers of the environmental epidemiology division at Utrecht University, the Netherlands, and associates. They added that their study is the first to use longitudinal statistical methods to assess the relationship over an extended period.

The researchers enrolled 4,146 women (1,327 atopic and 2,819 nonatopic). Complete data were available for 2,832 children whose mothers completed questionnaires at baseline on their dietary habits during pregnancy. The questionnaires assessed frequency of the women's consumption of vegetables, fresh fruit, fish, eggs, milk, milk products, nuts, and nut products; possible responses ranged from “never” to “several times per day.”

“Because we mentioned peanut butter as an example of nut products in the questionnaire and because peanut butter is a commonly used spread on sandwiches in the Netherlands … we assumed that the largest proportion of nut products is peanut butter,” the researchers wrote.

Children were followed up at 3 months and then once a year from ages 1 through 8; a dietary assessment was conducted at age 2. At age 8, 13.2% of the children had asthma symptoms, and another 3.9% had asthma diagnosed by a doctor.

Daily consumption of nut products was the only factor assessed that showed a significant association with increased incidence of asthma symptoms. In an interview, Ms. Willers noted that the lack of a significant association between asthma symptoms and daily consumption of nuts—as opposed to nut products—may have been due to the small sample size of women (1.4%) who ate nuts daily. In addition, she said, the nut products consumed were made largely from peanuts, but women who ate nuts daily also may have eaten less allergenic types of nuts.

In a crude analysis, women who ate fruit daily were significantly less likely to have children who wheezed than were those who ate fruit only regularly or rarely (odds ratio 0.82), but that association disappeared after adjustment for socioeconomic factors, parental atopy, and other factors.

The researchers said their findings are limited by their inability to obtain more information on specific foods and portion sizes. They said they included the main food groups associated with asthma, but other foods and nutrients cannot be ruled out as having been responsible for the asthmatic symptoms identified.

One of the study investigators reported having received an unrestricted research grant from GlaxoSmithKline over a 3-year period; the remaining authors reported no financial conflicts.

Women who eat nut products such as peanut butter daily throughout pregnancy may significantly increase their children's risk of developing asthma symptoms, according to a Dutch cohort study.

At 8 years of age, children whose mothers reported daily consumption of nut products were at significantly increased risk for steroid use (odds ratio 1.62), dyspnea (OR 1.58), and wheeze (OR 1.42), compared with children of women who reported only rarely (no more than three times per month) eating nut products. The data were adjusted for factors such as parental atopy, maternal smoking in pregnancy, and breast-feeding. The associations were independent of the children's diets.

The investigators stressed that these findings should be replicated in other studies “before influencing dietary advice given to pregnant women” (Am. J. Respir. Crit. Care Med.;177:1-8).

Previous research on the effectiveness of maternal dietary allergen avoidance during pregnancy in prevention of childhood allergic disease has been “inconclusive,” wrote Saskia M. Willers of the environmental epidemiology division at Utrecht University, the Netherlands, and associates. They added that their study is the first to use longitudinal statistical methods to assess the relationship over an extended period.

The researchers enrolled 4,146 women (1,327 atopic and 2,819 nonatopic). Complete data were available for 2,832 children whose mothers completed questionnaires at baseline on their dietary habits during pregnancy. The questionnaires assessed frequency of the women's consumption of vegetables, fresh fruit, fish, eggs, milk, milk products, nuts, and nut products; possible responses ranged from “never” to “several times per day.”

“Because we mentioned peanut butter as an example of nut products in the questionnaire and because peanut butter is a commonly used spread on sandwiches in the Netherlands … we assumed that the largest proportion of nut products is peanut butter,” the researchers wrote.

Children were followed up at 3 months and then once a year from ages 1 through 8; a dietary assessment was conducted at age 2. At age 8, 13.2% of the children had asthma symptoms, and another 3.9% had asthma diagnosed by a doctor.

Daily consumption of nut products was the only factor assessed that showed a significant association with increased incidence of asthma symptoms. In an interview, Ms. Willers noted that the lack of a significant association between asthma symptoms and daily consumption of nuts—as opposed to nut products—may have been due to the small sample size of women (1.4%) who ate nuts daily. In addition, she said, the nut products consumed were made largely from peanuts, but women who ate nuts daily also may have eaten less allergenic types of nuts.

In a crude analysis, women who ate fruit daily were significantly less likely to have children who wheezed than were those who ate fruit only regularly or rarely (odds ratio 0.82), but that association disappeared after adjustment for socioeconomic factors, parental atopy, and other factors.

The researchers said their findings are limited by their inability to obtain more information on specific foods and portion sizes. They said they included the main food groups associated with asthma, but other foods and nutrients cannot be ruled out as having been responsible for the asthmatic symptoms identified.

One of the study investigators reported having received an unrestricted research grant from GlaxoSmithKline over a 3-year period; the remaining authors reported no financial conflicts.

Women who eat nut products such as peanut butter daily throughout pregnancy may significantly increase their children's risk of developing asthma symptoms, according to a Dutch cohort study.

At 8 years of age, children whose mothers reported daily consumption of nut products were at significantly increased risk for steroid use (odds ratio 1.62), dyspnea (OR 1.58), and wheeze (OR 1.42), compared with children of women who reported only rarely (no more than three times per month) eating nut products. The data were adjusted for factors such as parental atopy, maternal smoking in pregnancy, and breast-feeding. The associations were independent of the children's diets.

The investigators stressed that these findings should be replicated in other studies “before influencing dietary advice given to pregnant women” (Am. J. Respir. Crit. Care Med.;177:1-8).

Previous research on the effectiveness of maternal dietary allergen avoidance during pregnancy in prevention of childhood allergic disease has been “inconclusive,” wrote Saskia M. Willers of the environmental epidemiology division at Utrecht University, the Netherlands, and associates. They added that their study is the first to use longitudinal statistical methods to assess the relationship over an extended period.

The researchers enrolled 4,146 women (1,327 atopic and 2,819 nonatopic). Complete data were available for 2,832 children whose mothers completed questionnaires at baseline on their dietary habits during pregnancy. The questionnaires assessed frequency of the women's consumption of vegetables, fresh fruit, fish, eggs, milk, milk products, nuts, and nut products; possible responses ranged from “never” to “several times per day.”

“Because we mentioned peanut butter as an example of nut products in the questionnaire and because peanut butter is a commonly used spread on sandwiches in the Netherlands … we assumed that the largest proportion of nut products is peanut butter,” the researchers wrote.

Children were followed up at 3 months and then once a year from ages 1 through 8; a dietary assessment was conducted at age 2. At age 8, 13.2% of the children had asthma symptoms, and another 3.9% had asthma diagnosed by a doctor.

Daily consumption of nut products was the only factor assessed that showed a significant association with increased incidence of asthma symptoms. In an interview, Ms. Willers noted that the lack of a significant association between asthma symptoms and daily consumption of nuts—as opposed to nut products—may have been due to the small sample size of women (1.4%) who ate nuts daily. In addition, she said, the nut products consumed were made largely from peanuts, but women who ate nuts daily also may have eaten less allergenic types of nuts.

In a crude analysis, women who ate fruit daily were significantly less likely to have children who wheezed than were those who ate fruit only regularly or rarely (odds ratio 0.82), but that association disappeared after adjustment for socioeconomic factors, parental atopy, and other factors.

The researchers said their findings are limited by their inability to obtain more information on specific foods and portion sizes. They said they included the main food groups associated with asthma, but other foods and nutrients cannot be ruled out as having been responsible for the asthmatic symptoms identified.

One of the study investigators reported having received an unrestricted research grant from GlaxoSmithKline over a 3-year period; the remaining authors reported no financial conflicts.