Pregnant women who followed a Mediterranean diet experienced a protective effect against asthma-like symptoms and atopy in their children, according to the results of a prospective cohort study reported in the January 15 Online First issue of Thorax.
“Dietary intake of specific nutrients or food groups during pregnancy could play a role in the risk of asthma and atopy in offspring, but specific dietary patterns have not been implicated,” write Leda Chatzi, MD, PhD, from the University of Crete in Heraklion, Greece, and colleagues. “In general, the Mediterranean diet is characterised by elevated intake of plant foods such as fruits and vegetables, bread and cereals (primarily wholegrain), legumes and nuts. Low to moderate amounts of dairy products and eggs, and only little amounts of red meat are included in the diet. This dietary pattern is low in saturated fatty acids, rich in carbohydrates, fibre and antioxidants, and has a high content of monounsaturated fatty acids and n-3 polyunsaturated fatty acids, which are primarily derived from olive oil and fish intake.”
The investigators recruited women presenting for antenatal care at all general practices in Menorca, a Mediterranean island in Spain, during a 12-month period beginning in mid-1997. After 6.5 years of follow-up, 460 children were included in the analysis. Food frequency questionnaires were used to evaluate maternal dietary intake during pregnancy and children’s dietary intake at age 6.5 years, and a priori defined scores evaluated adherence to a Mediterranean diet. Follow-up included parental questionnaires on the child’s respiratory tract and allergic symptoms, as well as skin prick tests, with 6 common aeroallergens, for the children.
At age 6.5 years, prevalence rates were 13.2% for persistent wheeze, 5.8% for atopic wheeze, and 17.0% for atopy. According to the Mediterranean Diet Score during pregnancy, one third (36.1%) of mothers had a low-quality Mediterranean diet, and the rest had a high-quality Mediterranean diet.
After adjustment for potential confounders and use of the “low” score as the reference, a high Mediterranean Diet Score during pregnancy was found to be protective for persistent wheeze (odds ratio [OR], 0.22; 95% confidence interval [CI], 0.08 – 0.58), atopic wheeze (OR, 0.30; 95% CI, 0.10 – 0.90), and atopy (OR, 0.55; 95% CI, 0.31 – 0.97) at age 6.5 years.
Adherence to a Mediterranean diet during childhood was negatively associated with persistent wheeze and atopy, but this did not reach statistical significance.
“Our results support a protective effect of a high level of adherence to a Mediterranean diet during pregnancy against asthma-like symptoms and atopy in childhood,” the study authors write.
Limitations of the study include no information on maternal food allergy, and parental reports on children’s diet and symptoms creating possible information bias.
“Further studies are needed to better understand the mechanisms of this protective effect and the most relevant window of exposure,” the study authors conclude. “Further follow-up of this cohort will allow determining if this protective effect persists in older children.”
This study was supported by the Instituto de Salud Carlos III red de Grupos Infancia y Media Ambiente, the Fundacio “La Caixa,” the Instituto de Salud Carlos III, red de Centros de Investigacion en Epidemiologia y Salud Publica and EU grant NewGeneris. One of the study authors has received support in part from the National Center for Environmental Health – Centers for Disease Control and Prevention, Atlanta, Georgia; the GA2LEN project; and the Ministry of Education and Science, Spain. Another study author has received support from the Oficina de Ciencia y Tecnología, Generalitat Valenciana.
Thorax. Published online January 15, 2008.
Clinical Context
Dietary habits seem to play a role in the risk for wheezing and atopy. According to Romieu and colleagues in the April 2007 issue of Clinical and Experimental Allergy, fish intake during pregnancy was linked to a lower risk for eczema, atopy, and atopic wheeze in the offspring. In the June 2007 issue of Thorax, Garcia-Marcos reported that a Mediterranean diet in female children seemed to protect against severe asthma.
In the November 1997 issue of Nutrition Reviews, Trichopoulou described a Mediterranean diet: high intake of fruits, vegetables, wholegrain bread and cereals, legumes, and nuts; low to moderate dairy products and eggs; and low intake of red meat. Overall, there is low intake of saturated fatty acids and high intake of fiber, antioxidants, monounsaturated fatty acids, and n-3 polyunsaturated fatty acids (from fish and olive oil).
This cohort study of pregnant women and their offspring from Menorca, a Mediterranean island in Spain, evaluates whether adherence to a Mediterranean diet during pregnancy and childhood affects the prevalence of asthma-like symptoms and atopy in the children.
Study Highlights
- 507 pregnant women in a Mediterranean region were recruited in a 12-month period.
- Data were available for 468 of their offspring at age 6.5 years.
- 8 children were excluded because of total energy intake values less than 800 kcal/day or more than 3000 kcal/day.
- Parents were interviewed every year about the child’s medical conditions in the previous 12 months.
- Demographic data were obtained during pregnancy and at the child’s age of 6.5 years.
- 415 (90.2%) children had height and weight data at age 6.5 years.
- For assessment of childhood dietary intake at age 6.5 years, a 96-item food frequency questionnaire and point values for Mediterranean-related foods (vegetables, legumes, fruits, nuts, cereal, fish, dairy products, olive oil) and non–Mediterranean-type foods (sweets, fast foods) were used to categorize diet as optimal, medium-quality, or low-quality Mediterranean.
- For assessment of maternal dietary intake during pregnancy, a 42-item food frequency questionnaire and point system for Mediterranean-type foods were used to categorize diet as high or low in Mediterranean diet quality.
- Primary outcome measures at age 6.5 years were persistent wheeze (defined by at least 1 episode of “whistling or wheezing from chest, but not noisy breathing from nose” in the previous 12 months and preceding years), atopic wheeze (current wheeze and atopy), and atopy (skin prick test).
- Skin prick testing was conducted on 412 (89.6%) children at age 6.5 years.
- Adjustment was made for possible confounding factors: sex, parental asthma, maternal factors (atopy, age at pregnancy, social class, education, smoking during pregnancy, supplement use during pregnancy), breast-feeding, lower respiratory tract infections at age 1 year, birth weight, gestational age, birth order, number of siblings, and body mass index at age 6.5 years.
- Childhood adherence to a Mediterranean diet was low quality for 9.3%, intermediate for 53.7%, and high for 37.0%.
- Maternal adherence to a Mediterranean diet was low quality for 36.1%.
- At age 6.5 years, 13.2% of children had persistent wheeze, 5.8% had atopic wheeze, and 17.0% had atopy.
- High level of childhood adherence to a Mediterranean diet was not significantly associated with wheeze, atopic wheeze, and atopy at age 6.5 years.
- High level of maternal adherence to a Mediterranean diet during pregnancy was protective for all outcome measures in children at age 6.5 years:
- Persistent wheeze (OR, 0.23; 95% CI, 0.09 – 0.60)
- Atopic wheeze (OR, 0.34; 95% CI, 0.12 – 0.97)
- Atopy (OR, 0.55; 95% CI, 0.32 – 0.97)
- Lower risk for childhood wheeze was associated with maternal intake of certain foods:
- Vegetables more than 8 times per week (OR, 0.36; 95% CI, 0.14 – 0.92)
- Fish more than 2.5 times per week (OR, 0.34; 95% CI, 0.13 – 0.84)
- Legumes more than once per week (OR, 0.36; 95% CI, 0.13 – 1.01)
- Lower risk for childhood atopy was associated with maternal intake of vegetables more than 8 times per week.
- Maternal adherence to a Mediterranean diet was linked with childhood adherence to a Mediterranean diet.
Pearls for Practice
- Maternal adherence to a Mediterranean diet during pregnancy is linked to a lower risk for persistent wheeze, atopic wheeze, and atopy in the offspring during childhood.
- Adherence to a Mediterranean diet during childhood does not significantly affect the risk for persistent wheeze, atopic wheeze, and atopy in childhood.
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