Researchers found that a Mediterranean diet during pregnancy may be more protective against childhood asthma than a child’s own diet.
by Crystal Phend, Staff Writer, MedPage Today
HERAKLION, Greece, Jan. 15 — A Mediterranean diet during pregnancy may be more protective against childhood asthma and atopy than a child’s own diet, researchers found.
- Inform patients that the Mediterranean diet emphasizes whole grains, fruits and vegetables, fish, and olive oil.
- Explain to interested patients that the study supports a benefit to the Mediterranean diet during pregnancy.
Women on the Spanish island of Menorca who closely followed the diet rich in whole grains, fruits and vegetables, and olive oil were less likely to have children with wheeze, atopy, or both than women who did not (P=0.002), found Leda Chatzi, M.D., of the University of Crete here, and colleagues.
These associations were independent of childhood diet, they reported online in the journal Thorax.
The researchers had previously linked children’s adherence to a traditional Mediterranean diet with lower risk of allergic rhinitis in a cross-sectional study that appeared last year in Thorax. (See: Mediterranean Diet Linked to Lower Pediatric Atopy)
But because previous studies had not looked at the impact of a dietary pattern beyond specific foods in pregnancy, the researchers conducted a longitudinal study among 507 women seen for antenatal care at all general practices in Menorca over a 12-month period and 468 of their children with complete outcome through age 6 1/2.
At that age, most of the children (89.6%) underwent skin prick testing for common allergens. The prevalence of atopy was 17%. Persistent wheeze and atopic wheeze were present in 13.2% and 5.8%, respectively.
Food frequency questionnaires were used to assess usual dietary intake in the women during pregnancy and in the children at 6 1/2.
Among the children, 53.7% were classified by food frequency scores as having medium adherence to a Mediterranean diet and 37% had high adherence.
High adherence in childhood was less often associated with persistent wheeze (odds ratio: 0.46, P=0.523), atopic wheeze (OR: 0.64, P=0.902), and atopy (OR: 0.49, P=0.213) than lower adherence, but none of the associations were significant.
Of the mothers, 63.9% had high adherence to a Mediterranean diet during pregnancy.
Those women were significantly less likely to have children with persistent wheeze (OR: 0.23, 95% confidence interval: 0.09 to 0.60), atopic wheeze (OR: 0.34, 95% CI: 0.12 to 0.97), or atopy (OR: 0.55, 95% CI: 0.32 to 0.97) at age 6 1/2.
Maternal diet in pregnancy was strongly linked to children’s later diet (P=0.002), but adding childhood diet to the model did not change the associations and the interaction was not significant.
The associations in pregnancy also remained strong for persistent wheeze (OR: 0.69 per unit increase, 95% CI: 0.50 to 0.97) and atopic wheeze (OR: 0.79 per unit increase, 95% CI: 0.55 to 1.13) when Mediterranean diet adherence scores were treated as a continuous variable.
The components of the Mediterranean diet that appeared to be most important for the protective effect were vegetable intake more than eight times a week (OR: 0.36 for persistent wheeze and OR: 0.40 for atopy), fish more than two to three times a week (OR: 0.34 for persistent wheeze), and consumption of legumes more than once a week (OR: 0.36 for persistent wheeze).
Maternal red meat consumption more than three to four times a week tended to increase the likelihood of persistent wheeze and atopic wheeze in the children.
The protective effects thus “probably reflect high fetal exposure to several antioxidant compounds and their adverse effect on oxidative stress damage of lung tissues,” the researchers suggested.
The greater effects of diet during pregnancy than a child’s subsequent diet suggest there may be an optimal window of exposure before an allergic response is established, they said.
“Allergen specific responses are already evident at birth and allergic disease is often manifest within the first month of life,” they added, “suggesting that the processes that lead to allergic diseases can be initiated very early in immune development.”
Further studies are needed to define the mechanism and most important window of exposure, they said, as well as to determine if the effect persists in older children.
The study was supported by the Instituto de Salud Carlos III red de Grupos Infancia y Media Ambiente and de Centros de Investigacion en Epidemiologia y Salud Publica, the Fundacio “La Caixa,” and a grant from the European Union.
One of the researchers was supported in part by the CDC, the GA2LEN project, and the Spanish Ministry of Education and Science. Another reported additional support from the Oficina de Ciencia y Tecnología, Generalitat Valenciana.
The researchers reported no financial conflicts of interest.
Primary source: Thorax
Chatzi L, et al “Mediterranean diet in pregnancy is protective for wheeze and atopy in childhood” Thorax 2008; DOI: 10.1136/thx.2007.081745.
Additional resources on this topic:
- Allergies: An Integrative Approach
- Food and Environmental Allergies: Controlling the Body’s Burden
- Modulation of Asthma and Allergy by Addressing Toll-Like Receptor 2
- Pesticides Linked to Asthma in Women
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Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco
Published: January 15, 2008
|To hear more about this topic first-hand, attend Food as Medicine for Digestive Health and Wellness at the 2009 Integrative Healthcare Symposium. Integrative Practitioner members get 15% off Symposium registration when they enter discount code7470.|