Asthma is one of the most common chronic disorders in childhood, affecting an estimated 7.1 million children under 18 years, according to the American Lung Association. It’s a condition that ranks as a chief cause of school absenteeism and emergency room visits for children age 15 and under. Asthma is highly prevalent in the U.K. with 10-15% of children and 5-10% of adults diagnosed with the disease. Intrigued by the influence of maternal diet on childhood disease development, researchers at the University of Aberdeen in the U.K. are engaged in a multi-phase study focusing on the impact of food-source vitamin E on childhood asthma development with promising results.
“Since 1997-98 we have been conducting a birth cohort study whereby we recruited 2,000 pregnant women during early pregnancy and characterized their diet,” explained Dr. Graham Devereux, a professor of respiratory medicine and an honorary consultant physician at the University of Aberdeen. “Our first finding was of an association between cord blood immune responses and maternal vitamin E intake. At the two- and five-year follow up, maternal vitamin E was associated with symptoms and lung function. These findings have subsequently been replicated by birth cohorts in the U.S. and Japan.”
Their pilot study, published earlier this year in the Journal of the Academy of Nutrition and Dietetics, detailed their investigations into the feasibility and acceptability of encouraging 43 pregnant women who either had asthma themselves or whose partners had asthma to increase their intake levels of dietary vitamin E from 8 mg per day to 15 mg per day. The women in the control group received dietary advice and were encouraged to consume vitamin E-rich food options such as breakfast cereals, coleslaw, seeds, sunflower oil and flapjacks. The researchers based their findings on a four-day food diary kept by the women, which detailed the foods consumed and portion sizes.
Though they were able to prove that children born to mothers with a lower vitamin E intake during pregnancy were more likely to have poor lung function and subsequently develop asthma by the age of five, their dietary approach was not entirely well-received by their study subjects. “The dietary intervention was put to the user group of Asthma U.K. and proved to be rather unpopular because it was too complex; simplicity was what the patient body most desired,” Dr. Devereux told Nutraceuticals World.
But the team was not to be deterred. They are now working with a local food producer to develop a range of vitamin E-enhanced foods with similar looking and tasting placebos.
The food enhancements were made using a careful selection of food ingredients such as sundried tomatoes instead of tomatoes, wheat germ instead of corn flour, and sunflower oil instead of vegetable oil. “We are about to start a pilot study in pregnant women to see if this food intervention is acceptable and feasible."
The BBC specifically reported the development of a special vitamin E-rich soup which will be consumed by a group of 50 women three times a week. The researchers hope to determine if the new approach will be better tolerated and have the desired effect on blood serum vitamin E levels. If this phase of study proves successful, there are plans to study the effect on a larger group of 1,000 women.
When asked why food-source dietary vitamin E was preferred over standardized vitamin E supplements, Dr. Devereux said previous condition-specific trials using vitamin supplements were largely unsuccessful. “Humans have never consumed vitamin E in isolation, we have evolved consuming our nutrients in food form,” he said. “It is possible that vitamin E is a marker for a dietary pattern and that it is the complex mixture of nutrients associated with vitamin E that may be beneficial.”
In a recent interview with BBC News, Dr. Devereux said, “I wondered whether it might be the other nutrients that go with vitamin E in food that may be responsible for the effect. There may be interactions between vitamin E and the other nutrients.”
The other nutrients he suspected to have the beneficial effect were fatty acids, zinc, selenium and vitamin D—“nutrients which we know have been associated during pregnancy with childhood asthma,” he said.
So far, the modified diet approach has received support from U.K. nutritionists and asthma experts. “In general these studies [using diet supplement tablets] have been disappointing in that they have failed to show reductions in the risk of developing asthma in the treated subjects,” Professor Ian Hall an asthma expert from the University of Nottingham, told BBC News. “The current study adopts a novel approach by using natural supplementation in soup rather than a tablet based approach. It will be interesting to see if this proves more successful.”
Vitamin E and Childhood Asthma
U.K. researchers are working to determine if maternal food-source vitamin E intake can impact the development of asthma in children.
By Joanna Cosgrove, Online Editor