High fat meals a bad idea for asthmatics

Researchers at the University of Newcastle randomised 40 asthmatic subjects to receive either a high-fat, high-calorie meal of fast food burgers and hash browns containing about 1,000 calories, 52% of which were from fat; or a low-fat, low-calorie meal consisting of reduced fat yogurt, containing about 200 calories, and 13% fat. Sputum samples were collected before the meal and four hours afterward, and analyzed for inflammatory markers.

Those who had eaten the high-fat meal had a marked increase in airway neutrophils and TLR4 mRNA gene expression. TLR4 is a cell surface receptor that is activated by nutritional fatty acids: TLR4 'senses' the presence of saturated fatty acids, and prompts the cell to respond to the fatty acids as if they were an invading pathogen, releasing inflammatory mediators.

While the study didn't definitively distinguish between the effect of high fat and high calorific energy, this increase in TLR4 activity suggests that dietary fat is very relevant.

Subjects who had consumed the high fat meal also had reduced bronchodilator response as measured by FEV1% predicted and FEV1/FVC%, when compared to those had consumed the low-fat meal – in other words they did not respond so well to their asthma medication for several hours after the meal – a result that the researchers had not expected.

High dietary fat intake has previously been shown to activate the immune response, and therefore inflammation. However, the effect of a high fat meal on airway inflammation, which contributes to asthma, had not been investigated.

The research was presented at the American Thoracic Society 2010 International Conference in New Orleans

Courtesy ofScience Daily.

First Published in May 2009

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