He searched for years and eventually lighted on a mixture of oleic acid (a fatty acid found in various vegetable oils) and nitrogen-containing compounds called amines.

ECONOMIST: To make engines cleaner, add H2O

Fast food often contains high levels of saturated- and trans-fatty acids, which are known to affect immunity, while fruit is rich in antioxidants and other beneficial compounds, say the researchers.

BBC: Fast-food 'linked to childhood asthma and eczema'