The walnuts were unique as rich sources for n-6 and particularly n-3 polyunsaturated fatty acids.

BBC: Walnuts

This regulates the metabolism of a group of molecules called long-chain polyunsaturated fatty acids.

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However, Dr Haby said more research was needed before the link between polyunsaturated fats and asthma could be proved.

BBC: Margarine 'may increase asthma risk'

Liquid oils are usually unsaturated fats, including monounsaturated fats in olive and canola oils and polyunsaturated fats in safflower, corn, soybean and fish oils.

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Lead researcher Dr Michelle Haby, from the Centre for Community Child Health, Royal Children's Hospital, Melbourne, told BBC News Online why polyunsaturated fats might be linked to asthma.

BBC: Margarine 'may increase asthma risk'

Polyunsaturated fats, contained in walnuts and soy oil, are good.

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The authors suggest that the increase in the number of children developing asthma could be significantly reduced if more were breastfed or given a diet lower in polyunsaturated fats.

BBC: Margarine 'may increase asthma risk'

Of the types of fat saturated, polyunsaturated, monounsaturated and trans fat saturated fat and trans fat increase the risk of coronary artery disease by raising blood cholesterol levels.

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Meanwhile, it will increase polyunsaturated fat by 167%.

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Welcome to Polyunsaturated Alcatraz.

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