Abstract
Intensive methods of rearing fish, broilers, egg layers and pigs can reduce the proportion of cis polyunsaturated fatty acids (PUFAs) to saturated fatty acids in the food. Irradiation, and deepfreezing and cook-chill systems may also reduce PUFAs. It is not known whether microwave exposure converts cis fatty acids to trans. We request that all food items produced by intensive farming and/or processing be regularly analyzed for PUFAs and labelled accordingly. Changes in the methods of feeding food animals, poultry and fish, and their processing, may be partly responsible for the continued high incidence of coronary heart disease.