The following appeared as part of an article in a health magazine.
　　"A new discovery warrants a drastic change in the diets of people living in the United States. Two scientists have recently suggested that omega －3 fatty acids play a key role in mental health. Our ancestors， who ate less saturated fat and more polyunsaturated fat， including omega －3 fatty acids， were much less likely to suffer from depression than we are today. Moreover， modern societies－－－such as those in Japan and Taiwan－－－that consume large quantities of fish report depression rates lower than that in the United States. Given this link between omega －3 fatty acids and depression， it is important for all people in the United States to increase their consumption of fish in order to prevent depression."