This suggests that infants who do not receive enough DHA and ARA in early infancy may end up with lower IQs. The consumption of fish was inversely associated to the incidence of dementia, and in particular to Alzheimer's disease. The results of this study suggest that eating a diet high in total fat, saturated fat and cholesterol may increase the risk of senility whereas the consumption of fish may reduce the risk of senility, as we grow older. Very high intakes of fish oil decreases blood clotting which could be a problem if one has internal bleeding in a car crash or a hemorrhagic stroke. Indeed, Eskimos have been known to die from nose bleeds on their very high omega-3 diet.
Fish has more nutrients than fish oil supplements and so are generally preferable.
Also, adding fish to the diet will reduce the consumption of other meat and poultry products which are generally higher in SFAs. Fish is a fairly high satiety food but fish oil supplements have little satiety value so would tend to add calories to ones ad libitum energy intake. Fats and oils in human nutrition. Food and Nutrition Paper No. 57. FOA, Rome, Italy.