Animal fats are not great for Alzheimer's disease either, researchers have discovered. Saturated or trans - unsaturated (hydrogenated) fats found in animals and dairy, as well as synthetic products such as margarine - can increase the risk of developing the disease.
But, conversely, unsaturated, unhydrogenated fats - found in the fish oils, such as essential fatty acids (EFAs), omega-3 and -6, and in cold-pressed olive oil - seem to have a protective effect against the disease.
The researchers monitored 815 residents of a community centre who were all aged over 65 years, and did not have Alzheimer's at the start of the study.
During the next four years, the participants completed a food questionnaire that revealed the role that the good and bad fats played. Those who were in the highest level of intake of animal fats had a 2.2 times greater chance of developing Alzheimer's compared with those in the lowest fifth.
(Source: Archives of Neurology, 2003; 60: 194-200).