New study counters previous research linking intake of dietary fat with increased risk of dementia
December 24, 2002
ST. PAUL, MN – High dietary intakes of total fat, saturated and trans fats and cholesterol have long been associated with such health risk factors as heart disease, obesity, diabetes, and several forms of cancer. And while researchers continue to articulate ways in which a high-fat diet may negatively impact overall health, there appears to be at least one devastating health condition that cannot yet be tied to the percentage of fat one consumes: dementia.
According to a study reported in the December 24 issue of Neurology, the scientific journal of the American Academy of Neurology, dietary intake of fat was not associated with an increased risk of dementia. For this study, more than 5,000 subjects from the Rotterdam Study, a large,population-based study examining risk factors for a variety of diseases among the elderly, were followed for an average of six years by researchers from Erasmus Medical Center in Rotterdam, the Netherlands.
"Previous research has suggested that fat may be involved in the development of dementia," said Monique Breteler, MD, Ph D, senior study author. For example, smaller studies with animals have linked cholesterol to the risk of dementia and the development of Alzheimer's Disease (AD), while cholesterol lowering medications have been linked to a lower prevalence of AD in humans. Furthermore, specific fatty acids, such as those found in olive oil, vegetable oils and fatty fish, were associated with a reduced risk of dementia. "Based on these observations, we set out to examine further whether or not dietary cholesterol increases and some fatty acids may reduce the risk of developing dementia."
The study population comprised 5,395 participants who had normal cognition, lived independently and had reliable dietary assessments. Participants were also assessed regarding such variables as age, gender, body mass index, prevalent diseases, level of education, smoking habits, alcohol use, and intake of dietary supplements.
After an average of six years, with adjustments made for the variables given above, researchers concluded that the intake of total fat, saturated and trans fats and cholesterol was not associated with an increased risk of dementia. Additionally, intakes of specific fatty acids and/or cholesterol lowering medications were not associated with a reduced risk.
"While we feel there are several validating features of our study relative to previous studies, including the population-based, longitudinal design, length and consistency of follow-up, and our adjustments for several potential confounders," comments Breteler, "we feel it is premature to conclude with certainty that fat intake is in no way associated with dementia." Breteler and colleagues recommend more large prospective studies with long-term follow-up.