New research underscores the importance of eliminating butter, fatty meats and other sources of saturated fat from your diet. A study published online on June 17, 2013 in the journal JAMA Neurology suggests that saturated fat is bad for the brain, not only because it clogs cerebral blood vessels, but also because it deprives the brain of a protein it needs to protect itself from Alzheimer’s disease (AD). The chemical, a molecule called apolipoprotein E (ApoE), searches out toxic amyloid beta proteins that can harm neurons and escorts them away from the brain. Loose beta-amyloid that is not bound by ApoE is more likely to form the plaques and tangles that are a hallmark of AD.
The researchers recruited 20 adults in their late 60s with normal cognition and 27 similar adults with mild cognitive impairment (MCI, cognitive decline that is worse than average, but does not impair daily activity). Tests showed that participants with MCI had higher levels of beta-amyloid in their cerebrospinal fluid than those who did not have MCI. The groups of healthy and MCI participants were divided into two subgroups; one consumed a diet high in sugar and saturated fat, and the other a diet low in sugar and saturated fat. After four weeks, the researchers found that participants who ate a diet high in saturated fat had lower levels of ApoE in their cerebrospinal fluid, and had accumulated higher levels of beta amyloid.