We are all largely familiar with good cholesterol, bad cholesterol, and how cholesterol is a risk factor, or a possible precursor for many cardiovascular diseases. That said, what is less known is that cholesterol is, in effect, essential for the brain to function effectively. Healthy cholesterol has been shown to help improve memory retention and learning. It has also been known to assist in the production of various hormones.
Further, new research has suggested that cholesterol may be involved in dementia progression. Notwithstanding that, studies have also shown high blood cholesterol to be associated with an increased risk of Alzheimer’s disease and vascular dementia. This is especially compelling, considering that the brain is protected by the blood-brain barrier, a highly selective semipermeable border, that prevents solutes like cholesterol from entering the extracellular fluid of the central nervous system.
A study published by the journal of PLOS Medicine at the National Institute of Ageing in Baltimore has said that disturbances of cholesterol catabolism (conversion of cholesterol into bile) may play a role in the development of dementia. In order to investigate this hypothesis, researchers recruited more than 1800 participants from two different prospective studies: The Baltimore Longitudinal Study of Ageing, and The Alzheimer’s Disease Neuroimaging Initiative.
Researchers tested whether cholesterol catabolism was associated with brain abnormalities typical of Alzheimer’s and vascular dementia. They also wanted to draw an association between exposure to cholesterol medication (that blocks bile acid absorption into the bloodstream) and an increased risk of dementia. The test considered over 26,000 patients from GP clinics in the UK. The researchers also examined numerous autopsy samples to determine if individuals diagnosed with Alzheimer’s did in fact have altered bile acid levels in their brains.
The study found that males showed an increased risk of vascular dementia compared to females. The findings also suggested that cholesterol catabolism and bile acid synthesis may potentially impact dementia progression through sex-specific effects on brain signaling pathways.
Unfortunately, the study was only able to examine few autopsy samples. Therefore, further research is required to better understand the relationship between cholesterol and dementia. Even so, this study provides relevant insight into the role cholesterol and bile acid play in the progression of dementia, and may provide impetus in the future to help slow its progression.
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Edited by Malavika