Study suggests “good” cholesterol may lower risk of Alzheimer’s

A recent study published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association suggests that higher levels of small high-density lipoproteins (HDLs or “good” cholesterol) could help lower the risk of older people developing Alzheimer's disease in their lifetime. 

Researchers studied “good cholesterol” in cerebrospinal (CSF) fluid, the fluid that surrounds the brain and spinal cord, and its link to the risk of Alzheimer's. The study involved 180 participants all aged 60 or above. 

The study involved using a range of cognitive tests to examine participants’ cognitive abilities. They extracted CSF and plasma samples and isolated the DNA. They then tested the DNA for the APOE4 gene, which is a potential risk factor for the neurodegenerative disorder Alzheimer’s. 

Then, the researchers studied how many small HDL particles could be found in the CSF, concluding that higher levels were found in participants with better cognitive function. Even after accounting for the APOE4 gene and other factors like age, sex and education, the result was the same. 

Author of the study Hussein Yassine told Medical News Today: “The discovery of lipid particles (LDL, HDL) in [the] blood led to several advances in drug discovery for cardiovascular disease treatment and prevention. Here for the first time, we measure HDL particles in cerebrospinal fluid as a surrogate of brain HDL and find that greater levels of small HDL correlate with better performance on cognitive measures.”

Cholesterol is found in the body in two main forms: low-density lipoprotein (LDL) and HDL. LDLs are commonly seen as bad cholesterol, as they can accumulate in the bloodstream and cause increased risk of heart attacks and strokes. HDLs, on the other hand, is seen as “good” cholesterol and helps return cholesterol to the liver where it is broken down. Research is currently underway to better understand how HDL levels affect other parts of the body such as the brain. 

“Good” cholesterol is found in foods such as olive oil, avocados, salmon, whole grains, beans and even wine. It’s important to eat enough of these kinds of foods to boost HDL cholesterol in the body and maintain good overall cholesterol levels. 

Although the study offers intriguing findings that could be used to inform the development of biomarkers to predict Alzheimer’s progression, there are some limitations that must be acknowledged. Namely, the relatively small sample size and that more research is needed to understand how HDLs in the brain interact differently compared with those in general circulation. 

Alzheimer’s disease is a type of dementia that affects more than 850,000 people in the UK according to the NHS. There is currently no cure for Alzheimer’s, but making certain lifestyle choices to maintain overall health and wellbeing can help reduce the risk of developing the neurodegenerative disease later in life.