A new study has found that the types of fats and cholesterol in a person’s blood may influence their chances of developing Alzheimer’s disease, a condition that causes memory loss and is the most common form of dementia.
The study, led by researchers at UT Health San Antonio, looked at different blood fat markers in more than 800 older adults and found some surprising connections to brain health.
Scientists already know that people with a higher risk for heart disease also tend to have a higher risk of developing dementia. This is because heart and brain health are closely linked.
Problems that affect the heart and blood vessels, like high cholesterol or clogged arteries, can also affect blood flow to the brain. In turn, poor blood flow may lead to damage in brain cells and increase the chance of memory problems over time.
The researchers used data from the Framingham Heart Study, a famous long-term health study that began in 1948 in Framingham, Massachusetts. In this study, people have been examined regularly for decades, making it a rich source of health information.
For this latest research, the team focused on participants who were 60 or older and did not have dementia when they were examined between 1985 and 1988. They followed the participants’ health until 2020 to see who developed Alzheimer’s disease.
They found that certain types of fat particles in the blood were connected to a higher or lower risk of Alzheimer’s. One type of cholesterol particle, called small dense LDL cholesterol, or sdLDL-C, was linked to a higher risk.
These particles are a small, sticky form of “bad” cholesterol that is more likely to clog arteries and cause heart disease. The researchers found that for every increase in sdLDL-C, the chance of developing Alzheimer’s went up by 21%.
Interestingly, another fat-related marker called ApoB48 was linked to a lower risk of Alzheimer’s. ApoB48 is involved in moving fat from the intestines into the bloodstream after we eat. While it’s also tied to heart disease in some cases, in this study, higher levels were associated with a 22% decrease in Alzheimer’s risk.
Another surprising result came from looking at HDL cholesterol, commonly known as “good” cholesterol. Normally, high levels of HDL are seen as good for heart health.
But in this study, people who had the lowest levels of HDL cholesterol were actually 44% less likely to develop Alzheimer’s compared to others with higher levels. This unexpected finding shows that the relationship between cholesterol and brain health is more complex than we once thought.
Overall, people with lower levels of sdLDL-C and higher levels of ApoB48 had a lower chance of getting Alzheimer’s. And strangely, lower levels of HDL cholesterol were also linked with reduced risk.
The researchers say that these findings show how fats in the blood may affect the brain in ways we don’t fully understand yet. They believe that tracking blood fats could someday help doctors identify people at higher risk for Alzheimer’s before symptoms begin. It might also lead to new ways to prevent dementia by managing blood fat levels through diet, lifestyle, or medicine.
Dementia is a major global health concern. In 2019, about 57 million people worldwide were living with it, and this number is expected to grow to over 150 million by 2050.
However, in some high-income countries like the United States, rates of dementia have actually gone down in recent years. Experts believe this may be partly due to better control of heart disease risk factors, like blood pressure and cholesterol.
The lead author of the study, Dr. Sokratis Charisis, explained that the results highlight just how closely heart and brain health are linked. The team hopes that more research will help us learn whether changing certain fats in the blood could lower the risk of Alzheimer’s disease.
Their findings were published in the journal Neurology on May 30, and the team included scientists from UT Health San Antonio, Boston University, and other U.S. research centers.
If you care about Alzheimer’s disease, please read studies about the protective power of dietary antioxidants against Alzheimer’s, and eating habits linked to higher Alzheimer’s risk.
For more health information, please see recent studies that oral cannabis extract may help reduce Alzheimer’s symptoms, and Vitamin E may help prevent Parkinson’s disease.
The research findings can be found in Neurology.
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