It’s been engrained in you that a high level of good cholesterol, known as HDL cholesterol, is good because it moves extra cholesterol out of the bloodstream, keeping your arteries safe from buildup.
Well, you can log this new research into the file “no good deed goes unpunished” because, in certain instances, good cholesterol can in fact hurt you. Especially when it comes to your memory.
Here’s what you need to know about HDL and the simple way you can protect your brain from any damage…
What’s good for the heart is good for the brain has long been the medical motto, so when the nation’s number one hospital for heart care – the Cleveland Clinic – proclaims: “An HDL above 60 offers you protection against heart disease. It’s the one number in your lipid panel that you want to be high,” shouldn’t we take note?
Yes, but in this case, it’s smart to be skeptical because some very trustworthy medical experts are raising serious concerns about having an HDL this high. They point to alarming research that shows you can in fact have too much of a good thing.
Harvard Cardiologist Speaks Out Against High HDL
This isn’t the first time we’ve warned readers of our publications about the dangers of high cholesterol. As we’ve previously reported, long time heart researcher Professor Børge G Nordestgaard MD, DMSc at the University of Copenhagen, Denmark, said: “Doctors like myself have been used to congratulating patients who had a very high level of HDL in their blood. But we should no longer do so…”
And Sekar Kathiresan, a “superstar” cardiologist at the Broad Institute of MIT and Harvard, expressed similar sentiments, saying, “When I started medical school in 1992, I was taught that anything that raised HDL cholesterol must be good for you. We can now safely disregard that notion.”
So, what’s the problem with very high HDL cholesterol?
Very High HDL Linked to Disease and Death
A new review published in the European Heart Journal in April gives us the answer.
The researchers wrote that extremely high HDL is linked to an increased risk of age-related macular degeneration, infectious diseases, cardiovascular mortality, mortality from any cause, and, most of all, dementia.
This is clearly an issue that warrants more research, so scientists from Boston University decided to look more closely at the effect of high HDL levels on dementia specifically.
15 Percent Higher Risk of Dementia
Their study, published in the journal Neurology in October, involved 184,367 Californian residents with an average age of 70 who were dementia-free when the study began.
The participants filled out a health survey and had their cholesterol levels measured an average of 2.5 times over the following two years. Researchers followed them for a total of 17 years during which 25,214 people developed dementia.
After dividing the participants into five groups according to their HDL levels, and after taking many factors into account that affect dementia risk, the researchers found those in the top fifth (with an HDL above 65md/dL) had a 15 percent higher rate of dementia compared to those in the middle three groups. Participants in the bottom fifth (with an HDL below 41mg/dL) had a seven percent higher rate of dementia compared to those in the middle groups.
So, the people with HDL cholesterol in the normal range fared the best, with the lowest dementia risk.
What’s more, researchers only found a slight association between LDL “bad” cholesterol and a higher risk of dementia. This doesn’t surprise me since many alternative doctors point to high cholesterol foods like eggs for a sharper noggin.
Senior author Maria Glymour further explained the results, saying, “this study is especially informative because of the large number of participants and long follow-up.
“The elevation in dementia risk with both high and low levels of HDL cholesterol was unexpected, but these increases are small, and their clinical significance is uncertain. Our results add to evidence that HDL cholesterol has similarly complex associations with dementia as with heart disease and cancer.”
But despite the small increases in dementia risk from the Boston University study, two other large studies have made the high HDL-dementia connection. What’s more, they were better able to answer the question…why?
Large HDL Particles Harm The Brain
In the first study, published last year, high HDL cholesterol increased the risk of Alzheimer’s disease and all other forms of dementia among 111,984 participants.
In the second study, published earlier this year, almost one hundred international scientists collaborated on a study that included 39,106 participants with clinically diagnosed Alzheimer’s and 401,577 control participants without the condition. They found those with genetically caused high HDL had a higher risk of the disease.
The senior author of both studies, Ruth Frikke-Schmidt, explained the possible reason for the connection between high HDL cholesterol and dementia, saying, “High HDL cholesterol is associated with the presence of large, buoyant HDL particles that may be dysfunctional in local cholesterol transport inside the brain and across the blood-brain barrier, and this may have implications for cholesterol supply to the brain cells and clearance of sticky waste products.”
In other words, these big chunks of HDL might be too much for healthy brain tissue to handle, and as a result, cause problems for normal brain function that impacts memory.
So, Where Should My HDL Level Be?
Obviously, this is just the beginning of the conversation, and far more research is needed. However, the implications the results of these three studies have on your memory are too important to ignore.
While it’s unlikely that the Cleveland Clinic will change their “heart-healthy” recommendations for pushing your HDL cholesterol level above 60 mg/dl any time soon, you can arm yourself with the knowledge that having a good HDL in a normal range is more than enough for your heart, your memory, and your overall health.
The normal HDL range for men is 40 mg/dl to 60 mg/dl. And for women it’s 50mg/dl to 60mg/dl.
If you’re taking cholesterol-lowering medications or other drugs specifically to increase HDL cholesterol levels, we recommend getting your cholesterol levels measured at your next appointment and talking to your doctor about this research.
The Awakening From Alzheimer’s Team
High-density lipoprotein revisited: biological functions and clinical relevance (2023) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10119031/
Both high and low HDL cholesterol tied to increased risk of dementia https://www.aan.com/PressRoom/Home/PressRelease/5117
Plasma high-density lipoprotein cholesterol and risk of dementia: observational and genetic studies (2022) https://pubmed.ncbi.nlm.nih.gov/33964140/