When you think of cholesterol, you probably think of heart disease. But without this fat-like substance, you wouldn’t be able to think at all and your brain would not function normally.
Your Brain Needs Cholesterol to Function
The brain has the highest concentration of cholesterol in the body with 25 percent of the body’s total amount. Because it is so crucial, the brain makes its own supply. It improves membrane stability, reduces permeability, and may influence serotonergic function. The fatty substance is also necessary for synapse formation and myelin production.
Without enough of this essential brain nutrient, a person could experience brain and mental health problems — most commonly in the form of memory problems and/or depression. Research found that lower levels of cholesterol in the blood are associated with a heightened risk of developing major depressive disorder, as well as an increased risk of death from suicide.
There is a well-established link between cholesterol and brain function. In a study of 789 men and 1105 women, which examined the relationship between total cholesterol (TC) and cognitive performance, it was found that:
Lower naturally occurring TC levels are associated with poorer performance on cognitive measures, which place high demands on abstract reasoning, attention/concentration, word fluency, and executive functioning.”
Cholesterol in Action in Your Brain and Body
Your cholesterol dependency begins before you are born. There is rapid accumulation in the brain of this substance during the last three months of pregnancy. After birth, the brain continues to grow at a rapid pace, requiring a large and constant supply of cholesterol. That’s why human breast milk is a particularly rich source. This much-maligned yet essential substance is found in all body tissues. Without it, you wouldn’t be able to make vitamin D or your sex hormones.
In your brain, cholesterol has four main functions:
1. Antioxidant – The brain is 60% fat, making it vulnerable to damage from chemicals called free radicals. Cholesterol is a protective antioxidant in the brain, disabling free radicals before they can do any harm.
2. Insulation – The highest concentration of cholesterol is found in the myelin sheath, the insulating layer that wraps around and protects each nerve cell.
3. Barrier – Cholesterol forms part of the cell membrane, controlling what substances can pass in and out of the cell, and giving the cell structure.
4. Firing of neurotransmitters – Cholesterol ensures that neurotransmitters fire properly between nerve cell synapses.
Cholesterol is a multi-tasker in your brain when it comes to cognitive function. Because of this, it is hardly surprising that a deficiency can have numerous detrimental effects. Scientific research has determined that a deficiency is associated with various brain conditions, including dementia, depression, Parkinson’s, and autism.
Cholesterol and Dementia
The cerebrospinal fluid of patients with Alzheimer’s disease has been shown to be substantially low in cholesterol. Not surprisingly, then, high brain cholesterol in later life is associated with a reduced risk of developing dementia, and higher memory scores in tests.
Studies have determined that high cholesterol level is positively correlated with longevity in people over 85 years old, and in some cases has been shown to be associated with better memory function and reduced dementia.”
Cholesterol Deficiency and Depression
Writing in European Neuropsychopharmacology, scientists describe how significantly lower levels of cholesterol have been found in patients with depression and mood disorders, including bipolar disorder, major depressive disorder, and schizoaffective disorder, and is associated with increased risk of suicide.
Previous work has identified abnormalities in serum cholesterol levels in patients with mood and anxiety disorders as well as in suicidal patients.”
Science does not know precisely why or how these things are related, despite a range of theories. Further research is needed.
Cholesterol Deficiency and Autism
Cholesterol supplementation is a helpful medical treatment in some children with autism spectrum disorders (ASD). The Smith-Lemli-Opitz Syndrome (SLOS) is a genetic condition characterized by defective cholesterol biosynthesis. Children with SLOS have a high incidence of autism.
SLOS is treated with dietary cholesterol supplementation, which has been shown to result in less autistic behavior, as well as fewer infections, less irritability and hyperactivity, and improved sleep and social interactions.
Cholesterol ought to be considered as a helpful treatment approach while awaiting an improved understanding of cholesterol metabolism and ASD”.
Cholesterol Deficiency and Parkinson’s Disease
LDL cholesterol is sometimes referred to as “bad” cholesterol (a myth, as we shall see below). Yet low LDL cholesterol is associated with the development of Parkinson’s disease. One study, which looked at the incidence of Parkinson’s in the elderly, found that people with the lowest LDL had a 3.5 times greater risk of developing the disease than those with the highest LDL levels.
Why are statins so heavily prescribed?
Millions of people — most of them elderly — take statins on a daily basis. The role of this medication is to reduce blood cholesterol levels.
There is a great deal of controversy surrounding statin use and cognitive decline. Some studies have concluded that statins can even improve cognitive function, including memory. Yet people regularly report that they experience memory problems and mental confusion after taking the drug.
So frequent are these reports that the US Food and Drug Administration decided, in 2012, to issue safety warnings on the labeling of statins concerning possible memory loss. Since then, there have been calls for those warnings to be removed (presumably from pharmaceutical companies, and not from the people reporting memory loss and confusion).
Meanwhile, in the UK (described as the statin capital of Europe), statins are currently the most widely prescribed medication. The UK also has higher than average rates of dementia in Europe (1.65% in the UK, 1.55% across the EU), according to the organization Alzheimer Europe.
Whatever statins are doing, they don’t appear to be aiding in the prevention of dementia. On the contrary, because they lower brain cholesterol, statins may be contributing to cognitive decline.
A small study of eighteen elderly people with dementia and taking statins describes what happened when they were taken off the medication, and then put back on them.
The participants underwent tests to measure brain function using established tests. Significant changes were observed: an improvement in cognition with discontinuation of statins and worsening when they were reintroduced. In their conclusion, the researchers wrote:
“Statins may adversely affect cognition in patients with dementia.”
One possible reason for this may be that statins cross the blood-brain barrier and remove cholesterol from the brain. It was once thought that only the fat-soluble statins — atorvastatin, lovastatin, fluvastatin, simvastatin — were able to cross the blood-brain barrier. Now recent research suggests that water-soluble statins are also able to do the same.
If high cholesterol plays a protective role against dementia in the elderly, then the risk-benefit ratio of lowering cholesterol in this population may need to be reevaluated.”
Is there good and bad cholesterol?
You may have heard of “good” and “bad” cholesterol. The fact is, there is only one type of cholesterol, and it’s called cholesterol. That’s it. There are, however, different types of cholesterol transport systems.
Cholesterol is transported around the body by different carriers, known as lipoproteins. There are several types, the main ones being high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL).
High LDL is considered “bad” because it delivers cholesterol from the liver to other parts of the body, including the arteries. HDL is considered “good” because it transports cholesterol to the liver, for recycling. So the premise is that anything that lowers cholesterol is good, and anything that raises it is bad.
How can something supposed to be bad also be good?
This is where it starts to get messy. There are plenty of studies that find that HDL is protective against heart disease, and high LDL levels are a risk factor. However, there are also plenty of studies that find no association whatsoever between total cholesterol levels and the risk of heart disease. It’s hard to know what to make of it.
The vilification of cholesterol began with the famous Framingham Heart Study. This study was launched in 1950 with the aim of examining aspects of diet and lifestyle that might predispose people to heart disease. Framingham in Massachusetts was chosen because it was considered a typical American community.
Participants were examined every two years to see who had developed heart disease. Risk factors taken into consideration were smoking, obesity, high blood pressure, abnormal electrocardiograms, and genetic predisposition.
Surprisingly, even though this was the study that originally fingered cholesterol as a significant risk factor in heart disease, what it actually found was that high cholesterol was only a risk factor in people under the age of 47. For everyone over the age of 47, it was no longer a risk factor.
Also importantly, the study revealed that levels of heart disease and death were higher in those whose cholesterol had decreased during the period of the study, compared to those whose cholesterol had gone up. The lower the cholesterol, the greater the risk of heart disease.
So, men over 47 with low cholesterol were more likely to get heart disease than men with high cholesterol. Similarly, the link between heart disease and cholesterol was found to be non-existent in women over 50.
The cholesterol paradox
The mystery deepens. It is well established that patients in hospitals with coronary artery disease are more likely to survive if they have high cholesterol. This protective effect of high cholesterol is known in the scientific community as the cholesterol paradox.
The greatest paradox is perhaps the observation, which has been made on many occasions, that low levels of LDL cholesterol (that’s the “bad” one) are linked to higher overall mortality in patients with heart failure. If you want to survive, you’re better off with high levels of not-so-bad-after-all LDL cholesterol. You’ll find quite a bit about the mysterious “cholesterol paradox” online, including this:
The recently presented ACCELERATE trial dumbfounded many experts by failing to demonstrate any cardiovascular benefit of evacetrapib (cholesterol-lowering medication) despite dramatically lowering low-density lipoprotein cholesterol and raising high-density lipoprotein cholesterol in high-risk patients with coronary disease.”
Questions to consider
There are so many paradoxes in nutrition that they are becoming the norm. Anything that contradicts old, entrenched beliefs can be explained away as a paradox, a mystery. Giving up those beliefs and studying the evidence is out of the question.
This evidence suggests that “Cholesterol-lowering therapy in the elderly is questionable” when it has been found that in people over 85, the higher the blood cholesterol level the longer the remaining life.
Here the question that arises is: If something is so essential to brain and mental health, why would you want to take a medication that enters the brain and removes it? If you’re taking statins, it’s a question for you to ask and your physician to answer.
Maria Cross is a nutritional therapist with nearly thirty years of experience in the field. She specializes in nutrition and mental health, and her book ‘How to Feed Your Brain’ will be published later this year (2023). Subscribe to her website for a free brain food guide: allyoucaneat.org.uk Follow Maria on Twitter: @MariaXCross, or Medium: medium.com/@mariacross, or Substack: mariacross.substack.comShare this article!
The information is interesting and believable. My “mantra” is…read all you can re:most topics and use wisdom in applying them to yourself. Grannie (age 80).
What a fascinating article Debbie and Maria. Cholesterol, good or bad some forms good maybe some not maybe! What a paradox indeed.
Cholesterol is much more complex than we are led to believe. Things are often called a paradox when they disprove a long-held belief… sometimes it just means it’s time to re-examine those beliefs.
Fascinating. I learned new things from this piece, for example the basic function of HDL and LDL. I will better prepared when I receive my next set of blood tests. Fortunately, I’m not in a position to be on statins. That is a confusing aspect to this!
It certainly is confusing, Sandra. People often feel pressurised by their doctors to take statins, and I’m always hearing from my clients how they take themselves off them because of the side-effects. Muscle pain and mental confusion being the most common.