Hypertension puts us at higher risk of heart disease and stroke. It also appears to be a risk factor for cognitive decline and dementia, but the scientific evidence is mixed.
In 2017, the government dramatically changed guidelines for defining healthy blood pressure, especially for those aged 65 and older. Before then, 150/80 was the threshold for hypertension, now it’s 130/80, a whopping 20 points lower.
To be sure, some maverick doctors thought the change was just a scam to sell more blood pressure meds. I’m agnostic on the subject. I tend to think 140 is the threshold for worry, but that’s pretty much just my opinion. If your blood pressure is high – whatever that means to you – I’m against the meds and in favor of natural ways to reduce blood pressure.
BUT… today’s important news does not depend on someone’s opinions about what’s high and what’s not.
The latest research suggests that whether your blood pressure is considered high or normal, focusing on one specific feature of your blood pressure reading may be a far more promising way to keep your brain in top condition.
When it comes to high blood pressure and memory health, the strategy of lowering blood pressure produced mixed results in human trials.
The most recent analysis was published in the Journal of the American Medical Association in May. Researchers gathered data from 14 trials covering 96,157 participants with an average age of 60.
They found that lowering blood pressure protected memory by reducing the risk of cognitive decline by seven percent.
Protects Memory by Protecting Blood Vessels
Lead author, Dr. Michelle Canavan, said that lowering blood pressure reduces the amount of damage to blood vessels in the brain.
“When brain blood vessels, particularly small blood vessels, are subjected to prolonged high blood pressure levels, they can be damaged, causing brain cell death and dysfunction, which can result in slower brain processing and decline in memory over time.”
On the other hand, another study found contradictory findings. As I said, the evidence is mixed.
This study, published in the journal Alzheimer’s & Dementia three years ago, concluded that “developing hypertension at older ages may protect against dementia.”
Now that’s what I’d call a surprise.
Researchers reasoned that because blood vessels become stiffer with age, higher blood pressure is needed to improve blood flow.
What’s the right answer?
Sorry to say another recent paper on blood pressure didn’t come any closer to answering this question, but it did point researchers in a brand-new direction.
The Importance of Pulse Pressure
Researchers from Australia provide a great deal of evidence for elevated pulse pressure, not blood pressure, as a principal driver of cognitive decline and dementia.
Pulse pressure is the difference between the upper systolic and lower diastolic blood pressure reading. A normal pulse pressure is between 30 and 50, but this commonly increases with age as arteries lose flexibility.
Age-related elevation of pulse pressure is typically caused by increased systolic pressure while diastolic pressure remains unchanged or decreases slightly.
In their paper, published in Frontiers in Neuroscience in June, the researchers focused on factors that can cause a breakdown in the blood brain barrier (BBB).
Save Your Blood Brain Barrier, Save Your Memory
Drawing on a large body of evidence they propose that elevated pulse pressure causes inflammation, free radical damage, mechanical stress from excessive force, microbleeds, cellular dysfunction, and cell death in the blood brain barrier leading to brain damage.
If you’re a regular reader you may recall that the blood brain barrier is made up of cells designed to allow nutrients to pass freely into the brain, while keeping toxins and other harmful pathogens away from brain tissue.
Free radicals and inflammation also increase production of amyloid beta proteins that are linked to dementia. Drugs targeted at amyloid may have been unsuccessful because of the failure to address elevated pulse pressure which “delivers initial and continuous insults to the blood brain barrier,” they write.
For the same reason, elevated pulse pressure may also hinder stem cell therapies which have the potential to repair damage to the blood brain barrier and treat dementia.
The lead author of the paper, Professor David Celermajer, said that disruption of the blood brain barrier “is an important paradigm shift in our understanding of the pathogenesis of dementia.”
In his view, “a fifth to a quarter of Alzheimer’s might be due to this problem, but I think in almost anyone who is destined to get Alzheimer’s for whatever cause, genetic or otherwise, a high pulse pressure is an accelerant.”
Natural Approaches to Reducing Pulse Pressure
If pulse pressure is so important to memory health, then you’ve got to learn to keep it in check. Fortunately, there are natural approaches shown in the research to lower elevated pulse pressure.
These include aerobic exercise or high intensity interval training, getting a good night’s sleep, losing excess weight, eating a Mediterranean-style diet, and making sure you get enough omega 3 fats from fatty fish or flax seeds, as well as an adequate supply of vitamin K from green leafy vegetables.
In several studies, a supplement of aged garlic extract also lowered elevated pulse pressure.