anticholinergic drugs, dementia, Alzheimer's, cognitive decline, preventing dementia, deterioration from Alzheimer disease, prevent Alzheimer disease

What causes Alzheimer’s disease? That is the billion-dollar question which remains unanswered to this day. A lot of money has been spent trying to find answers to the mystery of dementia. Most experts in the field point to the buildup of proteins like amyloid beta () and tau and the formation of plaques and neurofibrillary tangles. But this approach doesn’t take into account the role of the vascular system in the development of dementia. New research suggests that leaky blood vessels may play an independent and crucial role in cognitive decline and Alzheimer’s disease.

Blood Vessels in the Brain Matter!

Some people may think of blood vessels a bit like a straw or a garden hose. That is, one continuous hollow tube. In reality a blood vessel is made up of microscopic cells that are firmly attached together. If those attachments become degraded or permeable because of age, infection or inflammation they may begin to leak. Researchers at the University of Southern California believe that blood vessel leakage could a key marker that may show up much earlier in the development of dementia than things like tau and amyloid beta (Nature Medicine, online, January 14, 2019).

One hundred sixty-one people over 45 years old took part in the five-year study. All of them completed cognitive tests that resulted in a score from 0 (normal) to 3 (severe dementia). The scientists also analyzed cerebrospinal fluid for markers of brain capillary permeability. In addition, the volunteers submitted to contrast-enhanced MRIs.

The researchers report a strong correlation between breakdown of the blood brain barrier (BBB) and poor performance on the cognitive tests. Here, in their own words, is their conclusion:

“Our data show that individuals with early cognitive dysfunction develop brain capillary damage and BBB breakdown in the hippocampus irrespective of Alzheimer’s Aβ [amyloid beta] and/or tau biomarker changes, suggesting that BBB breakdown is an early biomarker of human cognitive dysfunction independent of Aβ and tau.”

Translating the Importance of this Research:

We recognize that conclusion is a bit dense to interpret. Keep in mind that billions of dollars have been spent on the amyloid beta (Aβ) and tau theory of dementia. Buildup in the brain of these proteins is believed to cause Alzheimer’s disease.

Drug companies have invested heavily in medications that could lower levels of amyloid in the brain. To date the results have not been promising. The authors of the new research in Nature Medicine report that leaky capillaries can be detected long before Aβ and tau show up.

We interpret that to mean the triggers to dementia may be something the drug companies have not yet considered. The authors conclude:

“Our present findings support that neurovascular dysfunction may represent a previously under appreciated factor contributing to cognitive and functional decline, independent of the classic pathophysiological hallmarks of AD [Alzheimer’s disease].”

In other words, leaky blood vessels could be a big deal and neuroscientists ought to start paying closer attention.

Intestinal Permeability?

Perhaps you have heard of leaky gut. Gastroenterologists have a much classier name: intestinal permeability. When there is damage to the intestinal lining there may be “leakage” of “toxins” into the blood stream. Remember, the lining of blood vessels is made up of cells. The lining of the small and large intestines is also made up of cells firmly attached to each other. Celiac disease, ulcerative colitis (Crohn’s disease, etc) and irritating drugs such as nonsteroidal anti-inflammatory drugs (NSAIDs) have been associated with this syndrome.

Many conventional practitioners have resisted the concept of a leaky gut. If, however, you go to the National Library of Medicine ( and search intestinal permeability you will discover thousands of references. Here is just one article published in the highly reputable BMC Gastroenterology (Nov. 18, 2014).

The authors conclude:

“In summary, intestinal permeability, which is a feature of intestinal barrier function, is increasingly recognized as being of relevance for health and disease, and therefore, this topic warrants more attention.”

What Causes Leaky Brain Blood Vessels?

Scientists have known about the blood brain barrier (BBB) for over 100 years. Researchers discovered that if they injected a blue dye into a blood vessel of an animal it would stain the organs of the body, but not the brain. On the other hand, if they injected the blue dye into spinal fluid it would stain the brain but not the rest of the body.

Thus the concept of the BBB was born. In other words, some chemicals could not penetrate from the blood stream into the brain and vice versa. This so-called barrier was thought to protect the brain from toxins and other assaults (Frontiers in Neuroscience, Dec. 16, 2014).

It is, of course, far more complicated than that. We won’t bore you with why some compounds get into the brain and others do not. Suffice it to say, the most obvious question arising from this new research is: what causes leaky brain blood vessels or neurovascular permeability? The answer is also complicated. Brain inflammation can do it. So can the resulting tissue trauma after head injury (Comprehensive Physiology, July 1, 2015). Toxins and brain infections may also disrupt the blood brain barrier and lead to leaky blood vessels.

The Infectious Theory of Alzheimer’s Disease

We are about to tread on thin ice, but the science is accumulating that brain infections may be a significant contributor to dementia. We are talking about herpes virus infections. These are the viruses that cause cold sores and other infections. If you think that sounds too crazy, here are two links to articles that provide scientific evidence to support this hypothesis.

New Research Confirms Link | Herpes Virus Infections and Alzheimer Disease

New Research Confirms Link | Herpes Virus Infections and Alzheimer Disease

Can Antiviral Herpes Drugs Reduce the Risk of Alzheimer Disease?

Can Antiviral Herpes Drugs Reduce the Risk of Alzheimer Disease?

If you would like to dig a bit deeper into this fascinating topic, why not listen to a radio interview we did with Dr. Robert D. Moir. He is Assistant Professor in Neurology at Harvard Medical School. He is also Assistant Professor in Neurology at MGH Neurology Research. His research focuses on the biochemical and cellular mechanisms involved in neurodegeneration in Alzheimer’s disease and aging. His most recent publication is on herpes virus and amyloid beta (Aβ) in Neuron, July 11, 2018.

During this interview you will learn about the brain microbiome. Yes, there are bacteria, viruses and fungi living in our brains. You will also learn about the powerful antibacterial activity of amyloid beta. The FREE one-hour interview can be downloaded at this link. You can also listen to the streaming audio by clicking on the green arrow above the photo of Dr. Moir.

Show 1132: Are Infections to Blame for Alzheimer Disease?

Whether it is possible to reverse capillary permeability and delay or prevent the onset of dementia remains to be seen. We think this new research is incredibly exciting. If the entrenched theories of dementia can be revised, neuroscientists might discover some new approaches to overcome these devastating brain diseases.

Nature Medicine, Jan. 14, 2019

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  1. Cindy
    Seattle, WA

    HMMMM….. SO INTERESTING! I have a rather intensive supplement regimen and several of those supplements have blood-thinning properties. If I happen to get a slight cut, I’ll always bleed a lot. I have perfect health, but I actually had to submit to the “full-meal deal” colonoscopy because there was a tiny amt. of blood in the stool sample… I knew at the time that it was probably because of those blood thinners, I wasn’t worried, and of course the colonoscopy was negative!
    But I wonder: would this possible “leakiness” extend to the brain, by chance? I have very low “markers” for Alzheimer’s, and I sure want to keep it that way! Comments??? please!

  2. NJangel
    New Jersey

    I’ve recently read supporting science/studies where hesperedin and diosimin are useful to support blood vessels. Both I believe are bioflavanoids.

  3. Linda
    North Carolina

    After reading about the leaky brain and the connection to herpes virus infection, I thought about my 92 year old mother who is still driving and able to care for herself. About 5 years ago she had a short bout with a cold sore (i.e.herpes) and was prescribed antiviral medication which she refused to take. In any case, her cognitive functions continue to be in tact. Perhaps there needs to be an epidemiological study to see how many dementia and non-dementia patients have had a herpes infection. In the case of my mother the viral connection is not clear. She is a woman who eats very well and still mows her own lawn. There still seems to be a lifestyle component that is also at play here. Very interesting article. Thank you for always being on top of the latest research.

  4. Molly K. K.

    Is there any way to prevent leaky brain blood vessels?

  5. B.V.
    Chapel Hill, NC

    We love and appreciate all of your columns and emails. It appears to us that you do a very good job of providing free info; and we should recognize that you can’t provide massive amounts of info – which costs you time and money to produce – for free. Some of these folks willingly pay $100 or more for a brief visit to a physician, but balk at paying a few dollars to get thorough, well-researched materials from your organization. At ages 81 and 84, my wife and I feel fortunate to have access to your information – both free and priced. Keep up the wonderful work you’re doing, and ignore the gripers.

  6. Charles

    I am bruising in my arms and legs more easily than when I was younger. I am now in my 70s. I have been looking for some food or supplement to strengthen my skin and capillaries. I take collagen for my skin and eat black currants for my capillaries. I have begun to avoid turmeric and garlic, which seem to thin my blood. Results have been poor so far. Now it appears that easily broken or penetrated brain capillaries may be a cause of dementia, so I am increasing my research. Anybody got some ideas about this?

  7. SJ

    Of course drug companies are heavily invested in finding a magic pill for Alzheimer’s disease, but has anyone looked into a correlation between the constant prescription writing for patients and the quality of food a person eats? The rise in this disease also follows the rise in drugs given and the overly-processed foods that are now abundant in most homes. These convenience foods are full of gmo sugars and artificial flavors, etc. Someone should do a study on how all of the above effects our brains.

    • Leslie

      When I upped the amount of fruit I eat, to several servings day, I stopped bruising. Even if I bump hard into a wall or do whatever would normally cause a bruise I don’t develop one. I try to eat an apple every day and whatever else I have. My partner always had terrible bruises on his legs and since he started eating more fruit those have stopped also. Hope that helps..

    • Jeannette

      Hi Colorado, You echo my thoughts totally. Currently in the UK there is a big push to make food manufacturers make their food healthier (less sugar etc) but also to make food stores label their products clearly regarding ingredients that most of us would like to avoid. Our older generations some who lived to great ages did not suffer the frequency of dementia as do current folk of similar ages and I am not aware that there was any notable numbers of younger folk being diagnosed with dementia. Of course our medical profession (here in the UK) make people paranoid – listing the first stage of dementia as ‘no dementia’ make of that what you will – certainly enough to make the UK population paranoid. Eat and sleep well, exercise often, and laugh a lot.

  8. James H

    Since we are talking viral components for a possible trigger of mental decline, I have been reading about how the tea derived from the Honeysuckle blossom and leaves have a very effective antiviral effect on colds, flu, and other maladies. I would extrapolate then that it, the tea, could also affect the virus that triggers cold sores. Is this thought of as sound logic when applied to any virus infections?

  9. Jampot

    If leaky blood vessels in the brain do turn out to contribute to dementia I wonder what effect blood thinners or even a daily aspirin might have. Lots more to learn.

  10. Kathy

    I just read an article elsewhere encouraging the use of Vitamin C supplements to reduce the development of Alzheimer’s. It stressed that supplements are far better than trying to get sufficient vitamin C via foods. Apropos to this current People’s Pharmacy post, the article says that vitamin C reduces the “leakiness” of blood cells that leads to Alzheimer’s development.
    The vitamin C supplements should be taken throughout the day to maintain a high level of vitamin C in the bloodstream, as too much at one time is excreted in urine.

    I find it compelling that I read 2 consecutive articles from different sources telling me how to decrease the likelihood of developing Alzheimer’s. It seems to be a no-brainer to me. No pun intended!

  11. Anne

    While I’m glad you are keeping up with this subject, it’s so discouraging. I keep comparing myself to my mother and worrying about myself. She had a lot of gastrointestinal problems, and even ended up having a small stroke. Along with that, she bruised very easily as she got older, although part of that was thinning skin. I also have that problem. She had lots of spider veins in her legs, and mine are getting worse with age, especially around my ankles and feet.

    But she also had high blood pressure, and mine is low. And I know I mentioned before that my dad was the one who had all the cold sores, although my mother and I got them, too. He never had any kind of dementia.

    It’s obvious that no one really knows yet what causes this awful disease. It seems like we are constantly being told something different. One minute it’s keeping our brains active by playing computer games, then it’s cold sores causing the problem, and now it’s leaky blood vessels in the brain. Tomorrow it will be something else.

    Also, my parents, one of my brothers, and I had/have ADHD which can certainly make you feel like you have some kind of dementia at times!

  12. Pat
    Roanoke, Virginia

    My father and mother died at the age of 84. Both had cold sores all their life.
    Neither one had any sign of dementia. My father died of a heart attack, and
    my mother died from pneumonia.


    Both very interesting concepts. It might be interesting to compare the effect of milk thistle on capillary leakage,since it does greatly improve leakage from the capillaries in the lower leg

  14. Richard Stevens

    I think you are a very irritating website. you raise a lot of interesting issues and then the reader finds he/she cannot continue without paying and logging in to the rest of the material. You really need to learn from Europe. That health should not be commodified and made a commercial proposition.

    • Joe Graedon

      Richard, there is zero charge to download an mp3 file of our radio show or the free streaming audio interview. If you wanted a CD, we have to produce and send it to you.

      • Kevin

        I can see why Richard assumed there was a charge. The most prominent ad for the show only says $9.99. It does not say it’s for a CD, and it does not say the mp3 is free in that ad. You have to read plain print elsewhere to learn that information. Why doesn’t the prominent ad say Free only, and have the order page default to the mp3 instead of the CD? I think your current ad prevents many from hearing the show, and causes some to buy a CD to hear a show once, which produces wasteful plastic that lasts forever.

    • Christine

      The Peoples Pharmacy is one of the most generous organizations out there. I get the sense that they aren’t driven by profit and I commend them for all the good they do

      • Jeanne

        Agreed! Thank you Graedons!

    • Brenda

      Do your research before you speak so badly about things.

    • Mary
      Houston, Texas

      I read a lot of medical info from the UK – it is easily accessed and sometimes fills in gaps about issues my husband is having (with a rare blood disorder). I do however take exception that the US is somehow inferior because of the “commercialization” of medicine.

      First: This website provides much-needed information that balances other websites. And should the producers be on welfare so they can donate their time producing this service?
      Second: My husband goes to a hospital in the world’s largest medical center, and we have met MANY people from around the world (lots from Europe) coming to Houston for medical care.
      And Last: I belong to a Facebook disease group where there many are UKers among other nationalities so I read about both sides of their healthcare systems.

      No one country has the lock on medical care.

    • Carey

      A lot of the links to studies that the Graedons post require subscriptions to access. What this means is that they pay a lot of money to have these subscriptions to access the studies that they write about. I’m not talking about Peoples Pharmacy content; I’m talking about their sources for finding the information that they tell us about. Those studies also must be very technical, so the Graedons must spend a lot of time pulling out the relevant information.

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