Does Fungal Infection Cause Alzheimer’s?

does fungal infection cause Alzheimer's

Some scientists have proposed infection as a cause of Alzheimer’s disease, and now a group of researchers may have retrieved the smoking gun: Different Brain Regions are Infected with Fungi in Alzheimer’s Disease.(1) Does fungal infection cause Alzheimer’s?

The researchers found that in brain matter from ten different patients with Alzheimer’s, all of them were infected with fungi. There was no fungi in the brains of ten control patients.

The amyloid plaques that are characteristic of Alzheimer’s are composed of a protein, amyloid beta, and they show strong antimicrobial activity. In fact the pathogen that is most sensitive to amyloid beta is the fungus, Candida albicans.(2)

As fungi are typically slow-growing organisms, this can explain the disease’s slow progression. There are also at least two reports in the literature of people being cured of Alzheimer’s disease when doctors found fungi (Cryptococcus) and treated the patients with anti-fungal drugs. Their mental status returned completely to normal.(3,4)

If true, this makes sense of many of the facts around Alzheimer’s and provides a basis for prevention and treatment.

Fungi thrive on sugar and iron

Alzheimer’s disease has been called “type 3 diabetes”(5); the brain in Alzheimer’s is characterized by insulin resistance and faulty insulin and IGF-1 signaling.

Fungi thrive on sugar. If glucose levels in the brain and its blood vessels was chronically high or uncontrolled, then it provides a an easy food source for fungi. A list of the different species of fungi found in Alzheimer’s brains (6) shows Candida albicans and Saccharomyces cerevisiae among them.

In one study, a full 25% of diabetics had an oral Candida infection.(7) Poor blood sugar control was associated with a 13-fold increase in risk of a Candida infection. Candida is the most common cause of fungal infections, and it thrives on sugar.

Saccharomyces cerevisiae is the yeast that ferments beer and wine, and also can cause infections. In fermentation, it uses the sugar in mash or grape juice to make alcohol. So it thrives on sugar too.

Therefore there’s a mechanistic link.

  1. Alzheimer’s is characterized by loss of control of blood sugar in the brain
  2. Fungi thrive on sugar
  3. Fungi have been found in Alzheimer’s brains, but not controls

There’s another factor, iron, which has been shown to be elevated in the brains of Alzheimer’s (and Parkinson’s) patients.

Here, I could do no better than quote Eugene D. Weinberg (whom I interviewed) on iron and infection:

Iron is dangerous because it is an essential growth factor for most bacterial, all fungal and all protozoan infections as well as for all cancer cells. Although viruses do not have independent metabolism, enhanced host iron is needed for viral synthesis.

Iron is crucial growth factor for pathogenic microorganisms, and they have a number of ways of obtaining it, including breaking down tissue (such as in hemolysis) or ingesting ferritin. In the eternal arms race between pathogens and hosts, we have developed a number of ways to withhold iron from pathogenic invaders.

Of course, if iron is abundant and dysregulated and therefore just lying around, pathogens including fungi have an easy time of it. So if iron is abundant and dysregulated in the brain, then pathogenic fungi may invade and cause Alzheimer’s.

One further mechanism links infection with Alzheimer’s, and that is the declining immune system in aging. Older people suffer from more infections because of this.

How to prevent Alzheimer’s

It follows from all of the above that Alzheimer’s can be prevented.

The first step is to avoid insulin resistance and diabetes to ensure less of a food supply for pathogenic fungi. You do this by:

  1. Staying lean
  2. Exercise, preferably a combination of strength training and HIT.
  3. Avoid large amounts of refined carbohydrates.

The second step is to keep iron levels in the low normal range. This deprives invading pathogens of their critical growth factor.

Practicing hormesis will also increase the degree to which iron is regulated and sequestered, so that free iron isn’t available to cause damage and provide sustenance for microorganisms.

The authors of the first-cited paper point out that

There are at present a number of highly effective antifungal compounds with little toxicity. A combined effort from the pharmaceutical industry and clinicians is needed to design clinical trials to test the possibility that AD is caused by fungal infection.

I know that if I or a loved one had Alzheimer’s, I wouldn’t be waiting around for a clinical trial that may never happen. (There’s little money in anti-fungal drugs.) I would be harassing a doctor until he agreed to a course of anti-fungal treatment.

PS: More like this in my books Dumping Iron and Stop the Clock.

PPS: Check out our Supplements Buying Guide for Men.

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  1. Doug says:

    I’ve been reading your series on the under-appreciated role of iron overload in health with a great deal of interest since a few years ago I did the 23 and Me test and found out that I’m a C282Y homozygote, which is the most common genotype leading to hereditary hemochromatosis.
    I got a genetic test done by my doctor to confirm, and also got my ferritin checked a couple of times, which was already at about 500 ng/mL (three tests with the results 500, 475, and 520) at the age of 32. I was prescribed a course of therapeutic phlebotomy and had a pint of blood taken out of me every week for 12 consecutive weeks until my ferritin was 39 ng/mL. It probably added years to my life.
    Reading your blog made me realize that it’s been too long since I got it checked and I need to get on this again to keep it under control. In a way I’m almost fortunate in that having the actual genetic diagnosis makes it easier to get prescribed the phlebotomy. Even with the diagnosis of a genetic disorder, while getting the phlebotomies done I got a fair amount of fatuous “I wish I had that problem!” comments from the blood center personnel who still had the “some is good, more is better, too much is just right” perspective on iron levels, so I realize that anyone with genetically normal iron metabolism is swimming upstream when they want to reduce their “normal” levels.
    The reason hemochromatosis is so under-diagnosed (about 0.5 percent of white people have the same trait I do) is that it presents as somewhat premature aging as it damages your heart, liver, pancreas, joints, and everything else. In extreme cases it can discolor the skin, which along with the pancreatic damage caused doctors to call it “bronze diabetes” before iron overload was identified as the cause.
    Anyway, keep up the great work, and I look forward to the upcoming book on iron.

  2. Undercover Slob says:

    There are numerous theories on the development of Alzheimer’s and this is the newest that I’ve come across. Fungus pervasion certainly sounds as if it’s a viable culprit there but what of statins and hyperinsulemia in general? I understand how it is that the latter can facilitate fungus growth but doesn’t the cholesterol blocking mechanism in statins say just as much about the degeneration of brain matter? Furthermore, wouldn’t the preponderance of inflammatory sugar molecules in the brain be itself, a direct causative factor in brain tissue degeneration? Perhaps there is no single bullet here. Perhaps it can be a myriad of factors that would case this disease.

    Something to consider; is it the fungus that causes Alzheimer’s or does the Alzheimer’s condition allow for the fungi to propagate? I just want to be clear that this new implication of fungus does not preclude the other very viable culprits. For instance, “Diabetes 3” independent of the fungus issue, is a very daunting thing indeed.

    • P. D. Mangan says:

      All good points, Undercover. In the paper were mentioned a couple of cases of “Alzheimer’s” being cured when they discovered a fungus and gave anti-fungal meds. Whether that applies to all cases is obviously an open question, but the fact that they found in fungus in 10/10 Alzheimer’s and 0/10 controls is pretty compelling.

      • Undercover Slob says:

        Sure is compelling. However, I wonder if the presence of fungi in Alzheimer’s situations isn’t almost a forgone conclusion if the brain itself has already been compromised through the usual metabolic derangement. In other words, could’t the fungi just be the “looters” in the wake of the disaster? I mean, candida itself is always present in the biome so maybe the conditions that CAUSE Alzheimer’s also ALLOW the fungi to flourish in that region.

        That instance which you mentioned about “curing” Alzheimer’s was very interesting, however. In relation to that, there are also those studies that showed 9/10 Alzheimer’s patients either arrested their condition or else reversed their brain deterioration when regularly ingesting coconut oil…now, this is where the science flummoxes me as the lauric acid in coconut oil are known to destroy fungal cells while apparently, the ketone promoting properties of coconut oil are theorized to AID the growth of candida as they can utilize ketone bodies robustly.

        Do you have insight on this, P.D.?

        • Cloudswrest says:

          “while apparently, the ketone promoting properties of coconut oil are theorized to AID the growth of candida as they can utilize ketone bodies robustly.”

          I don’t think this latter effect would be very important in an environment with a surplus of glucose. Given this I would think the effect of lauric acid would dominate.

          • Undercover Slob says:

            What I was referring to was the application of coconut oil towards a more proactive approach to Alzheimer’s so a surplus of glucose wouldn’t be the issue (hopefully), since to do that, you’d need to get more insulin sensitive. I think what happens is then, just like the human physiology, is that it takes time to adjust their metabolism toward the processing of ketones and in the meantime, that’s where the lauric acid can do it’s damage to the fungus.

          • P. D. Mangan says:

            I agree. As far as I know, the preferred energy source for Candida and other yeasts is sugar.

        • P. D. Mangan says:

          The fungi could be the looters, yes, but since they’re known pathogens, that shows that they are more likely to be the cause of disease. Candidiasis, for instance, is an infection, even though normal people carry it. Normal people carry lots of things, like Staph aureus and E. coli, and if they get into the wrong places and multiply, then illness results.

  3. Stephen Werner says:

    “One further mechanism links infection with Alzheimer’s, and that is the declining immune system in aging.”
    Body’s immune system may play larger role in Alzheimer’s disease than thought.

    • Undercover Slob says:

      Well, that might explain the preponderance of the fungi. Of course, there is probably no single catalyst in the brain’s degeneration of that ilk but none of these aforementioned conditions is anything to scoff at. There is one thing that IS common to most Alzheimer’s cases and that is the relative advanced age of those who develop it. If I could make a guess as to what could be the over arching cause and with all due respect to iron overload, fungal pervasion and cholesterol depletion via statins, I would say that a lifetime of excess sugar/carbohydrate intake along with refined vegetable oils and their respective oxidation capacities would be #1.

  4. Scott says:

    Have you seen this?

    This is all very interesting!

  5. Max says:

    Here’s a new piece linking Alzheimer’s to dormant viral and bacterial causes. I haven’t read the underlying journal article, but in this review they drop the iron bomb toward the end :

    “We are saying there is incontrovertible evidence that Alzheimer’s Disease has a dormant microbial component, and that this can be woken up by iron dysregulation. Removing this iron will slow down or prevent cognitive degeneration – we can’t keep ignoring all of the evidence,” Professor Douglas Kell said.

    • P. D. Mangan says:

      Thanks, Max. Douglas Kell has written extensively on how iron is involved in the pathology of nearly everything.

  6. Sam says:

    I haven’t read your site in a while. It’s odd how you’re writing about fungus and I just read today about how people are using methylene-blue for life extension and to treat Alzheimers. Also helps mitochondrial dysfunction or so some say.

    And dirt cheap at the small rates it’s taken.

    • P. D. Mangan says:

      Interesting connection, Sam. Maybe mechanism of methylene blue effect on Alzheimer’s is antifungal.

  7. EH says:

    Your first link is broken, it should be to:
    “Different Brain Regions are Infected with Fungi in Alzheimer’s Disease” in Nature Scientific Reports by Pisa et. al. October 2015

  8. EH says:

    This looks interesting for choosing an antifungal that will make it past the blood-brain barrier:
    “CNS pharmacokinetics of antifungal agents”( PDF link, Expert Opin. Drug Metab. Toxicol. (2007) by Kethireddy & Andes)

    It looks like Flucytosine and fluconazole achieve the best brain concentrations (=”parenchymal concentrations”) but it is unclear if they will work on the fungal infections that cause Alzheimers. Other anti fungal drugs may be effective. Flucytosine costs $2000/day in the US, $22 in UK according to Wikipedia, and it has some nasty side-effects. Fluconazole is less than $2/day and has somewhat fewer side effects, but according to WP, other antifungals are preferred for CNS, though it does not say why.

    Fungal infections of the CNS: treatment strategies for the immunocompromised patient. (abstract, CNS Drugs. 2007;21(4):293-318. by Black & Baden) says “Oral fluconazole is effective for the CNS manifestations of coccidioides” but for the more common infections: “Amphotericin B and flucytosine are used to initiate treatment for CNS yeast infections caused by Candida and Cryptococcus neoformans. Voriconazole is preferred for aspergillus, although amphotericin B, particularly in lipid formulation, is also useful.” so the lipid formulation Amphotericin B looks like the the best bet for use against Alzheimer’s. It has severe side effects including potential organ damage (though the lipid type is not as bad) and must be administered by IV at present. WP says co-administration of flucytosine allows a lower dose of Amphotericin B. This is not something to try at home.

    Voriconazole has fewer serious side effects than Amphotericin B, but they are still considerable. It works orally and is effective against both candida and as aspergillus. It isn’t cheap in the US, $128 per 30 50mg pills. This is probably the best combination of effectiveness/tolerability of the drugs listed so far, but keep in mind these are the heaviest CNS-effective antifungals which are used for immunocompromised patients, something less toxic might work for people who are basically healthy.

  9. alan green says:

    If there is fungi, that is secondary.
    First step is break down of blood brain barrier. This allows microbleeds and iron accumulation after breakdown of blood. So if PD says organism which cause infection like iron, the iron is there.

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