Call it the $64,000 question.

For decades, scientists have been trying to figure out exactly what sets off the brain changes that lead to the devastating memory loss of Alzheimer’s disease.

And so far… no "smoking gun."

Sure, we have a lot of leads, with recent studies pointing to everything from blood vessel damage to inflammation raging in your gray matter.

But hold on to your hat -- because a new study may have discovered the first "domino" in Alzheimer's brain changes.

And it may shock you.

The evidence points to none other than a pair of VIRUSES from the same family of bugs that can sock you with chicken pox or a run-of-the-mill cold sore!

In a study published in Neuron, researchers analyzed 600 tissue samples from the brains of folks who'd passed away, some of whom had Alzheimer's.

And the researchers found two viruses -- herpesvirus 6A (HHV-6A) and herpesvirus 7 (HHV-7) -- in the brain tissue of Alzheimer's patients at TWICE the rate that they did in the brain tissue of those without Alzheimer's.

Now, HHV-6A and HHV-7 are pretty common critters. They infect nearly ALL human beings, typically in childhood.

Some of us may have mild symptoms like fever and rash when we first get infected, while others carry the viruses for a lifetime without even knowing it.

Since they can lie dormant and hide out in our nerves and nervous system for years, it's not a stretch to think that these viruses could hitch a ride up to the brain if they were to "wake up."

And if your immune system isn't strong enough to keep these nasty viruses dormant, they could slowly but surely cause permanent damage to your gray matter -- potentially setting off Alzheimer's.

So, it's a good idea to have your doc test to see if you've got either of these viruses in your system.

But even if you don't, you should also get tested for the virus that causes cold sores (herpes simplex 1, or "HSV-1") – because as I shared with you in the August 2016 issue of my Nutrition & Healing newsletter, previous studies have found HSV-1 in the brains of those with Alzheimer's.

There’s also evidence that HSV-1 can trigger the formation of Alzheimer's signature "plaques and tangles."

Unfortunately, there's not a pill in the world you can pop to "cure" you of ANY virus.

But it is possible to keep them "inactive"... or at least slow them down... with natural anti-viral supplements like garlic, grapefruit seed extract, oil of oregano, and olive leaf extract.

And an amino acid called lysine is particularly powerful against herpes viruses. I usually recommend 1,000 to 3,000 mg a day.

To beef up your overall immunity, try taking 20 mg of zinc and 1,000 mg of vitamin C as part of your everyday routine.

Eliminating stress... getting plenty of sleep... and slashing sugar can all fortify your immune system against viruses, too.