My Family Tragedy That Didn’t Have to Happen

It can look exactly like dementia, but sometimes it is a simple vitamin deficiency, one that can be reversed if you catch it in time.

There is a kind of brain damage that comes on when the body runs short of a single vitamin, and it looks so much like Alzheimer’s that families are usually told that is exactly what it is. It has a name, Wernicke-Korsakoff syndrome, and it comes from a lack of thiamine, or vitamin B1. Caught early, it can often be reversed. Missed, it turns into permanent memory loss that no one can undo.

For me, this is not a distant medical story. It is my own brother, and it has been the hardest thing I have ever watched. Years of unchecked celiac disease had progressed to diverticulitis and an emergency bowel resection, so his gut was already badly damaged. It was about three years ago that I first began to wonder about a vitamin deficiency, when he called me on the phone asking me about vitamins. Even in that conversation I could hear that something was wrong, that he was already slipping. I sent him B vitamins, but by then he could not remember to take them, and once the decline became obvious it was steep and fast. His doctors called it Alzheimer’s. I suspected a thiamine deficiency, but there was little research to point to, and no one, not his doctors, not the people around him, believed me. I will live the rest of my life knowing my theory was probably right, and that I should have pushed harder to get him diagnosed and treated while there was still time.

He is in hospice now, and I am mourning the big brother I grew up with, the one who stood up to the bullies in the neighborhood and cheered me on through every part of my life. My heart is broken. He is a father of two grown children, one with special needs, and I will miss him for the rest of my life. The hardest part is knowing the fix could have been so simple.

For a long time this was thought to be rare, seen mostly in heavy drinkers, but lately it has been turning up in a new group of people and drawing a lot more attention. A 2026 review in the journal Obesity looked at six people who developed it while taking the popular GLP-1 weight-loss shots, and the outcomes were devastating. One of them died, four were left with permanent memory loss, and only one made a full recovery. The drug itself was not really the cause. What did the damage was the near-starvation it created, since these shots cut appetite so sharply that some people stop eating enough to keep their thiamine up, and the body holds only a small reserve to begin with.

Thiamine is the fuel your brain cells use to turn food into energy, and because your body cannot store much of it, just a few weeks of poor eating or poor absorption can drain your supply. When the brain runs low, the first stage, Wernicke’s encephalopathy, comes on pretty fast, with confusion, an unsteady walk, and sometimes strange eye movements. Treated quickly with thiamine, it can be reversed. Left alone, it moves into the permanent stage, Korsakoff syndrome, and by then the downhill trajectory of memory loss continues.

It is far more common than people realize, and it is not only a drinker’s problem. Anyone whose gut is inflamed or damaged, or who simply is not eating well, can end up short. Watch for it especially in anyone with:

• Heavy alcohol use
• GLP-1 weight-loss medications
• Celiac disease, Crohn’s, ulcerative colitis, or IBS
• Diverticulitis, or any gut or weight-loss surgery
• Anorexia or a long stretch of barely eating
• An older person who is frail or not eating much

And these are the early warning signs worth taking seriously:

• Sudden confusion or memory trouble that seems to come on fairly quicly
• A new unsteadiness or poor balance
• Strange eye movements or vision changes
• A decline that happens over months or weeks, faster than ordinary Alzheimer’s, which usually takes years. 

The good news is how fixable this can be. Caught early, plain B1 can turn it around. In a serious case it takes large doses of thiamine given by IV, to get past a damaged gut and into the bloodstream fast. Either way it is cheap and simple, and nothing like the dead end most families are handed.

So if you have an aunt, a grandmother, a parent, or anyone you love who suddenly seems out of it, foggy, or forgetful, it does not hurt to give them a good, high-quality B vitamin. The B vitamins, and thiamine most of all, are well-known nutrients for brain health, and they are very safe. But whatever you do, do not simply let a blanket diagnosis of Alzheimer’s or dementia get stamped on someone you love while the doctor throws up his hands and says there is nothing to be done. There may be something you can do. Try this first.

Sources:

• Wernicke’s Encephalopathy Following Semaglutide Treatment for Obesity, Obesity (2026)
• Vitamin B1 (thiamine) and dementia, Annals of the New York Academy of Sciences