Browse evidence-based analysis of health-related claims and assertions
When there’s too much homocysteine in your blood, it can mess up key energy sensors in your liver, making it harder for the liver to stop storing fat—so more fat builds up inside it.
Mechanistic
When rats take betaine supplements, their livers make more of a special enzyme that helps clean up a harmful chemical called homocysteine, so less of it builds up.
When rats eat a poor diet that lacks certain nutrients, their livers get fatty—but giving them betaine (a natural compound) helps keep the fat out, probably because it lowers a harmful chemical called homocysteine in the liver.
For older people with moderate hearing loss, using hearing aids for seven years doesn’t seem to make their memory or thinking skills noticeably better or worse than not using them.
Quantitative
Older people with moderate hearing loss who use hearing aids may be less likely to develop memory problems or dementia over seven years, but the data isn’t strong enough to say for sure it’s because of the hearing aids.
Correlational
Older people with moderate hearing loss who wear hearing aids are less likely to develop dementia over seven years than those who don’t—about 5 out of 100 vs. 7 or 8 out of 100—so hearing aids might help protect the brain, even if other factors could be influencing the result.
Getting two shots of the shingles vaccine might help lower your risk of getting dementia, no matter your age, race, or whether dementia is caused by Alzheimer’s or blood vessel problems.
Getting the shingles vaccine might help older adults stay sharper longer — a study found they were 16% less likely to develop mild memory problems in the first few years after vaccination.
Women who got two shots of the shingles vaccine seem to have a bigger drop in their risk of getting dementia compared to men who got the same shots — maybe because men and women’s bodies react differently to the vaccine.
People who got the shingles vaccine twice were 27% less likely to develop dementia later on than people who got a different vaccine (Tdap), even after accounting for the fact that healthier people tend to get more vaccines — so the shingles vaccine might be doing something special to protect the brain.
Getting two shots of the shingles vaccine when you're 65 or older might also help lower your chances of getting dementia later on—even if you never even had shingles.
No matter how old you are, if you have hearing loss and use a hearing aid, your age won’t change how well you understand speech or how hard you feel you have to listen.
People with hearing loss say it feels easier to listen when they wear hearing aids, even though tests don’t show their brains are working any better at processing sound.
Wearing hearing aids doesn’t seem to make your memory or thinking skills better on tests, even though you might feel like it’s easier to listen and understand people.
People with hearing loss who use hearing aids can understand speech better—by a noticeable amount—in quiet rooms and slightly better in noisy places where people are talking, making conversations clearer.
Getting the shingles vaccine doesn’t make people more likely to die or get sick from other reasons, so if some studies link it to dementia, it’s probably not because vaccinated people are sicker overall or getting more medical checkups.
Getting the shingles shot might help keep your memory sharper for a little while—especially in the first year after you get it—but that benefit slowly fades over six years, like a temporary shield against dementia, not a permanent fix.
Older people who got the shingles shot seem to be less likely to develop dementia than those who got the flu shot or the whooping cough/tetanus/diphtheria shot — and that’s probably because the shingles vaccine itself is doing something special, not just because getting any vaccine is good for you.
If you're 65 or older, getting the newer shingles shot (recombinant vaccine) cuts your chance of getting shingles by about a third over six years compared to the older shot, and it works just as well for men and women.
Getting the shingles shot might help women stay free of dementia for longer—about 22% longer over six years—and men too, but not quite as much, around 13%. And the benefit seems to be stronger in women than in men.
People 65 and older who got the newer shingles shot lived about 164 extra days without being diagnosed with dementia over six years compared to those who got the older shingles shot—suggesting the newer shot might help delay dementia, at least a little.
When the cold sore virus (HSV-1) infects brain cells in a lab dish, it seems to turn up the volume on two proteins that help make a sticky substance linked to Alzheimer’s disease.
When mice get a common cold sore virus in their brains, scientists see more of a sticky protein buildup that’s linked to Alzheimer’s disease—so maybe the virus helps cause that buildup.
When the cold sore virus (HSV1) infects brain cells in a lab dish, it causes more of a sticky protein (beta-amyloid) to build up inside the cells and less of the protein that normally makes it — which might help explain why this virus could be linked to Alzheimer’s-like brain changes.