Browse evidence-based analysis of health-related claims and assertions
Low grip strength is strongly correlated with increased risk of premature mortality.
Assertion
Among middle-aged American Indians, people who ate more fat — especially saturated fat — were more likely to die from heart disease than those who ate less, even when other health factors were taken into account.
Correlational
Studies that found a link between saturated fat and heart disease are more likely to get published than those that found no link — which might make it look like there’s a connection when there isn’t.
Descriptive
Even when researchers used better methods to measure what people ate or adjusted for more health factors like smoking and exercise, the link between saturated fat and heart disease still didn’t show up.
We don’t know yet if swapping butter for bread or olive oil makes a difference for heart health — there just isn’t enough solid data from long-term studies to say for sure.
Whether you're a man or woman, young or old, eating more saturated fat doesn't seem to affect your heart disease risk any differently — the link is about the same across all groups.
Eating foods high in saturated fat, like butter and red meat, doesn't appear to raise your risk of heart attacks, strokes, or other heart problems, according to a big review of long-term studies on thousands of people.
Scientists aren’t very confident in what they know about how saturated and trans fats affect health — more research could easily change what we think today.
People who eat a lot of trans fats (especially from fried and processed foods) are more likely to die from any cause, but this doesn’t seem to affect their risk of stroke or diabetes clearly.
A specific type of fat found naturally in dairy products is linked to a much lower risk of developing type 2 diabetes, even though people don’t eat much of it.
Eating more saturated fat from butter, meat, or cheese doesn’t clearly make people more likely to die early or get heart disease or diabetes, but the studies aren’t perfect, so we can’t be totally sure.
Eating man-made trans fats found in fried and processed foods is linked to a higher chance of dying from heart disease or having a heart attack, but the natural trans fats in dairy and meat don’t seem to have the same effect.
The red ink used in the study contains a chemical (2-anisidine) that’s not allowed in human tattoos because it might cause cancer.
When tumors did appear in sun-exposed mice with red tattoos, they grew faster than tumors in mice without tattoos.
All mice that got regular UV light exposure developed skin cancer, no matter if they had tattoos or not.
Red tattoos alone, without sun exposure, didn’t cause any skin tumors in mice.
In mice that got sunburns from UV light, those with red tattoos got their third skin tumor a bit sooner and the tumors grew a little faster than in mice without tattoos.
Even in skin that looks perfectly healthy, some cells already have the same DNA mutations found in skin cancers—but they’re rare and don’t cause cancer yet.
Certain spots on our DNA are fragile and tend to break during cell division—even in healthy skin—leading to big rearrangements, and one spot on chromosome 7 breaks more than any other.
Every year, your skin cells make about 0.22 tiny copying mistakes when copying DNA in long repeating sequences—like typing 'AAAAA' and accidentally adding or losing an 'A'—and these mistakes build up as you age.
People with darker skin have far fewer DNA mutations from sun exposure—even in areas never exposed to sunlight—because melanin acts like a natural sunscreen inside their skin cells.
Large DNA deletions in skin that never gets sunburned are linked to past sun exposure—likely because UV light breaks DNA strands, and the cell’s repair job often messes up, deleting big chunks.
As people get older, their skin cells naturally accumulate more DNA errors from normal chemical reactions inside the body—about 0.4 new errors per year—like a biological clock ticking.
Even skin that never gets direct sunlight still shows DNA damage from past sun exposure, and this damage doesn’t get worse as people get older—it just stays the same.