Browse evidence-based analysis of health-related claims and assertions
In the fat around the heart and blood vessels of heart failure patients, a specific enzyme called MAO-A is much more common and makes more harmful chemicals than its cousin MAO-B.
Descriptive
Even with different fat diets and different amounts of vitamin E, the rats' testicles and sperm storage areas looked normal — vitamin E didn’t change their appearance.
Giving rats 40 IU of vitamin E per kg of food stopped almost all fat damage — giving them even more (100 IU) didn’t help any further.
When fat tissue around the heart and blood vessels was soaked in a blue dye called methylene blue for a day in the lab, it made less of a harmful enzyme and produced fewer damaging chemicals, which might help explain how the dye could protect cells.
Correlational
Even when rats ate a lot more of the kind of fat that's more likely to go bad (polyunsaturated), their fat damage didn't go up as long as they got enough vitamin E.
When rats didn't get any vitamin E in their food, their bodies showed more signs of fat damage, no matter what kind of fats they ate.
When rats ate diets with different types of fats, giving them a specific amount of vitamin E (40 or 100 IU per kg of food) greatly lowered signs of fat damage in their bodies, and that amount was enough to stop most of the damage.
Mice with a human gene variant called ApoE4 have less of certain fat molecules in their brains than normal mice, no matter what they eat.
The way olive oil is made and stored in different places might help it last longer, but we can't say for sure which part makes the difference.
Scientists can tell if olive oil is going bad by shining light on it and watching how the color changes — darker spots mean the good stuff is breaking down, and brighter spots mean bad stuff is forming.
Olive oil from Al-Jouf stays fresher longer than olive oil from Pakistan when left out at room temperature, based on how quickly it breaks down.
The belly fat in mice makes a lot of a heat-boosting chemical when it’s cold—but when the mice are inflamed or have this bacteria, that fat stops making it, while other fat types don’t change as much.
When mice were made sick with a bacterial toxin, they got colder in the cold—but so did mice that were fed a specific gut bacteria, even though they ate the same amount and didn’t gain weight.
Scientists found that a fat chemical (15-HETE) physically sticks to a key energy sensor (AMPK) in fat cells, turning it on and helping the cells burn more energy to make heat.
Mechanistic
When scientists grew fat cells with this specific bacteria (Sphingomonas), the cells stopped making a key fat-burning chemical and heat-producing proteins—but when they used a different common bacteria (E. coli), nothing changed.
When scientists gave a specific fat chemical (15-HETE) to mice whose heat production was blocked, it brought back their ability to burn fat and generate heat, even if the bacteria or enzyme blocking it were still present.
People who are overweight or obese tend to have less of a specific fat-related chemical (15-HETE) in their blood than lean people, and the more weight they have, the less of this chemical they have.
In mice, a type of gut bacteria called Sphingomonas paucimobilis moves to belly fat during inflammation and blocks the body’s ability to burn calories for heat by interfering with a key fat-burning chemical and its signaling pathway.
When young men slept less, their bodies released more of the stress-related chemical norepinephrine, especially at night and in the morning, which may be a sign their stress system was overactive.
Causal
When young men slept less, they burned a little more energy during the night because they were awake longer—but this extra burn didn’t add up to more total energy burned over the whole day.
Even after sleeping only 3.5 hours a night for three nights, young men burned the same total amount of energy and used the same mix of carbs and fats as when they slept 7 hours.
When young men slept less, their body’s internal temperature dropped slightly over two days, suggesting their body’s natural daily temperature cycle was disturbed.
As you heat any oil, the number of smelly, toxic aldehyde chemicals goes up steadily — and soybean oil spikes the most right at frying temperatures.
After sleeping only 3.5 hours a night for three nights, young men reported feeling much hungrier and more tempted to eat, and less full after meals, even when they ate the same food as when they slept longer.