Browse evidence-based analysis of health-related claims and assertions
Kids absorb beta-carotene from pumpkin and spinach differently, and poop tests show almost the same difference as blood tests—so maybe we can use poop instead of blood to check nutrition without needing a needle.
Correlational
In Indonesian kids, pumpkin gives the body about 1.8 times more vitamin A (from beta-carotene) than spinach does, but some kids get way more and others way less — it really varies from person to person.
Quantitative
Scientists made a new way to measure how well kids absorb vitamin A from pumpkin or spinach by testing their poop — no needles needed!
Descriptive
We need the same global rules for testing honey at borders using high-tech tools so people don’t end up eating honey that’s secretly poisonous.
Causal
LC-MS is a good way to find plant toxins in honey, but we need other tools too if we want to check for lots of different toxins at the same time.
Even though some bad stuff in honey can make people feel similarly sick—like having nausea or dizziness—they might actually harm the body in different ways behind the scenes.
Mechanistic
Eating honey that's been contaminated with natural plant toxins can make people really sick — with vomiting, nausea, and dizziness — and in some cases, it can even be deadly.
Even though honey is natural, it can sometimes contain toxins from poisonous flowers that bees visited, and eating that honey might be harmful to people.
After taking vitamin A supplements for three weeks, two people ended up getting more usable vitamin A from beta-carotene—even though their bodies were breaking it down less, which is kind of surprising.
Taking a lot of vitamin A every day for about three weeks might make your body break down beta-carotene (from food) into vitamin A less efficiently.
Taking a specific dose of vitamin A every day for about three weeks might make your body get rid of much less of a certain form of beta-carotene through urine, based on a small observation in two healthy adults.
Taking a lot of vitamin A every day for about three weeks might help two healthy people absorb more beta-carotene from their food, based on how much showed up in their urine over the next month.
A special form of iron called liposomal iron can raise blood iron levels in women with low iron, and many people feel better using it because it's easier on the stomach.
Eating even a small amount of meat or fish with a plant-based meal can help your body absorb more iron from the plants.
Calcium can make it harder for your body to absorb iron from food, especially in women and kids, but taking calcium supplements over time might not actually lead to low iron because your body could adjust.
Stuff in plant foods like beans and tea can make it harder for your body to absorb iron, especially if you're eating foods with added iron—because they bind to the iron and make it harder to use.
Vitamin C helps your body absorb iron from plant foods better, and the more vitamin C you eat with your meal, the more iron you absorb—up to a point.
Even though only a small part of the iron we eat comes from meat, fish, and poultry, our bodies absorb a lot more of that type—so much that it makes up over 40% of all the iron we actually take in.
Lab mice get more than 20% of their energy from gut bacteria breaking down food, which is way more than humans do, so mouse studies might overestimate how much we rely on our gut microbes for energy.
Your gut bacteria don’t change how much waste they produce overall, but they do change what kinds of waste chemicals—like butyrate and lactate—are made, and this mix is different for everyone depending on their unique gut bug lineup.
Most of the stuff your gut bacteria eat turns into helpful chemicals like butyrate, and your body soaks up almost all of it—very little ends up in poop.
What you eat—especially fiber and complex carbs—mostly decides how much gut fermentation happens, and eating more of these carbs can boost fermentation by up to five times compared to a standard Western diet. The types of gut bacteria you have don’t really change the overall amount.
The gut bacteria in people eating lots of fiber can provide up to 12% of their daily energy, while those on a typical Western diet get only 2%–5% from their gut bugs — so what you eat changes how much energy you get from your microbiome.
Primates with thicker tooth enamel tend to eat harder, tougher foods — probably because thicker enamel helps their teeth survive the heavy crunching without cracking.