People who ate more spermidine had healthier liver scores — and the same people lost weight
People who ate more spermidine had healthier liver scores — and the same people lost weight.
People who ate more spermidine had healthier liver scores a year later. That's what a study of over two thousand six hundred older adults found. Spermidine is a compound in vegetables, whole grains and mushrooms, and it's sold as a longevity supplement. But the same people also lost the most weight.
People who ate the most spermidine had the biggest drop in two fatty-liver scores
People who ate the most spermidine had the biggest one-year drop in two fatty-liver scores.
The researchers followed over two thousand six hundred overweight older adults, all with high blood sugar and blood pressure, for a year. They estimated everyone's spermidine from a questionnaire about what people usually ate. Then they sorted people into three groups by intake. The highest third had the biggest drop in two scores doctors use to gauge a fatty liver, plus slightly lower liver enzymes and blood sugar.
The same group that ate the most spermidine also lost the most weight
The same group that ate the most spermidine also lost the most weight.
You'd think that means the spermidine helped their livers. But look at that same group again. They also lost the most weight. Their waist shrank almost four centimetres. Spermidine comes from vegetables, beans and whole grains, so the people eating the most of it were the ones sticking best to the Mediterranean weight-loss diet everyone in the study was already on. The spermidine group is really the lost-the-most-weight group.
Those 'liver scores' aren't scans — they're formulas built mostly from your waist and weight
Those "liver scores" aren't scans — they're formulas built mostly from your waist and weight.
Here's the fact that changes everything. The two numbers that dropped the most aren't liver scans. They're formulas, and both are built mostly from body size. The Fatty Liver Index is calculated from your waist size and your weight-for-height, plus two blood measures. The Hepatic Steatosis Index has that same weight-for-height baked right into it. So when this group shrank its waist and its weight, those liver scores dropped automatically. The formula guarantees it, even if nothing at all changed inside the liver.
A questionnaire and a body-size formula turn weight loss into 'your liver improved'
A questionnaire and a body-size formula turn weight loss into "your liver improved."
Now put the three pieces together. The researchers never measured spermidine in anyone's blood. They estimated it from that food questionnaire. The people who reported eating the most of it were the best dieters, so they lost the most weight. And the liver score is really a formula built from that weight. So the machine quietly relabels ordinary weight loss: you lost weight becomes your liver improved. And the numbers show it. Once the researchers adjust for the weight and the diet, that headline drop of nearly nine points roughly halves.
Isolate spermidine, and the direct liver tests stay flat while cholesterol rises
Isolate spermidine, and the direct liver tests stay flat while cholesterol rises.
So the researchers ran the clean test. They isolated spermidine, stripping out the weight loss and every other food. And the blood tests that truly rise when a liver is under stress didn't budge. The only liver numbers still lower were the two body-size formulas. And the LDL, the bad cholesterol that clogs arteries, actually rose. So on its own, the molecule left the real liver flat and cholesterol higher. This is an association in older adults already dieting, estimated from a questionnaire. It's not a trial of a spermidine supplement, and not a reason to take one.
The test that would settle it: give spermidine directly, hold weight steady, scan the liver
The test that would settle it: give spermidine directly, hold weight steady, scan the liver.
Here's the experiment that would settle it. Give some people spermidine and some a dummy pill, and hold their weight and diet steady, so nothing else can move. Then read the liver with a scan, not a body-size formula. If the spermidine group's liver fat drops on the scan, the molecule earns the credit. Until a trial like that runs, higher spermidine intake stays a marker of a better diet, not a proven treatment.
A marker of a better diet, not a pill that fixes your liver
In these older adults, more spermidine tracked healthier "liver" scores. But those scores are body-size formulas, and the same people lost the weight that moved them.
So in these older adults, more spermidine tracked healthier liver scores. But that score is a body-size formula, and on its own the molecule moved no real liver test. So for the next supplement headline, you'll know what to ask. Was the food measured, or guessed from a questionnaire? Is the marker a real test, or a formula? And did the group also lose weight?
