Every durian season brings the warning back, usually attached to a story about someone found dead beside a fruit and a bottle. The warning is not superstition. There is a published mechanism. It is also considerably weaker evidence than the stories imply, and almost nobody repeating it mentions which part was actually tested.
The mechanism
Alcohol is cleared in two steps. Alcohol dehydrogenase turns ethanol into acetaldehyde, which is toxic and responsible for flushing, nausea, headache and racing heart. Aldehyde dehydrogenase, ALDH, then converts acetaldehyde into harmless acetic acid.
Block the second step and acetaldehyde accumulates. This is exactly how disulfiram, the alcohol aversion drug, works: it inhibits ALDH deliberately so that drinking becomes unpleasant. It is also why many people of East Asian descent flush after one drink, since a common genetic variant makes ALDH less effective.
Durian is rich in sulphur compounds. So is disulfiram. That is the entire basis of the theory.
What the study measured
The reference everyone cites without naming it is:
Maninang, J.S., Lizada, M.C.C. and Gemma, H. (2009). “Inhibition of Aldehyde Dehydrogenase Enzyme by Durian (Durio zibethinus Murray) Fruit Extract.” Food Chemistry, 117(2), pages 352 to 355.
The same authors published a corrigendum to it in Food Chemistry 120(4), page 1122, in 2010.
The researchers found dose-dependent inhibition of ALDH by durian extract, reducing enzyme activity by up to 70% at a concentration of 0.33 ppm. They pointed to sulphur-rich constituents such as diethyl disulfide as the likely cause.
That is a real result and it is the reason the folk warning deserves respect rather than mockery.
The part that gets left out
The enzyme in that experiment was yeast ALDH, tested in vitro. It was not human ALDH, it was not tested in a person, and no dose was established at which eating durian and drinking produces a given effect in a human body.
So the honest summary is: durian extract demonstrably inhibits an ALDH enzyme in a dish. That makes the proposed mechanism plausible. It does not establish how much durian, with how much alcohol, does what to a person.
Are the death stories real?
Deaths have been reported anecdotally and in news coverage, including a widely repeated case of a man found dead with durian and wine. In none of them has the combination been established as the cause. People die beside food and drink for other reasons, and a striking coincidence travels much further than a coroner’s finding.
There is no good evidence that durian plus alcohol kills a healthy person.
What is likely to actually happen
If the mechanism holds in humans at realistic doses, the effect is a worse version of a normal hangover: flushing, nausea, headache, palpitations, feeling drunker than the amount consumed would explain. Unpleasant rather than dangerous.
There is also a simpler explanation nobody needs a study for. Durian is calorie dense and fat rich, alcohol is an irritant, and a large quantity of both at once causes bloating and indigestion in people with entirely normal enzymes.
The sensible position
Do not drink heavily with a large quantity of durian. Not because it will kill you, but because the mechanism is plausible, the upside is nil, and feeling appalling is a real cost.
If you have had durian and want a drink, leave a few hours. If you are eating durian at a stall with friends and someone hands you a beer, one beer is not a medical emergency.
And if anyone tells you the science is settled in either direction, they have not read the paper.
Related
- What not to eat with durian, the rest of the pairing warnings, most of which have nothing like this much behind them
- How much durian is too much
- Durian calories and nutrition, including the potassium risk that is genuinely serious for one group
- Durian types and their D numbers