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Fatti di pesce

15.11.21Elaine Holmes

15.11.21

Elaine Holmes

What about that smell ...

One of the chemicals present in fish is trimethylamine-N-oxide (TMAO), which when it degrades to trimethylamine gives fish that fishy smell. TMAO  has had some bad press as the concentrations of this chemical in blood and urine have been associated with heart disease and diabetes. So if eating fish is generally good for you, is TMAO really the bad guy? Like most matters in dietary health, it all depends on the broader dietary and lifestyle pattern. 

As well as being found in high concentrations in some fish, TMAO is also made by the gut bacteria which break down dietary choline which is found in various foods including meat, particularly red meat. So eating meat can also increase the levels of  TMAO  in our blood and urine. After choline is broken down to trimethylamine by the gut bacteria, the oxide is made in the liver and enters the blood stream. Scientists have shown that TMAO can alter cholesterol metabolism and can result in hyperactivity of the blood platelets leading to formation of atherosclerotic plaques but other studies have failed to show the link with heart disease. Since production of trimethylamine is a fundamental property of the gut microbiome that has co-evolved with humans and TMAO acts as a cellular protectant in fish exposed to high levels of salinity or pressure, there has to be an up-side to the molecule.

Eat like the Japanese

Certainly the Japanese, who eat more fish and less red meat than western societies and have the lowest mortality rates from heart disease experience such upside. Any chemical when considered in isolation can have some negative effects but as humans are exposed to thousands of chemicals through their diet and environment, it is more appropriate to consider the action and properties of these chemicals as part of the overall dietary pattern. So the take-home message here has to be that including fish in your diet has health benefits. 



Eat like the Japanese

Certainly the Japanese, who eat more fish and less red meat than western societies and have the lowest mortality rates from heart disease experience such upside. Any chemical when considered in isolation can have some negative effects but as humans are exposed to thousands of chemicals through their diet and environment, it is more appropriate to consider the action and properties of these chemicals as part of the overall dietary pattern. So the take-home message here has to be that including fish in your diet has health benefits.