Can Certain Foods Cause Fishy Odor?

November 16, 2025 •

3 min read

According to the Cleveland Clinic, a rare metabolic disorder known as trimethylaminuria (TMAU) can make a person's sweat, breath, and urine smell like rotten fish. This unusual symptom raises the question: can certain foods cause fishy odor?

Quick Summary

Certain foods can trigger a fishy body odor, primarily in individuals with the metabolic disorder trimethylaminuria (TMAU). This is due to the body's inability to break down the chemical trimethylamine, which is produced during digestion of precursors found in foods like seafood, eggs, and certain vegetables. Avoiding high-choline and carnitine foods is key to managing symptoms.

Key Points

TMAU is a metabolic disorder: The rare condition, trimethylaminuria (TMAU), is a genetic disorder where the body cannot properly break down the compound trimethylamine (TMA), causing a fishy odor.
High-choline foods are the primary trigger: The most significant dietary triggers are foods rich in choline, such as eggs, organ meats, legumes, and certain cruciferous vegetables.
Carnitine and TMAO are also culprits: Other dietary precursors include carnitine, found in red meat, and trimethylamine N-oxide (TMAO), prevalent in saltwater fish and shellfish.
Dietary management is key: A low-choline diet, managed with a dietitian's help, is the main way to control symptoms by restricting precursor foods.
Non-dietary treatments exist: Beyond diet, using pH-balanced soaps, managing stress, and sometimes taking antibiotics or supplements like activated charcoal can also help.
Not everyone needs major dietary changes: A persistent fishy odor is the key, as temporary or mild odor from foods is not indicative of TMAU for most people.

Understanding the Link Between Diet and Fishy Odor

While good hygiene is the first line of defense against body odor, a persistent, fishy smell that doesn't go away with washing could point to a rare metabolic disorder called trimethylaminuria (TMAU), or “fish odor syndrome”. This condition is primarily linked to how the body processes specific compounds from food, particularly those rich in choline, carnitine, and trimethylamine N-oxide (TMAO).

The Science Behind Trimethylaminuria

The human body typically breaks down foul-smelling trimethylamine (TMA)—a chemical produced by gut bacteria during digestion—into an odorless compound. This process is managed by an enzyme called flavin-containing monooxygenase 3 (FMO3).

However, people with primary TMAU have a mutated FMO3 gene, causing them to lack a fully functional enzyme. As a result, TMA builds up in the body and is released through bodily fluids like sweat, breath, and urine, creating a strong, fish-like smell. In secondary TMAU, a temporary version of the condition can be triggered by a number of factors, including certain medical conditions affecting the liver, hormonal changes (such as those during menstruation), or an overgrowth of TMA-producing gut bacteria.

Foods That Can Trigger Fishy Odor in Individuals with TMAU

For those with TMAU, specific dietary choices can exacerbate symptoms. The primary culprits are foods high in choline, carnitine, and TMAO.

High-Choline Foods

Choline is an essential nutrient, but gut bacteria can convert excess amounts into TMA. Foods rich in choline include:

Eggs: Especially the yolks.
Organ Meats: Liver and kidney are particularly high in choline.
Legumes: Such as beans, peas, and soybeans.
Cruciferous Vegetables: Including broccoli, cabbage, cauliflower, and Brussels sprouts. Some also contain indoles, which can inhibit FMO3 enzyme activity.

High-Carnitine and TMAO Foods

Carnitine and TMAO are other precursors that can lead to increased TMA production.

Red Meat: Especially beef, is a significant source of carnitine.
Seafood: Saltwater fish and crustaceans contain high levels of TMAO, which gut bacteria reduce to TMA. Freshwater fish generally have lower levels.

Lecithin and Supplements

Lecithin and carnitine supplements, sometimes used for athletic performance or health reasons, can also increase TMA levels. Fish oil supplements containing lecithin should also be avoided.

Managing the Condition with Dietary Changes

Effective management of TMAU often involves a low-choline diet. However, since choline is a vital nutrient for brain health, especially in children and pregnant women, consulting with a registered dietitian is essential to ensure a nutritionally balanced eating plan.

A Low-Choline Diet Strategy

Protein Sources: Prioritize lower-choline protein sources like poultry (chicken, turkey) or plant-based proteins such as legumes (beans, lentils). Opt for smaller portions of red meat and freshwater fish over saltwater varieties.
Vegetables: Stick to vegetables outside the brassica family, and enjoy a wide variety of fruits.
Dairy: Most dairy products like milk, cheese, and yogurt are fairly low in choline, but some milk from wheat-fed cows may have higher TMA levels. Low-choline alternatives include nut or rice milks fortified with calcium.


Food Category	High-Choline / TMAO	Low-Choline Alternatives
Protein	Seafood (saltwater), Eggs (yolks), Organ Meats, Soybeans	Poultry, Egg Whites, Tofu (lower choline), Lentils, Freshwater Fish
Vegetables	Broccoli, Cabbage, Cauliflower, Brussels Sprouts	Leafy Greens (Spinach, Kale), Potatoes, Carrots, Onions
Dairy	Milk from wheat-fed cows (avoid)	Nut Milks, Rice Milk, Calcium-Fortified Dairy Alternatives
Supplements	Lecithin, Choline, Carnitine Supplements	Riboflavin (Vitamin B2), Probiotics

Other Management Strategies

Beyond diet, other techniques can help reduce the symptoms of TMAU:

pH-Balanced Soaps: Using soaps with a pH between 5.5 and 6.5 can help neutralize the volatile, alkaline TMA on the skin.
Stress Management: Since stress can trigger or worsen sweating, and thus the release of TMA, managing stress levels is beneficial.
Medication: In some cases, a doctor may prescribe a short course of antibiotics to suppress the TMA-producing gut bacteria or activated charcoal to bind to TMA in the gut.

Conclusion

For most people, dietary changes to address body odor are minimal, perhaps involving a temporary reduction of pungent foods like garlic or curry. However, a persistent, fishy body odor that isn't resolved by standard hygiene is a strong indicator of trimethylaminuria (TMAU). Understanding the connection between this metabolic disorder and specific food compounds, particularly choline and carnitine, is the first step toward effective management. By adjusting your diet and adopting supplemental care strategies, it is possible to significantly reduce the unpleasant symptoms associated with TMAU.

For more information on the genetic aspect of this condition, visit the National Human Genome Research Institute for details on the FMO3 gene.

Frequently Asked Questions

You should consider avoiding or significantly limiting foods high in choline and carnitine. This includes egg yolks, organ meats (liver, kidney), soybeans, certain beans and peas, saltwater fish and shellfish, and cruciferous vegetables like broccoli, cauliflower, and Brussels sprouts.

In individuals with TMAU, yes, eating saltwater fish can cause a fishy odor within a few hours. However, most people with properly functioning FMO3 enzymes can consume fish without experiencing this specific odor because their bodies effectively process the trimethylamine.

Yes, supplements containing high doses of choline, carnitine, or lecithin can overwhelm the body's ability to process these compounds, potentially leading to a fishy odor, even in people without genetic TMAU.

Primary trimethylaminuria is a genetic condition caused by an inherited mutation in the FMO3 gene. Secondary trimethylaminuria is acquired later in life and can result from liver disease, hormonal changes, or an overgrowth of TMA-producing bacteria in the gut.

Yes, some studies suggest that green tea and chlorophyllin (a derivative of chlorophyll found in leafy green vegetables) may help reduce body odor by inhibiting bacterial growth and neutralizing odor-causing compounds. This can be a helpful dietary addition for general body odor management.

TMAU is diagnosed with a urine test that measures the ratio of trimethylamine to trimethylamine N-oxide. This can be performed after consuming a high-choline meal to see how effectively your body processes the compound.

No, a low-choline diet will not cure TMAU, but it can significantly help manage and reduce the odor symptoms. Since TMAU is often a genetic condition, there is currently no cure, but symptom management can greatly improve quality of life.