When you pee and something smells a little off, it's natural to feel alarmed. In most cases, though, the culprit behind stinky urine isn't serious. Rather, it's more likely the result of the food you've eaten.
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How Food Affects Urine Odor
Urine isn't exactly known for smelling like roses. After all, it's a waste product. But, though urine's odor isn't generally appealing, what about when it smells unusually bad? It's possible the foul smell is a sign of an underlying condition, but it probably has more to do with what you had for lunch.
"I always tell my patients that what they eat and drink often ends up in the bladder," says Michael Ingber, MD, a northern New Jersey-based urologist and director of urogynecology for Saint Clare's Health System and an assistant clinical professor of urology at Weill Cornell Medical College in New York City. Just like some foods are more odorous as they enter the body, they're also pungent on their way out.
According to Dr. Ingber, there's not necessarily a consistent chemical explanation for this phenomenon — different foods may cause stinky pee for different reasons. "There is no specific compound in these foods that gets excreted," he notes.
Foods That Cause Smelly Urine
So which foods are the worst offenders? Asparagus tends to get top billing for changing the smell of urine, but eating this green veggie isn't a guarantee of a rotten cabbage smell.
According to research published in January 2018 in Pharmacometrics & Systems Pharmacology, some people don't excrete the sulfurous metabolites that cause this signature odor. Not everyone can sniff out the smell from asparagus, either. "There is a genetic issue in those who can actually smell the odor after eating asparagus," Dr. Ingber says.
Asparagus aside, several other foods can have notable effects on urine odor. "Acidic, spicy foods can cause urinary bladder irritation, which leads to things like urinary urgency, frequency and discomfort related to bladder filling," says Dr. Ingber. "Certain items like tomatoes, coffee and wine fall into this category. In terms of odor, food and drink containing curry, coffee and Brussels sprouts have also been found to cause odorous urine."
Don't be surprised if some foods change the color of your pee too. According to Harvard Health Publishing, many foods — including asparagus, beets, blackberries, carrots and rhubarb — can temporarily alter the hue of urine. Harvard notes that medications and certain vitamins (such as B and C) can also have this effect.
Read more: How Vitamins Can Affect Urine Odor
Though some foods cause foul-smelling urine, can others make for more aromatic scents? You may have heard, for example, that eating pineapple will give you tropical-scented pee. But research doesn't support these claims. "There are no particular foods or beverages I'm aware of that will do this," says Dr. Ingber.
In rare cases, a disorder called maple syrup urine disease can sweeten the smell of urine. But "this is a rare genetic disorder in which patients are unable to metabolize certain branch-chain amino acids," Dr. Ingber notes. "This causes the urine to develop a sweet smell like maple syrup."
Stinky Urine and Health Conditions
A whiff of stinky pee usually isn't cause for concern, but some underlying medical conditions may need to be ruled out, especially if foul-smelling urine is a regular occurrence. According to Dr. Ingber, urinary tract infections or bacteria in the urine are the most common medical causes of putrid pee.
Less often, smelly urine could be a sign of a disorder called trimethylaminuria. "This is a condition where the body is not able to metabolize trimethylamine, which can be found in certain foods," he explains. Ketosis, the metabolic state brought on by a low-carbohydrate diet, may also affect urinary smell. "The urine ends up having high ketones, which results in darker urine and a very pungent, strong odor."
If you notice an offensive urine smell, try to remember if you recently ate any potent or pungent foods. And if your urine consistently has an unpleasant odor or you experience other symptoms along with changes in smell, seek medical attention.
Read more: Should You Avoid Certain foods With a UTI?
- Michael Ingber, MD, urologist; director of urogynecology, Saint Clare’s Health System, northern New Jersey, and clinical assistant professor of urology, Weill Cornell Medical College, New York, New York
- Pharmacometrics & Systems Pharmacology: “Crowdsourced Asparagus Urinary Odor Population Kinetics”
- Harvard Health Publishing: “Urine Color and Odor Changes”