Urine Smells Funny After Eating Asparagus

Dear Dr. Dave and Dr. Dee,

My boyfriend's urine smelled awful after eating asparagus. We both ate the same meal, but my urine was fine. My boyfriend says that everyone's urine smells after eating asparagus, and since mine doesn't, then I'm the strange one, not him. No one in my family has ever had urine odor from eating anything. Is he right, or might he have a problem?

Signed,

Worried

Dear Worried,

There is nothing wrong with your boyfriend. Not everyone has smelly urine shortly after eating asparagus, but many do. About half of the population will notice this odor after eating asparagus because of the sulfur-containing amino acids which break down after ingestion (see details below).

The Michigan Asparagus Advisory Board at www.asparagus.org considers asparagus to be one of the most nutritionally well-balanced vegetables, supplying significant nutrients and fiber for a healthy diet.

DETAILS: Why eating asparagus causes one's urine to have a strong, unique odor

As archived in the Boston Globe (www.boston.com), below are more details about why asparagus causes urine to have a unique odor:

Sulfur-containing amino acids in asparagus break down during digestion, creating an odor when urine is excreted. "It's the same sulfur group that makes skunks smell," said Barbara Hodges, a dietitian with Boston University's nutrition clinic, the Evans Nutrition Group (Hodges cited in Boston.com, 1994).

However, not everyone has the urine odor or perhaps not everyone can smell it. "There's something of a dispute," said Dr. David Stollar, chairman of biochemistry at Tufts University Medical School (Stollar cited in Boston.com, 1994). Some scientists think only half of the population can break down the sulfurous amino acids into their smellier components. Other scientists think that asparagus is digested the same by everyone, but that only half can smell the odor.

The unusual urine smell is nothing to worry about because "the syndrome does not have any pathological significance" (Dictionary of Medical Syndromes cited in boston.com, 1994).

For more information about asparagus, go to www.asparagus.org

The Boston Globe article can be found at www.boston.com/globe/search/stories/health/how_and_why/060694.htm