DEAR DR. BLONZ: Please forgive the indelicacy of this question, but is there something in asparagus that makes urine smell? My husband and I love asparagus, and now that it's spring, it is plentiful in our local market. We eat it every now and then, and I always seem to notice a telltale odor the next time I visit the bathroom. I only notice it after asparagus. My husband doesn't experience this. -- G.A. Sacramento, California
DEAR G.A.: Asparagus, garlic and onion are members of the lily family. These healthful vegetables all have sulfur-containing compounds that can give rise to distinctive odors. In the case of asparagus, though, the peculiar odor isn't noticeable in the raw vegetable. Rather, it comes from metabolic byproducts that are produced and then pulled out of the bloodstream by the kidneys soon after asparagus has been eaten.
There are some variables at play here: One is whether an individual produces the substances, and another is whether an individual is able to detect the odor. Most, but not all of us, produce varying concentrations of the byproducts. Some individuals are nonsmellers, while others are smellers but they can only detect the substances at certain concentrations. A capsule review of some of the science can be found at tinyurl.com/majcajz.
DEAR DR. BLONZ: When I hear about recalls of peanuts and other nuts (and nut butters) because of salmonella, I am puzzled. I had only thought this was an issue with raw nuts, not cooked ones. I was hoping you could explain. -- D.I., via email
DEAR D.I.: Nuts, whether they are peanuts, walnuts, almonds, pistachios, cashews or others, are great players in a healthful diet. In addition to providing healthful fats, they contain fiber and beneficial phytochemicals. No wonder that observational studies report that nut consumption is inversely associated with the incidence of cardiovascular disease and cancer.
Regarding peanuts, if we assume that roasting is done correctly, any salmonella contamination of a peanut should be completely eliminated during the roasting process, whether it's an oil roast or a dry roast. Oil roasting and dry (oven) roasting take place at temperatures well above the temperature needed to destroy this organism. It has to be done right, though, to assure that all the nuts get up to the right temperature. (An explanation of the temperatures used in peanut processing can be found at tinyurl.com/b6z7xa.)
Assuming the roasting is not the issue, the risk can come from what goes on afterward. Think, for example, of doing a great job of washing your hands, only to dry them off with a dirty towel. If a company does not have proper hygiene and food-safety protocols, their products are at risk anywhere along the line -- from the roaster to the final container. Recalls are designed to overcompensate and stop the outbreak while the food-safety detectives identify how the food was tainted and how it got into your store. Check the Food and Drug Administration website (fda.gov) for recalls, and watch for the brands you frequently buy.
Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to firstname.lastname@example.org. Due to the volume of mail, personal replies cannot be provided.