Q: Is soda really bad for your kidneys?
A: Yes. Drinking 16 ounces or more daily (whether diet or regular) doubles your risk of chronic kidney disease, according to an NIH study of more than 900 people. The researchers already knew that consuming any type of soft drink—the average American adult guzzles 59 gallons' worth per year—is associated with several risk factors for kidney disease (hypertension, diabetes, and kidney stones), but the spike in the cola category was remarkable.
Experts suspect that the ingredient phosphoric acid may be the culprit; it's been repeatedly linked to "urinary changes that promote kidney stones," say the study authors. Cola has an additional knock against it: Consumption is associated with significantly lower bone density in women, increasing the risk of osteoporosis and bone fractures, says a separate study.Q: Can cracking your knuckles cause arthritis?
A: Nope. If you're suffering from osteoarthritis in your hands, it certainly has nothing to do with this nervous tic. One study at the former Mount Carmel Mercy Hospital in Detroit compared 74 people (age 45 and older) who had been chronic knuckle crackers for decades with 226 who always left their hands alone; researchers found no difference in the incidence of osteoarthritis between the two groups.
But there are reasons to stop this annoying habit: The same study found knuckle crackers to be far more likely to have weaker grip strength and greater hand swelling, both of which can limit dexterity. As for osteoarthritis, that's more likely due to genetics and increasing age.Q: It’s safe to follow the 5-second rule for dropped food, right?
A: It's probably not even safe to follow a 1-second rule: The transfer of bacteria from a contaminated surface to food is almost instantaneous—or, at the very least, quicker than your reflexes. In one study, Clemson University food scientist Paul Dawson, PhD, and students contaminated several surfaces (ceramic tile, wood flooring, and carpet) with Salmonella. They then dropped pieces of bologna and slices of bread on the surfaces for as little as 5 seconds and as long as 60 seconds.
After just 5 seconds, both food types had already picked up as many as 1,800 bacteria (more bad bugs adhered to the moisture-rich bologna than the bread); after a full minute, it was up to 10 times that amount.