I've heard dogs can smell when people are sick. Do they sense a change in a person or do they actually smell that something isn't quite right?
A bit of both. Dogs have a remarkable sense of smell -- bloodhounds have almost 50 times as many scent receptors as humans; that translates to a sense of smell that's 10,000 to 100,000 times better than what we have.
Researchers in Germany followed a program developed at the Cleveland Clinic that trained dogs to detect the smell of a waste product of lung cancer. The German dogs can smell your breath and identify lung cancer correctly 93 percent of the time. A Japanese pooch sniffed the breath and stool samples of more than 300 people and correctly identified which people had bowel cancer 98 percent of the time. Other studies demonstrate dogs can detect early-stage breast cancer, melanomas and bladder cancer with an accuracy rate of 88 percent to 97 percent.
How is this possible? Malignant tumors exude tiny amounts of volatile organic compounds that aren't in healthy tissue. Dogs can sniff out each one in concentrations as dilute as parts per trillion. The dogs' ability to smell VOCs may lead to a new test to detect cancer. If it gets inexpensive enough, maybe we'll all have a breath analysis once a year to spot early, otherwise undetectable, disease.
Cancer isn't the only disease that stinks. Medical dogs can smell a change in blood sugar levels and the presence of ketones (toxic acids in the bloodstream that signal low insulin or high blood sugar) and then alert their owners or others to a potential diabetic seizure.
Dogs also can be trained to detect changes in behavior (when your tell isn't your smell) and recognize the onset of high blood pressure, a heart attack and epileptic seizures, and to get a person the help he or she needs.
Health tip of the week: Kefir, chia and purslane: 3 little-known foods that are good for you
The best foods for you might be ones you've never heard of. Some of these are ancient, but thanks to food trends, they're now at your fingertips.
What it is: A milk drink that has a slightly sour taste. (It's fermented, but don't let the sound of it scare you away. We love the stuff).
What it does: Its vitamin K2 helps keep alive osteoblasts, cells that are responsible for forming new bone. Vitamin K2 also escorts calcium into your bones so it can do one of its jobs: making bones stronger.
What it is: Yes, the stuff that puts the "hair" on chia pets. It's a whole grain that was used by the Aztecs as their main energy source.
What it does: Contains omega-3 fatty acids, and can help restore your energy levels and decrease inflammation. Similar to cornstarch, chia can be used as a thickening agent and as a substitute for whole grains in your diet. It is great at holding moisture. We make muffins with it.
What it is: A leafy green that's slightly crunchy and tangy; poised to become the next arugula in food circles.
What it does: Reputed to contain higher amounts of omega-3 fatty acids than other greens (though the biggest bang per serving still comes from fish). It also contains about the same amount of calcium and magnesium as spinach.
Dr. Michael Roizen is chief wellness officer at the Cleveland Clinic and co-founder and chairman of the RealAge Scientific Advisory Board. Dr. Mehmet Oz is a professor and vice chairman of surgery at Columbia University, as well as medical director of the Integrated Medicine Center and director of the Heart Institute at New York Presbyterian/Columbia Medical Center. To submit questions and find ways to grow younger and healthier, go to RealAge.com.