We and our dogs know how it feels to be sore and stiff after a hunt. And we humans know why: We overdid it. But if the fun we gained was greater than the pain, we just do it again. Paul Milbury, Ph.D., sees it differently. A research scientist in the antioxidant lab at Tufts University, Milbury understands the microbiological process of overexercising. He says we can have our gain without the pain.
According to Milbury, the key is to control the “free radicals”–unstable atoms with single, unpaired electrons–that are released when we exert ourselves. These free radicals travel around the body trying to find partners for their electrons by latching onto other atoms or molecules. In fact, that’s how our immune system carries away bacteria, so certain controlled free radicals are essential. When we damage muscle cells through overexertion, however, the mitochrondria (powerhouses) in those cells create uncontrolled free radicals, which can result in a chain reaction and extreme muscle soreness.
If two free radicals latch together, a neutral molecule results. But when free radicals react with neutral molecules, more free radicals are created and the chain reaction begins, causing inflammation and soreness. It ends when enough free radicals latch together and become neutral. It ends a lot faster, however, when “antioxidants” are present to grab free radicals and turn them into non-reactive compounds. Under some conditions, a lack of antioxidants can result in chronic inflammation.
“Vitamins C and E work especially well as antioxidants,” says Milbury, “They recycle glutathione, which is in all cells and is the frontline defense against free radicals.” The two work especially well in tandem, he explains. Vitamin C reduces damage as it’s being done, and its effectiveness is prolonged by the presence of E. Vitamin E is somewhat effective right after exercise, but more so up to 72 hours later.
IT’S IN THE BAG
Dogs make their own C and don’t need supplements when hunted once or twice a week. And highly conditioned dogs accustomed to hunting almost daily do not benefit from more C. But a placebo-controlled experiment done in a 1,300-acre fox-and-coyote pen proved, by timing how long each hound ran before exhaustion, that some dogs benefit greatly from 70 milligrams of C per pound (3.5 grams divided into four doses for a 50-pound dog) if expected to run three days or more [see Hunting Dogs, December 1990]. The dogs that benefit are youngsters without full muscle development, adults in less than top-notch condition and aging dogs.
Many vitamins, minerals, enzymes and certain acids are antioxidants, but most are found in fruits and vegetables that few canines get except in the wild, and even then, mostly through what their prey eat. As Milbury points out, however, the major dog-food companies spend a greater percentage of their budgets on health research than do makers of food for humans. Their interest in such antioxidants as lutein and vitamins A, beta-carotene and E is showing up in the bag, especially in foods like Purina’s Pro Plan Performance Formula and Iams’ Eukanuba Premium Performance.
Last year we looked at a season-long Iams study [Hunting Dogs, October 2002] in which pointers fed Eukanuba Premium Performance had 55 percent more bird finds than those on a maintenance diet. Greater stamina through controlling free radicals was one reason.
Besides better stamina, Milbury says numerous studies indicate that diets high in antioxidants, especially C, E and flavonoids (substances plants produce to defend against parasites and bacteria) are associated with lower incidents of cancer, heart disease and other problems of aging, plus better ability to function late in life.
Feeding Hard-Working Dogs
–Outside dogs need 30 percent more calories from December through February than they do from June through August.
–Dogs working extremely hard in very cold weather can double or triple their calorie requirements.
–Hard-working dogs running 20 miles a week or more require premium food.
–Gradually switch from maintenance to premium food 7 to 10 days before conditioning or hunting begins.
–If unable to condition, begin supplementing your dog’s diet with vitamin C on the first day of hunting.