Complete Care for Your Aging Cat - Amy Shojai [35]
“Your body can adapt and adjust even at the molecular level to the environment that it finds itself in,” she says. “Of the environmental factors that we encounter on a daily basis, diet has arguably the most important influence on both health and disease.”
“Nutrigenomics is revolutionary in that it doesn’t look at the cards you’re dealt, but how those cards are played (expressed),” says Dr. Towell. “Although genes are critical for determining predilections, nutrition modifies the extent to which different genes are expressed. Simply put, genes load the gun but environment pulls the trigger.”
“When a gene is expressed, the DNA opens up and a copy—called mRNA--is made,” says Dr. Perea. The mRNA is essentially the code for the protein or hormone of interest, and this code is used by other systems in the cell to synthesize the protein. Nutrigenomics evaluates how specific nutrients effect gene expression by measuring the mRNA for proteins or hormones of interest.
Nutrients act like dietary signals. These signals influence gene and protein expression, and metabolite production, creating a specific pattern. Resulting patterns can be viewed as “dietary signatures” which can be studied in healthy and diseased populations. By recognizing what constitutes a healthy dietary signal, researchers can adjust nutrients fed to unhealthy pets while monitoring unhealthy dietary signals to measure improvement, and learn how to better formulate diets.
Human medicine has great interest in applying nutrigenomic science to such health issues as aging, cancer, and more. Veterinarians have an advantage, since it’s easier to control what animals eat during nutritional trials. Several commercial diets already use nutrigenomic principles, with more on the horizon.
The University of Illinois recently completed a study sponsored by Natura Pet Products to evaluate the effect of a high protein versus a high carbohydrate diet on the expression of different metabolic genes in cats, in utero through nine months of age. Among other things, it showed that kittens fed a high protein diet developed significantly higher mRNA levels for the insulin receptor gene, says Dr. Perea. “It is unclear how this affects the cat’s overall health, but it may help to shed light on how high protein foods can be beneficial for cats with diabetes mellitus, and how diet impacts development.”
Scientists at Hill’s Pet Nutrition have identified genomic differences in a number of areas including those associated with arthritis, aging, and obesity in dogs. A specific omega-3 fatty acid called eicosapentaenoic acid (EPA) has been shown to “switch off” an enzyme that causes cartilage degradation. After eating the EPA diet for a month, 82 percent of the dogs no longer limped and had increased range of motion.
“This is an exciting area in osteoarthritis particularly in cats,” says Dr. Towell. “It may well be a disease that is more of a chronic inflammatory condition throughout the body.” She believes a nutrogenomic diet addressing feline arthritis could have positive benefits for cats.
Nutrigenomics goes beyond addressing a specific health issue. It helps re-program the way genes are expressed. “We know which genes are differentially set and how they’re expressed in overweight animals because we’ve seen how they are in lean animals,” says Dr. Towell. Obese animal’s genes are expressed to preferentially store excess energy as fat. “That’s one of the genes that’s been turned on, and doesn’t get turned off. Lean individuals burn those calories rather than store them, and use fat as an energy source.”
The dogs fed the standard food remained fat storers, but the group fed the experimental neutrigenomic-designed food more closely resembled lean dogs—they’d been transformed into fat burners. The “fat storer” gene wasn’t shut off, but it was dialed down. Nutrigenomics may not be able to completely prevent a disease,