Senior pet food formulations may help aging dogs cope with the physical changes that come with growing older by using functional ingredients and adjusting nutrient levels. Likewise, specifically formulated dog foods can tantalize aging canines’ declining senses.
“Nearly half of the pet population is estimated to be in the senior stage of life,” said Juan Gomez, global director for Alltech's companion animal business. “As life span increases, chronic age-related changes like arthritis, reduced mobility, visual and hearing loss, and cognitive decline take place.”
Some of those changes were documented in the Journal of Gerontology. In November 2017, that journal published results from an experiment that looked at how inflammation, immune responses and other factors changed as dogs aged. The results may point out ways that senior pet food can help keep animals healthy, longer in life. Mars Petcare’s WALTHAM Centre for Pet Nutrition sponsored and conducted the experiment.
Effects of aging on dogs
In the experiment, 80 Labrador Retrievers were monitored from adulthood, starting in 2003 or 2005, to death or old age in 2015 and 2016. Throughout the study, scientists measured levels of certain chemicals in the dogs’ blood. As the dogs aged, these chemicals’ levels changed, including:
- 51 percent increase in DNA damage. The study showed a 51 percent increase in 8-Hydroxydeoxyguanosine (80HDG) levels. 80HDG is a specific marker of oxidative damage to DNA.
- 30 percent increase in C-reactive protein (CRP). CRP levels will rise in response to inflammation, showing that aging dogs can suffer from increased levels of inflammation.
- 86 percent decrease in Heat Shock Proteins (HSP70). HSP70 measures the ability to respond to cellular damage, and this study shows a significant decrease in this ability as dogs age.
Understanding the ways aging dogs’ bodies change may lead to ways to fight the decline in health that accompanies those changes.
Fighting age-related declines in dogs’ health with nutrition
“In a study conducted by WALTHAM Centre for Pet Nutrition, Mars Petcare found that dogs experience oxidative stress as they age,” Richard Butterwick, PhD, global nutrition advisor at WALTHAM, said. “Oxidative stress has been associated with numerous health conditions, including cognitive dysfunction. While not scientifically conclusive, there is some data suggesting that supplementing antioxidants in pet food may decrease oxidative stress. With this possibility in mind, Mars Petcare utilizes a variety of different antioxidants in its senior dog products such as, vitamins E and C, beta-carotene, lutein and taurine to help provide the type of nutrition that we believe senior dogs need.”
Other pet food ingredients used by Mars Petcare in senior dog foods include:
- Antioxidants to help support the immune system
- High-quality protein sources to help maintain muscle mass
- Flavorful palatants to address the less acute sense of taste of senior dogs
- Diets formulated to help manage weight and minimize stress on joints
- Natural sources of glucosamine and chondroitin, and omega-3 fatty acids to help support healthy joints.
- Omega-6 and omega-3 fatty acids for healthy skin and a shiny coat.
Those omega-3 and -6 fatty acids may protect more than a pet’s skin and coat. One type of omega-3 fatty acid, docosahexaenoic acid (DHA), may help the brain function well later in life, Gomez said. Numerous scientific studies have found that higher levels of DHA may protect against cognitive decline in humans and dogs
“Fish oil and microalgae are sources of DHA, an essential fatty acid, which is an integral part of neuron cell membranes,” he said. “Selenium is another essential element vital for brain function and is involved in several neurological processes.”
Products made from certain varieties of yeast, such as Alltech’s Sel-Plex, can provide selenium, he said. That nutrient may protect neurons against oxidative stress in animals by decreasing the formation of plaques and minimizing DNA and RNA oxidation, which may be responsible for cognitive decline.
“One important aspect is that there is no individual functional ingredient that is the answer or silver bullet to stop the changes associated with aging,” Gomez said.
Instead, pet food formulators must determine how the ingredients work in synergy with other parts of a pets’ diet to address age-related health issues, he said. Nutritional requirements change as pets age, due to changes in the ability to digest and to absorb nutrients. Likewise, senior pet food formulations may need to adjust levels of vitamins, minerals and electrolytes. However, the aging process differs according to a pet’s breed, size, genetics, housing, social environment, activity and nutrition.
“For dogs as they age, their metabolism changes and caloric needs decrease typically after the age of 7 for most breeds,” Gomez said. “Senior dogs have an increased need for dietary protein, however, and may benefit from diets with an increased protein-to-calorie ratio, providing a minimum of 25 percent of calories from protein. Cats get older, and typically after the age of 11, they need increased protein and energy due to a decreased ability to absorb fat and protein and hence the need of a highly digestible nutrient-dense diet."
Aging dogs senses of smell and taste decline
The aging process adds insult to injury by reducing dogs’ senses of smell, taste and vision. Pet food formulators can crank up the flavoring to entice older pets.
“As pets age, their sense of smell and taste becomes less acute, which can cause a disinterest in food,” Butterwick said. “As a pet food manufacturer, Mars Petcare brands have developed senior pet food with intensified aromas and flavors to increase the appeal for aging dogs. In terms of palatability, older animals tend to find room temperature wet food more palatable because of the soft texture, as older dogs teeth may become more sensitive, making it difficult to chew dry food.”
Along with adjusting for weaker senses of smell and taste, senior pet food formulation may need to avoid the negative palatability effects of a particular functional ingredient used to fight aging. While most functional ingredients do not alter palatability due to their low inclusion rate, high levels of fish oil can negatively affect expansion rate during the process affecting palatability, said Gomez.
When a senior pet food achieves high palatability, enticing sensory characteristics, proper nutrition and uses beneficial functional ingredients, that recipe may help the growing population of older dogs age gracefully.
Aging dogs and humans benefit from functional ingredients
