During a recent Ask the Petfood Pro chat, Dr. John Menton, senior business development director – Pet at Kerry, walked through the key physiological changes pets experience as they age and the nutritional interventions, from omega-3 fatty acids and beta glucans to pre-, pro- and postbiotics, that manufacturers can use to support senior pets' immunity, joint health, oral health, and skin and coat condition.
1. Pets age like humans — and suffer similar chronic conditions. Menton noted that because pets live alongside people and benefit from secure food sources and veterinary care, they often live long enough to develop conditions that parallel human aging.
"We see dogs and cats develop joint issues, arthritis, like we do as we get older," he said. "They put on weight as they get older. We see issues, immobility, stiffness, cognitive decline. They get diabetes, all the diseases that emerge in humans."
2. There is no single clinical definition of "senior." Rather than a fixed age threshold, Menton pointed to physiological signals as the more reliable indicators. Small-breed dogs may not show age-related signs until 9–11 years, while giant breeds can begin at 5–7.
"When you start seeing joint stiffness, and you start seeing eye health, coat getting duller, you know it's an indication that the dogs or cats are starting to become senior," he said, adding that cats tend to cross that threshold around age 10 due to their more uniform size.
3. Preventive nutrition should start well before the senior stage. Menton was direct that waiting until a pet is elderly to introduce targeted nutrition is a missed opportunity.
"The biggest mistake is to wait for their senior," he said. He recommended looking for anti-inflammatory ingredients as pets move from adult to mature, and adding gut and immune modulators proactively at the mature-to-senior transition rather than reacting to decline after it begins.
4. Omega-3 fatty acids are among the most broadly supported ingredients. EPA- and DHA-rich fish oil has strong evidence for reducing inflammation across multiple systems, including joint health, skin barrier function and immune signaling.
Menton noted a practical formulation constraint: "You can really only get in 2% omegas into hard kibbles, because it'll start to get too moist." He said freeze-dried and wet formats allow for higher inclusion levels and better stability.
5. Gut health is central to whole-body aging. Menton described the gut-immune connection as a recurring theme across nearly every system he discussed.
"A large part of the immune system is associated with the digestive system and gut," he said, noting that as pets age, microbial diversity declines and intestinal permeability can increase.
He recommended pre-, pro- and postbiotics given throughout life, not just in senior formulas, to maintain a resilient microbiome that supports immune function, reduces systemic inflammation and benefits skin, joint and cognitive health through the gut-brain axis.
6. Beta glucans and key micronutrients support immune resilience. For innate immune health specifically, Menton called out yeast-derived beta glucans as particularly important.
"Beta glucans isolated from yeasts for maintaining immune health, but also for innate immune health" were among the ingredients he highlighted, alongside vitamins C and E, zinc, selenium, B vitamins and high-quality protein as sustaining immune function as T-cell and B-cell activity naturally declines with age.
7. Oral health has systemic consequences that are often underestimated. Menton argued that periodontal disease is one of the most underappreciated drivers of systemic decline in aging pets.
"Once you have periodontal disease, bacteria is getting into your gum line," he said. "It's very easy for bacteria to start getting into the bloodstream, and that could start leading to heart issues, liver, kidney stress."
Beyond mechanical interventions like dental chews and polyphosphate agents, he pointed to probiotics and postbiotics that can disrupt quorum sensing — the bacterial signaling mechanism that enables biofilm formation — as a promising emerging category.
8. Skin and coat nutrition overlaps significantly with immune and joint support. Aging skin produces fewer ceramides, fatty acids and sebum, Menton explained, leading to dryness, increased shedding and greater infection risk.
"Fish oil, that's the EPA DHA rich — it has an anti-inflammatory effect," he said, adding that linoleic acid, high-quality protein (particularly methionine and cysteine for hair structure), zinc, biotin and vitamins C and E have the strongest evidence for skin and coat health. He also flagged hydration as frequently overlooked, especially in cats.
9. Postbiotics are an emerging technology worth watching across multiple systems. Menton returned to postbiotics repeatedly as a platform ingredient class with growing science behind it.
"We're seeing postbiotics, probiotics for skin, for joint health, for muscles, for mental health, for stress, all linking into the gut-brain axis," he said.
He acknowledged that the clinical evidence base is still developing but described the category as one with strong potential to modulate systemic inflammation across multiple organ systems simultaneously.
10. Personalized nutrition and novel formats are on the horizon. Looking ahead, Menton pointed to two convergent trends: freeze-dried formats that better preserve heat-sensitive actives like probiotics and vitamins compared to traditional kibble, and the emergence of genotype-specific formulations enabled by consumer pet DNA testing.
"I saw in some marketing in France that said 60% of people were willing to actually get their pet's DNA," he said. "I think we'll continue to see those trends coming, including, potentially, wearable health monitoring technology adapted from the human wellness space."
Click here to view the video chat or see other Ask the Petfood Pros.
