Senior dog food causing thirst? 11yo Lab fix

Three senior foods tried and all three caused the same problem — that's not bad luck, that's a pattern worth taking seriously. Excessive thirst and urination in an older dog after switching food can point to a few things: high sodium content, elevated protein that's stressing the kidneys, or mineral imbalances that the kidneys are struggling to process. Before I suggest anything, I want to make sure I understand the full picture. What breed mix is your dog exactly, how much do they weigh, and have you had any bloodwork done recently — particularly kidney values like BUN, creatinine, or a urine specific gravity test?

That borderline kidney result changes things significantly — and honestly it explains everything. Harringtons, Wagg, and Burns Senior are all reasonably decent foods, but none of them are formulated for a dog with compromised kidney function. They have standard senior protein levels, which is still too much for kidneys that are already struggling. The thirst and urination you're seeing is your dog's kidneys working overtime to flush out the protein waste products they can't efficiently process. This isn't a senior food problem — it's that she needs a renal-supportive food, not just a senior one. Has your vet mentioned dietary management at all, or just monitoring?

Good energy and stable weight at 11 with borderline kidneys is actually a really positive sign — it means you caught this early and have real room to make a difference through diet. The fact that your vet hasn't flagged food yet is common; it often gets overlooked until values worsen. Here's my recommendation: Royal Canin Renal Support dry food. It's specifically formulated with restricted, high-quality protein so the kidneys produce less waste, controlled phosphorus to reduce the filtration burden, and omega-3s to support kidney tissue. It's not a prescription food so you don't need a vet sign-off, and it's available on Amazon UK. The key difference from every food you've tried is that it's built around kidney workload, not just age. I'd expect the thirst and urination to settle within two weeks if this is the right fit.

Go slower than the standard 7-day transition — I'd do 10 to 14 days. Start at about 25% new food mixed with whatever she's currently on, and hold at each stage for three days before increasing. The main things to watch are thirst and urination levels from day three onward — you should see improvement or at least no worsening compared to the other foods. Also keep an eye on her stool consistency; renal diets are lower in fibre than some senior foods so it can shift slightly. If the thirst and urination are no better or worse by day ten, stop and get the kidney values rechecked before going further — that would suggest the kidneys have changed since her last bloods and the vet needs to be in the loop. But I'd be optimistic. The pattern you described is very consistent with protein load, and this food directly addresses that.

That sounds like exactly the right approach. It's worth mentioning the dietary change to your vet proactively — they may want to bring the six-month recheck forward to three months given you're making an active intervention, which would actually give you useful data on whether the food is helping the underlying values. Hope she does well on it.