Pudel air-dried kangaroo liver for dogs on linen

Vitamin A, zinc and iron: nutrients behind a dog's immune system

No treat makes an immune system stronger, and we'd be wary of anyone who says theirs does. A dog's immune system runs on the same nutrients as the rest of the dog. Vitamin A, zinc and iron are three that the textbooks list as involved in normal immune function, and all three come from food, organ meat in particular.

What do vitamin A, zinc and iron do?

Vitamin A is involved in the maintenance of skin and the gut lining — the surfaces that meet the outside world first (NRC, 2006). Liver is where it concentrates: beef liver carries around 5,000 µg RAE per 100 g (USDA FoodData Central).

Zinc is a component of many enzymes, including those behind cell division. Muscle meat carries as much zinc as liver, around 4–5 mg per 100 g, so plain jerky does the job.

Iron sits at the centre of haemoglobin, which carries oxygen to every cell, immune cells included. Liver is the standout at around 5 mg per 100 g, roughly double lean beef muscle (USDA FoodData Central). Kangaroo meat is a natural source of all three (FSANZ).

Liver is very rich in vitamin A, so a little goes a long way — a few small pieces a day for a medium dog, with all treats under about 10% of daily food.

Which cuts, and how much?

Kangaroo liver and beef liver carry all three in one piece: one ingredient, naturally dried, nothing added. Muscle cuts like kangaroo jerky cover the zinc and iron without the vitamin A load, so jerky is the everyday reward and liver the occasional switch-up. The kangaroo range follows that pattern, and all of it counts toward the same ceiling, since treats stay under about 10% of the day's food.

Will more help? No. The NRC sets upper limits for vitamin A and zinc as well as minimums, because too much of either causes its own problems. A dog on a complete diet isn't short of these; adding more just makes the liver store more vitamin A. If your dog seems to pick up every bug going, that's a vet conversation, not a shopping one.

Every dog is different. For an ongoing issue, your vet is the first call — this is general information, not veterinary advice.

Keep reading: Iron for dogs: natural sources and why meat iron is different · Zinc for dogs: what it does for skin and coat, and where it comes from

Sources

Pudel · Reviewed September 2026 · Single-protein, naturally dried dog treats, made in Australia. General information, not veterinary advice.

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