Riboflavin (Vitamin B2)

They need a steady supply. Riboflavin dissolves in water and the body stores only small amounts, so a complete food that supplies it at every meal is the easiest way to cover it.

Riboflavin is vitamin B2, a water-soluble vitamin that cats use in many energy-producing reactions. The National Research Council's 2006 report on the nutrient requirements of dogs and cats includes riboflavin among the vitamins cats need from food, and complete cat foods add it to reach the target. If your cat has a medical condition, ask your veterinarian before adding supplements.

Source: nap.nationalacademies.org

Riboflavin is in cat food to supply vitamin B2. Liver and eggs contain some, but heat and light can break riboflavin down, so manufacturers add a measured amount to the vitamin premix. It may appear as riboflavin or riboflavin supplement on the label.

Riboflavin has a natural yellow color, and the body removes extra amounts through the urine. That is why high B vitamin intake can make urine look brighter yellow. The color comes from the vitamin itself. Any sudden change in a cat's urine color or habits is worth mentioning to a veterinarian.

Riboflavin breaks down when exposed to light, especially ultraviolet light. Pet food makers account for this by using protective packaging and by adding enough riboflavin to cover expected losses over shelf life. Keeping dry food in its original bag and away from direct sunlight also helps the vitamins last.

Pettings gives riboflavin 4 out of 5 and lists it as a vitamin. It appears on 148 of the 149 dry cat foods we list. We score it with the other B vitamins added to meet nutrient targets. Each food's page shows how it scores overall.