Taurine is such a scarce and valuable nutrient that all members of the cat family, from the smallest to the largest, are instinctively drawn to hunt for prey that contains high levels of the sulfur-rich amino acid, and they prefer the most taurine-dense parts of those animals.
The Hardest Working Muscles Contain the Most Taurine
In general, the harder a muscle works, the more taurine it contains. The hardest working muscle in the body by far is the heart because it never stops beating. No other muscle even comes close! That is why hearts contain the highest concentrations. Following this same rule, skeletal muscles that get worked harder contain more taurine than those that don’t. In birds, the dark meat corresponds to the harder working muscles and therefore contain more taurine than the white meat. Because domestic chickens don’t fly, their breast meat is paler than the hind quarters that they use to propel themselves around in the barnyard.
Not All Organs are Equal
When big cats like leopards make a kill, they almost always eat the heart first. When lions hunt in groups, the socially dominant members eat first and they almost always start with the heart. This is usually followed by other internal organs high in taurine like the eyes, brain, liver and lungs. Only then do they move on to the skeletal muscle meat, and here too, they show a clear preference for the taurine-rich dark meat, eating the hind quarters first. This way, if they get chased off by hyenas or disturbed by another animal, they will have eaten the best parts with the most taurine.
Smaller wild cats are also instinctively drawn to taurine rich prey, including mice, rats, birds and insects when available. When food is limited, they will eat an entire mouse head first, or an entire bird. But when food is plentiful and they aren’t driven by hunger, small cats have a tendency to eat the parts containing the most taurine and leave the rest. High taurine parts include the heart, the head (because brain and eyes are exceptionally high in taurine), and other internal organs. This is also why it’s common to find partially eaten corpses if you have outdoor cats, most often with the head and/or heart missing.
The History of Taurine Deficiency in Cats
In the 1970s, pet food makers believed that cats were able to internally synthesize taurine (an amino acid only found in animal tissues) from other plant-derived amino acids in the same manner as dogs and humans, and began formulating dry cat foods made from grains, with little actual meat content. This proved to be catastrophic, but the results did not show up right away because most cats were still going outdoors and hunting rodents and birds. But by 1981, as more domestic cats became blind from retinal degradation and died because their hearts became too weak to pump adequately, scientists realized that they were suffering from a nutritional deficiency, and that taurine was an essential amino acid for cats. In other words, they could not make it in their bodies and needed to consume it in their diets from meat-based foods. Still, it took another six years until the press began reporting on it and manufacturers began adding supplemental taurine to their formulations.
What Does Taurine Do Inside the Heart?
Over the last few decades, it has become abundantly clear that taurine plays a key role in the transport of positively charged calcium ions in the heart, and an equally important role in controlling how sensitive heart cells are to the calcium ions they encounter. In other words, taurine is essential to the normal functioning of the electrical system of the heart. It is the master switch for one of the most fundamental elements of life: the heartbeat.
Without an adequate supply of taurine within each heart cell, the heart will not beat properly. When taurine levels fall too low, heart contractions may become too weak to circulate oxygenated blood and remove toxins. Studies have demonstrated that an irregular heartbeat can be induced by reducing taurine, and then can be cured by restoring taurine back to normal levels. While the exact mechanisms are not entirely understood, this is an area of very active scientific research because taurine supplementation is thought to hold great promise in preventing or reversing many heart disorders, diabetes, and other common ailments in both people and pets. Look for taurine to become an increasingly important part of the conversation in health conscious circles, natural pet forums, and in the medical/veterinary community.
Protecting Your Cat’s Health with the Right Treats
Despite the current requirements for supplemental taurine in cat foods, there has been ongoing concern over both the quantity and quality of the taurine in processed dry foods. As result, many cat lovers look for ways to supplement their cat’s diet with healthier and more trusted sources of taurine. Feeding their cats raw or freeze-dried raw hearts as a highly nutritious treat has become a popular way to ensure they are getting enough taurine.
Special thanks to our friends at Fresh is Best for the research that went into this article.