Basics of Nutrition: Nutritional Fat Guide for Dog and Cat Owners

Triglyceride is the scientific term for dietary fats, aka lipids. These compounds are not water soluble and can be solubilized in nonpolar organic solvents. 

Simple triglycerides have three fatty acids bound to glycerin with ester bonds. The length of fatty acids impacts the characteristics of lipids for melting temperature and aroma during hydrolysis in food products.  For vegetable liquid fats, these fatty acids are shorter, unlike hard fats. Fatty acids can be mono- and polyunsaturated or saturated.  Unsaturated fats have flexible fatty acids and are usually in liquid form except for trans fat, which is an end product of chemical hydrogenation. Saturated fat is not a flexible fatty acid and packs very well. This gives the fat a solid texture. 

Compound lipids are fatty acids linked to nonlipid molecules such as lipoproteins. These can serve other bodily functions in the body. 

Butter and coconut fats are very valuable among the fats because they contain a considerable amount of short-chain fatty acids (SCFA) and medium-chain triglycerides (MCT).

SCFA are very valuable for gut health. These can also be synthesized in the gut microbes during fermentation of moderately soluble fibers, aka prebiotics. MCTs are very valuable because they can be digested as fat and absorbed into the bloodstream easily. 

MCTs are important for bodily function and also a beneficial source of energy for dogs with digestive disorders. Some research suggests it is better for dogs with fat digestion problems, but too much MCT can impact palatability and overall food intake by dogs. 

Here is the chemical sturucture of some fats : 

Simple fats are very functional for the body, and they are the main source of body energy storage. Animals also store energy as glycogen; however, this is stored in muscle at a certain amount. Fats also provide insulation and physical protection from organ damage. Fat also insulates nerve fibers and helps the transmission of signals. 

Complex fats such as phospholipids and glycolipids serve as structural components for cell membranes and help cells transport nutrients and metabolites in and out of cells. Lipoproteins help transport fat in the bloodstream. Cholesterol helps the body produce bile salts for fat digestion and absorption. It is also the precursor for steroid hormones.

Essential fatty acids, EFAs, are also precursors for active compounds called prostacyclins, prostaglandins, leukotrienes, and thromboxanes. These compounds have hormone like functions in the body. They help regulate functions like body temperature, blood clotting, blood pressure, inflammation control, vasodilation, vasoconstriction, and gastric acid secretion.  

In the diet, fats provide 8.5 kcal/gram in the food. The calorie content of fats is much higher than that of proteins and carbohydrates. Therefore, they can increase the calorie density of pet food. Fatty diets are also very palatable for dogs and cats, and therefore pet parents should be careful with fat-rich pet foods. 

The N-6 and N-3 fatty acids are the most essential. From N-6 linoleic acid (omega 6) fatty acids, gamma linoleic acid (GLA) and arachidonic acid (AA) can be produced. AA is essential for cat pregnancy and neonatal development. 

From N-3 alpha linoleic acid (omega 3), essential eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are formed. DHA is very important for reproduction and development phase of the pets. 

For linoleic acid, corn, soy, and sunflower oil are good sources, along with poultry fat and pork fat. 

Conjugated linoleic acid is also an essential fatty acid for pets. It is reported that it supports decent body composition in overweight pets. 

All in all, fats are quite essential for cats and dogs because they are a good source of energy and provide building blocks of very functional molecules in the body. They help hormones to be produced and protect tissue from inside and outside. Most of us justs consider fats as an energy source but it is more than that.