ω-6 and ω-3 Polyunsaturated Fatty Acids: Inflammation, Obesity and Foods of Animal Resources

Obesity, as defined by the World Health Organization (WHO), is excessive fat accumulation that can pose health risks and is a disorder of the energy homeostasis system. In typical westernized diets, ω-6 polyunsaturated fatty acids (PUFAs) vastly exceed the amount of ω-3 PUFAs, with ω-6/ω-3 ratios ranging from 10:1 to 25:1. ω-6 PUFAs, such as arachidonic acid, have pro-inflammatory effects and increase obesity. On the other hand, ω-3 PUFAs, including eicosapentaenoic acid and docosahexaenoic acid, have anti-inflammatory and anti-obesity effects. Linoleic acid (LA) and alpha-linolenic acid (ALA) are synthesized in almost all higher plants, algae, and some fungi. However, in humans and animals, they are essential fatty acids and must be consumed through diet or supplementation. Therefore, balancing LA/ALA ratios is essential for obesity prevention and human health. Monogastric animals such as pigs and chickens can produce meat and eggs fortified with ω-3 PUFAs by controlling dietary fatty acid (FA). Additionally, ruminant animals such as feeder cattle and lactating dairy cows can opt for feed supplementation with ω-3 PUFAs sources and rumen-protected microencapsulated FAs or pasture finishing. This method can produce ω-3 PUFAs and conjugated linoleic acid (CLA) fortified meat, milk, and cheese. A high ω-6/ω-3 ratio is associated with pro-inflammation and obesity, whereas a balanced ratio reduces inflammation and obesity. Additionally, probiotics containing lactic acid bacteria are necessary, which reduces inflammation and obesity by converting ω-6 PUFAs into functional metabolites such as 10-hydroxy-cis-12-octadecenoic acid and CLA.