Anserine

Knee pain is a common complaint in clinical practice, and pes anserinus tendino-bursitis syndrome (PATB) has been frequently diagnosed based only on clinical features that may cause equivocal interpretations. Patients complain of characteristic spontaneous medial knee pain with tenderness in the inferomedial aspect of the joint. Studies with different imaging modalities have been undertaken during the last years to identify whether these patients suffer from bursitis, tendinitis, or both. Nevertheless, little is known regarding the structural defect responsible for this disturbance. Due to these problems and some controversies, we suggest the term "anserine syndrome" for this condition. Diabetes Mellitus is a known predisposing factor for this syndrome. Overweight and osteoarthritis seem to represent additional risk factors; however, their role in the pathophysiology of the disease is not yet understood. Treatment includes non-steroidal anti-inflammatory drugs, physiotherapy, and injections of corticosteroid, with highly variable responses, from 10 days to 36 months to achieve recovery. The lack of knowledge about its epidemiological, etiological, and pathophysiological aspects requires future studies for this common and intriguing disorder.

Taurine (a sulfur-containing β-amino acid), creatine (a metabolite of arginine, glycine and methionine), carnosine (a dipeptide; β-alanyl-L-histidine), and 4-hydroxyproline (an imino acid; also often referred to as an amino acid) were discovered in cattle, and the discovery of anserine (a methylated product of carnosine; β-alanyl-1-methyl-L-histidine) also originated with cattle. These five nutrients are highly abundant in beef, and have important physiological roles in anti-oxidative and anti-inflammatory reactions, as well as neurological, muscular, retinal, immunological and cardiovascular function. Of particular note, taurine, carnosine, anserine, and creatine are absent from plants, and hydroxyproline is negligible in many plant-source foods. Consumption of 30 g dry beef can fully meet daily physiological needs of the healthy 70-kg adult human for taurine and carnosine, and can also provide large amounts of creatine, anserine and 4-hydroxyproline to improve human nutrition and health, including metabolic, retinal, immunological, muscular, cartilage, neurological, and cardiovascular health. The present review provides the public with the much-needed knowledge of nutritionally and physiologically significant amino acids, dipeptides and creatine in animal-source foods (including beef). Dietary taurine, creatine, carnosine, anserine and 4-hydroxyproline are beneficial for preventing and treating obesity, cardiovascular dysfunction, and ageing-related disorders, as well as inhibiting tumorigenesis, improving skin and bone health, ameliorating neurological abnormalities, and promoting well being in infants, children and adults. Furthermore, these nutrients may promote the immunological defense of humans against infections by bacteria, fungi, parasites, and viruses (including coronavirus) through enhancing the metabolism and functions of monocytes, macrophages, and other cells of the immune system. Red meat (including beef) is a functional food for optimizing human growth, development and health.