Collagen is a vital component of structural matrix throughout most tissues and organs in the human body. It is concentrated in cartilage, where it plays a significant role in the integrity of joint-related connective tissues. The important role played by collagen in joints is vividly shown by the severe generalized arthritis associated with collagen gene mutations.
Food containing collagen
The amount of collagen in the diet can be increased by consuming specific foods, such as meats with gristle or connective tissue still intact. Collagen also can be found in foods containing gelatin. Dietary supplements also can be used to increase the amount of collagen contributed by the diet. An example of such a supplement is collagen hydrolysate, which is prepared by enzymatic hydrolysis of collagenous tissue, such as bone, hide, and hide split from pigs and cows. Collagen hydrolysate is soluble in cold water and is composed of proteins with a molecular weight of 3 to 6 kD.
Amino acids found in collagen
Collagen hydrolysate provides high levels of amino acids. Among these are glycine and proline, two amino acids that are essential for the stability and regeneration of cartilage. To synthesize a single picogram of collagen type II, more than 1 billion glycine molecules and 620 million proline molecules are required. In the absence of these amino acids, the anabolic phase of cartilage metabolism can be impaired.
In studies of rats and humans, concentrations of the amino acids proline, hy-droxyproline, and glycine after administration of collagen hydrolysate (10 g in humans) increased significantly compared with placebo . In a single-blind, randomized, and placebo-controlled study of 60 male sports students, the amino acid concentrations in peripheral blood after a daily intake of 10 g of collagen hydrolysate for 4.5 months were measured. It was found that levels of the amino acids glycine, proline, and hydroxyproline were significantly higher in the treated group than in the control group. The concentrations of alanine, asparagine, glutamic acid, and tryptophan also were higher.
Mechanism of action
It has been shown that about 90% of orally administered collagen hydrolysate is resorbed within 6 hours from the gastrointestinal tract . It also has been found that collagen hydrolysate has a special affinity for cartilage, and that this affinity to cartilage has a stimulating effect on the synthesis of chondrocytes.