Milk contains primary proteins of high biological value, such as casein and whey, but it also has a range of other protein substances that reputedly offer potent health and recovery benefits for hard-training bodybuilders and other athletes. One of those potential hidden treasures is lactoferrin. It’s a glycoprotein, which means its structure includes a carbohydrate attached to a simple protein. The simple protein in lactoferrin contains 703 amino acids in a precise configuration.
Lactoferrin also exists in animal exocrine secretions, such as saliva, gastric juice and bile. During inflammation, lactoferrin is released from neutrophils, which are a type of white blood cell. It appears to enhance immunity and to lower inflammation through several mechanisms. One way is by potently binding to iron, which many infectious organisms, such as bacteria, need to replicate in the body. Lactoferrin also appears to offer protective benefits against a wide range of fungi and viruses, including HIV, which causes AIDS; however, most studies have exposed such infectious organisms to lactoferrin in vitro’i.e., in test tubes’not in the body.
When taken orally, some lactoferrin is converted into lactoferricin, which also has potent immune-system stimulation and protective effects, particularly in the intestine. But the question is, Since lactoferrin is a protein and since proteins exposed to the harsh acidic environment of the stomach are degraded into smaller peptide chains of amino acids, wouldn’t such degradation nullify lactoferrin’s biological activity?
We know degradation occurs when peptide-based hormones, such as growth hormone and insulin, are taken orally. Oral delivery simply results in an expensive’and inactive’amino acid supplement. Would lactoferrin suffer a similar fate?
Even though lactoferrin derived from bovine (cow) whey has been sold since the 1980s in isolated form (very expensive!), few studies have examined the metabolic fate of lactoferrin in humans. Still, a recent study followed 12 healthy adults who received various forms of lactoferrin through a nasogastric tube, a tube inserted into the nose and routed down the esophagus toward the stomach (don’t try this at home).1 Up to 79 percent of lactoferrin survived stomach degradation. The higher the iron binding of the lactoferrin, the greater the survival. A study of rats reached a similar conclusion.2
The results indicate that lactoferrin and likely many other active protein peptides contained in whole milk’can survive initial stages of protein digestion, which would leave the biological activity of the peptides intact. The benefit for bodybuilders would involve heightened immunity, increased muscular recovery due to lower muscle inflammation following intense exercise and maintenance of a stable gastrointestinal environment amenable to muscular gains.
Editor’s note: Muscle-Link’s Muscle Meals meal replacement is fortified with lactoferrin. See page 59 of the February ’02 IRONMAN for more information.
1 Troost, F.J., et al. (2001). Gastric digestion of bovine lactoferrin in vivo in adults. J Nutr. 131:2101-2104.
2 Kuwata, H., et al. (2001). Functional fragments of ingested lactoferrin are resistant to proteolytic degradation in the gastrointestinal tract of adult rats. J Nutr. 131:2121-2127.