What are bioactive peptides?

Expert response from GMOAnswers Admin_1

Tuesday, 17/05/2016 10:56

A “bioactive peptide” refers to relatively short chain of amino acids (peptide) that has a biological effect in people or animals. Bioactive peptides are made up of amino acids linked chemically in a specific sequence; it is the specific order or sequence of the amino acids that gives the peptide its unique activity. Proteins are generally regarded as being longer sequences of amino acids (usually more than 200 amino acid long sequences.) However, there is no general rule as to what length distinguishes a protein from a peptide. There are 20 amino acids that make up peptides and proteins. Amino acids are made in our body and are also absorbed from the diet in the intestine after the proteins and/or peptides are eaten. Amino acids themselves have important functions in our body; they are converted to proteins, hormones and neurotransmitters which are all necessary for life.

Examples of bioactive peptides made in our bodies and that circulate in our bloodstream are insulin, two chains of amino acids (A chain = 21 amino acids and B chain = 30 amino acids), oxytocin (nine amino acids) and growth hormone (191 amino acids). These are all called “peptide hormones,” but as you can see they differ a lot in their length and also in their function in the body. Insulin is important to maintain healthy levels of glucose in your body and also is important to promote growth. Oxytocin is a hormone that is important in signaling the release of breast milk in mothers and is used medically to induce labor. Growth hormone is important for normal growth. If there is a lack of these peptide hormones in people (for instance a lack of insulin in Type I diabetic patients), they must be administered by an injection. Oxytocin is sometimes administered as a nasal spray. The reason that bioactive peptides do not work if given by mouth is that the acid and enzymes in the stomach and intestines would break down the peptides into smaller two and three amino acid long peptides or individual amino acids thereby destroying the bioactive peptides and their ability to exert their effects. However, the two and three amino acid peptides and individual amino acids resulting from the intestinal digestion would get absorbed and used for making protein, and other substances in the body. In other words, the bioactive peptide would act just like any dietary protein for nutrition purposes.

There are some bioactive peptides with very specialized structures that are made in our intestines that protect the intestinal lining from damage due to toxic substances made by some types of bacteria (for instance, ones that cause food poisoning). These bioactive peptides seem to resist digestion by the enzymes in the intestine and some early research suggests that giving these natural peptides to people or animals with disrupted intestinal function by mouth does not destroy the peptides and they may make it to the intestine where they may help protect the intestinal lining from further damage. Of course, this is very early type of research but does suggest that some types of bioactive peptides that are specially designed to exist in the intestine may be able to survive digestion and exert protective effects in the gut.