Benders'dictionary of nutrition and food technology

253insulin Peptide hormone secreted by the β-islet cells of the pancreas;controls glucose metabolism. diabetes mellitus is theresult of inadequate supply of insulin or tissue resistance to itsaction. Since insulin is a protein it would be digested if taken bymouth so must be injected. Originally the hormone was preparedfrom beef or pork pancreas, but these differ slightly in structurefrom human insulin, and lead to antibody formation after prolongeduse. Most insulin for therapeutic use is now humaninsulin, the product of biosynthesis from the human insulin gene.See also diabetes; glucose tolerance; hypoglycaemic agents;metabolic syndrome.insulinaemic index The rise in blood insulin elicited by a test dose(usually 50 g) of a carbohydrate food compared with that afteran equivalent dose of glucose.See also glycaemic index.insulin-like growth factors See somatomedins.insulinoma insulin-secreting tumour of the β-islet cells of thepancreas.insulin resistance Resistance of target tissues to the actions ofinsulin, leading to hyperinsulinaemia and hyperglycaemia,commonly associated with abdominal adipose tissue. Only themetabolic actions of insulin are affected; the slower actions mediatedvia map kinases are unaffected, so there is an exaggeratedmitotic response to insulin, causing increased proliferationof vascular smooth muscle, leading to atherosclerosis andhypertension.See also metabolic syndrome.integrating motor pneumotachograph (IMP) Apparatus for measuringenergy expenditure indirectly from oxygen consumption.It meters the expired air and removes a proportion for analysis.See also spirometer.intense sweeteners See sweeteners, intense.interesterification Exchange of fatty acids between triacylglycerolsin order to modify the properties of the fat; may beachieved by heat treatment or using fungal lipase.interferon A family of proteins that are secreted by macrophages(IFN-α), fibroblasts (IFN-β) and lymphocytes (IFN-γ) inresponse to viral, bacterial or lectin stimulation. They havepotent antiviral activity, acting by inhibiting translation of viralRNA, and inhibit proliferation of cancer cells.interleukins A family of cytokines that act as signalling moleculesbetween leukocytes.intermediate moisture foods These are semimoist with about25% (15–50%) moisture but with some of the water bound (and