Benders'dictionary of nutrition and food technology

276Osmotic laxatives include magnesium salts (epsom salts),lactitol and lactulose.Emollient laxatives (faecal softeners) include liquid paraffinand docusates (which act as detergents to permit penetration ofwater into the faecal mass).A number of drugs are used to increase intestinal motility.lazybed Narrow strip of land, about 500–800 m in length, usedtraditionally in the Andes for growing potatoes, and adopted inIreland about 1640; one lazybed will provide enough potatoes fora family for a year.LC-MS Liquid chromatography linked to a mass spectrometeras the detection system.LD 50 An index of acute toxicity (lethal dose 50%); the amount ofthe substance that kills 50% of the test population of experimentalanimals when administered as a single dose.LDL Low-density lipoprotein, see lipoproteins, plasma.leaching The process of extracting soluble compounds from afood with water or another solvent; may be deliberate (as, e.g.,in water extraction of sugar from beet, or solvent extraction ofoil from oilseeds), or accidental, when vitamins and mineralsleach into cooking water and are lost.lead A mineral of no nutritional interest, since it is not known tohave any function in the body. It is toxic and its effects are cumulative.May be present in food from traces naturally present inthe soil, as contamination of vegetables grown near main roads,which absorb volatile lead compounds formerly used as a petroladditive, from shellfish that have absorbed it from seawater, fromlead glazes on cooking vessels and in drinking water where leadpipes are used. Traces are excreted in the urine.lean body mass Measure of body composition excluding adiposetissue, i.e. cells, extracellular fluid and skeleton.Lean Cuisine TM A range of frozen meals prepared to a specifiedenergy content.leathers, fruit Fruit purées dried in air in thin layers, 4–5 mm thick,then built up into thicker preparations.leaven yeast, or a piece of dough kept to ferment the next batch.leavening Baked goods may be leavened mechanically by airincorporated in dough mixing, or steam produced in baking;chemically using a baking powder (sodium, potassium or ammoniumbicarbonate together with an acid); or biologically by yeastfermentation.leben See milk, fermented.Lecigran TM soya bean lecithin preparation, claimed to lowerblood cholesterol.