L

Select a term to view the definition:
  • Lactase nonpersistence

    Professional Description:

    Determined by biopsy or genetic testing, is a genetically programmed decrease of the enzyme lactase, leading to lactose malabsorption, and for some, to lactose intolerance.

  • lacto- ovo vegetarian

    Professional Description:

    An eating pattern based on grains, vegetables, legumes, seeds, nuts, dairy products and eggs but excludes meat, fish or fowl or products containing these foods.

  • lacto vegetarian

    Professional Description:

    An eating pattern based on grains, vegetables, legumes, seeds, nuts, and dairy but excludes meat, fish or fowl and eggs or products containing these foods.

  • Lactobacillus

    Professional Description:

    A genus of bacteria of the family Lactobacillaceae, occurring as large, gram-positive, asporogenous, rod-shaped organisms. They are anaerobic or microaerophilic and occur widely in nature and in the human mouth, vagina, and intestinal tract. They are separable into two groups, the homofermentative group producing only lactic acid, and the heterofermentative group producing other end-products of fermentation.

  • Lactose intolerance

    Professional Description:

    A clinical syndrome of one or more of the following symptoms: abdominal pain, nausea, diarrhea, flatulence, and bloating after the ingestion of lactose or lactose-containing foods.

  • Lactose Malabsorption

    Professional Description:

    Lactose malabsorption is a physiological problem that presents as lactose intolerance. It is caused by the imbalance between the amount of ingested lactose and the capacity for lactase to hydrolyze the disaccharide due to a deficiency in levels of the lactase enzyme. It is measured by a breath hydrogen test after the ingestion of a lactose load.

  • Lactose Nonpersistance

    Professional Description:

    Lactose nonpersistance is a genetically programmed decrease of lactase resulting in lactose malabsorption, and in some cases results in lactose intolerance.

  • Lactulose/Mannitol Test

    Professional Description:

    Clinical test to measure intestinal permeability. After an overnight fast and having passed the first morning urine, subjects drink a test solution containing lactulose and mannitol, and urine is collected for the next five hours. Mannitol is absorbed through small pores in the enterocyte membrane, and decreased excretion indicates reduced mucosal surface area. In contrast, lactulose in unable to pass through the healthy mucosa, so increased excretion of lactulose indicates increased intestinal permeability or "leaky" mucosa.

  • Lead time

    Professional Description:

    Before a health condition has fully developed, there is usually a period of time when risk factors and early symptoms are present but the condition has not yet progressed to the point of symptomatic disease diagnosis.

  • Learning

    Professional Description:

    The act, process, or experience of gaining knowledge or skill.

  • Learning objectives

    Professional Description:

    Brief, clear, specific statements of what learners will be able to perform at the conclusion of instructional activities.

  • Learning outcomes

    Professional Description:

    Statements of what a student is expected to be able to do as a result of a learning activity.

  • Leptin

    Professional Description:

    A peptide hormone that is produced by fat cells and plays a role in body weight regulation by acting on the hypothalamus to suppress appetite and burn fat stored in adipose tissue.

  • Letter to the Editor

    Professional Description:

    Letter written and submitted by a non-publications staff member, usually complementing or criticizing the coverage of an issue by the publication.

  • Leukonychia

    Professional Description:

    The occurrence of white spots, streaks, or patches under the nails due to the presence of air bubbles between the nail and its bed.

  • Likert Scale

    Professional Description:

    A type of response format used in surveys developed by Rensis Likert. Likert items have responses on a continuum and response categories such as "strongly agree," "agree," "disagree," and "strongly disagree."

  • Lipase

    Professional Description:

    An enzyme that is used by the body to break down dietary fats into a readily absorbable form. When insufficient levels of lipase are produced, dietary fats cannot be absorbed as easily, often resulting in the production of greasy, light-coloured stools (or steatorrhea). Most of the body’s lipase is produced by the pancreas.

  • LOAEL

    Professional Description:

    A LOAEL is the Lowest Observed Adverse Effects Level, which would be the lowest continuing intake at which the adverse effect was observed in one or more individuals.

  • Logarithm

    Professional Description:

    The power to which a number must be raised to obtain a secondary number. For example, 10 to the power of 6 would be 1,000,000 (one million).

  • Logistic regression

    Professional Description:

    A statistical method which determines the likelihood that an observation will fall into one of two categories of a dichotomous dependent variable based one or more continuous or categorical variables.

  • Longitudinal Studies

    Professional Description:

    The investigator identifies exposed and non-exposed groups of people, each a cohort, and then follows them forward in time, monitoring the occurrence of the predicted outcome.

  • Loop diuretics

    Professional Description:

    act on the ascending loop of Henle in the kidney to inhibit reabsorption of sodium; thereby promoting sodium and subsequent water excretion in the urine. Furosemide is the most common loop diuretic prescribed to patients with heart failure and edematous disorders such as liver failure and nephrotic syndrome. Loop diuretics are the most powerful diuretics for promoting urinary sodium and water excretion.

  • Low Birth Weight

    Professional Description:

    An infant weighing less than 2500 g or 5.5 lbs.

  • low intensity exercise

    Professional Description:

    Low-intensity exercise is defined as working at a heart rate of about 60% to 65% of your maximum heart rate (which is equal to 220 - your age = maximum heart rate, thus if you are 20 years old, 220 - 20 = 200 max HR). High-intensity exercise is defined as working at about 75 to 85% or more of your maximum heart rate.