Introduction to Nutritional Sciences Practice Flashcards

Comprehensive vocabulary flashcards covering the basics of nutritional science, nutrient classification, dietary guidelines, physiological structures of the GI tract, and clinical disorders.

Nutrition

The sum total of all processes involved in the intake and utilization of food substances by living organisms, including ingestion, digestion, absorption, transport, and metabolism of nutrients.

Metabolism

All chemical processes that occur within a living organism to maintain life, involving the conversion of food to energy and the exchange of oxygen for carbon dioxide during cellular respiration.

Nutrient

A substance found in foods that performs one or more physiological or biochemical functions in the body.

Bioavailability

The degree to which a nutrient is available to the body for use, such as the varied access to iron-dependent on whether a diet includes meat or is restricted to vegetarian/vegan sources.

Organic Molecules

Molecules that contain carbon atoms; examples include carbohydrates, alcohol, fats/lipids, vitamins, and protein.

Inorganic Molecules

Molecules that do not contain carbon atoms, specifically water and minerals.

Essential Nutrients

Nutrients that must be obtained from the diet because they are necessary for bodily functions and cannot be produced by the body in adequate amounts, such as lipids, proteins, vitamins, and water.

Nonessential Nutrients

Nutrients used by the body to promote health that do not need to be consumed in the diet because they can be found or produced in the body, such as cholesterol, carnitine, and creatine.

Conditionally Essential Nutrients

Nutrients that are typically nonessential but can become essential under specific circumstances, such as creatine during Chronic Kidney Disease.

Macronutrients

Nutrients required in quantities larger than $1\,g/day$ to preserve normal bodily functions, which include lipids, carbohydrates, and proteins.

Micronutrients

Nutrients required in quantities less than $1\,g/day$ to preserve normal bodily functions, specifically vitamins and minerals.

Energy Yielding Nutrients

Nutrients that are transformed into energy when broken down in the body, including lipids ($9\,kcal\,g^{-1}$), carbohydrates ($4\,kcal\,g^{-1}$), and proteins ($4\,kcal\,g^{-1}$).

Epidemiological Studies

Observational studies that examine the relationship between exposures (diet/lifestyle) and health outcomes without intervening; they identify patterns or correlations but cannot determine causality.

Case-control Studies

Retrospective studies that compare a group of individuals with a condition (cases) to a group without it (controls) to see the impact of dietary differences over time.

Cohort Studies

Studies where a group of people is monitored over a long period of time to track health conditions and dietary habits.

Depletion Studies

Research that involves feeding a diet devoid of a specific nutrient until symptoms of deficiency appear, then readding the nutrient at graduating levels until symptoms disappear.

Scurvy

A disease caused by a deficiency in Vitamin C, characterized by bruising, bleeding gums, loosening teeth, and fatigue; it was the major cause of mortality among sailors between the 16th and 18th centuries.

Vitamin C

A nutrient used by enzymes like prolyl-hydroxylase to catalyze the addition of hydroxyl groups to collagen, allowing it to crosslink into a strong triple peptide helix.

GULO (L-Gulonolactone oxidase)

An enzyme present in rats and other mammals that allows them to synthesize Vitamin C, which humans lack.

Estimated Average Requirements (EAR)

The average daily level of intake designed to meet the requirements of $50\%$ of healthy individuals; it corresponds to a risk of inadequacy of $0.5$ on a graph.

Recommended Dietary Allowance (RDA)

The average daily level of intake designed to meet the requirements of nearly all ($97-98\%$) healthy individuals, used to plan nutritionally adequate diets.

Tolerable Upper Intake Level (UL)

The maximum daily intake level unlikely to cause adverse health effects; it is not a recommended level and is often determined through case series of accidental excessive intake.

Adequate Intake (AI)

An intake level assumed to ensure nutritional adequacy that is established when there is not enough information to determine an RDA.

Dietary Guidelines for Americans (DGA)

Science-based advice focusing on habitual dietary patterns to promote health, prevent chronic disease, and meet nutrient needs through nutrient-dense foods.

Nutrient-dense Foods

Foods that contain higher amounts of macro/micronutrients per weight, with less saturated fat, sugar, and salt.

Dietary Fibers

Absorbable carbohydrates that delay digestion, impact sugar absorption rates, act as bulking agents for feces, and serve as an energy source for gut microflora.

Food Fortification

The deliberate process of increasing the content of one or more micronutrients in a food or condiment to improve nutritional quality and provide a public health benefit.

Goitre

An enlargement of the thyroid gland caused by iodine deficiency; it was significantly reduced in the US after the 1924 fortification of table salt.

Anthropometric Assessment

An assessment of the human body’s physical dimensions and composition, including weight, height, BMI, waist circumference, and DEXA.

Body Mass Index (BMI)

A metric calculated as weight in $kg$ divided by height in $m^2$; it is an estimate of body fat but does not account for muscle-to-adipose ratios or bone density.

Visceral Fat

Fat stored deep within the abdomen around internal organs; it is metabolically different from superficial fat and its accumulation correlates with higher risk of cardiovascular diseases.

DEXA (Dual Energy X-Ray Absorptiometry)

An assessment tool that uses two x-ray beams to identify bone density and estimate body proportions of lean mass and fat mass.

Acute Disease

A health condition that appears suddenly and lasts for a short duration, such as COVID-19 or cholera.

Chronic Disease

A health condition or non-communicable disease that is persistent, long-lasting, and develops slowly, such as cardiovascular disease or diabetes.

GERD (Gastroesophageal Reflux Disease)

A condition where acidic gastric contents bypass the lower esophageal sphincter and enter the esophagus, causing irritation, heartburn, and reflux.

Epiglottis

A specialized flap of tissue in the lateral pharynx that controls access to the larynx or esophagus depending on whether air or food is passing through.

Mastication

The mechanical breakdown of food in the mouth using the teeth and tongue to increase surface area and form a bolus.

Peristalsis

Wavelike muscular contractions and relaxations that move food through the gastrointestinal tract.

Chyme

The acidic mixture resulting from food being mixed with gastric juices in the stomach.

Enterocytes

Key epithelial cells within the intestinal lining, particularly in the jejunum, that contain villi and microvilli to facilitate nutrient absorption.

Segmentation

A bidirectional 'chopping' motion in the GI tract that exposes food to digestive secretions.

Gastrin

A hormone triggered by the sight, smell, or arrival of food in the stomach that stimulates gastric motility, protein digestion, and powerful muscle contractions.

Secretin

A hormone triggered by acidic chyme entering the small intestine; it signals the pancreas to release bicarbonate-rich juices to neutralize acidity.

Cholecystokinin (CCK)

A hormone triggered by the arrival of lipids and protein in the small intestine; it signals the release of pancreatic juices and bile for emulsification.

Ghrelin

A hormone released when the stomach is empty that stimulates hunger and the release of other hormones.

Celiac Disease

A chronic digestive and autoimmune disease where the consumption of gluten (found in wheat, rye, and barley) triggers antibodies that attack and flatten the intestinal villi.

Irritable Bowel Syndrome (IBS)

A functional disorder characterized by abdominal cramping, bloating, and diarrhea, often attributed to diet, hormones, or emotional states, and lacking the inflammation seen in IBD.

Inflammatory Bowel Disease (IBD)

An autoimmune-associated condition involving inflammation of the GI tract lining, including Ulcerative colitis (limited to the colon) and Crohn’s disease (often affecting the ileum).