HNSC 2140 Term Test 1 Materials

Three historical stages of nutrition science

Pre-1900s focus on macronutrients only; 1900–1980 discovery of micronutrients and deficiency diseases; modern nutrition focuses on optimal health and chronic disease prevention

Macronutrients definition

Nutrients required in large amounts including carbohydrates; proteins; fats

Micronutrients definition

Nutrients required in small amounts including vitamins and minerals

Justus Liebig contribution to nutrition

Proposed protein energy and some minerals were sufficient for nutrition before micronutrients were known

E.B. Hart contribution to nutrition

Showed minor dietary components beyond macronutrients were required for animal growth

Casimir Funk contribution to nutrition

Isolated compounds preventing beriberi and coined the term vitamine later vitamin in 1912

Joseph Goldberger contribution to nutrition

Showed pellagra was caused by niacin deficiency rather than infection in 1914

Beriberi cause

Deficiency of vitamin B1 thiamin

Pellagra cause

Deficiency of niacin vitamin B3; tryptophan can be converted to niacin

Golden era of nutrition

Period around 1980s when many Nobel Prizes were awarded for nutrition discoveries

Modern nutrition focus

Role of nutrition in optimal health prevention of chronic disease and effects of undernutrition and overnutrition

Overnutrition health risks

Obesity; cardiovascular disease; diabetes; pulmonary problems

Functional foods definition

Foods providing nutrients plus additional health benefits beyond basic nutrition

Example of functional food oats

contain fiber which helps reduce cholesterol and improve blood sugar and blood pressure control

Example of functional food blueberries

Contain phytochemicals including anthocyanins with antioxidant anti inflammatory and potential anticancer effects

Anthocyanins definition

Plant pigments providing color and antioxidant protective properties in foods like blueberries

Nutraceutical definition

Supplement derived from food isolated to provide concentrated beneficial compounds not classified as medicine

Food industry role in nutrition advice

major provider of dietary advice to the public

Dietary Reference Intakes (DRI)

Umbrella term for nutrient intake reference values used to plan and assess diets of healthy individuals

Four DRI components

Estimated Average Requirement; Recommended Dietary Allowance; Adequate Intake; Tolerable Upper Intake Level

Estimated Average Requirement (EAR)

Daily intake estimated to meet requirements of 50% of healthy individuals in a life stage and gender group

Recommended Dietary Allowance (RDA)

Average intake sufficient to meet nutrient needs of nearly all 97–98% healthy individuals

Adequate Intake (AI)

Intake level assumed to ensure adequacy when scientific evidence is insufficient to establish RDA

Tolerable Upper Intake Level (UL)

Maximum daily intake unlikely to cause adverse effects in almost all healthy individuals

Meaning of intake in DRIs

Represents average intake over time rather than a single day intake

Difference between DRI and RDA

DRI is the overall system of reference values while RDA is one value within the system

Reasons for establishing DRIs

Harmonization with US standards; new scientific evidence; focus on chronic disease prevention; need for upper intake limits

Old Canadian RNI nutrient categories

Carbohydrates; lipids; proteins; vitamins; minerals; water

Definition of nutrient requirement

Lowest continuing intake needed to maintain adequate nutrition based on specific indicators

Factors influencing nutrient requirements

Genetics; body size; sex; age; activity level; pregnancy; lactation

Nutrigenomics definition

Study of how nutrients influence gene expression and how genetics influence nutrient needs

Infant nutrient requirement basis

Requirements based on human milk especially colostrum in first months

Colostrum benefits

High energy; antibodies for immunity; antioxidants; well balanced nutrients; but low iron content

Child nutrient requirements

Support rapid growth and development

Adult nutrient requirements

Support maintenance and tissue repair

Conditional essentiality definition

Nutrients normally nonessential become essential during illness injury or physiological stress

Example of conditional essentiality glutamine

Essential during GI injury or inflammation as fuel for enterocytes and cell proliferation

Example of conditional essentiality arginine

Essential during burns surgery renal failure or infancy due to increased demand or limited synthesis

Essential nutrient definition

Nutrient must be obtained from diet because body cannot synthesize enough

Nonessential nutrient definition

Nutrient body can synthesize in adequate amounts

Relationship between EAR and RDA

RDA equals EAR plus two standard deviations covering nearly all individuals

When coefficient of variation is used in RDA calculation

Used when standard deviation of requirement is unknown typically assumed at 10–15%

Meaning of Adequate Intake (AI)

Used when evidence insufficient to calculate EAR and RDA and indicates greater uncertainty

Situations requiring AI values

Insufficient data; inadequate assessment methods; nutrient interactions; low usual intake; lack of long term studies

Meaning of UL value

Highest intake unlikely to cause harm but not recommended as intake goal

Reasons UL values are needed

Supplement use; fortified foods; functional foods; extreme diet practices increasing toxicity risk

Key factors in UL development

Evidence of adverse effects; relevance of data; dose response relationship; sensitive populations; identification of critical endpoints

NOAEL definition

Highest intake with no observed adverse effects

LOAEL definition

Lowest intake where adverse effects are observed

Uncertainty factor definition

Safety factor applied when data are incomplete or uncertain in UL calculation

Primary nutrient deficiency

Caused by insufficient intake of a nutrient

Secondary nutrient deficiency

Caused by disease malabsorption metabolic disorders or abnormal nutrient losses

Example of deficiency osteoporosis

Bones become porous brittle often occurring after menopause

Example of deficiency osteomalacia

Bones become soft and pliable due to poor mineralization

Iron deficiency effect

Causes anemia due to reduced hemoglobin levels

Iron excess effect

Leads to hemochromatosis causing iron accumulation and tissue damage

Calcium excess effect

Can lead to calcification of soft tissues and organ damage

Energy recommendations versus nutrient recommendations

Energy intake set using equations based on age sex weight and activity rather than RDA

Adult protein RDA

0.8 grams protein per kilogram body weight per day

Acceptable Macronutrient Distribution Ranges (AMDR)

Fat 20–35% energy; carbohydrate 45–65% energy; protein 10–35% energy

Life stage infancy 0–6 months

Requirements based on body weight and human milk supporting exclusive breastfeeding

Life stage infancy 7–12 months

Requirements based on human milk plus solid foods

Life stage toddlers

1–3 years with rapid growth

Life stage early childhood

4–8 years when children typically begin school

Life stage adolescence

9–13 years and 14–18 years with sex specific recommendations emerging

Life stage young adulthood

19–30 years when peak bone mass occurs

Life stage middle adulthood

31–50 years

Life stage older adulthood

51–70 years and over 70 years with increased variability and absorption concerns

Pregnancy nutrient needs

Folate; calcium; and protein needs increase

Lactation nutrient needs

Increase to support milk production

Criteria used to set DRIs

Human milk content; extrapolation; maximal retention; functional outcomes; biochemical tests; disease outcomes; factorial approach; intake of healthy populations

EAR use in diet planning

Used to assess adequacy of intakes in individuals and groups and plan group nutrition

RDA use in diet planning

Used as intake goal for individuals

AI use in diet planning

Used as intake goal when RDA unavailable

UL use in diet assessment

Used to assess risk of excessive intake rather than adequacy

Guiding principles of DRIs

Evidence based; health outcome focused; systematic review; population specific; long term intake; public health relevance; practicality

Types of research used to establish DRIs

Epidemiological studies; case control studies; surveys; biochemical tests; animal studies; clinical trials; systematic reviews

Gold standard research method

Randomized clinical intervention trials

Systematic review definition

transparent evaluation combining multiple studies to answer a specific question

Meta analysis definition

Statistical pooling of data from multiple studies within a systematic review

Characteristics of good research

Control group; blinding; placebo use; randomization; replication; peer review; adequate sample size; relevant population

Meaning of correlation does not equal causation

Association between variables does not prove one causes the other

Best DRI value for institutional meal planning

RDA because it aims to meet needs of nearly all individuals

Why RDA does not guarantee adequacy for all individuals

Individual variation means some people may still have higher needs

Best DRI value for individual intake advice

RDA adjusted for age sex and physiological condition

Information needed for personalized nutrient advice

Age; sex; current diet; physical activity; health status; smoking status; supplementation use

Cell physiology definition

Study of cell structures and processes involved in nutrient metabolism and cellular function

Plasma membrane structure

Phospholipid bilayer composed of lipids; proteins; and carbohydrates forming glycolipids and glycoproteins

Glycocalyx definition

Carbohydrate layer formed by glycolipids and glycoproteins on the cell surface

Types of membrane proteins

Integral proteins embedded in membrane; peripheral proteins loosely attached to membrane surface

Functions of membrane proteins

Transport of substances; receptors for signaling; enzymatic activity

Dietary influence on plasma membrane

Fatty acid composition of diet influences fatty acid composition of membrane phospholipids

Cytoplasm structure

Contains cytoskeleton components and fluid phase with soluble molecules

Cytoskeleton components

Intermediate filaments and microtubules providing structural support

Substances found in cytoplasmic fluid phase

Glucose; amino acids; oxygen; carbon dioxide and other small soluble molecules

Metabolic pathways in cytoplasm

Glycolysis; pentose phosphate pathway; glycogenesis; glycogenolysis; fatty acid synthesis

Mitochondria function

Site of energy metabolism where oxygen is used and carbon dioxide produced

Mitochondrial structure

Double membrane organelle with inner membrane folded into cristae

Location of electron transport chain

Inner mitochondrial membrane

Metabolic pathways in mitochondria

TCA cycle; fatty acid oxidation; pyruvate metabolism