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HUB3006F > Nutrition & Health > Flashcards

Nutrition & Health Flashcards

1
Q

What are the criteria for a nutrient to be classified as indispensable/essential?

A
  1. Must be required for growth, health or survival
  2. Absence/deficiency of substance in diet will lead to characteristic signs of deficiency disease
  3. Growth failure & signs of deficiencies can only be prevented by:
    a. The nutrient itself
    b. A precursor of nutrient
  4. Not synthesised in the body & is required for critical function in body
  5. When intake is below a critical intake level - the growth response & severity of signs of deficiency is proportional to amount consumed
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2
Q

What are the exceptions to the criteria for nutrient classification as indispensable/essential?

A
  1. Some can be synthesized in the body from a precursor (e.g. VitA or Niacin)
  2. De novo synthesis in the body (Vit D from sunlight)
  3. Synthesis by microbes in the gut (Vit K)
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3
Q

What are examples of dispensable/non-essential nutrients?

A
  • Non-essential Amino Acids
  • Specific fats/CHO
  • Alcohol
  • Food additives
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4
Q

What are 2 non-essential nutrients that still have health benefits?

A
  1. Fluoride:
    o Low dosages = prophylactic decrease in dental cavities
    o Too much leads to fluorosis
  2. Fiber:
    o Insoluble (whole wheat, bran):
    - NB for gastro-intestinal function
    - Prevents constipation & colon cancer
    o Soluble (oat bran):
    - Fermentation leads to short chain fatty acids which :
    • Provide energy for colonocytes
    • Decrease plasma cholesterol
    • V important in moderating the comp of microbiome
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5
Q

What are conditionally essential nutrients?

A

Essential in some populations but not in others

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6
Q

What are examples of populations with conditionally essential nutrient needs?

A
  1. Premature infants:
    o Have immature metabolic enzyme systems
    o They can’t synthesise/digest all the nutrients needed
  2. Hyper-catabolic patients:
    o Increased protein degradation
    o Decreased protein synthesis
    o i.e. Glutamine use > Glutamine production
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7
Q

What are Dietary Reference Intakes (DRIs)?

A

Is a collective term, including:

- Estimated Average Requirement (EAR)
- Recommended Dietary Allowance (RDA)
- Adequate Intake (AI)
- Tolerable upper Intake Level (UL)
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8
Q

What is the Estimated Average Requirement?

A
  • Intake that meets the estimated needs of a nutrient of 50% of individuals in a specified gender group, at the given life-stage.
  • Includes an adjustment for an assumed bioavailability of respective nutrient
  • Used for setting the RDA
  • Insufficient scientific evidence for EAR -> no RDA set
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9
Q

What is the Recommended Dietary Allowances?

A
  • Intake that meets the nutrient needs of almost all individuals in that gender group, at the given life-stage
  • EAR + 2SD (standard deviations)
  • RDA applies to individuals, not to groups
  • Goal for dietary intake for the individual
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10
Q

What is Adequate Intake?

A
  • Experimentally derived intake levels or approximations of observed mean nutrient intakes by a group of healthy people, who have normal circulating nutrient blood concentrations, growth, or other functional indicators of health.
  • AI recommendation when scientific evidence is inadequate to set an EAR
  • Indicates that substantially more research is needed to established EAR & RDA
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11
Q

What is the Tolerable Upper Intake Level?

A
  • Max nutrient intake by an individual, which is unlikely to pose risks of adverse health effects in almost all individuals in a specified group.
  • Set to protect the most sensitive individuals in the healthy general population
  • Applies to chronic daily use
  • Not a recommended level of intake
  • Contains NOAEL & LOAEL
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12
Q

When did Tolerable Upper Intake Levels become necessary?

A

When food fortification occurred/became mandatory in many countries & Supplementation became available on the market (allowed people to meet these max levels).

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13
Q

What is a NOAEL?

A
  • No-Observed-Adverse-Effect-Level (NOAEL):
    o Highest intake/experimental oral dose of a nutrient at which no adverse effects have been observed in the individuals investigated
    o This does not mean that there is no potential for adverse effects with such a high intake.
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14
Q

What is a LOAEL?

A
  • Lowest-Observed-Adverse-Effect-Level (LOAEL):
    o The lowest intake at which an adverse effect has been identified.
    o If insufficient data to set a NOAEL - use LOAEL as guideline.
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15
Q

What are the applications of DRIs?

A
  1. Can use it to plan or assess a diet
  2. DRIs were purposefully developed for applying standards to groups & individuals - before they only had the RDA which was only for groups of people who were healthy and not any single individual.
  3. Food Labels
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16
Q

What are Dietary Goals?

A
  • Quantitative dietary recommendations

- Intended for use by health professionals

17
Q

What are Dietary Guidelines?

A
  • Qualitative dietary guidance – in terms of food not nutrients
  • Intended for use by the general public
  • Public can use to assess/plan their own diet
  • Express DRIs and dietary goals in terms of food
  • Simple, practical advice for optimal food choices
  • Each country has own set of guidelines
18
Q

What do all diets emphasise limitation of?

A
  1. Refined starches
  2. Added sugars, sweets
  3. SSBs (Sugar-sweetened beverages)
  4. Bakery Foods
  5. Processed Meats
  6. Fast foods & takeaways
  7. Trans-fats, salts
19
Q

What is nutritional genomics?

A

= [Genotype + Environment (Diet)] which form a functional phenotype

  • Health-disease continuum is a player
  • Is an overarching term for:
    o Nutrigenetics
    o Epigenetics
    o Nutrigenomics
20
Q

What is Nutrigenomics?

A

The effect of the environment (nutrients) on gene expression

  • Nutrients can influence production of hormones
  • Hormones can influence signal transduction & production of transcription factors
  • These can increase/decrease transcription
21
Q

What is the nutrigenomic effect of Vitamin A, D and poly-unsaturated fatty-acids?

A
  • They interact with intracellular receptors which influence transcription factors -> influence transcription via promoter area
22
Q

What is the nutrigenomic effect of Vitamin C?

A

(An anti-oxidant) It prevents oxidative damage of RNA

23
Q

What is the nutrigenomic effect of Zinc?

A

Necessary for certain transcription factors in the promote area & influences DNA binding.

24
Q

What is the nutrigenomic effect of Vitamin K?

A

Important for post-translational mods of certain proteins in order to become biologically active.

25
Q

What is Epigenetics?

A
  • Heritable, but reversible changes in the expression of a gene or trait
  • Don’t involve mutations/SNPs - i.e. no changes in DNA sequence
  • Examples:
    o Histone Modification
    o Methylation
26
Q

What is Nutrigenetics?

A

The study of the environmental (dietary) effects on phenotype outcomes.
o Studies the effect of genotype x diet on a phenotype indicator

27
Q

What is Precision Nutrition?

A
  • Dietary changes/recommendations based on genotype
  • Pursues development of comprehensive & dynamic nutritional recommendations based on shifting, interacting parameters in a persons internal & external environment throughout life
28
Q

What are some ethical issues related to Nutrigenetics?

A
  1. Direct-to-consumer marketing (DTC): Cutting out the health professional, needs consumer education
  2. Discrimination: Loss of privacy, employment, social discrimination
  3. Children: Testing for adult onset disorders?
  4. ‘unintended information’ - Finding out about Alzheimers etc.
  5. Cost: Accessible for all?
  6. Trigger unhealthy quests for health
29
Q

What is a monogenic disease?

A
  • High penetrance
  • Single gene involved
  • E.g. cystic fibrosis
30
Q

What is a polygenic disease?

A
  • Low penetrance
  • Many genes (polymorphisms) involved
  • E.g. Diabetes, cancer, CVD
31
Q

What type of evidence is needed for genotype based nutrition?

A

Evidence should:
1. Predict a robust increase or decrease in disease risk or improvement in treatment outcome in relation to a specific dietary pattern, food or nutrient intake

  1. Confirm causality – subsequent genotype-based intervention must decrease disease risk or improve treatment outcome
    o Associations from observational studies need to be verified in dietary intervention studies to provide evidence of causality
32
Q

Types of Genetic screening for genotype based Nutrition

A
  1. Susceptibility screening for prevention
    a. Screen healthy people at risk (due to family history, other indicators) for a disease
    b. Screen healthy people in general for alleles associated with common multifactorial diseases (obesity, CVD, etc.)
  2. Screening individuals to optimize treatment outcomes
    a. Remember contribution of a single SNP to disease risk is small
    b. A SNP can be good or bad
33
Q

What is the Candidate Gene Approach to Nutrigenetics?

A
  • Hypothesis driven
  • Relies on current understanding of biology & physiology of disease
  • Known/presumed biological function/metabolic pathways
34
Q

What is the Genome Wide Association Approach to Nutrigenetics?

A
  • Investigates the entire genome
  • No prior assumptions
  • Identify previously unsuspected loci associated with disease
  • Can narrow down locus more accurately
  • BEWARE of incidentalomics:
    o Unexpected incidental findings (false +’s)
35
Q

What are some contributors to chronic inflammation?

A 
o	Autoimmune effects
o	Excess body fat
o	Genomics & epigenetics
o	Infection
o	Smoking
o	Inflammatory diet
o	Microbiome
o	Physical trauma
o	Antigens 
o	Lack of sleep 
o	Emotional upsets/stress
36
Q

What are some biomarkers associated with chronic inflammation?

A

o Mediators involved in or produced as a result of inflammatory process
o NB to use valid markers – reflect inflammatory status & be predictive of future health status
o No consensus as to which markers best represent low-grade I or differentiate between acute & chronic I
o Ongoing research

37
Q

What is an inflammatory score (IS)

A
  • IS of -1 = Max anti-inflammatory effect

- IS of +1 = Max pro-inflammatory effect

38
Q

Example of a pro-inflammatory dietary pattern

A

Wester Type diet:

  • Increased: Red meat, fat dairy products, refined grains, sugars
  • Decreased: Fruit, veg, legumes
  • Energy dense, nutrient poor
  • 0 < IS < +1
  • Core Mechanisms:
    o Excess Energy:
    • Results in weight gain -> central obesity -> activates inflammatory pathways
    o Increased Saturated Fats:
    • Increased SF -> increased weight & adipose tissue
    • Changes in membrane & lipid raft comp -> altering cell signalling
    • Activates inflammatory paths in cells
    • Contributes to metabolic stress
    o Carbs:
    • Lack of fiber -> increased energy density & decreased nutrients
39
Q

Example of anti-inflammatory dietary pattern

A

Mediterranean & DASH diets:

  • Increased: Fruit, veg, whole grains, fish
  • Moderate: Alcohol, olive oil, chicken, legumes
  • Decreased: Red meat, high fat dairy products, refined grains, salt, added sugar
  • -1 < IS < 0

HUB3006F (8 decks)

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