DRIs Flashcards
DRIs are developped in join collaboration of
between Health and Welfare Canada + USDA, NIH, US Academy of Sciences (FNB of IOM)
Why there are different nutrition recommendations
due to different interpretations of the scientific evidence.
Why is not correct to say daily intakes
Intake of vitamin A is very variable from day to day, so it is not occur on a daily basis, and you do not to take it daily, because you can use it from fat source
Compared to water soluble riboflavin, which you need to restore more often
Limitations of old dietary guidelines
a lot of guidelines were determined on average intake, but not in physiological role EFAS- are based in average intake, just assuming adequacy, but not as valid as vitamin C for example, where ascorbic acid is measured as an antioxidant capacity in the body
Desrcibe the structure of DRIs organiszation, how lower and upper intake levels are established
Standing Committee for the Scientific Evaluation of Dietary Reference Intakes: oversees the 5 year process.
Nutrient Expert Panels develop, in conjunction with two subcommittees, the series of DRI Reports, based on a review of the scientific literature.
Total: 7 reports from 7 individual sub-committees dealing with 7 areas of nutrient requirements
What does nutrient expert panels do ( what thet analyze)- 5 things
- Develop a series of DRI reports, in conjunction with the two subcommittees by analyzing:
- The role the nutrient plays at each life stage;
- The role the nutrient plays in the development of chronic disease;
- The indicator of adequacy of the nutrient;
- The estimate average requirement of the nutrient for each life stage;
- The interpretation of the current intake data of North American population groups.
- In total, 7 reports from 7 individual subcommittees are submitted, dealing with 7 areas of nutrient requirements.
In what 7 groups all nutrients are divided
What is DRI committee mandate
Mandate: to look at nutrient intakes for the prevention of nutrient deficiencies AND to consider levels of intake needed to prevent chronic disease.
What is the use for UL committee and DRIs subcommittee
UL committee: derives the tolerable upper intake levels for all nutrients since supplementation and food fortification are now a major source of nutrition in addition to food itself
Uses of DRIs sub-committee: deals with appropriate applications for reference intakes (assessment of intakes, planning for intakes of groups/individuals and nutrition education)
4 general concepts for DRIs
- EAR – Estimated Average Requirement (from which RDA is determined)
- RDA – Recommended Dietary Allowance, which replaces the former RDA and RNI
- AI – Adequate Intake (alternative reference when EAR and consequently RDA are not available)
- UL – Tolerable Upper Intake Level
The trend established to focus on chronic disease prevention has been taken further: ( 4 points)
(1) look at the RDA values for micronutrients (importance in chronic disease prevention)
(2) recommendations for deficiency disease prevention AND chronic disease prevention
(3) common use of food and nutritional supplements à establish upper levels of intake
(4) also include non-essential food components such as phytochemicals for chronic disease prevention.
RDA follow what distribution
Same scientific approaches for RDA used to derive RNI: individual variability in requirements must be considered
Many biological variables in a population follow a Gaussian distribution ->many nutrient requirements for a population follow this distribution
RDA: average daily intake level sufficient to meet the needs ___ people, at what stage
97-98%
individuals in a particular life stage and gender group.
RDA are set for groups or individuals?
level of nutrient intake to meet nutrient requirements of individuals and NOT groups. (Individuals consuming nutrients to the RDA level would be unlikely to develop a deficiency).
draw the distribution with % where EAR and RDA will be labelled
The basis of setting the RDA ( 5 points)
1- Define intake of nutrient that provides adequate intake for 50% of HEALTHY individuals in a life stage and gender group. Index of adequacy differs for each nutrient and for life stage.
2- Safety factor for optimal tissue stores.
3- Factor that accounts for additional needs for growth such as for pregnancy and lactation.
4- Bioavailability: factor can be added to account for nutrients with less than 100% absorption.
5- To account for variability in nutrient needs 2 SD are added to get the final RDA value.
When setting RDA we should have a measurable ___
Outcome
why there is a problem with data from healthy population?
One general limitation: young adults that are tested, so on elderly assumptions are made based on young, but not the research, the same thing for childhood
What studies should be also considered apart from usual intake distribution of healthy people
- Deficiency states
- Balance studies (You have a daily loss of nutrients through skin, urine, etc.-> how much you need to take to meet your losses. Given nutrient free diet and then look how much of the nutrient they are losing and then determine the level. Not many studies)
- Animal research
Experimentally obtained data via balance studies, epidemiological studies or extrapolated from data on other age groups.
Deficiency and balance studies show a quantitative relationship between intake below a certain level and deleterious changes in biochemical & physiological responses.
RDA must account for
•Individual variability in a population (i.e., coefficient of variability of population) -
Depending on the variability, SD can be narrow or wide
Infancy is the very variable, so you need to take SD that are larger
- Bioavailability (The ability to absorb the nutrient ( iron from meat or vegetables), iron requirements as well ass zinc are higher for vegetarian based diet, phytates, tannins, oxylates restruct iron absorption
- Sex and age differences (
Different body composition, different hormones-> different needs
All stages of growth adds more all nutrient requirements)
•Physiological state (pregnancy, lactation)
What is EAR and how it is derived
dietary intake of a nutrient meeting the needs of 50% of the population. Typically derived from balance studies and serves as the foundation for setting the RDA.
- Based on a specific criterion of adequacy
- E.g.: EAR for vitamin C is based on “an amount thought to provide antioxidant protection as derived from the correlation of such protection with neutrophil ascorbate concentrations”.
Using EAR what can you determine
•Suitable method to assess the prevalence of inadequate intakes for GROUPS
How SD of EAR should be calculated if there no SD available
- Assume CVEAR = 10%
- CVEAR = SDEAR/EAR
- SD = (EAR x CV)
•
- RDA = EAR + 2SDEAR
- RDA = EAR + 2(EAR x 0.1)
- RDA = EAR (1.2)
Major difference between RDAs and RNIs
- When possible, the reduction in the risk of chronic degenerative disease is included in the formulation of the RDA.
- Concepts of probability and risk explicitly underpin the determination of the DRIs, and applications.
- Upper levels of intake are established.
- Food components that may not meet the traditional concept of a nutrient are considered.
The main criticism of the former RDAs and RNIs were that the indices of nutritional adequacies that were used were based on insufficient information, as there were no metabolic studies to estimate their recommendations. The mean intakes of the healthy population, lacking signs of deficiencies, were used as the standard for nutrient adequacies and recommendations, which may not reflect the actual requirement or a person or a group of people.
Energy requirements are estimated based on
Energy requirements are estimated on an individual basis using sex, age, height, weight, and physical activity level to estimate total energy expenditure.
Why mean intake should be used as a reference number to set the requirement for energy requirement
- It is assumed that for energy there is a high correlation between intake and expenditure (or requirement) so that energy balance is closely maintained.
–> A healthy individual will ordinarily meet energy needs by adjusting food intake.
-Risk that setting higher intakes will cause an overconsumption of energy
Is diet analysis is suffient to judge nutritional adequacy
- RDAs are a reference point ONLY in evaluating diets of individuals
- Allow estimate of probable risk of deficiency for an individual when diet is assessed over time
Can tell only the probability of the deficiency
If the person intake is below RDA, does it mean he has deficiency
what is the cut-off
and when the person is said to be deficient (what percent of RDA)
- Intake below RDA cannot give certainty of nutritional deficiency
- Probability of risk increases the lower the intake goes below RDA. Cut-off = 2/3 of RDA
- Someone consuming a nutrient at 50% of RDA is likely to be deficient.
Why comparing the mean intake of a group with the EAR is not a good approach
Draw the scheme how nutrient intake (x axes) and risk of inadequacy (y axes) with EAR, rda, AI and UL
Difference between RDA and UL depends on the nutrient and life stage
Risk of deficiency or adverse effects with the different nutrient requirement indices.
EAR: intake at which there is 50% risk of deficiency.
RDA: level of intake at which the risk of deficiency is very small (2-3%)
AI: no consistent relationship to EAR or RDA.
If intake between RDA and UL ->risks of inadequacy and adverse effects are close to zero.
At intakes above the UL, the risk of adverse effects increases.
Key recommendatons from nutrition handbook guidelines
Benefit of not eating whole grains-> middle east high phytate level (unleavened bread) zinc deficiency , because of competitive
Folate fortification only for white flour not for whole grain flour
Now there is evidence, that dairy fat from dairy is protective against obesity, developing insulin intolerance
For pediatric , saturated fat from dairy is protective
oils - As a substitute for saturated fat, higher linoleic acid is showed against CVD disease
Recommendations about added sugar, saturated fats, sodium, and alcohol
What is the guideline 1 (nutritious foods) from CFG 2019
- Choose protein foods that come from plants more often.
- Choose foods with healthy fats instead of saturated fat
- Varied diet to obtain essential nutrients as recommended by RDA
- Encourage more plant-based foods and less highly processed foods,
- A variety of plant food sources to decrease heart disease and bowel cancer risk.
- Also results in increased intake of phytochemicals (protection against chronic diseases).
- Lower sat. fat intake to prevent heart disease
What is guideline number 2 (some foods should not be consumed regularly) and guideline 3 (some skills are needed)
- Sodium: essential hypertension & cerebral hemorrhage.
- Advises us to use food labels,
- be aware of food marketing,
- limit foods high in sodium, sugars or saturated fat.
Recommendation limits from CFG for Na, sat fats and free sugars
Difference between total sugars, free sugars and added sugars
