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.
How requirements for RDA can be met
-Requirements can be reached by a well balanced diet.
Should you consume all the nutrients daily?
- Intakes of the required nutrient are averaged over a period of time.
- Certain nutrients show a high day to day variability of intake (vit. A) or low variability (protein, vit. B6)
RDAs is designed to 1),2),3)
- Prevent chronic disease – this aspect is now being considered as part of the RDA development
- Developed to maintain good health and avoid deficiency but NOT designed to
- Overcome nutrient deficiencies
- Recover from illness
- RDAs were not developed to overcome nutritional deficiencies. Similarly, many diseases can have specific nutrient requirements.
- RDAs were developed with the idea of prevention of occurrence of deficiency diseases and prevention of deterioration of biochemical functions.
Period of time needed to compensate a deficient intake depends on
Body pool size, nutrient turn-over
Like the former RNI and RDA, new DRIs must account for
- Individual variability in a population (i.e., Coefficient of Variability of Population)
- Bioavailability
- Gender and age differences
- Physiological state (Pregnancy, Lactation)
Why comparing the mean intake of a group with the EAR is not a good approach
How calcualte target mean intakes using EAR
Target mean intake for group = EAR/(1-[2 x CVintake])
Where CV = SDintake/Mean intake
How to plan the desired intake for groups
How many people should be covered and then how much deficiency will be and why not higher
Planning for groups (example): set the level of intake to cover all but 2.5% of pop. Requirements => if 2.5% is eating < EAR => estimated prevalence of deficient intakes is 1%
Targeting lower prevalence of deficient intakes (e.g. 0.1%) => most individuals would have intakes much greater than their actual needs.
How DRIs differ from the former RDAs and RNIs
1.Where possible, reduction in the risk of chronic degenerative disease is included in the formulation of the recommendation (In elderly depressed immune function, so was proposed that higher intake of vitamin E can help)
●
- 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.
When AIs are used
•Adequate Intakes (AIs) – used instead of RDAs when an EAR cannot be calculated. Both the RDA and the AI may be used as goals for individual intake.
Criticism of RNIs
indices of nutritional adequacy sometimes based upon insufficient information à group mean intakes used as the standard for nutritional adequacy. (If not associated with nutritional deficiencies -> they could be used as valid indices for setting the RNI)
These mean values do not incorporate the 2SD from the mean safety factor.
What are ULs
•Tolerable Upper Intake Levels (ULs) – Intakes below the UL are unlikely to pose risks of adverse health effects in healthy people.
-UL: maximum intake unlikely to pose health risks. Not intended to be recommended intake (no established benefit of intakes above the RDA or AI).
What is the standard to set AIs and again problem of RNIs
- Experimental and observational data used -> mean intake that sustains a desired indicator of health
- Such indices were used incorrectly in 1990 Nutrition Recommendations and earlier RDA
How should you interpret personal intake in referance to AI
•If an individual’s intake is > or equal to AI:
⇒ Diet is almost certainly adequate
•If the intake falls below the AI:
⇒ No quantitative (or qualitative) estimate can be made of the probability of nutrient adequacy because the point where risk increases cannot be determined
Group intake in reference to AI value
If group mean/median intake ≥ AI -> Low prevalence of inadequate intakes is likely
BUT: proportion of individuals with intakes ≤ AI cannot be referred as having inadequate intakes.
UL level refers to nutrient intake from what sources
-Refers to total intake from food, fortified food, nutritional supplements and water intake (i.e., hard water).
If there is no UL to the nutrient, should I stub my mouth with it?
-If no UL for a nutrient, does not mean that intake at any level is without risk, but that safe level undetermined.
Importance of UL in part due to commonplace fortification and supplement use
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.
What value is usually used for requirements in infancy?
AI: used as the appropriate index for the requirements for all nutrients in infants up to one year of age.
What age categories DRI table has
- Adulthood divided into fewer categories than infancy to adolescence (importance of growth on nutrient requirements). Categories reflect less drastic changes in requirements than childhood and adolescence.
- Pregnancy also associated with rapid changes in requirements.
- Infancy
How dietary guidelines are usually presented
- Technical numbers (RDA) converted into educational devices (Canada’s Food Guide)
- Dietary guidelines help select quantities/combinations of foods for optimal long-term health.
- Quantitative advice: percentages of total energy (i.e. saturated fat <10% of energy)
- Optimal proportions of energy-yielding macronutrients
- Do not usually describe nutrients but food components, food groups (i.e., cereals and grains)
- Do not usually express weights of nutrients to be consumed as per the RDA
- Semi-quantitative advice on consumption of a food component
What dietary guidelines can and cannot do vs RDA
•Can target to improve behavior towards a future goal for the population (e.g. ↓ fat)
≠ RDA (amounts of nutrients needed)
•Target the intake of every man, woman and child
≠ RDA (separate numbers for males and females of different age categories)
•Primarily examine macronutrients
à rely more on epidemiological and food consumption data than do RDA
Is there RDA for fat
-EFA = required nutrients; fat is not (no RDA)
Should the population predominantly be eating <rda></rda>
- Risk of EFA deficiency
- Major shift in types of foods eaten à to little animal protein à decreased consumption and bioavailability of e.g. Fe, Zn, Ca
- RDAs, developed with bioavailability associated with mixed protein diet, would have to be readjusted
- Risk for children => transition from high fat diet to no more than 30% of energy from age 2 to end of linear growth
Focusing on total fat would not make sense necessarily if not looking at quality of fat
Nutrition Recommendations handbook describes
RDA and a set of dietary guidelines (Nutrition Recommendations).
New Nutrient Recommendations: shift of emphasis from nutritional deficiencies prevention only towards disease prevention.
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
What are recommendations about the alcohol
-Alcohol: above 5% of energy -> increase risk of cancers, heart disease and other (osteoporosis, dementia, liver diseases, hypertension, obesity, fetal alcohol syndrome, accidents, domestic violence)
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
Why soy can be a support to bones
Soy- isoflavones that are related to bone health, because acts like estrogen
What is the danger with seafood
Seafood- mercury poisoning, more dangerous from bigger fish, smaller ( sardines) have virtually no mercury
When the first food guide was developed in Canada and why it was developed
Food guides:
- Translate nutrient requirements and health impacts of food intakes into a practical pattern of food choices.
- Not prescriptive. Incorporate concepts of variety & flexibility.
1942: Canada’s first food guide, the Official Food Rules. Since 1942, the food guide has been revised many times, most recently in 2019. - The Food Guide is intended to assist the people of Canada two years of age and older in making food choices that promote health (defined as social, mental and physical well-being).
- It describes a pattern of eating consistent with national nutrition guidelines.
CFG supports what and make emphasis about
•Describes a pattern of eating that…
is sufficient to meet nutrient needs
contributes to a reduced risk of nutrition-related health problems
supports the achievement and maintenance of a healthy body weight
reflects the diversity of foods available to Canadians
- Supports Canadians’ awareness and understanding of what constitutes a pattern of healthy eating
- Emphasizes that healthy eating and regular physical activity are important for health
What was the difference between CFG in 2007 and 2019
Revised: 2002-2007
- Focus: nutrient targets, energy levels, food groups & serving sizes.
- Nutrient targets for vitamins, minerals, macronutrients.
- Targets based on DRI + advice from the Expert Advisory Committee on DRIs and Health Canada’s DRIs Internal Working Group.
- Energy Levels: used to establish numbers of servings from each food group.
On what principles the new food guide was developed and why
New Food Guide
- The Old Food Guide Was Just Too Long.
- The Food Guide Is Not Culturally Inclusive.
- It’s Done Away with Serving Sizes and Food Groups.
- It Recognizes that Healthy Eating is More than The Foods We Eat.
- The New Food Guide’s Emphasis on Filling Half Our Plate With Plants.
A major criticism is that the old food guide prescribed way too much food. The recommendations were unrealistic for the average consumer which led people and even health professionals to avoid using the guide as a counselling tool. I myself once experimented with the recommendations and found myself eating SO much more food than I was comfortable eating
Why is the message in new food guide is better than from the old one
Focus group research revealed that this plate model was much easier to understand than portion sizes and number of daily servings.
While the old food guide pamphlet had 6 individual pages, the new food guide has only two pages and the messages are simple and to the point. Instead of long winded sentences in the last food guide, the new food guide includes short statements that get right to the point:
Eat a variety of healthy foods each day.
- have plenty of vegetables and fruits (visually: half your plate)
- -choose whole grain foods (visually: a quarter of your plate)
- -eat protein foods (visually: a quarter of your plate)
- -make water your drink of choice (Replace sugary drinks with water)
Does new CFG focuses only on food consumed?
No
Reminds Canadians to cook more often, (plan what you eat, involve others in planning and preparation of meats)
- eat meals with others (take time to eat)
- be mindful of their eating habits (notice when you are hungry and full),
- and enjoy food (Culture and food traditions can be a part of healthy eating)
The new Canada’s Food Guide, goes beyond simply what to eat and getting to how we eat:
- encourages more plant-based foods and less highly processed foods,
- -eating more mindfully and together.
- -The new food guide is much wider in scope than the old, single-page rainbow food guide.
offers an online suite of resources including actionable advice, videos and even recipes at
•If a group of people consumed an amount of protein equal to the average requirement for their population group (EAR), what percentage would receive an insufficient amount?
- Answer = 50%
- The EAR refers the usual intake level that is estimated to meet the requirement of half the healthy individuals in a life stage and gender group
- This means that 50% of individuals cannot meet their nutritional needs at that intake
based on population probability of risk for deficiency not individual risk and this takes into account:
This takes into account variability of requirements for a nutrient among individuals versus variabilities of intake for that population.
•
•If 2.5 % of the mean population intake is below the EAR, what is the estimated prevalence of deficient intakes?
- Answer = 1%
- If the population is eating < 2.5% of EAR, due to differences in nutrient requirements among individuals, only 1% have risk for deficiency as some individuals will not be deficient consuming the nutrient at below the EAR.
