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Nutrition lecture 1

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winniesmith2's version from 2017-10-12 11:33

Section 1

Question Answer
Definition of nutrition (1) Vorster the processes whereby cellular organelles, cells, tissues, organs, systems, and the body as a whole obtain and use necessary substances obtained from foods to maintain its structural and functional integrity
Definition of nutrition (shorter) the provision of essential nutrients necessary to support human life and health
Nutrient classification 1:Essential and non-essential nutrients.
Essential nutrients (indispensable) must be derived from the diet – no de novo synthesis or insufficient synthesis.
Non-essential nutrients synthesised at a level in excess of need or present in diet which may impact health e.g.. dietary fibre.
Conditionally essentials cannot be synthesised in sufficient amounts under certain circumstances e.g. pregnancy, lactation.
Macronutrients consumed in large amounts ±10 x g per day
Micronutrients consumed in small amounts ± mg per day
Macro-mineralse.g. Ca, Na, Cl, Mg, K, required in greater amounts than other micro-nutrients
Trace elements chromium (Cr), boron (B), molybdenum (Mo)
Essential nutrients -Carbohydrates (fibre); energy. -Fats (concentrated energy, insulation, endocrine function)(leptin) -Proteins (growth and repair)(+all 3 are macronutrients) -Minerals (normal function(homeostasis)-Vitamins(growth and health) (Micronutrients)
Describe good carbohydrates low glycaemic index = slow rise in blood sugars and insulin
Examples of good carbohydrates vegetables, whole fruit, legumes, potatoes and whole grains, etc.
Describe bad carbohydrateshigh glycaemic index = rapid rise in blood sugars and insulin
Examples of bad carbohydrates sugar-sweetened beverages, fruit juices, pastries, white bread, white pasta, white rice, etc.
Saturated fat Leads to increase blood cholesterol levels and low-density lipoprotein (LDL) levels, increased risk for CVD/CHD, T2DM. Primarily animal-based, and is found in high-fat meats and dairy products.
Typical sources of saturated fats include:•-fatty cuts of beef, pork, and lamb. •-dark chicken meat and poultry skin. •-high fat dairy foods (whole milk, butter, cheese, sour cream, ice cream). •-tropical oils (coconut oil, palm oil, cocoa butter). •-lard
Trans Fat (trans fatty acid)can raise LDL cholesterol (bad cholesterol) and lower HDL levels (good cholesterol). Can raise your heart disease risk 3 times higher than saturated fat.
Sources of trans fat found in foods that contain partially hydrogenated vegetable oils.•fried foods (French fries, doughnuts, deep-fried fast foods). •margarine. •vegetable shortening. •baked goods (cookies, cakes, pastries). •processed snack foods (crackers, microwave popcorn).
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Section 2

Question Answer
Definition of Diet 1:The kinds of food that a person, animal or community habitually eats e.g. "a vegetarian diet"
Types of Diet (what people eat)Omnivorous -Carnivorous -Vegetarian; lacto, ovo, lacto-ovo, demi, semi, pollo, pesco -Vegan; raw, palaeo,
Definition of Diet 2:a special course of food to which a person restricts themselves, either to lose weight or for medical reasons e.g. "I'm going on a diet". OR the practice of attempting to achieve or maintain a certain weight
Dietary standards tells you what you should eat
Why do we need dietary standards to: -Be able to assess the adequacy of an individual’s or a population’s diet. -Provide guidance for individuals. -Provide food labelling information. -Enable government planning of food supply. -Protect populations against nutrient deficiency or excess.
Are dietary standards universal?no! -Dietary reference values are standards set by the health departments of governments to fulfill national requirements and conditions. -Or by organizations such as WHO to cater for global requirements and food patterns in terms of production and availability.
Why should dietary standards differ by country?Because; +National systems vary - according to national health priorities and policies. - according to predominant health status, socioeconomic status, body mass and rates of growth. -according to the composition of foods or other lifestyle influences that determine bioavailability of nutrients.
What did the food and nutrition board of national research council USA do in 1943 Recommended Daily Allowances (RDA) to “provide standards to serve as a goal for good nutrition” – to avoid undernutrition
What did the British medical association (BMA) do in 1950Introduced UK Recommended Daily Amounts (RDA) Based on statistical distribution. Mean= average requirement. RDA= mean +2SD
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Section 3

Question Answer
Define RDA (Recommended Daily Amounts)The average amount of the nutrient which should be provided per head of a group of people, if the needs of practically all members of the group are to be met.
What is a calorie? Energy required to raise 1g of water by 1 degree Celsius (small calorie). Large Calorie- Kilocalorie (Kcal) = Kilogram calorie.
What is wrong with the term RDAThe term “recommended” wrongly suggests a level of intake that an individual must consume on a daily basis in order to avoid adverse consequences. The intended interpretation o f RDA is that RDA is the mean and +2SD around this number is a safe nutrient intake and either side of this (too little AND too much) is a marginal intake and then danger of disease (key point; on both sides). HOWEVER, the interpretation of RDA by the public is prescriptive, that RDA is the exact amount you need, any less gives a danger of disease but anymore is a safe level of intake (incorrect)
COMA Committee of medical aspects
What questions did the COMA 1991 review ask 1. What level of intake is necessary to maintain circulating or tissue concentrations within normal ranges? 2. What level of intake is necessary to avoid clinical deficiencies in individuals or populations? 3. What level of intake has been established as being effective in treating clinical deficiency? 4. What level of intake has been shown to maintain normality in a biomarker of adequacy?
What did COMA introduce new dietary standards termed: dietary reference values (DRV)
What did the DRV system do abandoned the use of the term ‘recommended’ to avoid misunderstanding. The values are based on the assumption that patterns of intake within a population will be normally distributed.
What does the EU usePRI (Population Reference Intake)
What does North America use DRI (Dietary Reference Intake)
What do Antipodes useNIV (Nutrient Intake Value)
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Section 4

Question Answer
What is the DRV Guidelines that can be used to define the composition of diets that will maintain good health.
Applications of dietary reference valuesAllows comparison with Food Balance data, Menu planning and Food labelling
Explain how DRV can be used for comparison with food balance data-Monitor adequacy of food supply at the national level. -Track trends in the food supply and detect inadequacies across whole population.
Explain how DRV can be used for menu planningStandards for nutrient provision based upon DRVs set guidelines for menu planning for caterers in hospitals, schools or other institutional settings.
Explain how DRV can be used for food labelling Many of the food labeling schemes used in supermarkets are based upon published DRVs for specific nutrients
Definition of DRVA general term which covers all the figures of EAR, RNI & LRNI.
Definition of estimated average requirements (EAR)The estimated average requirement (mean) of a group for a particular nutrient or for energy
Definition of reference nutrient intake (RNI)The amount of a nutrient (mean + 2SD) which is sufficient for almost all individuals (97.5%). It exceeds the requirement of most people. Habitual intakes > RNI are almost certain to be adequate.
Definition of lower reference nutrient intake (LRNI)The amount of a nutrient (mean – 2SD) which is sufficient for only a few individuals (2.5%). Habitual intakes < LRNI will almost certainly be inadequate.
The relationship between nutrient intake and nutrition-related risk: LRNI (lower reference nutrient intake 97.5%)High risk that intake is inadequate
The relationship between nutrient intake and nutrition-related risk: RNI (reference nutrient intake (2.5%))low risk that intake is inadequate
The relationship between nutrient intake and nutrition-related risk: UL (tolerable upper limit)High risk that intake is excessive
UK DRVs are mapped onto a normal distribution curveEAR is the mean(average) LRNI = 97.5% will have requirements greater than this. RNI = 97.5% will have requirements less than this.
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Section 5

Question Answer
When do we use Safe intakes -Used if there is too little data to set RNI, EAR, etc. -Safe intakes usually applied to children. -Level of intake that is considered to be a low risk for deficiency and for toxicity. e.g. UK safe intakes set for biotin and pantothenic acid.
What is the use of DRVs For assessing diets of groups or populations and for food labelling purposes.
DRVs; For assessing diets of groups or populations-Useful comparison in surveys -Benchmarks for population
DRVs; for food labelling purposes -Range of DRVs has an advantage over use of RDA -Labelling with EAR instead of RDA is suggested -Consumers more likely to interpret EAR correctly -Otherwise may try to consume nutrients at the level of RDA - which is virtually certain to be in excess of requirements
Using DRVs as benchmarks- UK. What are they not intended for to be guidelines for individuals: -Estimates of nutrient intakes for individuals lack sufficient precision. -Impossible to estimate what the true requirements for any individual are likely to be.
Using DRVs as benchmarks- important for -The nearer the average intake of a group within a survey is to the RNI, the less likely it is that any individual within that group will have an inadequate intake -LRNI value provides a better indicator of the likely risk of widespread deficiency If average intake of a group is close to the LRNI, high probability that some individuals within that group have inadequate intake
Using DRVs as benchmarks- clinical settingIn healthy individuals dietary intakes below or close to the LRNI could indicate a dietary problem: More in-depth assessment of biochemical or clinical indicators required.
Presentation of DRVs -DRV tables published for all nutrients. -Attempt to show nutrient requirements as affected by individuals characteristics. -Split by age and sex. -May consider pregnancy and lactation.
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