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Introduction to Nutrition

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1 Introduction to Nutrition
Lecture II

2 Dietary Reference Intakes
Collective term which includes four values: EAR Estimated average requirement RDA Recommended dietary allowance AI Adequate Intake UL Upper Intake Level

3 Estimated average requirement
Average daily nutrient intake estimated to meet the requirement of half the healthy (& assume intake of other nutrients are adequate) individuals in a particular age (life stage) and gender group. Meet the requirement -maintain normal function and health

4 How are requirements estimated
Observation of population groups - intakes associated with absence of deficiency signs. Intakes needed to maintain balance (e.g. nitrogen balance studies for protein). Depletion-repletion studies - intakes needed to prevent deficiency (clinical or biochemical changes)

5 How are requirements estimated
Intakes needed to maintain circulating levels of nutrient or tissue concentration (tissue saturation) Intakes associated with biological markers of adequacy - functional adequacy e.g enzyme activity

6 Recommended Dietary Allowance
Average daily nutrient intake that is enough (or more than enough) to meet the requirement of 97-98% of the healthy individuals in a particular age (life stage) and gender group To determine need EAR and variability (SD) of EAR (assume distribution of requirements is normal) RDA = EAR + 2 SD

7 Adequate Intake Used when insufficient information to determine RDA
recommended average daily nutrient intake based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups ) of apparently healthy persons that are assumed to be adequate

8 Tolerable Upper Intake Level
highest average daily intake likely to pose no risk of adverse health effects to almost all individuals in the life stage and gender group. As intake exceeds UL potential risk of adverse effects increase Need for this value came from increased fortification of foods and use of supplements


10 STAPLES Cereals: Bread (from whole grain or enriched flour), wheat flour, corn (maize), corn­meal, dried cereals, macaroni, spaghetti, rice, cereal porridges. Starchy fruits, roots, tubers/ground provisions: Banana, plantain, breadfruit, yam, potato, dasheen, coco/ eddoe, cassava servings

11 LEGUMES Kidney beans, gungo/pigeon peas, black-eye peas, cow peas, other dried peas and beans, peanuts, cashew nuts, sesame seeds, pumpkin seeds. 3-4 servings

12 VEGETABLES Dark green leafy and yellow vegetables: Callaloo/spinach, dasheen leaves, cabbage bush, pak choy, string beans, pumpkin, carrot. Other vegetables: Squash, cho-cho, (christophene, chayote), cucumber, tomato, garden egg/aubergine Servings

13 FRUITS Mango, guava, citrus (orange, grapefruit, limes, tangerine), pineapple, West Indian cherry, pawpaw/papaya, golden apple/Jew/June plum, sugar apple/sweet sop Servings


15 The Key to a Balanced Diet!
The Food Guide Pyramid The Key to a Balanced Diet!

16 Exchange System Lists

17 1 ounce of ready to-eat cereal
WHAT COUNTS AS A SERVING? Food Groups Bread, Cereal, Rice, and Pasta 1 slice of bread 1 ounce of ready to-eat cereal 1/2 cup of cooked cereal, rice, or pasta Vegetable 1 cup of raw leafy vegetables 1/2 cup of other vegetables, cooked or raw 3/4 cup of vegetable juice Fruit 1 medium apple, banana, orange 1/2 cup of chopped, cooked, or canned fruit 3/4 cup of fruit juice Milk, Yogurt, and Cheese 1 cup of milk or yogurt 1-1/2 ounces of natural cheese 2 ounces processed cheese Meat, Poultry, Fish, Dry Beans, Eggs, and Nuts 2-3 ounces of cooked lean meat, poultry, fish 1/2 cup of cooked dry beans or ½ cup tofu counts as a serving. 2 tablespoons of peanut butter or 1/3 cup of nuts count as 1 ounce of “meat” according to the USDA. The USDA Food Guide Pyramid offers a booklet with their educational materials and they have established what they want to call a serving to allow for countable “units” for adding up total servings. The chart lists typical serving sizes according to the USDA.

18 Exchange Lists Categories
Starch (80 kcal) 15 grams carbohydrate 3 grams protein 0-1 grams fat Vegetable (25 kcal) 5 grams carbohydrate 2 grams protein 0 grams fat This slide lists the energy nutrient values for the starch and vegetable exchange. The chart in the Moore book shows the exchange categories, the energy nutrients of each category, and sample food plans to meet these needs.

19 Exchange Lists Categories
Fruit (60 kcal) 15 grams carbohydrate 0 grams protein 0 grams fat Protein- legumes, meats, cheeses ( kcal) 0 grams carbohydrate 7 grams protein 1-8 grams fat (depending on whether food is very lean, lean, medium fat or high fat) The energy nutrient values are given in this slide for the fruit and protein exchange categories.

20 Exchange Lists Categories
Milk ( kcal) 12 grams carbohydrate 8 grams protein 0-8 grams fat (depending on amount of fat in milk) Fat (45 kcal) 0 grams carbohydrate 0 grams protein 5 grams fat The energy nutrient values are given in this slide for the milk and fat exchanges. The final tool for helping oneself to meet nutrient needs is to assess, evaluate, then adjust one’s diet with the help of a computer dietary analysis. The diet analysis program packaged with this book can help one to take all of this information about essential nutrient requirements and design a personalized program for one’s individual needs. This process is ongoing and an important ingredient in achieving optimal nutrition for a lifetime.

Low 1,600 Mod 2,200 High 2,800 Grain Group Servings 6 9 11 Vegetable Group Servings 3 4 5 Fruit Group Servings 2 Milk Group Servings 2-3 Meat Group (ounces) 7 Total Fat (grams) 53 73 93 Total Added Sugars (teaspoons) 12 18 Women who are pregnant or breastfeeding, teenagers, and young adults to age 24 need 3 servings of Dairy or other Calcium-rich foods. “Meat” group amounts are in total ounces. The USDA has also designed a chart of three sample diets indicating the number of servings corresponding with one’s caloric needs.

22 Standards For Food Labeling
RDA not used on food label since it is gender and age specific FDA developed the Daily Values Reference Daily Intake (RDI) for vitamins and minerals Daily Reference Value (DRV) for nutrients without RDAs Only used on food labels

23 Reading Food Labels

24 Nutritional Assessment Why?
The purpose of nutritional assessment is to: Identify individuals or population groups at risk of becoming malnourished who are malnourished

25 Nutritional Assessment Why? 2
To develop health care programs that meet the community needs which are defined by the assessment To measure the effectiveness of the nutritional programs & intervention once initiated

26 Direct Methods of Nutritional Assessment
These are summarized as ABCD Anthropometric methods Biochemical, laboratory methods Clinical methods Dietary evaluation methods

27 Anthropometric Methods
Anthropometry is the measurement of body height, weight & proportions. It is an essential component of clinical examination of infants, children & pregnant women. It is used to evaluate both under & over nutrition. The measured values reflects the current nutritional status & don’t differentiate between acute & chronic changes .

28 Other anthropometric Measurements
Mid-arm circumference Skin fold thickness Head circumference Head/chest ratio Hip/waist ratio

29 Anthropometry for children
Accurate measurement of height and weight is essential. The results can then be used to evaluate the physical growth of the child. For growth monitoring the data are plotted on growth charts over a period of time that is enough to calculate growth velocity, which can then be compared to international standards

30 Measurements for adults
Height: The subject stands erect & bare footed on a stadiometer with a movable head piece. The head piece is leveled with skull vault & height is recorded to the nearest 0.5 cm.

31 WEIGHT MEASUREMENT Use a regularly calibrated electronic or balanced-beam scale. Spring scales are less reliable. Weigh in light clothes, no shoes Read to the nearest 100 gm (0.1kg)

32 Nutritional Indices in Adults
The international standard for assessing body size in adults is the body mass index (BMI). BMI is computed using the following formula: BMI = Weight (kg)/ Height (m²) Evidence shows that high BMI (obesity level) is associated with type 2 diabetes & high risk of cardiovascular morbidity & mortality

33 BMI (WHO - Classification)
BMI < 18.5 = Under Weight BMI = Healthy weight range BMI = Overweight (grade 1 obesity) BMI >30-40 = Obese (grade 2 obesity) BMI >40 =Very obese (morbid or grade 3 obesity)

34 Waist/Hip Ratio Waist circumference is measured at the level of the umbilicus to the nearest 0.5 cm. The subject stands erect with relaxed abdominal muscles, arms at the side, and feet together. The measurement should be taken at the end of a normal expiration.

35 Waist circumference Waist circumference predicts mortality better than any other anthropometric measurement. It has been proposed that waist measurement alone can be used to assess obesity, and two levels of risk have been identified MALES FEMALE LEVEL > 94cm > 80cm LEVEL > 102cm > 88cm

36 Waist circumference/2 Level 1 is the maximum acceptable waist circumference irrespective of the adult age and there should be no further weight gain. Level 2 denotes obesity and requires weight management to reduce the risk of type 2 diabetes & CVS complications.

Objective with high specificity & sensitivity Measures many variables of nutritional significance (Ht, Wt, MAC, HC, skin fold thickness, waist & hip ratio & BMI). Readings are numerical & gradable on standard growth charts Readings are reproducible. Non-expensive & need minimal training

38 Limitations of Anthropometry
Inter-observers errors in measurement Limited nutritional diagnosis Problems with reference standards, i.e. local versus international standards. Arbitrary statistical cut-off levels for what considered as abnormal values.

39 DIETARY ASSESSMENT Nutritional intake of humans is assessed by five different methods. These are: 24 hours dietary recall Food frequency questionnaire Dietary history since early life Food dairy technique Observed food consumption

40 24 Hours Dietary Recall A trained interviewer asks the subject to recall all food & drink taken in the previous 24 hours. It is quick, easy, & depends on short-term memory, but may not be truly representative of the person’s usual intake

41 Food Frequency Questionnaire
In this method the subject is given a list of around 100 food items to indicate his or her intake (frequency & quantity) per day, per week & per month. inexpensive, more representative & easy to use.

42 Food Frequency Questionnaire/2
Limitations: long Questionnaire Errors with estimating serving size. Needs updating with new commercial food products to keep pace with changing dietary habits.

43 DIETARY HISTORY It is an accurate method for assessing the nutritional status. The information should be collected by a trained interviewer. Details about usual intake, types, amount, frequency & timing needs to be obtained. Cross-checking to verify data is important.

44 FOOD DAIRY Food intake (types & amounts) should be recorded by the subject at the time of consumption. The length of the collection period range between 1-7 days. Reliable but difficult to maintain.

45 Observed Food Consumption
The most unused method in clinical practice, but it is recommended for research purposes. The meal eaten by the individual is weighed and contents are exactly calculated. The method is characterized by having a high degree of accuracy but expensive & needs time & efforts.

46 Initial Laboratory Assessment
Hemoglobin estimation is the most important test, & useful index of the overall state of nutrition. Beside anemia it also tells about protein & trace element nutrition. Stool examination for the presence of ova and/or intestinal parasites Urine dipstick & microscopy for albumin, sugar and blood


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