1.6 Recommended Dietary Allowance
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1.6 Recommended Dietary Allowance (ESG4J)
In order to ensure that we consume adequate quantities of all the food types, nutritionists have compiled a list of guidelines known as the Recommended Dietary Allowance (RDA). The RDA defines the required intake of each nutrient type to meet the basic nutrient needs of almost all individuals in a gender group at a given life stage.
In order to ensure that we consume adequate quantities of all the food types, nutritionists have compiled a list of guidelines known as the Recommended Dietary Allowance (RDA). The RDA defines the required intake of each nutrient type to meet the basic nutrient needs of almost all individuals in a gender group at a given life stage. Food companies are required to advertise the nutrient composition on all products sold. This allows consumers to decide whether to purchase the food item. Table 1.6 shows the recommended dietary intake for males or females between 19 and 30 years old.
TEACHERS NOTE:
Learners DO NOT need to learn this table by heart, but they must be able to use it and interpret it if they are given such a table in tests / exams.
Recommended dietary allowance of vitamins and minerals
Nutrient | RDA (Male) | RDA (Female) | Unit | Top Sources |
Vitamins | ||||
Vitamin A | 900 | 700 | micrograms | carrots, carrot juice, turkey, pumpkin |
Vitamin C | 75 | 75 | milligrams | orange juice, grapefruit juice, bell peppers |
Vitamin D | 5 | 5 | micrograms | cereals, mushrooms, yeast, salmon, swordfish, trout, fish liver oil |
Vitamin E | 15 | 15 | milligrams | fortified cereals, tomato paste, sunflower seeds |
Minerals | ||||
Calcium | 1000 | 1000 | milligrams | fortified cereals, cow's milk, cheese, orange juice |
Iodine | 150 | 150 | micrograms | iodised salt |
Iron | 18 | 18 | milligrams | liver, pilchards, red meat, spinach |
Phosphorous | 700 | 700 | milligrams | maize-meal, milk, wheat flour |
Potassium | 4700 | 4700 | milligrams | potatoes, bananas, tomato paste, orange juice |
Sodium | 1500 | 1500 | milligrams | onion soup mix, table salt |
Macronutrients
The table below shows the relative quantities of macronutrients recommended for average adult (25-year old) male and female individuals.
Substance | Amount (males) | Amount (females) | Sources of nutrient |
Water | 2 L/day | 2 L/day | water |
Carbohydrates | 300 g/day | 230 g/day | rice, potatoes, pasta, bread, mealie meal, fruits |
Protein | 56 g/day | 46 g/day | duck, chicken, turkey, beef, fish, eggs, legumes (pulses and lentils), nuts, seeds, milk |
Fat | 70 g | 70 g | sunflower oil, olive oil, butter, margarine, lard, avocados, coconut, nuts, seeds, oily fish |
Cholesterol | As low as possible | As low as possible | egg yolk, chicken giblets, turkey giblets, beef liver |
Malnutrition, which is the lack of a balanced diet, is a major problem in South Africa. Key vitamins have been added to wheat and maize-meal in order to provide the recommended amounts. Iodine has been added to salt.
The nutritional needs of new-born babies are unique. A major challenge in South Africa is to encourage women to breastfeed children for their first six months after birth. Only \(\text{25}\%\) of babies are breastfed in this way. This leads to high levels of malnutrition, diarrhoea and poor growth.
What makes up a balanced diet?
Working out your daily nutrient intake
From our understanding of recommended dietary allowance we can understand what it is we consume and how important it is to our diet. The activity below requires you to use the information provided in these tables (and any other information you can find) in order to evaluate your diet with regards to the recommended daily allowances.
Measuring your daily nutrient intake (Essential investigation- CAPS)
- Keep a food diary for 3 days by writing down the food you eat. Make sure to note the time you eat, the type of food you eat, and how much of it you consume.
- Pick one of the days you recorded (that is the most typical of your normal diet), and draw a pie chart with the energy component of each food item you consumed. Make sure your pie chart includes a key. (See the Introduction to Life Skills Chapter if you are unsure of how to do this.)
- Draw another table with each food class (vitamins, proteins, carbohydrates, etc) listed. In one column, list the recommended dietary allowance and in the next column list the estimated amount of the food type you consume on a daily basis.
- Which food types do you consume in excess? Which ones do you consume too little of? What are the consequences of each?
The table below lists the energy components of some common food items. Study it and answer the following questions:
- Which food has the highest energy value? Why?
- Name the key food items you would include in a balanced diet
Nutrient composition of some common foods
Food type | Energy (kJ) | Protein (g) | Carbohydrate (g) | Total Fat (g) | Sodium (mg) | Iron (mg) | Vitamin A (IU) | Vitamin C (mg) |
rice, brown (250 ml) | 969 | 5 | 48 | 2 | 10 | 0.9 | 0 | 0 |
Muffin, blueberry (50 g) | 824 | 4 | 34 | 5 | 317 | 1.1 | 24 | 1 |
Beansprouts(250 ml) | 274 | 6 | 14 | 0 | 12 | 2.5 | 41 | 21 |
Carrots raw (1 medium) | 145 | 1 | 8 | 1 | 35 | 0.4 | 22644 | 7 |
Apples, raw, with skin (7cm diameter) | 341 | 0 | 21 | 2.6 | 0 | 0.2 | 73 | 8 |
Egg white, raw (1 egg) | 69 | 3 | 0 | 0 | 54 | 0 | 0 | 0 |
Lamb stew (250 ml) | 914 | 33 | 0 | 9 | 69 | 2.7 | 0 | 0 |
Chicken roasted (1/2 breast) | 218 | 30 | 0 | 10 | 69 | 0.6 | 107 | 0 |
Measuring your daily nutrient intake (Essential investigation- CAPS)
TEACHERS NOTE:
This answers to this activity will be learner-dependent.
Learners may use the Internet to look up food nutritional information, or simply use the information available on food packaging. It is important to note that this is a very complex, and personal activity for learners, and is likely to be challenging for a number of reasons:
- Learner's from poor-income families may be embarrassed to do this activity and list their meals, especially if food is very scarce or basic.
- Learners may be embarrassed by how little, or how much they eat.
- This activity may be difficult for learners struggling with eating disorders, which are prevalent in this age-group, especially amongst teenage girls.
- Obtaining accurate information will be challenging. The energy content of the food type will be affected by the cooking method and will vary tremendously, e.g. mashed potato with butter added vs. boiled potato vs. fried chips vs. oven chips.
- It will be difficult for learners to establish their portion sizes accurately.
- Packaging often only lists the energy content and macronutrients (carbohydrates, protein and fat) in a meal, and very rarely lists vitamins and minerals.
In light of the potential difficulties that may occur during this activity, both social and pragmatic, it is up to the teacher to decide how best to modify and asses this activity.
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