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 |
Table 1.6: RDA for males and females between 19 years and 30 years.
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 of babies are breastfed in this way. This leads to high levels of malnutrition, diarrhoea and poor growth.
Figure 1.23: Breastfeeding infants for first 6 months of life is vital to the infants' survival.
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.
The table below lists the energy components of some common food items. Study it and answer the following questions:
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:
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.