Recommended Dietary Allowance
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.
The table below shows the recommended dietary intake for males or females between 19 and 30 years old.
Recommended dietary allowance of vitamins
|Nutrient||RDA (Male)||RDA (Female)||Unit||Top Sources|
|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|
|Vitamin E||15||15||milligrams||fortified cereals, tomato paste, sunflower seeds|
|Calcium||1000||1000||milligrams||fortified cereals, cow’s milk, cheese, orange juice|
|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|
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||3.7 L/day||2.7 L/day||water|
|Carbohydrates||130 g/day||130 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||15||20% – 35% of total calories consumed*||sunflower oil, olive oil, butter, margarine, lard, avocados, coconut, nuts, seeds, oily fish|
|Cholesterol||As low as possible||egg yolk, chicken giblets, turkey giblets, beef liver|
*calories: a measure of energy consumption
Did you know?
Malnutrition, which is the lack of a balanced diet, is a major problem in Nigeria. 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 newborn babies are unique. A major challenge in some countries is to encourage women to breastfeed children for their first six months after birth. In South Africa, for example, only 25% of babies are breastfed in this way. This leads to high levels of malnutrition, diarrhoea and poor growth.
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.
Investigation: Measuring Your Daily Nutrient Intake
- 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|
|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|