Food composition is the detailed breakdown of the nutrients and other components found in a food. Knowing what a food is made of helps us plan balanced meals, manage health conditions and understand how cooking and processing affect the food we eat. The main components analysed in food composition are described below.
1. Macronutrients
- Carbohydrates: Provide energy and are found in staples such as rice, maize, plantain, cassava and legumes. They are broken down into sugars, starches and fibre.
- Proteins: Needed for growth, repair and maintenance of body tissues. Found in fish, meat, eggs, milk, beans and groundnuts. Proteins are made of amino acids, some of which must come from the diet.
- Fats: Supply concentrated energy, support cell growth and help absorb certain vitamins. Found in palm oil, groundnut oil, avocado, nuts and fatty fish. Fats include saturated, unsaturated and trans fats.
2. Micronutrients
- Vitamins: Organic compounds needed in small amounts for many body functions, such as vitamin C (ascorbic acid), vitamin A (retinol) and the B vitamins (including B12 and folate).
- Minerals: Inorganic elements essential for health, including calcium, potassium, iron, magnesium and zinc. They support bone health, fluid balance and enzyme activity.
3. Water
Water is essential for all body functions, including digestion, nutrient absorption and temperature control. It makes up a large part of most foods, especially fruits and vegetables.
4. Fibre
Dietary fibre is a type of carbohydrate that human enzymes cannot digest. It is found in fruits, vegetables, whole grains and legumes such as beans. Fibre aids digestion, helps regulate blood-sugar levels and can lower cholesterol.
5. Phytochemicals
These are bioactive compounds from plants that give health benefits beyond basic nutrition, such as flavonoids and carotenoids. They are found in fruits, vegetables, herbs and spices.
6. Additives and Preservatives
- Additives: Natural or artificial ingredients added to improve flavour, colour, texture or shelf life, such as salt, sugar and flavourings.
- Preservatives: Substances that extend shelf life by preventing spoilage. They may be natural (like vinegar or salt) or synthetic (like sodium benzoate).
7. Energy Content
The energy a food provides is measured in calories (kilocalories), and comes from carbohydrates, proteins and fats. Energy content is important for managing weight and overall health.
8. Water-Soluble and Fat-Soluble Components
- Water-soluble: Vitamin C and the B vitamins dissolve in water. They are not stored in the body and are passed out in urine, so they must be eaten regularly.
- Fat-soluble: Vitamins A, D, E and K dissolve in fat and are stored in body tissues.
9. Flavour and Aroma Compounds
Volatile compounds such as essential oils and esters are responsible for the smell and taste of food and shape our overall enjoyment of it.
10. Texture Components
Fibres and starches affect the texture and mouthfeel of food and how it behaves during cooking. For example, the texture of bread is influenced by its gluten and starch.
The Food Composition Table
A food composition table sets out the nutrients and other components present in different foods. Nutritionists, dietitians, researchers and consumers use these tables to make informed dietary choices. The table below is a simplified example showing the kind of information such a table provides.
| Food item | Serving size | Calories | Protein (g) | Carbohydrates (g) | Fats (g) | Fibre (g) | Sugars (g) | Vitamin C (%DV) | Calcium (%DV) | Iron (%DV) |
|---|---|---|---|---|---|---|---|---|---|---|
| Apple | 1 medium (182 g) | 95 | 0.5 | 25 | 0.3 | 4.4 | 19 | 14 | 1 | 1 |
| Chicken breast | 3.5 oz (100 g) | 165 | 31 | 0 | 3.6 | 0 | 0 | 0 | 1 | 4 |
| Broccoli | 1 cup (91 g) | 55 | 4 | 11 | 0.6 | 5.1 | 2 | 135 | 6 | 5 |
| Rice (white) | 1 cup cooked (158 g) | 205 | 4 | 45 | 0.4 | 0.6 | 0 | 0 | 2 | 2 |
| Salmon | 3.5 oz (100 g) | 206 | 22 | 0 | 13 | 0 | 0 | 0 | 2 | 5 |
| Almonds | 1 oz (28 g) | 160 | 6 | 6 | 14 | 3.5 | 1 | 0 | 8 | 6 |
%DV = percentage of the recommended daily value. The figures above are a standard illustrative example; actual values vary with the variety of food and how it is prepared.
Explanation of the Columns
- Food item: The name of the food being analysed.
- Serving size: The amount of food the nutritional information refers to.
- Calories: The total energy the food provides, measured in kilocalories (kcal).
- Protein (g): The amount of protein, important for tissue repair and growth.
- Carbohydrates (g): The total carbohydrates, which provide energy; this includes fibre and sugars.
- Fats (g): The total fat content, including saturated and unsaturated fats.
- Fibre (g): Dietary fibre, which aids digestion and supports health.
- Sugars (g): The amount of simple sugars present.
- Vitamin C (%DV): The share of the daily vitamin C requirement provided by one serving (based on about 60 mg per day).
- Calcium (%DV): The share of the daily calcium requirement per serving (based on about 1,000 mg per day).
- Iron (%DV): The share of the daily iron requirement per serving (based on about 18 mg per day).
How to Use a Food Composition Table
- Compare nutrients: Compare the nutrient content of different foods. For example, to increase protein intake you might choose fish or chicken over an apple.
- Monitor intake: Track how much of a particular nutrient, such as fibre or iron, you are eating to meet your dietary goals.
- Balance your diet: Use the information to combine macronutrients and micronutrients in each meal.
- Meet health goals: Adjust your diet to suit a goal, such as reducing fat or increasing iron for better energy levels.
Food composition tables are available from government nutrition databases, food manufacturers and nutrition textbooks. They are valuable tools for understanding and managing what we eat.
