FOOD NUTRITION: NUTRIENT CLASSES
Diagram
Nutrients needed in grams, and nutrients needed in milligrams
Macronutrients
Carbohydrate, protein and fat. Needed in grams, and they give energy and build the body.
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Micronutrients
Vitamins and minerals. Needed in milligrams or less, and they give no energy, but they make body processes work.
Figure 1: Macronutrients give energy and are needed in grams, while micronutrients give no energy and are needed in milligrams. Drawn in our own style from the nutrient discussion in Gropper et al., Advanced Nutrition and Human Metabolism, and in the Encyclopedia of Human Nutrition.
Introduction
Macronutrients and micronutrients are both nutrients, which means both are substances in food the body needs, but they differ in how much is needed and what they do. Macronutrients are carbohydrate, protein and fat: they are needed in grams each day, and they give energy and build the body. Micronutrients are vitamins and minerals: they are needed in milligrams or less each day, they give no energy, and they act as helpers that make the body processes work. Water is also needed in large amounts, but the books used here class the energy nutrients as macronutrients and the vitamins and minerals as micronutrients.
Quick comparison
Table 1: Macronutrients compared with Micronutrients
| Aspect | Macronutrients | Micronutrients |
|---|---|---|
| Which nutrients | Carbohydrate, protein and fat | Vitamins and minerals |
| Amount needed | Grams each day | Milligrams or less each day |
| Give energy | Yes, they are the energy nutrients | No, they give no energy |
| Main role | Energy, building and repair of the body | Helpers for enzymes, bones, blood and body processes |
| Measured in | Grams | Milligrams or micrograms |
| Deficiency | Lack of energy and loss of body tissue | A named deficiency disease or a failed body process |
| Stored | Fat is stored in body fat, protein in muscle | Some are stored, such as fat-soluble vitamins and iron, and some are not |
| In food | They make up most of the weight of food | They make up a tiny part of the weight of food |
| Examples in food | Bread and rice for carbohydrate, meat and beans for protein, oil for fat | Citrus for vitamin C, milk for calcium, liver for iron and vitamin A |
| Eaten in excess | Stored as fat, or used for energy | Some are passed out, some build up in storage |
Scientific explanation
Definition
Macronutrients are the nutrients needed in large amounts, carbohydrate, protein and fat, which give energy and build the body. Micronutrients are the nutrients needed in small amounts, vitamins and minerals, which give no energy but are needed for body processes to work.
Working principle
Macronutrients work as fuel and as building material: carbohydrate and fat are burned for energy, protein is used to build and repair muscle, enzymes and other body proteins, and fat is stored for later energy. Micronutrients work as helpers: many vitamins act as coenzymes that enzymes need to do their work, and minerals such as calcium build bones, iron carries oxygen in the blood, and iodine is needed to make thyroid hormones. Without micronutrients the macronutrients cannot be used properly, because the enzymes that burn them need their vitamin and mineral helpers.
Apparatus
The books used here name no laboratory apparatus for measuring or comparing either term, so no apparatus list is given.
Measurement procedure
The books used here give no standard laboratory procedure with volumes and steps for either term, so no procedure is invented here.
Factors affecting readings
For macronutrients, the mix of foods eaten decides the energy and the protein supply: a diet of staple grains gives carbohydrate, while meat, milk and pulses give protein. For micronutrients, the variety of the diet decides the supply: a diet of one staple food lacks the vitamins and minerals that other foods carry, and cooking in water loses water-soluble vitamins. The books used here give no intake numbers, so none are stated.
Formulas and calculations
The books used here give no formula for either term, so no formula is given here.
Industrial applications
- Macronutrients: staple grains and roots, eaten as the main source of carbohydrate energy.
- Macronutrients: meat, milk, pulses and oils, eaten as sources of protein and fat.
- Micronutrients: fruits and vegetables, eaten as sources of vitamin C, folate and minerals.
- Micronutrients: fortified foods, where vitamins and minerals are added to milk, flour and salt.
- Both kinds: a varied diet, which is the only way to cover macronutrients and micronutrients together.
Advantages and limitations
- Macronutrients, advantage: they give the energy and the building material the body runs on.
- Macronutrients, limitation: eaten in excess they are stored as fat, and a diet of one macronutrient alone cannot meet the need for the others.
- Micronutrients, advantage: tiny amounts keep enzymes, bones, blood and nerves working.
- Micronutrients, limitation: they give no energy, so they cannot replace food, and a diet of one staple food can lack them even when energy is enough.
FAQ
What is the difference between macronutrients and micronutrients?
Macronutrients are carbohydrate, protein and fat, needed in grams and giving energy, while micronutrients are vitamins and minerals, needed in milligrams and giving no energy.
Which are the macronutrients?
Carbohydrate, protein and fat.
Which are the micronutrients?
Vitamins and minerals.
Do micronutrients give energy?
No. They give no energy, but they help the body use the macronutrients.
Can a diet give enough energy but lack micronutrients?
Yes. A diet of one staple food can give enough calories yet lack vitamins and minerals.
References and further reading
- Gropper, Sareen S., Jack L. Smith and Timothy P. Carr. Advanced Nutrition and Human Metabolism. 7th ed., Cengage, 2016.
- Encyclopedia of Human Nutrition. 3rd ed., Academic Press, 2012.
- Google Books pages read for this article:
- Gropper, Sareen S., Jack L. Smith and Timothy P. Carr. Advanced Nutrition and Human Metabolism. 7th ed., Cengage, 2016 (Google Books page read)
