Basics of nutrition

Our food consists of three macronutrients (protein, carbohydrate and fat) and many micronutrients (vitamins and minerals). The macronutrients provide our energy and a lot of the structure of our bodies. The micronutrients are involved in a wide range of systems, hormones and enzymes that keep our bodies running smoothly. We need the right amounts of all of them to function at our very best.



Protein consists of twenty different amino acids. Nine of them are called essential amino acids because our bodies cannot make them and we have to eat them in our food. We are able to create thousands of unique proteins by altering the combinations of different amino acids.

Which part of the body is made of protein?  All of our muscles and connective tissues are made of protein but protein is also used to make skin, hair and our organs. Some of our hormones and enzymes are made of protein. The reading of our DNA is controlled by protein. Antibodies in our immune system are made from protein. Haemoglobin is a protein that transports oxygen in our blood and fats are transported by lipoproteins.


Fat consists of different fatty acids. They vary in length (because of how many carbon atoms are joined together) and in structural stability. Saturated fats are the most stable followed by monounsaturated fatty acids. Polyunsaturated fats are the least stable. There are at least two essential fatty acids that we must eat in our food. (Some experts argue that there are more than two.) 

Which part of the body is made of fat? The membrane, or outer wall, of every cell in our body is made from fat. Thirty per cent of all our cell membranes consist of cholesterol. The membrane controls what goes in and out of each cell. The sheath around all our nerves are made from fat. Sixty per cent of the structure of our brain is made from fat molecules. Vitamin D and all of our sex hormones are made from fat. 


Carbohydrate consists of various sugars. The most common sugar is glucose but our diets can also include fructose and galactose. Sucrose and lactose are combinations of these, while starch (potato, bread, pasta) is a long chain of attached glucose molecules. There are no essential carbohydrates because the liver can make glucose.

Which part of the body is made from carbohydrate? No part of the body is made from carbohydrate. There isn’t any real need to eat it. 



Vitamins are classified as either water-soluble or fat-soluble. There are 13 vitamins that humans need: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). The water-soluble vitamins are easily absorbed but the fat-soluble ones need fat in the diet to transport them into the body from the intestines. Vitamins have a wide range of essential functions and they ensure that the complex systems that operate throughout our bodies are running smoothly. A lack of certain vitamins can lead to dangerous deficiency diseases. It is essential that we eat a variety of fresh foods to ensure adequate intake of vitamins.


Dietary minerals are chemical elements that are essential for optimum function of our bodily systems. In order of abundance in the human body they include calcium, phosphorus, potassium, sodium, chlorine, and magnesium. Others, known as trace elements because they are needed in small amounts, include iron, cobalt, copper, zinc, manganese, molybdenum, iodine, and selenium. As with vitamins, we need to eat a good variety of unprocessed foods to obtain the minerals we need.