by Hannah Ng’uni
Today, we take a closer look at another food group essential for a healthy balanced diet. Fun fact, the word ‘protein’ is derived from the Greek word “proteios” and was invented by a Dutch chemist Mulder in 1838, it means ‘of prime importance.
Proteins – the basics
Protein is present is in plant and animal cells; these large, complex molecules are made up of building blocks called amino acids which are linked together to form long chains. The body links the amino acids in different sequences to form a variety of proteins, the function of a specific protein is determined by the type and sequence of the amino acids in that protein. There are 20 amino acids, some of these are produced by the body and others must be obtained from our diet.
When we eat protein foods, digestion begins in the stomach were the acid starts to break down the structure of the protein then through to the small intestine, these are further broken down by enzymes into individual amino acids and absorbed into the bloodstream were there are transported to our cells and tissues. Once here, the amino acids are assembled again to form new proteins for specific functions. It is more complex than this but that’s the general overview.
Why eat proteins?
Protein plays several roles in the body, there are thousands of different proteins in the body, each one has a specific function. Some of the main functions are summarised below.
- Repair and maintenance of body tissue. Hair, skin, eyes, muscles and organs are all made from protein.
- A source of energy if consumed in excess of what is required for body tissue maintenance.
- Creation of protein hormones such as insulin which controls blood sugar levels.
- The enzymes that increase the rate of chemical reactions in the body are proteins. There are thousands of enzymes, some help in digestion of food and creation of DNA etc.
- Involved in the transportation of the protein haemoglobin which carries oxygen around the body. Other proteins carry certain vitamins and minerals.
- Forms antibodies that help prevent infections, illness and disease by identifying and attacking bacteria and viruses. When your daily diet is low in protein, the body cannot make enough antibodies which can lead to a weakened immune response.
It is important to include a variety of protein foods in your healthy balanced diet to maintain body functions and stay in good health. But as with the other food groups, portion sizes, the quality or source of protein and method of preparation or what it is served with all contribute to the overall nutritional quality of the diet as these foods will contain other nutrients as well.
Sources include meat, fish, chicken, dairy foods, and soya alternatives e.g., milk and yoghurt, eggs, beans, peas, lentils, nuts, seeds, tofu.
Note that protein needs also vary through the life stages i.e., infants, adults, pregnant and breastfeeding, older adults, athletes, or when critically unwell.
Top tips from the Eatwell Guide (2016) and British Nutrition Foundation:
- Aim for 2 – 3 portions of protein foods (pink section) and 2-3 portions from dairy and alternative group (blue section)
- Choose lean cuts of meat and mince, and eat less red and processed meat like bacon, ham and sausages.
- Aim for at least 2 portions of fish every week, 1 of which should be oily, such as salmon or mackerel.
- Plant based sources are good alternatives to meat because they’re lower in fat and higher in fibre and protein.
Protein is an essential nutrient in a healthy balanced diet and helps our body’s organs and systems to function optimally. Protein is found in both animal and plant food sources therefore it is beneficial to include a variety of sources in the diet. It is advisable to consult your GP if you have any medical conditions before making changes to your diet.
British Nutrition Foundation (2021) Protein. https://www.nutrition.org.uk/healthy-sustainable-diets/protein/