Proteins
Published by Bupa's health information team, healthinfo@bupa.com, April 2008
Proteins are needed by your body for growth and tissue repair. Choosing healthy sources of protein and making sure you have the right amount will help to keep you in good shape.
What are proteins?
Proteins are found in many foods. They are complex substances made up of small units called amino acids. Different foods contain different types of amino acids, in varying amounts.
What do proteins do?
The protein in your diet is broken down into amino acids. These are used in tissue and muscle development, as well as tissue repair. Amino acids are also a good source of energy. Your bones, muscles and tissue walls all need a good supply of amino acids in order to stay healthy.
Where are proteins found?
Meat and fish are excellent sources of protein. You can also get protein from cereals, dairy products, eggs, nuts, lentils, peas, beans and some other vegetables.
The proteins in meat and fish are called complete proteins, because they provide all the amino acids your body needs. The proteins from plants are called incomplete proteins, because no single plant contains all the amino acids your body needs.
Can a vegetarian diet provide enough protein?
It's perfectly possible to get all the amino acids you need from a vegetarian diet, provided you eat a good variety of eggs, dairy products, pulses, cereals and vegetables.
Soya and soya products are particularly good sources of protein for vegetarians and vegans, as they contain the most complete of all plant proteins. If you don't eat dairy products, try soya, rice or oat milk fortified with calcium instead.
Try to eat a variety of protein sources for each meal, such as:
- beans on wholemeal toast
- houmous with pitta bread
- vegetable bean chilli with rice
- home-made vegetable burgers made from soya mince
How much protein do I need?
Nutritional needs vary from person to person, depending on gender, age and activity levels.
The UK Department of Health gives guidance on the correct levels of nutrient in the diet although these are not exact recommendations. The recommended daily intake of protein for adult men (aged 19 to 50) is 55.5 grams (g) and 45g for women of the same age group. According to the British Nutrition Foundation, the average British man eats 88g of protein per day and the average woman 64g. There's no evidence that eating this amount of protein is harmful to your health, however, the Department of Health recommends that your protein intake doesn't exceed twice the recommended daily intake.
Two-thirds of our protein intake in the UK comes from meat and meat products, including eggs and dairy. These foods can contain high levels of saturated fat, which may contribute to heart disease. Remember to include other valuable sources of protein in your diet as well, such as fish, cereals, bread, nuts, seeds, pulses and soya.
Can I have too little protein?
Normally, your body prefers to use carbohydrates and fat as sources of energy. However, if you are not eating enough calories, your body will begin to use the protein stored in your muscles as an energy source instead. This will make your muscles weak and flabby. People who are dieting and severely restricting their calorie intake run this risk.
Can I have too much protein?
Some diet books recommend eating a high-protein diet as a way to lose weight, but according to MRC Human Nutrition Research, there is no real evidence that this actually works. You shouldn't eat too much protein, especially if you have liver or kidney problems, as these can become overloaded. Also, if your main source of protein is meat and dairy products - which often contain a lot of saturated fat - you increase your risk of developing heart disease.
Further information
Food Standards Agency
020 7404 6504
www.eatwell.gov.uk
Weightwise
www.bdaweightwise.com
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