After water, protein is the main component of every cell in our body.

Why we need protein and the important role protein plays in our body

What is protein?

After water, protein is a major component of every cell in our body. Along with fat and carbohydrates, protein is a macronutrient we consume in our diet to supply the body with the 20 amino acids it needs to form the various proteins our body requires to build and repair tissues and make enzymes, hormones and other chemical compounds within our body.
Protein is found in a wide range of plant-based and animal foods. Animal protein includes meat, poultry, fish, eggs and dairy foods, while plant proteins include nuts, seeds, legumes and whole grains as well as small amounts in some vegetables. All essential amino acids (the ones our body cannot synthesise itself) can be obtained from plant protein sources.

The important role protein plays in our body and why we need it

The important role protein plays in our body and why we need it
Protein is arguably the most important nutrient required by the human body (except maybe water) as it vital for many important functions:

Muscle mass and tone
Muscles allow movement within the body; they connect to the bone via tendons and contract to create movement. When we exercise our muscle fibres tear. Dietary protein is used to synthesis muscle protein, rebuilding the muscle, and growing stronger muscle fibres. To build muscle mass and tone, adequate protein intake is important to ensure muscle growth exceeds muscle breakdown (1). Higher protein intake is also linked with reduced sarcopenia in older adults (2).

Energy
Like carbohydrates and fat, protein is a macronutrient and provides our body with a source of energy. When we have utilised all carbohydrate stores, the body will draw on protein as its fuel source

Heart Health
The heart is a muscle, therefore, requires adequate protein to maintain health and strength. Dietary protein intake may affect overall heart health when it comes to the type of protein we consume. Processed meats such as sausages, ham and bacon are high in saturated fat and salt. This is linked with higher rates of heart disease and high cholesterol levels, though lean animal cuts and plant-based proteins such as legumes, nuts, seeds, soy and whole grains may lead to lower blood pressure and LDL and total cholesterol levels (3).

Bone Health
Protein, calcium and Vitamin D are the key elements needed for strong bones. Bones are made up of collagen – a protein and bound together by calcium and phosphate and other trace elements like magnesium. Diets higher in protein have been associated with decreased bone loss and improved calcium reabsorption needed to continue to build strong bones and prevent osteoporosis. Higher protein intakes are also linked with reduced bone fracture incidence (4).

Satiety & weight control
Higher protein diets have been shown to have beneficial effects on weight control through several mechanisms. Increased protein intake increases the satiety hormone leptin after a meal (5), therefore results in lower caloric intake through the day. High protein meals reduce food cravings when compared with high carbohydrate meals (6).

Immunity system function
When we are sick our body creates antibodies to help fight infection. Protein is important for a healthy immune system, and specific amino acids have been shown to have a vital role in immune system function -(8).

References

1. Phillips, S., Hartman, J. and Wilkinson, S. (2005). Dietary protein to support anabolism with resistance exercise in young men. Journal of the American College of Nutrition, 24(2), pp. 134S–139S.

2. Deutz, N.E., et al. (2014). Protein intake and exercise for optimal muscle function with ageing: Recommendations from the ESPEN Expert Group. Clinical Nutrition, 33(6), pp. 929–936.

3. Appel, L., et al. (2005). Effects of protein, monounsaturated fat, and carbohydrate intake on blood pressure and serum lipids. JAMA, 294(19), p. 2455

4. Rizzoli, R. and Bonjour, J. (2004). Dietary Protein and Bone Health. Journal of Bone and Mineral Research, 19(4), pp. 527–531.

5. Dhillon J et al. (2016). The Effects of Increased Protein Intake on Fullness: A Meta-Analysis and Its Limitations. J Acad Nutr Diet, 116(6), pp. 968-83.

6. Gwin JA, Maki KC, Leidy HJ. (2017). Increased Protein Consumption during the Day from an Energy- Restricted Diet Augments Satiety but Does Not Reduce Daily Fat or Carbohydrate Intake on a Free- Living Test Day in Overweight Women. J Nutr, 147(12), pp. 2338-2346.

7. Wycherley TP, Moran LJ, Clifton PM, Noakes M, Brinkworth GD. (2012). Effects of energyrestricted high-protein, low-fat compared with standard-protein, low-fa diets: a metaanalysis of randomized controlled trials. Am J Clin Nutr. 96(6), pp. 1281-98

8. Daly, J.M., et al. (1990). Effect of dietary protein and amino acids on immune function. Critical Care Medicine. 18:S86–S93.

Muscle mass and tone
Muscles allow movement within the body; they connect to the bone via tendons and contract to create movement. When we exercise our muscle fibres tear. Dietary protein is used to synthesis muscle protein, rebuilding the muscle, and growing stronger muscle fibres. To build muscle mass and tone, adequate protein intake is important to ensure muscle growth exceeds muscle breakdown (1). Higher protein intake is also linked with reduced sarcopenia in older adults (2).

Energy
Like carbohydrates and fat, protein is a macronutrient and provides our body with a source of energy. When we have utilised all carbohydrate stores, the body will draw on protein as its fuel source.

Heart Health
The heart is a muscle, therefore, requires adequate protein to maintain health and strength. Dietary protein intake may affect overall heart health when it comes to the type of protein we consume. Processed meats such as sausages, ham and bacon are high in saturated fat and salt. This is linked with higher rates of heart disease and high cholesterol levels, though lean animal cuts and plant-based proteins such as legumes, nuts, seeds, soy and whole grains may lead to lower blood pressure and LDL and total cholesterol levels (3).

Bone Health
Protein, calcium and Vitamin D are the key elements needed for strong bones. Bones are made up of collagen – a protein and bound together by calcium and phosphate and other trace elements like magnesium. Diets higher in protein have been associated with decreased bone loss and improved calcium reabsorption needed to continue to build strong bones and prevent osteoporosis. Higher protein intakes are also linked with reduced bone fracture incidence (4).

Satiety & weight control
Higher protein diets have been shown to have beneficial effects on weight control through several mechanisms. Increased protein intake increases the satiety hormone leptin after a meal (5), therefore results in lower caloric intake through the day. High protein meals reduce food cravings when compared with high carbohydrate meals (6).

Immunity
When we are sick our body creates antibodies to help fight infection. Protein is important for a healthy immune system, and specific amino acids have been shown to have a vital role in immune system function -(8).