Nutrition Basics: Proteins


Proteins are complex molecules that make up tissues of the body such as muscle mass, bones, blood and hormones. They are constantly being broken down, repaired, replaced or maintained, this is how we can manipulate the size and shape of our muscle with training!

In are body proteins are composed of amino acids – they are nitrogen-containing building blocks that form proteins. There are 2 classes of amino acids:

1. Essential Amino Acids

These must come from your diet because the body cannot make them. They include:

Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine.

2. Nonessential Amino Acids

These can be manufactured by the body in sufficient quantities. They include:

Alanine, Arginine, Asparagine, Aspartic Acid ,Cysteine, Glutamic Acid, Glutamine, Glycine, Proline, Serine, Tyrosine.

The body can synthesize nonessential amino acids through a process called transamination (where the amine group from one amino acid is removed and transferred onto another acid and side chain)

Common sources of dietary protein include (non-vegetarian) beef, pork, poultry, seafood, (ovo-lacto vegetarian) eggs, (vegan) beans/legumes, tofu, nuts and dairy products. The quality of protein depends upon the protein efficiency ratio, protein digestibly, corrected amino acid score and the net protein utilisation.

Factors that affect protein quality include the amount of essential amino acids and the digestibility. Animal and dairy protein sources are highly digestible. Complementary proteins occur when at least 2 foods are combined and together contain all 9 essential amino acids required to make a complete protein. Examples include rice and legumes – rice is low in lysine but high in methionine – conversely, legumes are low in methionine but high in lysine. Other examples include peanut butter and bread, rice and lentils, etc.

Protein is vital to cell growth, maintenance and repair and many people do not consume a diet adequate in dietary protein particularly when training hard which is needed as the turnover of cells is so constant.

Protein plays an important role throughout the body, for example:

Enzymes are proteins and enzymes are catalysts of chemical reactions in the body.

Some hormones, such as insulin, are composed of amino acids. The immune system also relies on proteins. Antibodies are made of proteins and they help fight against foreign bacteria, viruses, allergens and toxins. Proteins also play a role in fluid balance and blood pressure regulation. If protein intake is insufficient, low levels of proteins in the blood will not be able to draw fluid from the tissues and across the blood vessels. Therefore, a condition known as edema can occur as seen with a swollen appearance from fluid collecting inside the tissues.

So, how much do you need?

The Recommended Dietary Allowance (RDA) for sedentary adults is 0.8 grams of protein per kilogram body weight (1kg = 2.2lbs). For example: 154lb female = 132/2.2 = 70kg 70kg female = 56g of protein per day Dietary protein needs change with type, level, and intensity of activity. Also, certain health conditions and injuries (i.e. pregnancy, lactating, broken bones, burns, etc.) will change the protein requirements. The Acceptable Macronutrient Distribution Range (AMDR) for protein for sedentary adults (>19 years) is 10-35% of daily calories coming from protein. Recommendations more centered on exercise and fitness have also been provided by leading organizations. The position of the International Society of Sport Nutrition that exercising individuals ingest protein ranging from 1.4 to 2.0 g/kg/day. Individuals engaging in endurance exercise should ingest levels at the lower end of this range, individuals engaging in intermittent activities should ingest levels in the middle of this range, and those engaging in strength/power exercise should ingest levels at the upper end of this range.

Ideas for Protein Recipes?

Try these recipes below for some ideas on high protein snacks or baked goods!

Protein Cookies

Protein Packed Banana Bread

Sweet Potato and Quinoa Brownies

10 Healthy On The Go Snacks For Busy Riders!

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