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Medikologia / Health  / Basic Nutrition 101: Protein

Basic Nutrition 101: Protein

Written by: Sarah Brown

Whenever chit-chatting with a sedentary person and dietary advice gets into conversation, people often make faces that say “what’s the deal with protein? Isn’t it a bit too much?”

Fact is, among the 3 macronutrients protein occupies first place in weight loss strategies. But why is it? Why can’t it be fat or carbohydrate? It turns out there’re good reasons for it. And this article will teach you all the essentials for better success.

What is protein?

Protein is a polymer, a large macromolecule composed of many repeated subunits. The subunits are made of amino acid sequences. And amino acids are the basic building blocks of protein. Think of them like cement blocks of a house. Its shape is determined by the order, sequence and amount of building blocks. To give you a better understanding of protein appearance, refer to the image below.

As you can see, the primary structure is composed of a chain of amino acids, namely the building blocks of the house (i.e. Met, Asp, Arg, etc.). Zooming out you’ll see how the structure forms a secondary one which can either be a Beta-sheet or an Alpha-helix. Stepping out again, the alpha and beta structures combine to form a third one, which in turn unites with a similar tertiary structure to form a quaternary one. Complex, isn’t it?

Now that we’ve cleared a protein’s basic structural composition, it’s crucial to know the digestive process for us to understand why it occupies the top place in any successful dietary strategy. Below is a simplified step-by-step protein digestion.

1.You eat meat

2.Meat (in the form of bolus) travels though the esophagus

3.Upon arrival at the stomach, acid is released and digestive enzymes are secreted by the pancreas (i.e. proteases and peptidases)

4.Enzymes break down protein into small blocks called amino acids (A.A.)

5.Amino acids are then transported to the bloodstream for absorption by different tissues.

6.A.A. are then absorbed by different cells

7.Once inside a cell, they are organized and re-arranged in different sequences to create a new protein (mediated by a machinery called “ribosome”).

8.The new protein is further used for different functions depending on the cell (i.e. antibody component, muscle tissue, hormone, etc.)

 

Why is protein important?

As you have seen in the example above different processes leading to protein creation is mediated by protein molecules themselves – from hormones, digestive enzymes, cell signaling, and ribosomes. Without these, metabolism alters and bad things occur from simple muscle atrophy to a decrease in lean body mass or worst case scenario – kwashiorkor, a form of protein malnutrition.

Now going down further amino acids are classified into essential and non-essential, this implies the body cannot “synthesize or create” every single molecule on its own. Therefore, emphasizing the importance of proper nutrient intake from several sources.

ESSENTIAL AMINO ACIDSNON-ESSENTIAL AMINO ACIDS
IsoleucineAlanine
HistidineAspargine
LeucineAspartic acid
MethionineCysteine
LysineGlutamic acid
PhenylalanineGlutamine
TryptophanGlycine
ThreonineProline
ValineSerine
Tyrosine

Quality of Protein

The scientific community coins the term “biologic value” when it comes to protein. This is used to assess whether or not a certain food contains all essential amino acids. Animal sources like poultry products (e.g. milk, cheese, eggs) along with fish and meat have a high biologic value, that is, essential amino acids are found in higher quantities. On the other hand plant food possesses a low biologic value due to the poor quantity of essential A.A. However, for vegans it’s always possible to combine different plant products to achieve a value similar to animal protein, for example wheat (which is lysine-deficient but methionine-rich) may be combined with kidney beans (a methionine-poor but lysine-rich food).

 

How much protein do you need?

The Recommended Dietary Allowance (RDA) for protein is 0.8 grams per kilogram of weight. If you weigh 80 kg (176 in pounds), 80kg x 0.8 equals 64 grams of protein.  And that’s the bare minimum for the average NON-EXERCISING population to prevent malnutrition. Simply cook 200 grams of chicken breast and drink a cup of milk. You’ll be good for the day.

But if you’re an active person, increasing the intake is crucial for synthesizing new protein and build a better physique. Fitness professionals recommend at least 0.8 gram per pound of body weight, which puts an average person between 100-150 grams a day. In fact, bodybuilders bring that number to more than twice the normal serving!

 

Is too much protein bad?

As far as research is concerned scientists haven’t found a strong evidence to back up the claim that high intake of protein leads to kidney damage (obviously if you already have a condition affecting the kidneys it’s only natural to decrease protein intake). Bodybuilders have eaten tons of protein for decades, yet, no one has shown up for nephrological related disease up to this day. So is excess protein bad? It’s hard to draw a conclusion. There’s not enough evidence.

 

How about inflammation?

Yes, you’ve probably heard that meat is acidic, which leads to inflammation. And that’s the point of eating veggies. Plant sources are alkaline. Combine them with protein and you’ll neutralize side effects. There’s no escaping it – fruits and vegetables are essential. From a caloric standpoint they may not provide much, but as far as health is concerned, they’ll make your life easier without feeling ill and prone to inflammatory conditions.

 

What makes protein so important in dietary strategies?

As we already emphasized, protein is a nutrient that shouldn’t be taken lightly due to its central role in different metabolic processes. But from a weight loss standpoint, there are two main reasons why it’s essential for success:

Number one:  high protein food provides more satiation compared to fat and carbohydrates alone. Studies have shown people tend to eat less when given protein rich meals due to its satiating effect. In the long run this contributes to lower caloric intake, leading to an increase of caloric expenditure.

Number two: among the 3 macronutrients, protein possesses the highest thermogenic effect. The thermogenic effect of food is a term describing the amount of energy required by the body to digest, absorb, and transport food. If described numerically, protein utilizes roughly 30%, followed by 8% for carbohydrates and 3% for fat. In simple terms whenever you eat around 400 calories worth of protein, 120 will be used just for digesting it!

 

Keypoints To Take Home:

In a nutshell, here’s what you need to remember:

-Protein is a biomolecule composed of small building blocks called amino acids.

-Amino acids (or proteins as a whole) are utilized for different physiologic functions such as cell signaling, hormones, enzymes, and other metabolic processes.

-Amino acids are divided into essential (meaning, the body cannot produces its own) and non-essentials).

-An insufficient amount of daily protein can slow things down and lead to side effects ranging from muscle atrophy to kwashiorkor, a form of protein malnutrition.

-The Recommended Dietary Allowance (RDA) for protein is 0.8 grams per kg (2.2 pounds) for sedentary individuals. But for active persons, at least 0.8 per pound is the minimum.

-Protein does cause inflammation. However, in conjunction with abundant servings of vegetables and fruits daily the negative effect is neutralized.

-Protein possesses the highest thermogenic effect compared to carbs and fat. Thus, your body burns more calories just by digesting it.

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