Protein Absorption

What is Protein?

Protein is a name given to nitrogenous organic compounds that consists of long chains of Amino Acids which form polypeptides. In simple terms they are a macronutrient essential for the building and repair of muscle in our body. They contain around 4 calories per gram, similar to carbohydrates, and are found in meat, pouty, fish, eggs, soy and dairy.

Everyone will have their own individual protein requirements and will metabolise protein at a different rate. This can be influences by such factors as age, activity levels, hormone levels and how much muscle you have. Generally we need more protein as we age to maintain our muscle mass. We also need more if we are physically active or trying to increase muscle mass. Muscle requires protein to grow but also to maintain health.

IGF-1 is a hormone that stimulates the synthesis of muscles (construction). This hormone is more abundant in some individuals than others. Having more of it means your body is better at using the protein you eat to form muscles than someone who has less. Having more protein in your diet or taking dietary supplements of amino acids can increase the response of IGF-1 to both food and physical exercise.

Why is it important

Protein has many vital roles within the body such as transportation, DNA replication and metabolic synthesis. The higher your muscle mass the more calories you burn at rest (BMR) so the higher your natural metabolism is. This burning or ‘thermal’ effect is roughly double the amount of equivalent carbohydrate or fat so having more protein in your diet generally results in greater fat loss and increased muscle gain.

Glucagon is a hormone that basically does the opposite to insulin (The effects are secondary and can’t be isolated but none the less worth mentioning). By antagonizing insulin Glucagon increases the amount of glucose in your blood up to normal levels when levels have dropped. This indirectly induces the breaking down of fat stores (lipolysis). This is beneficial as slightly less energy will be converted and stored as fat in tissues and the liver.

How protein is absorbed

When we eat protein is must be broken down into its original small building blocks, amino acids. Your stomach acid contains enzymes that facilitate this break down. Specialised cells will stagger the amount of amino acids that are able to infuse into the blood every hour. When facilitated, amino acids will move from the intestine to the blood stream which will deliver them around the body.

Issues with absorption

“Protein absorption—how quickly our bodies can absorb the amino acids into our bloodstreams.”

Transit time

Once protein is present in the stomach intestinal contractions slow down which reduces the rate in which the stomach empties. This increases the amount of time your body has to absorb nutrients from the protein. Carbs and fats move through much faster as they can be absorbed completely in a short period of time.

Proteins are made up differently; some are more biologically available than others, which means its easier for the muscles to use them. Generally viscous liquids take around 1.5 hours to move through the digestive tract. So, a protein shake won’t spend much time in the part of the tract that can actually absorb it. Whey is absorbed at around 8-10 grams of protein per hour. A shake containing 30g of protein would take 3 hours to absorb... so in theory half of the protein you drink is wasted as you only have 1.5 hours.

Cortisol

When trying to build muscle mass increasing protein intake and exercise come hand in hand. Once issue with absorption comes from this increase in exercise. Cortisol is a stress hormone that is released during periods of stress. Its main role is to enable the ‘fight or flight’ response. It’s beneficial to us as it lowers our sensitivity to pain, boosts our energy and gives a temporary increase in memory function to aid survival.

A negative effect of Cortisol is that it reduces protein synthesis and increases the rate in which the body burns amino acids for energy (broken into glucose). This reduces the amount of Amino Acids available to the body and lowers the rate of growth and repair.

Moderate to intense exercise is recognised as stress by the body which can increase Cortisol levels. Another side effect of this is increased intakes of food, especially carbohydrates which could affect weight loss.

Nitrogen Balance

Nitrogen is balanced when the amount of Nitrogen you take from food (protein sources) is equal to the amount of nitrogen that is excreted.

If intake exceeds excretion you set yourself into an anabolic state (state for growth) so gaining muscle is possible. If the excretion exceeds intake you set yourself in a catabolic state where muscle will be broken down for energy. Always try to keep your Nitrogen balance positive.

Tips and tricks

Slowing the transit time of your protein will increase absorption. Adding protein to something like cereal will help to bulk it up. Swapping for using water to milk will help to slow down shakes. Having solid protein in the form of say chicken will pass slower so try to get your protein for a mix of diet and supplements.

A read up on a study which involved male participants found that taking a 50g protein shake vs a 50g protein shake with supplemented digestive enzymes. The group with the digestive enzymes excreted less nitrogen than the group without. This means their bodies were in a more anabolic state and thus better suited for muscle growth.

Not only did the enzymes decrease nitrogen excretion they also improved the absorption of the whey protein. With 2.5g of enzyme over 4 hours 110% more protein had been absorbed than the group with no enzymes. A dose of 5 grams over 4 hours saw an increase of 127%!

The digestive enzymes help to break the protein into amino acids faster making them available to the blood quicker. This easy access increases absorption providing access to more muscles in the body.

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