Protein is one of those nutrients that always seems to be in the spotlight. Today we are continuing the Digestion Fundamental Series with an exploration of protein. Answering the basics: what protein is, how protein is digested, identifying sources of protein and how much protein we actually need. Nutrition nerds, this one is for you.
What is Protein?
Protein is an energy containing macronutrient- which mean our body requires the nutrient: protein in larger amounts to function properly just like it needs large amounts of carbohydrate and fats. Protein is made up of small compounds called amino acids. Our system needs 20 amino acids to work properly- 11 of these amino acids can be made internally nine amino acids have to be obtained from the foods we eat. This is the breakdown.
Essential Amino Acids// need to obtain from foods
-histidine
-isoleucine
-leucine
-lysine
-methionine
-phenylalanine
-threonine
-tryptophan
-valine
Non-Essential Amino Acids// body has the ability to make these and does so regularly
-alanine
-asparagine
-aspartic acid
Limiting Amino Acids// body produces these under times of stress
-arginine
-cysteine
-glutamine
-glycine
-ornithine
-proline
-serine
-tyrosine
What are the Functions of Protein?
Protein helps us to build, maintain and restore muscle organs and tissues. Every cell in our body contains protein, remember DNA from biology class? It’s backkkk..
What protein functions look like on a cellular level…
1) Catalyst// proteins can change the rate/speed of tini-tiny chemical reactions that occur in our body 24/7
2) Communicators// protein can function as chemical messengers otherwise known as hormones, by communicating cell to cell [ex. melatonin, the sleep aid hormone is produced from the amino acid tryptophan.]
3)Structural Roles// protein structurally makes up cardiac, skeletal, smooth muscle tissues – digestive track and connective tissue-skin,hair and nails.
4)Immune Health// proteins form a group called immuno-proteins they bind to harmful substances called antigens to inactivate them.
5)Transporters// proteins link-up with vitamins and minerals, carrying nutrients to regulate the flow of nutrients into and out of cells.
6)Buffers// proteins regulate acid-base balance to maintain the proper pH of blood and tissues.
7)Fluid Balance//protein status affects fluid balance. If protein concentration in the blood is less than normal fluid leaks into interstitial space causing swelling.
8)Storage//proteins attach to minerals like copper, iron and zinc in tissues and release minerals in times of need.
How the Body Digests Protein: 100
Digestion of protein skips the mouth and begins in the stomach with hydrochloric acid breaking downs bonds and uncoiling protein forming small units of protein called polypeptides, oligopeptides or the smallest free aminos acids. These peptides enter the small intestine for further breakdown from specific enzymes released from the pancreas and mucus secretions from the Brunner’s glands.
The end product is dipeptides, tripeptides and amino acids, which are then for absorb for use in the small intestine.
One of the perks of protein digestion is that this entire digestive process, happens slowly leaving us feeling satisfied for longer.
What are Food Sources of Protein?
Protein is categorized by quality which depends on the amino acid composition and on the extent of its digestibility. Complete vs. Incomplete vs. Limiting is a way of distinguishing proteins that contain all 9 essential amino acids in approx. amounts needed vs incomplete -which falls short of containing all 9 essential amino acids.
Complete vs Incomplete
Animal Based Sources of Complete Protein
-Meat
-Fish
-Eggs
-Dairy
Plant-Based sources of Complete Protein
-Soy
-Quinoa
-Hemp Seeds
-Chia Seeds
False: Eat all 9 essential amino acids at one sitting for better nutritional benefits.
Eating a various of incomplete proteins in the right quantity throughout the day will cover daily protein needs. Vegetarians and vegans need to pay closer attention to achieve adequate protein intakes.
Plant-Based Incomplete Protein
- Beans
- Legumes
- Nuts
- Seeds
- Grains// pasta, oats, rice, bran, wheat, corn, rye etc.
- Vegetables// brussel sprouts, broccoli, mushroom, artichoke,
- Fruits// dried prunes, raisins, avocado,
Each protein sources has different bioavailability- or ability to absorb after digestion.The egg is often used as the perfect example with a perfect bioavailability score- meaning absorption of protein from an egg is 100%. All animal proteins are highly bioavailable and plant proteins are typically less bioavailable. Plant proteins are still good sources of protein even though their bioavailability is lower.
Digestibility is important to consider as well. Animal proteins may be more difficult for some with physiological differences like lower than normal HCL levels in the stomach resulting in slowed transit time, bloating and constipation.
How much Protein do we need?
The amount of protein we need daily is varies based on the individual with age, body size -height and weight, physical activity and certain conditions warrant more or less protein per day.
Word to the Wise:More protein is not always better.
The body is capable of absorbing only so much protein at one time, excess protein can turn into body fat just as any excess in any form of energy-carbohydrate or fat intake. Plus excessive protein intake can potentially result in dehydration, bone damage and impaired kidney function resulting in kidney disease.
What else would you like to know about protein?
Ask your questions in the comment section below. Would love to here from you!
p.s. the monthly newsletter drops tomorrow so be sure to sign up at sidebarnutrition.com wait for the pop up and enter your email.
with gratitude,
jamie
Leave a Reply