When life gives you lemons, you ask for something higher in protein.
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To continue the story of macronutrients, today we play with proteins. What role do they play in our body (other than building muscle :D)? What are the sources and how much protein do we need daily?
What are proteins?
We see ads everywhere about how important it is to eat enough protein. It is true that proteins are some of the most important components of the human body (protein comes from proteus = primordial), but that does not mean that it must come into our body in impressive quantities. Proteins have a structural and hormonal role, they are found everywhere in our body: DNA, cells, enzymes, hormones, and neurotransmitters are protein structures.
We most need protein during breastfeeding and growth to form communication structures and connections in the body. In adulthood we no longer need to build the house, but to maintain it, right?
Proteins are made up of aminoacids. Each protein consists of about 20 aminoacids (think of a chain and each piece of it as an aminoacid). It is important to know that some aminoacids are non-essential, so they can be synthesized by the body from the other essential aminoacids (9 in number).
What are the best sources?
If we get most of our carbohydrates from plant sources, protein has both plant and animal sources, as you might know - hence the fight between vegans and carnivores. And now I'm going to explain a little bit. In nature, plants extract nitrogen and sulfur from the soil, and in the presence of photosynthesis they form aminoacids, the structures from which proteins are formed. So, plants are aminoacid factories, which later animals end up consuming and forming their specific proteins.
Furthermore, we learned in the article about carbohydrates that the body likes simple structures, and although we come with a so-called complete protein (those in animal products have up to 200,000 amino acids), which takes a long time to break, the body only takes the aminoacids it needs . In other words, the chain is broken, and the body retains only the links it needs for reconstruction.
Animal sources: meat (fish and seafood fall into this category), milk, eggs. They are considered to have complete protein (all 9 essential aminoacids are present).
Plant sources: vegetables, legumes (soy, chickpeas, beans, peas, lentils, etc.), whole grains, nuts, and seeds. Most have partial proteins, meaning they may lack essential aminoacids in their composition (except for soy, quinoa, buckwheat, hemp seeds, which are complete.) The combination of legumes with cereals creates complete protein, as legumes tend to be low in methionine and abundant in lysine, and cereals the other way around. However, the 2 components do not necessarily have to be eaten at the same time, but on the same day. And yet, it's so simple: peanut butter with toast, hummus with wholemeal bread, brown rice with beans and vegetables, tofu with noodles, etc...
So how much protein do we need?
Excess protein (whether animal or plant based) can have adverse health effects, as the residual compounds resulting from their burning are toxic and cause an acidic environment in the body, which is conducive to inflammation, colorectal cancers (due to eating red meat and processed meat), kidney stones, deteriorating bone health (to maintain acid-basic balance, calcium is taken from the bones, and people on a high-protein diet have 2 times higher levels of calcium in the urine - see blood tests, it can produce stones). And that's how the wheel spins… (more details here , page 223).
That is why, and because we do not lose so much protein through internal processes, the WHO (World Health Organization) recommendation for a healthy adult (not mentioning performance athletes or other cases) is only 10-15% (0.83 g / kg body weight) from the daily food intake.
In the case of people who do endurance exercises of medium-high intensity (run, for example) it is recommended 1.2-1.4g / kg body, and for those who exercise with weights of medium-high intensity, 1.6-2.2g / kg body weight. However, a study shows that a value greater than 1.62g / kg body of protein does not bring any extra results to athletes, in terms of muscle mass growth.
Recommendations
-On the day when you eat one type of animal protein, try to avoid eating the second one (if you ate meat, try not to eat dairy or eggs on the same day);
-Start adopting the concept of "meat free day" at least once a week and include in your diet several plant proteins, to avoid the risk of cardiovascular disease and cancer, kidney stones and gout ;
-Plant protein sources contain many fibers, which help good digestive health. Eat vegetables daily (they are aminoacid factories, remember?), 50% raw, if possible, but also whole grains and legumes ;
-If you are vegan, increase by 10% the volume of protein in your diet, compared to previous recommendations, due to the lower bioavailability of plant proteins;
- Diversify your diet!
Sources:
PROTEIN AND AMINO ACID REQUIREMENTS IN HUMAN NUTRITION, World Health Organization: https://apps.who.int/iris/bitstream/handle/10665/43411/WHO_TRS_935_eng.pdf?ua=1
International Society of Sports Nutrition Position Stand: protein and exercise: https://jissn.biomedcentral.com/articles/10.1186/s12970-017-0177-8#Sec13
Defining Meal Requirements for Protein to Optimize Metabolic Roles of Amino Acids: https://pubmed.ncbi.nlm.nih.gov/25926513/
A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults: https://bjsm.bmj.com/content/52/6/376
Proteinele, între moderație și exces, SDS: https://scoaladeslabit.ro/proteinele-intre-moderatie-si-exces
Cum să folosești proteinele pentru sănătatea ta?, SDS: https://www.youtube.com/watch?v=4I6G8UgJmMY
Lavinia Dinca
Nutritionist
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Română