Proteins have a structural role in our body (muscles, tissues, nails, etc.) or a functional role (enzymes, hormones, antibodies, transporters, receptors, etc.).
They can also serve as an alternative fuel to glucose and fatty acids. One gram of protein releases about 4.5 kcal in our body. Glutamine in particular is a privileged fuel for white blood cells, enterocytes, but also cancer cells.
Proteins provide us with cellular nutrients, amino acids.
Some of these amino acids can be made by our body, but others must be provided through our diet. There are nine of them and are then called “essential amino acids”.
The other amino acids are considered nonessential since they can be made by our body. However, it happens that the synthesis of some of them is insufficient compared to our needs. They will then be considered “conditionally essential”
Essential amino acids: not synthesized by the body and must be provided by the diet
- Leucine o
Conditionally essential amino acids: the synthesis capacities are not up to the needs under certain conditions
And non-essential amino acids
- Glutamic acid
- Aspartic acid
A distinction is made between proteins of animal origin (meat, poultry, eggs, fish, dairy products, etc.), proteins of vegetable origin (cereal products, pulses, etc.).
Their nutritional characteristics are different:
They provide all of the essential amino acids, which is why they are called “proteins of high biological value”. Are richer in iron, zinc and vitamin B12
BUT, some of them (like meat) are:
- Richer in saturated fats and arachidonic acid (precursor of inflammatory prostaglandins, vasoconstrictors, pro-platelet aggregants, etc.)
- Richer in leucine, which activates the mTOR pathway, an important mediator of inflammation
- Richer in pro-oxidant, pro-inflammatory iron and a proliferation factor for viruses, bacteria, fungi, parasites and cancer cells
- Richer in pollutants, in particular liposoluble
- Richer in microbial agents (bacteria and viruses) – even after cooking they emit endotoxins
- Richer in Maillard molecules responsible for the accumulation of pigments found in neurodegenerative pathologies and with carcinogenic effects in the event of aggressive cooking
Are often also high in carbohydrates and fiber
Are less fat or contain higher quality fatty acids
Are richer in group B vitamins (except vitamin B12), vitamin C and carotenoids.
BUT an amino acid is often lacking or only present in small amounts. This amino acid is then called “limiting amino acid”. It is therefore necessary to combine certain vegetable proteins with each other such as legumes (lentils, dried beans, chickpeas, etc.) with cereals (quinoa, rice, buckwheat, bread, pasta, etc.), to obtain all the amino acids in sufficient quantity. However, some plants like soybeans, quinoa. chia seeds, amaranth, have a protein profile as complete as that of meat.
One can therefore be vegetarian or vegan without any problem with regard to proteins (this is the case of very high level athletes, horses, bulls, gorillas, etc.), but on the other hand one becomes at risk – without suitable supplementation – of missing vitamin B12 and zinc. For the iron, which pregnant women, anemic women, children and teenagers in strong growth need, which cannot be given because of its dangerousness in supplements, an organic meat, not altered by heat (scorched / blackened), keeps a good risk / benefit ratio for a limited period of time. For the others, a vegetarian or “flexitarian” diet is the option most indicated by all the studies.
The recommendations for protein intake are 8-11% of total energy intake, with requirements increasing with age. Actual contributions are actually around 16% on average. We therefore have excessive protein intake on average. However, studies indicate that proteins are the category that accelerates aging the most and increases the risk of degenerative pathologies the most. We consume more than 1.4g of protein per kg, almost twice as much as needed, because
nutritionists recommend around 0.8g of protein per kg of protein. In practice, this corresponds to around 50 to 75 g of protein for people weighing 60 to 80 kg.
We are of course talking about grams of protein here, not food. Each food contains a varying percentage of protein.
So 100 g:
- of meat contain about 20 g of protein
- oilseeds and chestnuts 17 g
- of eggs contain about 12 g
- of cereals about 10 g
- lentils contain about 8 g
In addition, in this excess the place of animal proteins (more than 70%): meat, poultry, fish, dairy products has become ubiquitous.
For adults or women after menopause consuming more than one meat per week has a negative impact on health. Such consumption
- Contrary to beliefs in high-protein diets, increases the risk of overweight: in the large EPIC-PANACEA study on 103,455 men and 270,348 women followed in 10 European countries, for each increase in consumption of 250 g of meat per day, a weight gain of 2 kg is recorded per 5 years
- Increases the risk of diabetes, cardiovascular disease, Parkinson’s disease, all cancers – and not just colon cancer since a portion of meat per day increases the risk of all cancer by 10% and meats by 16% and meat eaters have about 3 times more Alzheimer’s disease than vegetarians
- Globally accelerated aging
- Overloads kidney work and risk of kidney failure
- Contributes to acidosis which has a long-term negative impact on bone density
- Inhibits the passage of tryptophan in the brain by competition with the branched amino acids which form the muscle: leucine, isoleucine and valine, which worsens the lack of impulse control and the risks of self-destructive behaviors: over food, attraction to sweet, l ‘ alcohol, tobacco, speeding on the road, aggressiveness …
- In addition to the drop in serotonin, which is responsible for drive control, there is the drop in its derivative, melatonin, essential for good sleep and antioxidant repairs during the night.
As we have said, animal proteins, whether meat or dairy products are associated with many negative effects. And their share should be considerably reduced except, and only with regard to red meat, rich in heme iron for the sub-populations which have increased needs: pregnant women, anemic women, children or teenagers in strong growth. Because the interest of meat does not lie in proteins but in vitamin B12 which does not exist in plants and minerals such as iron and zinc which exist in plants but are very poorly absorbed.
If meat is therefore of nutritional value for pregnant women, children and teenagers, its consumption should be done either at noon or in the morning, not in the evening. Because a large part of their energy is immediately available. This is called post-prandial energy dispersion. This dispersion is 25% (against 15% for carbohydrates and 3% for lipids), which energizes at the start of the day.
On the other hand, such a dispersion at supper, raises the body temperature when it should drop in favor of a reduction in inflammatory stress, alters the quality of sleep, the period of maintenance, repair, the evacuation of damaged proteins (autophagy ) and DNA repair.
Eating animal proteins, the most pro-inflammatory foods that exist (iron, arachidonic acid, mTOR-stimulating leucine, endotoxins, pollutants) at dinner is self-destructive.
Supper should focus on plants and complex carbohydrates, rather sedative and anti-inflammatory.
Meat is the most pro-inflammatory food. However, inflammation participates in all degenerative pathologies, at all stages of cancer development (initiation, promotion, invasion, angiogenesis, metastases).
Why is meat pro-inflammatory? It is rich in:
- Pro-oxidant and pro-inflammatory iron. Iron is also a growth factor for all pathogens such as viruses, bacteria, fungi, parasites, etc.) as well as cancer cells.
- Arachidonic acid, precursor of prostaglandins, powerful agents of inflammation, allergies, vasoconstriction and platelet aggregation.
- In leucine, an activating amino acid of the mTOR pathway, another conductor of inflammation and accelerator of aging.
- In substances including endotoxins and endocrine disruptors which pass into the blood after each ingestion.
In addition, the flora of the meat eater transforms the carnitine especially present in meats and choline especially present in eggs into TMAO, a substance that damages the arterial walls and almost all increases the risk of degenerative pathologies.
Meat is often cooked inappropriately and / or aggressively (at high temperature). These cooking methods are the source of toxic substances (heterocyclic amines for example) which are powerful carcinogens. The most toxic cooking method is the barbecue (especially if it is poorly done) which provides benzopyrenes and acrolein (involved in asthma, chronic respiratory diseases, cardiovascular diseases, Alzheimer’s disease … ). The carcinogens present in blackened or browned meats are as powerful as those in cigarettes and increase the risk of developing several cancers: colon, rectum, breast, prostate, pancreas, lung … Studies show that meat marinated with oil, lemon and spices like turmeric have significantly reduced toxicity than grilled meats.
-> You should favor non-aggressive preparations: sushi, tartars, ceviche, marinades, pochades, steam cooking, low temperature cooking, plancha, etc. and remember to marinate your meats before cooking.
Dairy proteins, the leading cause of food intolerance, involved in autoimmune pathologies, such as type 1 diabetes, also rich in leucine (proinflammatory) rich in lysine and poor in arginine (which potentiates the absorption of all fats), associated with saturated and trans fats, lactose, cataract and peripheral neuropathy factor, excess phosphorus (inhibitor of calcium and magnesium absorption), growth factors and tumor promoting estrogen , acne factor steroids, insulin stimulating factors (high insulin index), associated with multiple pollutants including dioxin … and corn proteins, too rich in leucine and associated with omega six fatty acids,already in excess in the diet cannot be considered as healthy food either.
For more details, refer to the DSN on Osteoporosis. You can very well get all the calcium you need from non-dairy products, as long as you don’t run out of vitamin D.
In practice :
- especially for iron (zinc and vitamin B12 can be provided by supplements), pregnant women, children and teenagers in strong growth, people deficient in iron, have a nutritional interest in consuming red meat, rich in heme iron (the richest is beef – this is ecologically incorrect, but we focus here on the purely nutritional plan) – no interest in consuming white meat, which is low in iron and more infected and inflammatory than red meat – these subgroups, during growth (up to 6 years for children, during the 18 months of strong growth in adolescents, the 9 months of pregnancy) can consume between 5 and 7 times a week (at lunch, not in the evening)
- women who have periods can consume it 2 to 3 times a week (to better adapt the advice to take an iron balance sheet);
- women after menopause and men have no interest in consuming meat – the consumption of quality meat (organic, from animals that have lived an outdoor life in decent conditions, not burnt …), for week does not seem to have any health consequences (“flexitarian” diet)
- replace it with vegetable proteins by making the right associations between pulses and cereals (couscous and chickpeas, rice and lentils, etc.) or by placing soy-based products (tofu, fermented tofu, tempeh, etc.) on your plate quinoa, chia seeds …
- vegetarians, such as people who lack iron, can increase the absorption of non-heme iron, especially found in lentils and soybeans by not drinking green tea at the end of iron-rich meals (tannins inhibit absorption) , by taking vitamin C at the end of these meals which increases the absorption of iron by 5-7 (See Module 1: FER)
- vegetarians, vegans and vegans should take a daily supplement that includes not only vitamin B12 – which most of them know – better in the form of methylcobalamin) – but also zinc (bioavailable as citrate or picolinate) – this supplement also contains other compatible vitamins and minerals (neither iron, nor copper, nor manganese) which may be lacking even in non-vegetarians (ex Physiomance Multi from Thérascience or Multigenics from Metagenics / Bionutrics), as well as vitamin D l ‘winter.
From November 2018, a movement called Green Monday supported by hundreds of scientists and personalities, will suggest that everyone no longer consume any animal protein on Monday (this is very insufficient, but we have to start well … studies show that the movement is underway: 1/3 of households declare themselves flexitarians; 11% of young people are vegetarians (20% in England), 4 out of 5 French people declare themselves in favor of a total and definitive abolition of intensive breeding. Other countries like Belgium launched the movement “Day without meat”.
Nutritherapy, a positive approach:
In nutritherapy, rather than prohibiting or restricting, as in traditional dietetics – which studies show very little effective -, we prefer to promote products that are both pleasure and health. If your patients introduce more pulses, quinoa, soy…, they will have no choice but to see that their meat consumption has decreased AND without frustration. Good foods drive out bad ones. If they consume olive oil, they do not consume sunflower oil. If they consume more fruit, they consume less pastries, etc…. We have a lot of healthy foods available to us. If we synthesize scientific publications, the foods associated with the greatest reductions in pathologies and / or the greatest gains in longevity are:
- The green vegetables
- Semi-whole grains without gluten
- Virgin olive oil and rapeseed oil
- Squash, tubers and starches (chestnuts)
- The mushrooms
- The seaweeds
- Herbs (turmeric and ginger in the lead) and herbs
- Red or black fruits and berries
- Green tea
- Dark chocolate with more than 74% cocoa.
These foods are considered healthy foods to be promoted on the plate on a daily basis, with no quantity restrictions (with some exceptions).
The other foods are considered to be “pleasures” foods to be enjoyed on festive occasions.
Meats and other animal proteins are part of it. Consumed every day they also lose their attractiveness. And they would be all the more appreciated if they are of good quality (when we eat much less we can afford the best quality) and therefore from animals not raised stressed and immunosuppressed in concentration camps, but in a natural environment as open and free as possible, with organic food, without “preventive” prescription of antibiotics.
A little history
The Dutch chemist Gerardus Johannes Mulder published in 1830 the first sum of his studies on the molecules he found in egg white, silk, blood and gelatin and which he called proteins. He writes: “It is arguably the most important component of living matter and without it life would not be possible. »In 1842, Liebig states that food proteins are essential for tissue formation and that urinary urea levels reflect the amount of protein ingested.
At the dawn of the 20th century, 16 amino acids were identified in protein hydrolysates.
Thomas Osborne, in 1911, at Yale University, discovered that certain amino acids
are essential for growth, while others are not.
It was William Rose, a pupil of Mendel, who in 1935 found the eighth essential amino acid, threonine, necessary to allow normal growth in rats fed on a mixture of amino acids instead of proteins.
Very recently, a last amino acid, histidine, has been recognized as essential in humans. But some of them, although synthesizable by the organism, can either undergo an alteration of their synthesis, or see their needs increased beyond the capacities of synthesis.
This is the case with taurine, isolated in 1827 by Tiedman. Sturman between 1977 and 1987 showed that it is essential for cerebral development while the synthesis capacities of the newborn are almost nil. Gaull came to regard taurine as a conditionally essential amino acid. In addition, numerous works have made it possible to accumulate a considerable body of knowledge on absorption, transport through membranes, metabolic fate, functions at nutritional or pharmacological doses of amino acids.
Role of proteins and amino acids:
The proteins consumed in food are digested, broken down into amino acids and these amino acids are recombined according to our cellular computing, the genome, into the proteins that we need:
- structural proteins (for example muscle fibers, connective tissue collagen, lens, etc.)
- cellular structure proteins
- mineral chelators / storage agents like ferritin, metallothionein, ceruleoplasmin
- enzymes responsible for biochemical functions
- hormones (like insulin, anti-diuretic hormone)
- hormone releasing factors (such as TSH, FSH, ACTH, etc.)
- growth factors (such as polyamines, nerve growth factor)
- agents of mitochondrial metabolism: mitofusins for the fusion of mitochondria, respiratory chain complexes such as cytochrome c)
- neuromodulators (such as endorphins / enkephalins)
- reaction agents, for example painkillers: bradykinin, substance P
- adhesion molecules (for white blood cells, platelets, etc.)
- molecules essential for sensory functions (such as gustine for taste)
- absorption enhancers (such as intrinsic factor for vitamin B12)
- anti-infectious agents (such as antibodies, lyzozyme, an anti-bacterial present in tears)
- anti-toxic agents like glutathione.
Proteins complexed with oses are glycoproteins (eg antibodies)
Proteins complexed with minerals are metalloproteins: insulin, gustine, nerve growth factor, p53 – trigger of apoptosis or cell suicide which protects against cancers – are zinc proteins.
Amino acids participate in energy metabolism, either directly as glutamine for lymphocytes and enterocytes, or indirectly through gluconeogenesis (production of glucose in the liver)
Amino acids are precursors of neurotransmitters, for example phenylalanine / tyrosine of catecholamines (norepinephrine and dopamine), tryptophan of serotonin and melatonin or directly neurotransmitters, such as taurine.
Amino acids are precursors of agents of various reactions which can have multiple functions: for example r /? / ‘Sfa / 77 / ne (produced from histidine) pro-inflammatory factor and allergic reaction in blood cells white, triggering the secretion of hydrochloric acid in the stomach, neurotransmitter in the brain or nitric oxide (NO °, produced from arginine) which can act as a vasodilator in endothelial cells, oxidative molecule in white blood cells (precursor of peroxynitrite), neuromodulator….
In summary, proteins, which depend directly on genes, are not only fundamental molecules for the tissues and organs of our body, such as muscles or connective tissues (25% of our proteins are collagen), but the biochemical tools that allow us to perform all the operations we need.
Author Jean-Paul Curtay