Dr Daniel S F Boarim – Diretor médico da Lapinha SPA

 

Uma dúvida recorrente: Entre os pesquisadores de nutrição, é ponto pacífico que o balanço das proteínas na dieta é essencial à manutenção ou ganho de massa muscular, mantendo o metabolismo e a composição corporal equilibrados. Também sabemos que dietas mais ricas em proteínas ajudam a promover a saciedade, podendo apoiar o emagrecimento. Porém – e aqui mora o paradoxo – estudos recentes apontam para um efeito inflamatório de dietas abundantes em proteínas, especialmente provenientes de fontes animais. Essas dietas tendem a desequilibrar a microbiota e criar um ambiente propício ao desenvolvimento de doenças crônicas. E aí? Como conciliar isso?

 

PROTEÍNAS PODEM SER PRÓ-INFLAMATÓRIAS?

 

Estudos atuais vêm revelando que dietas ricas em proteínas, especialmente aquelas ricas em alimentos de fontes animais, podem exacerbar a inflamação, atrelada à disbiose (desequilíbrio da microbiota do intestino) e ao risco de doenças crônicas. Um desses estudos descobriu que uma dieta abundante em proteínas (perfazendo 30% de energia) aumentou os marcadores de inflamação em indivíduos obesos em comparação com uma dieta adequada em proteínas, com 15% do VET (valor energético total). [1] Da mesma forma, outros estudos demonstraram que dietas ricas em proteína animal podem promover respostas pró-inflamatórias de macrófagos, exacerbando a colite.[2]

 

TIPO DE PROTEÍNA

 

O tipo de proteína também desempenha um papel significativo. As proteínas animais, especialmente as provenientes da carne, têm sido associadas ao aumento de marcadores inflamatórios, enquanto as proteínas vegetais não parecem ter o mesmo efeito.[1][3]. Por exemplo, um estudo comparando diferentes fontes de proteína descobriu que a proteína do soro de leite teve uma resposta inflamatória pós-prandial menor em comparação com as proteínas do bacalhau e da caseína.[4]

 

DIETAS DE PROTEÍNA ALTERAM A MICROBIOTA?

 

Além disso, dietas ricas em proteínas a longo prazo podem alterar a microbiota intestinal, aumentar a permeabilidade intestinal e levar à inflamação sistêmica.[5] Isto é particularmente preocupante no contexto de dietas ricas em gordura, onde a combinação de alto teor de proteína e alto teor de gordura pode agravar ainda mais as respostas inflamatórias.[6-7]

 

PROTEÍNAS PROMOVEM A SACIEDADE?

 

Por outro lado, foi demonstrado que dietas ricas em proteínas promovem a saciedade e por tabela reduzem a ingestão calórica, o que pode ajudar no controle de peso. Isso se deve aos efeitos combinados de níveis elevados de aminoácidos plasmáticos, aumento das concentrações de hormônios anorexígenos e aumento da termogênese induzida pela dieta.[8-9] Além disso, dietas ricas em proteínas podem ajudar a preservar a massa livre de gordura durante a perda de peso, o que, no longo prazo, é crucial para manter o gasto energético basal.[10]

 

DIETAS PLANT BASED

 

A fonte e a qualidade da proteína também desempenham papéis significativos. Aqui, mais uma novidade que fala a favor da plant based diet e dieta DASH: Observou-se que a proteína do soro de leite e as proteínas vegetais exercem efeitos favoráveis ​​na composição corporal e nos parâmetros metabólicos, reduzindo potencialmente o risco de desenvolver obesidade.[11] Veja bem, proteínas vegetais! Demonstrou-se também que aminoácidos específicos, como aminoácidos de cadeia ramificada (BCAAs), metionina e triptofano, influenciam positivamente os parâmetros relacionados à obesidade, embora a maioria das evidências venha de estudos em cobaias de laboratório.[12]

 

DIETA LOW CARB

 

Há uma hipótese, que acabou sendo distorcida a ponto de se tornar um modismo pernicioso, da assim chamada “alavancagem proteica”, que deu à luz as dietas “low carb”. Essa hipótese sugere que dietas pobres em proteínas podem aumentar a ingestão de energia total, incluindo carboidratos, e assim contribuindo para a obesidade. E, até certo ponto, há dados que a apoiam, mostrando que uma maior ingestão de proteínas está associada a uma menor ingestão total de energia, independentemente do teor de carboidratos ou gordura da dieta. [4-5]. Porém, isso está longe de abonar um plano alimentar exagerado em proteínas animais ou “livre” de carboidratos. É preciso lembrar que os carboidratos “do bem” vêm sendo confundidos com os “do mal”, levando à demonização de frutas, raízes e cereais integrais, certamente um desatino que não conta com qualquer respaldo científico.

 

RESUMO

 

Resumindo, as dietas adequadas em proteínas, podendo atingir proporções leve e calculadamente maiores, sem excluir os carboidratos saudáveis, podem ser benéficas para o controle do peso, promovendo a saciedade, preservando a massa magra e reduzindo potencialmente a ingestão global de energia. No entanto, os efeitos no longo prazo e as fontes proteicas devem ser considerados, pois proteína demais, especialmente as de fonte animal, apresenta efeitos inflamatórios, favorecendo o aparecimento de males crônicos. O tipo e a quantidade de proteína devem ser cuidadosamente levados em conta para mitigar essas reações indesejáveis. A solução desse aparente paradoxo se traduz, como sempre, no equilíbrio e no bom-senso. Nem tanto ao mar nem tanto à terra. Nem proteína demais, nem de menos.

 

Referências

 

1. 1. Lopez-Legarrea P, de la Iglesia R, Abete I, et al. The Protein Type Within a Hypocaloric Diet Affects Obesity-Related Inflammation: The RESMENA Project. Nutrition (Burbank, Los Angeles County, Calif.). 2014;30(4):424-9. doi:10.1016/j.nut.2013.09.009
   2. Kostovcikova K, Coufal S, Galanova N, et al. Diet Rich in Animal Protein Promotes Pro-Inflammatory Macrophage Response and Exacerbates Colitis in Mice. Frontiers in Immunology. 2019;10:919. doi:10.3389/fimmu.2019.00919. Copyright License: CC BY
   3. Markova M, Koelman L, Hornemann S, et al. \Effects of Plant and Animal High Protein Diets on Immune-Inflammatory Biomarkers: A 6-Week Intervention Trial. Clinical Nutrition (Edinburgh, Scotland). 2020;39(3):862-869. doi:10.1016/j.clnu.2019.03.019.
   4. Holmer-Jensen J, Karhu T, Mortensen LS, et al. Differential Effects of Dietary Protein Sources on Postprandial Low-Grade Inflammation After a Single High Fat Meal in Obese Non-Diabetic Subjects. Nutrition Journal. 2011;10:115. doi:10.1186/1475-2891-10-115. Copyright License: CC BY
   5. Snelson M, Clarke RE, Nguyen TV, et al. Long Term High Protein Diet Feeding Alters the Microbiome and Increases Intestinal Permeability, Systemic Inflammation and Kidney Injury in Mice. Molecular Nutrition & Food Research. 2021;65(8):e2000851. doi:10.1002/mnfr.202000851.
   6. Zhang M, Song S, Zhao D, et al. High Intake of Chicken and Pork Proteins Aggravates High-Fat-Diet-Induced Inflammation and Disorder of Hippocampal Glutamatergic System. The Journal of Nutritional Biochemistry. 2020;85:108487. doi:10.1016/j.jnutbio.2020.108487.
   7. Hussain M, Umair Ijaz M, Ahmad MI, et al. Meat Proteins in a High-Fat Diet Have a Substantial Impact on Intestinal Barriers Through Mucus Layer and Tight Junction Protein Suppression in C57bl/6j Mice. Food & Function. 2019;10(10):6903-6914. doi:10.1039/c9fo01760g
   8. Drummen M, Tischmann L, Gatta-Cherifi B, Adam T, Westerterp-Plantenga M. Dietary Protein and Energy Balance in Relation to Obesity and Co-Morbidities. Frontiers in Endocrinology. 2018;9:443. doi:10.3389/fendo.2018.00443. Copyright License: CC BY
   9. Westerterp-Plantenga MS, Lemmens SG, Westerterp KR. Dietary Protein – Its Role in Satiety, Energetics, Weight Loss and Health. The British Journal of Nutrition. 2012;108 Suppl 2:S105-12. doi:10.1017/S0007114512002589.
   10. Simonson M, Boirie Y, Guillet C. Protein, Amino Acids and Obesity Treatment. Reviews in Endocrine & Metabolic Disorders. 2020;21(3):341-353. doi:10.1007/s11154-020-09574-5. Copyright License: CC BY
   11. Gosby AK, Conigrave AD, Raubenheimer D, Simpson SJ.Protein Leverage and Energy Intake. Obesity Reviews : An Official Journal of the International Association for the Study of Obesity. 2014;15(3):183-91. doi:10.1111/obr.12131.
   12. Grech A, Sui Z, Rangan A, et al. Macronutrient (Im)balance Drives Energy Intake in an Obesogenic Food Environment: An Ecological Analysis. Obesity (Silver Spring, Md.). 2022;30(11):2156-2166. doi:10.1002/oby.23578.

 

 

ENGLISH

 

“Protein diet” – Does it help you lose weight or cause inflammation?

 

Dr Daniel S F Boarim, MD, Medical Director of Lapinha SPA

 

A recurring question: Among nutrition researchers, it is common ground that a balanced diet of proteins is essential for maintaining or gaining muscle mass, keeping metabolism and body composition balanced. We also know that diets richer in proteins help promote satiety, which can support weight loss. However – and here lies the paradox – recent studies point to an inflammatory effect of diets rich in proteins, especially those from animal sources. These diets tend to unbalance the microbiota and create an environment conducive to the development of chronic diseases. So what? How can this be reconciled?

 

CAN PROTEINS BE PRO-INFLAMMATORY?

 

Current studies have revealed that diets rich in proteins, especially those rich in foods from animal sources, can exacerbate inflammation, linked to dysbiosis (imbalance of the intestinal microbiota) and the risk of chronic diseases. One such study found that a high-protein diet (making up 30% of energy) increased markers of inflammation in obese individuals compared to a high-protein diet with 15% of total energy value.[1] Similarly, other studies have shown that diets high in animal protein can promote pro-inflammatory macrophage responses, exacerbating colitis.[2]

 

TYPE OF PROTEIN

 

The type of protein also plays a significant role. Animal proteins, especially those from meat, have been associated with increased inflammatory markers, while plant proteins do not appear to have the same effect.[1][3]. For example, a study comparing different protein sources found that whey protein had a lower postprandial inflammatory response compared to cod and casein proteins.[4]

 

DO PROTEIN DIETS ALTER THE MICROBIOTA?

 

Furthermore, long-term high-protein diets can alter the gut microbiota, increase intestinal permeability, and lead to systemic inflammation.[5] This is particularly concerning in the context of high-fat diets, where the combination of high protein and high fat can further exacerbate inflammatory responses.[6-7]

 

DOES PROTEIN PROMOTE SATIETY?

 

On the other hand, high-protein diets have been shown to promote satiety and thereby reduce caloric intake, which may aid in weight management. This is due to the combined effects of elevated plasma amino acid levels, increased concentrations of anorectic hormones, and increased diet-induced thermogenesis.[8-9] Furthermore, high-protein diets may help preserve fat-free mass during weight loss, which in the long term is crucial for maintaining basal energy expenditure.[10]

 

PLANT-BASED DIETS

 

The source and quality of protein also play significant roles. Here’s another piece of news that speaks in favor of the plant-based diet and the DASH diet: Whey protein and plant proteins have been shown to have favorable effects on body composition and metabolic parameters, potentially reducing the risk of developing obesity.[11] Well, plant proteins! Specific amino acids, such as branched-chain amino acids (BCAAs), methionine, and tryptophan, have also been shown to positively influence obesity-related parameters, although most of the evidence comes from studies in laboratory animals.[12]

 

LOW CARB DIET

 

There is a hypothesis, which has ended up being distorted to the point of becoming a pernicious fad, of the so-called “protein leverage,” which gave rise to “low-carb” diets. This hypothesis suggests that low-protein diets can increase total energy intake, including carbohydrates, and thus contribute to obesity. And to some extent, there is data to support this, showing that higher protein intake is associated with lower total energy intake, regardless of the carbohydrate or fat content of the diet. [4-5]. However, this is far from supporting a diet plan that is excessive in animal proteins or “free” of carbohydrates. It is important to remember that “good” carbohydrates have been confused with “bad” carbohydrates, leading to the demonization of fruits, roots and whole grains, which is certainly a nonsense that has no scientific basis.

 

ABSTRACT

 

In summary, diets that are adequate in protein, which can be achieved in slightly higher proportions and that do not exclude healthy carbohydrates, can be beneficial for weight control by promoting satiety, preserving lean mass and potentially reducing overall energy intake. However, long-term effects and protein sources should be considered, as too much protein, especially from animal sources, has inflammatory effects,

 

References

 

1. Lopez-Legarrea P, de la Iglesia R, Abete I, et al. The Protein Type Within a Hypocaloric Diet Affects Obesity-Related Inflammation: The RESMENA Project. Nutrition (Burbank, Los Angeles County, Calif.). 2014;30(4):424-9. doi:10.1016/j.nut.2013.09.009
2. Kostovcikova K, Coufal S, Galanova N, et al. Diet Rich in Animal Protein Promotes Pro-Inflammatory Macrophage Response and Exacerbates Colitis in Mice. Frontiers in Immunology. 2019;10:919. doi:10.3389/fimmu.2019.00919. Copyright License: CC BY
3. Markova M, Koelman L, Hornemann S, et al. \Effects of Plant and Animal High Protein Diets on Immune-Inflammatory Biomarkers: A 6-Week Intervention Trial. Clinical Nutrition (Edinburgh, Scotland). 2020;39(3):862-869. doi:10.1016/j.clnu.2019.03.019.
4. Holmer-Jensen J, Karhu T, Mortensen LS, et al. Differential Effects of Dietary Protein Sources on Postprandial Low-Grade Inflammation After a Single High Fat Meal in Obese Non-Diabetic Subjects. Nutrition Journal. 2011;10:115. doi:10.1186/1475-2891-10-115. Copyright License: CC BY
5. Snelson M, Clarke RE, Nguyen TV, et al. Long Term High Protein Diet Feeding Alters the Microbiome and Increases Intestinal Permeability, Systemic Inflammation and Kidney Injury in Mice. Molecular Nutrition & Food Research. 2021;65(8):e2000851. doi:10.1002/mnfr.202000851.
6. Zhang M, Song S, Zhao D, et al. High Intake of Chicken and Pork Proteins Aggravates High-Fat-Diet-Induced Inflammation and Disorder of Hippocampal Glutamatergic System. The Journal of Nutritional Biochemistry. 2020;85:108487. doi:10.1016/j.jnutbio.2020.108487.
7. Hussain M, Umair Ijaz M, Ahmad MI, et al. Meat Proteins in a High-Fat Diet Have a Substantial Impact on Intestinal Barriers Through Mucus Layer and Tight Junction Protein Suppression in C57bl/6j Mice. Food & Function. 2019;10(10):6903-6914. doi:10.1039/c9fo01760g
8. Drummen M, Tischmann L, Gatta-Cherifi B, Adam T, Westerterp-Plantenga M. Dietary Protein and Energy Balance in Relation to Obesity and Co-Morbidities. Frontiers in Endocrinology. 2018;9:443. doi:10.3389/fendo.2018.00443. Copyright License: CC BY
9. Westerterp-Plantenga MS, Lemmens SG, Westerterp KR. Dietary Protein – Its Role in Satiety, Energetics, Weight Loss and Health. The British Journal of Nutrition. 2012;108 Suppl 2:S105-12. doi:10.1017/S0007114512002589.
10. Simonson M, Boirie Y, Guillet C. Protein, Amino Acids and Obesity Treatment. Reviews in Endocrine & Metabolic Disorders. 2020;21(3):341-353. doi:10.1007/s11154-020-09574-5. Copyright License: CC BY
11. Gosby AK, Conigrave AD, Raubenheimer D, Simpson SJ.Protein Leverage and Energy Intake. Obesity Reviews : An Official Journal of the International Association for the Study of Obesity. 2014;15(3):183-91. doi:10.1111/obr.12131.
12. Grech A, Sui Z, Rangan A, et al. Macronutrient (Im)balance Drives Energy Intake in an Obesogenic Food Environment: An Ecological Analysis. Obesity (Silver Spring, Md.). 2022;30(11):2156-2166. doi:10.1002/oby.23578.