Protein is everywhere these days: fortified snack bars, pastas, cereals, even water. With such heavy marketing, patients may assume that more protein is always better. But does this marketing carry risks? Do all patients need a higher protein intake? Here’s how GPs can support their patients.
How much protein do we really need?
The current trend of protein-fortified foods and high-protein diets in the general population is not always supported by evidence, particularly for healthy individuals without increased protein needs. The recommended dietary intake is 0.8-1.0 grams of protein per kilogram of body weight, with higher requirements in older adults, those with chronic illness, or individuals recovering from surgery. True protein deficiency is rare outside of frailty, malnutrition, or restrictive diets.
The risks of overdoing it
Excessive protein intake, particularly from animal sources, carries potential risks. Large cohort studies and meta-analyses have linked high animal protein consumption with:
- Increased risk of type 2 diabetes, cardiovascular mortality, and all-cause mortality [1,2,3]
- Greater body weight and weight gain, especially in children where high intakes early in life increase later obesity risk [4,5,6]
- Faster decline in kidney function in those with existing kidney concerns, though evidence in otherwise healthy adults is mixed [7,8].
- Higher cancer and overall mortality risk when intake is predominantly from red or processed meat sources [9]
In contrast, high protein intake from plant sources is generally associated with reduced risks of all-cause and cardiovascular mortality, and a lower risk of type 2 diabetes, especially in women [2,3].
Beyond quantity: Quality and balance
Animal proteins are considered “higher quality” due to their complete amino acid profile and strong effect on muscle protein synthesis, which is important for preserving lean mass, particularly in ageing populations. However, long-term epidemiological data consistently show that diets higher in plant proteins (legumes, soy, nuts) are associated with lower risks of cardiovascular disease, diabetes, cancer, and mortality compared with diets high in animal protein [9].
Equally important is nutrient balance. When patients rely heavily on protein-fortified products, they may reduce their intake of fibre-rich wholefoods such as fruits, vegetables, and wholegrains which are nutrients with stronger evidence for preventing chronic disease.
In practice, most patients can be reassured that their protein intake is already adequate, and discussions should emphasise dietary balance. GPs can encourage patients to include lean protein alongside vegetables, wholegrains, and high-fibre foods. For those at risk (older adults, people with frailty, pregnant women, or patients with renal disease) advice should be individualised, and referral to a dietitian may be warranted.
– Sarah Marko, Accredited Practising Dietitian
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References
- Hernández‐Alonso, P., Salas‐Salvadó, J., Ruíz-Canela, M., Corella, D., Estruch, R., Fitó, M., Arós, F., Gómez-Gracia, E., Fiol, M., Lapetra, J., Basora, J., Serra-Majem, L., Muñoz, M., Buil-Cosiales, P., Saiz, C., & Bulló, M. (2016). High dietary protein intake is associated with an increased body weight and total death risk.. Clinical nutrition, 35 2, 496-506 . https://doi.org/10.1016/j.clnu.2015.03.016.
- Ye, J., Yu, Q., Mai, W., Liang, P., Liu, X., & Wang, Y. (2019). Dietary protein intake and subsequent risk of type 2 diabetes: a dose–response meta-analysis of prospective cohort studies. Acta Diabetologica, 56, 851-870. https://doi.org/10.1007/s00592-019-01320-x.
- Qi, X., & Shen, P. (2020). Associations of dietary protein intake with all-cause, cardiovascular disease, and cancer mortality: A systematic review and meta-analysis of cohort studies.. Nutrition, metabolism, and cardiovascular diseases : NMCD. https://doi.org/10.1016/j.numecd.2020.03.008.
- Koletzko, B., Demmelmair, H., Grote, V., Prell, C., & Weber, M. (2016). High protein intake in young children and increased weight gain and obesity risk.. The American journal of clinical nutrition, 103 2, 303-4 . https://doi.org/10.3945/ajcn.115.128009.
- Das, S., McClintock, T., Cormack, B., Bloomfield, F., Harding, J., & Lin, L. (2024). High protein intake on later outcomes in preterm children: a systematic review and meta-analysis. Pediatric Research, 97, 67 - 80. https://doi.org/10.1038/s41390-024-03296-z.
- Garcia-Iborra, M., Castanys-Muñoz, E., Oliveros, E., & Ramírez, M. (2023). Optimal Protein Intake in Healthy Children and Adolescents: Evaluating Current Evidence. Nutrients, 15. https://doi.org/10.3390/nu15071683.
- Ko, G., Rhee, C., Kalantar-Zadeh, K., & Joshi, S. (2020). The Effects of High-Protein Diets on Kidney Health and Longevity.. Journal of the American Society of Nephrology : JASN. https://doi.org/10.1681/asn.2020010028.
- Cuenca-Sánchez, M., Navas-Carrillo, D., & Orenes-Piñero, E. (2015). Controversies surrounding high-protein diet intake: satiating effect and kidney and bone health.. Advances in nutrition, 6 3, 260-6 . https://doi.org/10.3945/an.114.007716.
- Kühn, T., Kalotai, N., Amini, A., Haardt, J., Lehmann, A., Schmidt, A., Buyken, A., Egert, S., Ellinger, S., Kroke, A., Lorkowski, S., Louis, S., Schulze, M., Schwingshackl, L., Siener, R., Stangl, G., Watzl, B., Zittermann, A., & Nimptsch, K. (2024). Protein intake and cancer: an umbrella review of systematic reviews for the evidence-based guideline of the German Nutrition Society. European Journal of Nutrition, 63, 1471 - 1486. https://doi.org/10.1007/s00394-024-03380-4.