Protein supplementation dosage recommendations
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Protein Supplementation Dosage Recommendations for Different Populations
General Guidelines for Healthy Adults and Athletes
For healthy, exercising adults, most recommendations suggest a daily protein intake of 1.4–2.0 grams per kilogram of body weight (g/kg/day) to support muscle building and maintenance. This range is considered sufficient for the majority of individuals engaged in regular exercise, especially resistance training. For those aiming to maximize muscle protein synthesis (MPS), consuming 0.25 g/kg of high-quality protein per meal, or an absolute dose of 20–40 grams, is generally advised. These doses should ideally be distributed evenly every 3–4 hours throughout the day. Rapidly digested proteins with high essential amino acid (EAA) and leucine content are most effective for stimulating MPS. Pre-sleep casein protein intake (30–40 g) can also enhance overnight muscle protein synthesis without affecting fat breakdown. While whole foods can meet protein needs, supplementation is a practical way to ensure adequate intake, especially for athletes with high training volumes or those seeking to minimize caloric intake from other sources 110.
Protein Supplementation in Older Adults
Older adults require higher protein intakes than younger adults to maintain muscle mass and function due to age-related changes in protein metabolism. Recommendations for older people (>65 years) are at least 1.0–1.2 g/kg/day, with higher intakes (≥1.2 g/kg/day) suggested for those who are physically active or recovering from illness. For older adults with acute or chronic diseases, 1.2–1.5 g/kg/day may be necessary. Protein supplements are often best taken twice daily, ideally after exercise, with doses of 30 grams or more per serving. The timing (with or between meals) appears less critical, as studies show little suppression of appetite or food intake with supplementation. However, those with severe kidney disease (not on dialysis) may need to limit protein intake 4679.
Protein Needs in Critically Ill and Hospitalized Patients
In critically ill patients, higher protein intakes in the range of 1.2–2.5 g/kg/day have been suggested to help preserve muscle mass and stimulate protein synthesis. However, recent evidence indicates that increasing protein supplementation above 1.2 g/kg/day does not significantly improve clinical outcomes such as mortality, length of hospital stay, or incidence of acute kidney injury. Therefore, while meeting protein goals early in critical illness is important, there is no clear benefit to very high protein doses in this population 35.
Protein Supplementation for Cancer Patients
For patients undergoing systemic anti-cancer treatment, guidelines recommend a minimum protein intake of 1.0 g/kg/day to maintain or restore lean body mass. High-protein, low-volume oral nutritional supplements (ONS) taken twice daily can help most patients meet these recommendations, even when regular food intake is insufficient .
Protein Intake for Endurance Athletes and Special Diets
Endurance athletes are advised to consume 1.2–2.0 g/kg/day of protein, similar to strength athletes, to support recovery and offset muscle damage. Most athletes can meet these needs through diet alone, but about a quarter may fall short and benefit from supplementation. Nutritionist guidance is recommended to ensure adequate intake, especially for those following plant-based or Mediterranean diets, which may be lower in animal protein sources 810.
Considerations for Protein Source, Quality, and Timing
The quality of protein—its amino acid profile and digestibility—affects its effectiveness. Both animal and plant-based proteins can support muscle health, but a diverse intake is encouraged for overall nutrition. While the timing and frequency of supplementation (e.g., once, twice, or three times daily; with or between meals) do not significantly alter the benefits for muscle mass in older adults, ensuring total daily intake meets recommendations is most important 6910.
Conclusion
Protein supplementation dosage recommendations vary by age, health status, and activity level. Most healthy adults and athletes benefit from 1.4–2.0 g/kg/day, while older adults and those with illness may require 1.0–1.5 g/kg/day. Critically ill patients do not appear to benefit from doses above 1.2 g/kg/day. The source, quality, and even distribution of protein throughout the day are important, but the total daily intake remains the key factor for supporting muscle health and recovery across populations.
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