The Claim

In healthy older men undergoing resistance training, a daily protein intake of 1.6 g/kg/d causes a statistically significant increase in serum creatinine and alanine transaminase levels compared to a daily protein intake of 0.8 g/kg/d over an 8-week period, with both biomarker levels remaining within normal clinical reference ranges.

Source: Effects of 8 weeks of resistance training in combination with a high protein diet on body composition, muscular performance, and markers of liver and kidney function in untrained older ex-military men

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
74score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Cause and effect
1 study reviewed
In plain English

Healthy older men who lift weights and consume 1.6 grams of protein per kilogram of body weight daily show higher levels of serum creatinine and alanine transaminase after 8 weeks than those consuming 0.8 grams per kilogram, but both groups remain within normal clinical ranges.

See the scientific wording

In healthy older men undergoing resistance training, a daily protein intake of 1.6 g/kg/d leads to a statistically significant increase in serum creatinine and alanine transaminase levels compared to 0.8 g/kg/d, though both remain within normal clinical reference ranges, indicating transient physiological stress without evidence of organ damage over 8 weeks.

Why this might work

Eating more protein gives the body more amino acids, which build bigger muscles after weight training. The liver processes the extra amino acids, and as muscles grow and break down slightly during recovery, they release more creatinine and enzymes into the blood. These levels go up but stay within safe limits because the kidneys and liver are working normally.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Effects of 8 weeks of resistance training in combination with a high protein diet on body composition, muscular performance, and markers of liver and kidney function in untrained older ex-military men

    When older men lift weights and eat more protein (1.6 g per kg of body weight), their blood tests show slightly higher levels of a few harmless markers, but their kidneys and liver are still working fine — no damage found.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.