Arginine needs, physiological state and usual diets. A reevaluation

Area of Science:

• Biochemistry
• Human Physiology
• Nutritional Science

Background:

• Arginine is crucial for protein synthesis and ammonia detoxification.
• It serves as a precursor for polyamines and creatine synthesis.
• Arginine influences hormone secretion and immune responses.

Purpose of the Study:

• To question the assumption of sufficient endogenous arginine synthesis in adult mammals.
• To evaluate the benefits of arginine supplementation on metabolic and immune functions.
• To determine optimal arginine intake levels for health and recovery.

Main Methods:

• Review of existing evidence on arginine synthesis and requirements.
• Studies in rats examining arginine's effects on glucose tolerance, trauma recovery, and nitrogen balance.
• Human volunteer studies assessing immune response to arginine supplementation.
• Analysis of creatinine excretion to estimate arginine needs.

Main Results:

• Dietary arginine accelerates recovery from undernutrition and trauma in rats.
• Arginine supplementation reversed nitrogen loss and immune suppression post-trauma in rats.
• Healthy humans showed enhanced lymphocyte immunoreactivity with arginine intake.
• Creatinine excretion suggests suboptimal arginine intake in some adults.

Conclusions:

• Endogenous arginine synthesis may be insufficient for adult mammals, including humans.
• Arginine supplementation can enhance metabolic and immune functions.
• Further evaluation of arginine's role in health and disease is warranted, considering factors like orotic acid excretion and hormone levels.