Carnitine Metabolism in Clinical Nutrition

Carnitine is a conditionally essential nutrient that serves as a pivotal shuttle for long-chain fatty acids into the mitochondrial matrix, where they undergo β-oxidation to generate adenosine triphosphate. Endogenous biosynthesis occurs primarily in the liver and kidney from lysine and methionine precursors, but dietary intake—especially from meat and dairy products—remains critical to maintain tissue stores, notably in skeletal and cardiac muscle. In clinical nutrition, carnitine status influences energy homeostasis, insulin sensitivity, lipid profiles and redox balance, with deficiency states arising in primary transporter defects, chronic renal failure, liver disease, sepsis and prolonged critical illness. Supplementation strategies have been explored to ameliorate metabolic inflexibility, enhance mitochondrial function and support recovery in conditions such as type 2 diabetes, cardiovascular disease and critical-care survivorship. The dynamic interrelationship between free carnitine and its esterified forms (acylcarnitines) also provides an index of mitochondrial efficiency and substrate overload, offering both diagnostic and therapeutic avenues. Practical applications extend to the management of insulin resistance, attenuation of oxidative stress in coronary artery disease, modulation of muscle protein turnover and optimisation of fatty acid utilisation during rehabilitation following intensive care or major surgery. Emerging evidence highlights the global relevance of tailoring carnitine supplementation to patient phenotype, baseline deficiency and concurrent nutritional interventions to achieve clinically meaningful outcomes while avoiding potential oversupply and imbalanced acylcarnitine accumulation.

Research from Nature Portfolio

No recent Nature Portfolio content available.

Carnitine Metabolism in Clinical Nutrition publication trend

The graph below shows the total number of articles in carnitine metabolism in clinical nutrition across all publications each year (not limited to Nature Index journals).

Technical terms

L-carnitine: A quaternary ammonium compound that transports long-chain fatty acids across the mitochondrial inner membrane for β-oxidation.

Acylcarnitine: An esterified form of carnitine bound to fatty acyl groups, reflecting substrate flux and mitochondrial oxidative capacity.

β-oxidation: The stepwise enzymatic degradation of fatty acids in mitochondria to generate acetyl-CoA, reducing equivalents and ATP.

HOMA-IR: The homeostasis model assessment of insulin resistance, a calculated index from fasting glucose and insulin levels to estimate insulin sensitivity.

References

1. The effects of L-carnitine supplementation on glycemic markers in adults: A systematic review and dose-response meta-analysis. Frontiers in Nutrition (2023).
2. Mid-Term Evolution of the Serum Acylcarnitine Profile in Critically Ill Survivors: A Metabolic Insight into Survivorship. Nutrients (2023).
3. The Role of l-Carnitine in Mitochondria, Prevention of Metabolic Inflexibility and Disease Initiation. International Journal of Molecular Sciences (2022).
4. Effects of L-carnitine supplementation on oxidative stress and antioxidant enzymes activities in patients with coronary artery disease: a randomized, placebo-controlled trial. Nutrition Journal (2014).
5. Role of carnitine in disease. Nutrition & Metabolism (2010).
6. Role of carnitine and its derivatives in the development and management of type 2 diabetes. Nutrition & Diabetes (2018).
7. Supplementation of carnitine leads to an activation of the IGF-1/PI3K/Akt signalling pathway and down regulates the E3 ligase MuRF1 in skeletal muscle of rats. Nutrition & Metabolism (2013).