Naringenin Increases Insulin Sensitivity and Metabolic Rate: A Case Study

Area of Science:

• Biochemistry
• Metabolic Health
• Nutraceuticals

Background:

• Naringenin, a citrus flavonoid, demonstrates potential metabolic benefits in primary human adipocytes, including increased oxygen consumption and expression of key metabolic genes like uncoupling protein 1 (UCP1) and carnitine palmitoyltransferase 1β (CPT1β).
• Investigating the safety and metabolic effects of naringenin supplementation in humans is crucial for understanding its therapeutic potential.

Observation:

• A single female subject with diabetes ingested 150 mg of naringenin three times daily for 8 weeks.
• Measurements included body weight, resting metabolic rate, respiratory quotient, and blood chemistry (glucose, insulin, safety markers) at baseline and after 8 weeks.
• Cellular studies examined the role of peroxisome proliferator-activated receptors (PPARα, PPARγ) and protein kinases (PKA, PKG) in mediating naringenin's effects on adipocytes.

Findings:

• Naringenin supplementation resulted in a 2.3 kg body weight reduction and an increase in resting metabolic rate by 3.5% at 1 hour post-ingestion.
• Insulin levels decreased by 18%, while glucose levels showed no significant change. No adverse events were reported.
• Naringenin's effects on UCP1 and CPT1β mRNA expression in adipocytes were dependent on PPARα and PPARγ activation, but not PKA or PKG.

Implications:

• Naringenin supplementation appears safe in humans and may effectively reduce body weight and insulin resistance.
• The observed increase in metabolic rate, mediated by PPARα and PPARγ activation, highlights naringenin's potential as a metabolic enhancer.
• Further investigation in randomized controlled trials is warranted to confirm these findings and explore naringenin's efficacy for energy expenditure and insulin sensitivity.