Effect of ketogenic diets on insulin-like growth factor (IGF)-1 in humans: A systematic review and meta-analysis

• Published in: Ageing research reviews 2024-12, Vol.102, p.102531, Article 102531
• Main Authors: Rajakumar, Gayathiri, Cagigas, Maria Lastra, Wang, Tian, Pan, Angela Y., Pelaia, Tiana, Fuller, Stephen J., Fontana, Luigi
• Format: Article
• Language: English
• Subjects: Ageing; Cancer; Diet, Ketogenic - methods; Glucose metabolism; Humans; Insulin-like growth factor 1; Insulin-Like Growth Factor I - metabolism; Insulin-Like Peptides; Ketogenic diet
• ISSN: 1568-1637; 1872-9649; 1872-9649
• DOI: 10.1016/j.arr.2024.102531

Insulin-like growth factor (IGF)-1 plays a role in aging and cancer biology, with fasting known to reduce serum IGF-1 levels in human adults. However, the impact of ad libitum ketogenic diets (KDs) on IGF-1 levels remains unclear. Adhering to PRISMA guidelines, we conducted a meta-analysis of human trials by systematically searching Ovid, PubMed, Scopus, and CENTRAL Libraries until June 2023. Eligible studies prescribed KDs to adults of any health status, confirmed ketosis, and measured serum IGF-1. Protocols involving prescribed fasting or energy restriction were excluded. Mean differences (MD) and 95 % confidence intervals (CIs) were calculated longitudinally between pre- and post-intervention measurements for the KD groups. Among twelve publications meeting the inclusion criteria, 522 individuals participated, with 236 completing KDs. The intervention duration ranged from 1 to 20 weeks. Pooled results from ten trials showed a significant reduction in serum IGF-1 levels post-intervention (MD: −24.9 ng/mL [95 % CI −31.7 to −18.1]; p55 % fat) effectively induce ketosis and can lower serum IGF-1 by 20 %, fasting glucose by 6 % and insulin by 29 %. This clinically notable reduction in IGF-1 can be attained without the need for a prescribed fasting or severe calorie restriction regimen. Further investigation is warranted to explore the impact of KDs on ageing biomarkers and cancer management. •Insulin-like growth Factor-1 is integral to ageing pathways and may be modified by diet.•Prescribed isocaloric Ketogenic diets (KDs) can lower Insulin-like growth Factor-1 by 20 %.•First meta-analysis across both cancer and non-cancer populations on KDs and IGF-1.•Prescribed isocaloric Ketogenic diets (KDs) may lower glucose and insulin levels.•Ketogenic diets may be a feasible adjuvant diet to cancer therapies.