Plasma vitamin C and type 2 diabetes: genome-wide association study and Mendelian randomization analysis in European populations

Publication: Diabetes Care

Ju-Sheng Zheng, Jian’an Luan, Eleni Sofianopoulou, Fumiaki Imamura, Isobel D. Stewart, Felix R. Day, Maik Pietzner, Eleanor Wheeler, Luca A. Lotta, Thomas E. Gundersen, Pilar Amiano, Eva Ardanaz, María-Dolores Chirlaque, Guy Fagherazzi, Paul W. Franks, Rudolf Kaaks, Nasser Laouali, Francesca Romana Mancini, Peter M. Nilsson, N. Charlotte Onland-Moret, Anja Olsen, Kim Overvad, Salvatore Panico, Domenico Palli, Fulvio Ricceri,
Olov Rolandsson, Annemieke M.W. Spijkerman, María-José Sánchez, Matthias B. Schulze, Núria Sala, Sabina Sieri,
Anne Tjønneland, Rosario Tumino, Yvonne T. van der Schouw, Elisabete Weiderpass, Elio Riboli, John Danesh, Adam S. Butterworth, Stephen J. Sharp, Claudia Langenberg, Nita G. Forouhi, Nicholas J. Wareham

17 November 2020


Summary:

Type 2 is a condition with serious health problems. Previous research has shown higher blood levels of vitamin C were linked with lower future risk of type 2 diabetes and if this was proven, it could mean that giving vitamin C as a supplement may help in preventing the condition. Testing this theory is quite challenging due to finding the correct dose.

Researchers identified 11 genetic markers that can predict blood levels of vitamin C using a large sample of more than 50,000 adults. They tested the association of type 2 diabetes with genetically predicted vitamin C levels with a large sample size of more than 80,000 people with diabetes and up-to 840,000 people without diabetes.

They found a mismatch when comparing the link of diabetes with the genetically predicted vitamin C levels versus when used directly measured blood vitamin C levels. The researchers results for directly measured or genetically predicted blood vitamin C levels indicated that blood vitamin C is not likely to be a causal factor for the development of type diabetes. Therefore conclude that it is not justified to use vitamin C supplementation for the prevention of type 2 diabetes.

Researchers highlighted that the current research findings should be interpreted as showing no link of the micronutrient vitamin C with type 2 diabetes.

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