The Role of Copper Intake in the Development and Management of Type 2 Diabetes: A Systematic Review

Abstract

Diabetes mellitus is a worldwide public health issue with numerous complications. Several risk factors are associated with diabetes, mainly due to patients following an unhealthy lifestyle. Copper is a crucial trace element, with various physiological actions. Different intake levels of copper might contribute to diabetes development due to its dual action as both an anti- and pro-oxidant. Aim: Due to the inconclusive findings regarding the relationship between copper consumption and the management of diabetes, we decided to conduct this extensive systematic review. Up to this date, no similar study has been available in the literature. In this review, we used the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. Relevant articles were identified by searching the electronic databases CINAHL, EMBASE and Medline from their respective index dates to September 2022 using keywords such as “Copper Intake” and “Type 2 Diabetes”. Any paper that has investigated copper exposure through supplementation or any other method that indicates copper intake in human subjects with type 2 diabetes and measures at least one of the outcomes of interest related to diabetes was included in this review. This review is comprised of 4 cross-sectional studies, 3 cohort studies, 2 RCTs, and 2 interventional studies. Two cohort studies found positive associations between copper intake and the risk of developing T2DM, while no significant association was found in the third study. Regarding diabetes outcomes in the four cross-sectional studies, two found inverse associations, one found a positive relationship, and one found no significant association. In interventional studies, all studies found a protective effect of copper, including the RCT, while one found no significant association. The results are inconsistent concerning the association between copper consumption and the likelihood of developing diabetes are inconsistent. Individuals should receive an adequate dietary amount of copper that is within the RDA levels (900 µg/day) to avoid copper deficiency or toxicity. Further studies, especially RCTs, are strongly needed to enable researchers to elucidate more robust conclusions regarding this association.

Assessment of cooking methods and freezing on the nutritional value and health risks of heavy metals in four fish species consumed in Douala, Cameroon

“…Excessive copper intake leads to liver and kidney damage, anaemia due to reduced production of red blood cells, overproduction of reactive oxygen species and, consequently, diabetes. On the other hand, a deficiency leads to vomiting, diarrhoea, enteropathy, mental deficiency, hypothermia, osteoporosis and retarded growth [ 73 ].…”

Copper – a scoping review for Nordic Nutrition Recommendations 2023

“…All were further scrutinised, and finally, 30 articles were judged as relevant and cited. Upon the publication of the NNR2023 report ( 2 ), an updated search was conducted by the NNR2023 committee on 15th April 2023, in which one additional publication was found to be eligible ( 6 ). Additionally, we have included three publications that were not picked up by the search string ( 1 , 7 , 8 ).…”

Immunomodulation through Nutrition Should Be a Key Trend in Type 2 Diabetes Treatment

“…Another mechanism might be that copper is involved in the reactions of glutamic acid decarboxylase (GAD), which is a major beta-cell antioxidant that is altered by reactive oxygen species (ROS). Anti-GAD antibodies contribute to the pathogenesis of T2DM [166,167]. Copper in high doses is suggested to have a pro-oxidant activity, so it is also possible for copper to cause the production of ROS through the Fenton reaction, which can hinder many processes, including ones associated with insulin resistance development and impaired glucose metabolism [168].…”