Role of macronutrients, dairy products, fruits and vegetables in occurrence and progression of endometriosis: A summary of current evidence in a systematic review

Background: Current evidence on the role of macro- and micronutrients in the aetiopathogenesis of endometriosis is controversial. Objectives: In this systematic review, we aimed to investigate the effect of macronutrients, dairy products, fruits, and vegetables on the occurrence and progression of endometriosis. Materials and Methods: A systematic literature review of eligible articles retrieved from medical databases, including PubMed, Cochrane, and Academic Search, was performed from inception to May 2023. Main outcome measures: The role of nutritional diet effects in endometriosis. Results: Our search yielded 12 studies, including five prospective cohort trials and seven case-control studies. The analysis of this literature supports the idea that processed and unprocessed red meat increases the risk of endometriosis, while no conclusive evidence exists about the effects of other protein sources on the disease. Studies on total fat consumption, including monounsaturated, polyunsaturated, saturated, and trans-unsaturated fats, do not suggest a definitive association with endometriosis. Green leafy vegetables and fresh fruit consumption may reduce the risk of endometriosis. Furthermore, the evidence regarding fibre consumption is not conclusive. Dairy products were found to have a risk-reducing effect on the disease. However, there was no consensus about the role of vitamin D in endometriosis. Conclusions: The certainty of the relationship between endometriosis and outcomes of nutritional factors was "very low" to "low," which limits current literature from being applied for conclusive interpretations. Further large-scale randomised trials and consequent meta-analyses are recommended for high-level evidence. What is new? This article presents an overview of evidence-based studies on the relationship between endometriosis and macronutrients. In addition, the possible influence of other nutritional variables on the development of endometriosis and the limitations of nutritional studies.