Folate (vitamin B9) is not a primary treatment for diabetes, but there is some scientific rationale and preliminary evidence supporting its adjunctive use in people with diabetes, particularly for addressing certain complications and comorbidities. Folate is involved in homocysteine metabolism, and people with diabetes often have elevated homocysteine levels, which are associated with increased cardiovascular risk. Some studies have shown that supplementation with folic acid can reduce homocysteine levels in diabetic patients, potentially lowering the risk of cardiovascular events, which are a major cause of morbidity and mortality in diabetes.

Furthermore, metformin, a first-line medication for type 2 diabetes, can reduce folate absorption, leading to deficiencies in some patients. Folate supplementation may thus be recommended for diabetic patients on long-term metformin therapy to prevent deficiency and associated complications, such as anemia or neuropathy.

However, the direct effect of folate on glycemic control (like lowering blood glucose or improving insulin sensitivity) is not well established, and the evidence supporting its use for this purpose is limited and inconclusive. Therefore, folate is not used as a primary treatment for diabetes itself but may be considered to mitigate certain risks or deficiencies related to diabetes or its treatment. Overall, while there is some scientific basis for folate’s supportive use in diabetes care, the strength of evidence is moderate to low.