Type 2 Diabetes Mellitus According to the World Health Organization (WHO), there are more than 346 million individuals with diabetes, of which 90% are type 2. Global estimations for the year 2030 predict an epidemic increase that will reach 366 million. According to the National Nutrition and Health Survey of 2006 (ENSANUT2005), there are 6.4 million type 2 diabetic subjects in Mexico.

According to the calculation of the sample size, the investigators will include 120 adults with type 2 diabetes mellitus selected from the outpatient preventive medicine offices of health centres in the State of Mexico who will divided in two groups: supplement and placebo (60 per group). After having been invited to participate and obtaining the informed consent, study subjects will be evaluated for dietary information, as well as biochemical biomarkers of metabolic control, anthropometric, immune and inflammatory markers, gut microbiota and oxidative stress, before beginning the trial, and after 12 and 24 weeks of supplementation. They will have a monthly follow-up visit for evaluation of adherence and adverse effects, as well as delivery of the supplement.

Subjects will be randomly allocated to a supplementation with 1000 mg vitamin C, 400 IU vitamin D and 10 mg of zinc or placebo group, during 24 weeks. Subjects and researchers will be blinded to the supplement or placebo in order to guarantee double-blinding.

Inclusion Criteria:

• Between 25 and 55 years of age, as this is the age in which type 2 diabetes mellitus is more prevalent and there is less probability of encountering multiple diseases in the same subjects
• Both sexes
• Outpatients
• BMI ≥ 25

Exclusion Criteria:

• Without any other chronic disease (cancer, cardiovascular diseases, arthritis and Alzheimer's).
• Severe renal insufficiency.
• Nephrolithiasis or history of nephrolithiasis.
• Hyperoxaluria.
• Hemochromatosis.
• Hypercalcaemia.
• Hypervitaminosis D.
• Using insulin.
• Be taking drugs such as desferrioxamine, iron, cyclosporine, indinavir (protease inhibitors), warfarin, thiazide diuretic, orlistat, ion exchange resins (e.g cholestyramine, laxatives (e.g. mineral oil, senna), vitamin d analogues (e.g. ergocalciferol, calcitriol, and topical calcipotriene), tetracycline antibiotics, quinolone antibiotics, penicillamine, biphosphonates, levothyroxine, eltrombopag.
• Patients with hypersensitivity to any of the active substance(s) or to any of the excipients.
• Hypersensitivity to the by-products including honey, conifers, poplars, Peru balsam, and salicylate.
• Intake of probiotics or supplemental vitamin or mineral (vitamin D, C, zinc or calcium) for 4 weeks before the beginning of the study.
• Smoking and alcohol consumption (> 40 gr/ day for men and 25 gr/ day for women.
• Pregnant or lactating.
• Whose parents or grandparents are/were immigrant or of native origin.

Vitamin Supplement and placebo will be packaged by others not including the investigators, code will be kept secret until the end of the trial or unless a secondary effect is registered and merits the opening of the code