Vitamin D plays a key role in keeping normal mineral balance and maintaining bone health. There is accumulating evidence linking deficient vitamin D status with both type 1 and type 2 diabetes.

The purpose of this study is to evaluate the effect of high dose vitamin D supplementation (120000 units per month)for 6 months on glucose homeostasis and glycemic control,in vitamin D deficient patients with non-optimally controlled type 2 diabetes mellitus.

This is a randomized, double blind, parallel group, clinical trial for 6 months duration.

The study group participants will receive vitamin D supplementation (120,000 IU per month) versus the placebo group for 6 months. glycemic control indexes will be measured in T2DM diagnosed study subjects.

Patient will be randomized 1:1 to one of two treatment groups. Vitamin D group vs placebo group.

Randomization kits will include either vitamin D or vitamin D placebo. Blood screens will be taken prior, after 3 months from randomization and after 6 months from randomization. Anthropometric measurements will be drawn as well, at the same time points.

Determination of sample size In order to find a 0.5 mean difference in HgA1C between the two treatment arms (standard deviation 1.2) a 184 sample size will be required to achieve 80% power, 5% alpha (two sided test).

ADMINISTRATIVE AND LEGAL OBLIGATIONS:

Individual patient's medical information obtained as result of this study is considered confidential and disclosure to third parties.

The investigator should maintain a list of appropriately qualified people to whom trail duties are delegated.

Source and study documents will be locked under the supervision of the PI- principle investigator for 15 years.

Study documentations and storage The investigator should maintain a list of appropriately qualified people to whom trail duties are delegated.

All persons authorized to make entries and/or correction on CRF will be included on the investigators team list delegation log.

Study printout and electronic CRF's, ICF's and other study documents will be stored in the at Haemek medical center under the supervision of the PI. All identifying details will be completely erased.

The investigator and staff are responsible for maintaining a comprehensive and centralized filing system of all study- related documentation, suitable for inspection at any time.

Inclusion Criteria:

• Written inform consent must be obtained from the patient before any assessment is performed.
• Male or female patient, 18 years or older.
• Diabetes mellitus patients.
• HgA1C levels on randomization above 7.5% in the last 6 months.
• Low 25(OH) vitamin D levels : under 50nmol/l

Exclusion Criteria:

• Patient who are unable consume food orally.
• Life expectancy under 7 month.
• Unable to sign inform consent.
• Patient unwilling or unable to comply with study procedure.