General objective: To assess the effect of vitamin D supplementation on metabolic syndrome among food insecure and vitamin D deficient older adults in Karaj city, Alborz province in Iran. A two-arm randomised controlled trial (RCT) will be conducted by recruiting participants. Inclusion Criteria: Food insecure, metabolic syndrome; Vitamin D deficiency Exclusion Criteria: those who are already taking any type of vitamin D supplements, Individuals with a history of allergy, Those subjects with serious medical condition such as cancer, heart attack, stroke, and etc., Intervention group: The intervention will start from 10 of May 2017 to 11 of July 2017 for 2 months. The intervention group will receive 50,000 U vitamin D3 per week (equivalent to 1,250 μg) for 8 weeks plus pamphlets and brochures about nutrition and health at the beginning of the study. Control group: The respondents in control group will receive placebo plus brochures and pamphlets related to nutrition and health at the beginning of the study. The data collection process will identify the older adults for both groups; intervention and control. Consent will be obtained from those who are eligible. Anthropometric measurement (height, weight, body mass index, and waist circumference), blood pressure measurement, blood taking and three-day food record will be obtained during baseline from all study respondents in the intervention and control groups. Primary Output: Achieving 25 (OH) D upper than insufficient serum 25(OH) D level >30 ng/l. Secondary Output: Reduction anthropometry (body mass index (BMI) and waist circumference (WC), Improved Biomarkers indicators (lipid profile, fasting blood fast), improved blood pressure before and after intervention.

This study aims to find relationships between food insecurity, vitamin D intakes and its impact on metabolic syndrome among older adults in a city in Alborz province in Iran, known as Karaj. This study has 2 parts; the first part is to determine the prevalence of food insecurity and vitamin D deficiency among older adults in Karaj city. The second part is an intervention study examining effects of vitamin D supplementation on metabolic syndrome (diabetes, obesity, hypertension, and dyslipidaemia) among older adults who have at least have risk factors of metabolic syndrome, food insecure and vitamin D deficient. The first part; the data collection process will be performed in a few stages. The first stage will be to initiate contacting with the health centres in Karaj city to identify the older adults. Appointments will be set after screening the study subjects who will be eligible. Consent will be obtained from those who were eligible. The preliminary information on demographic data, socioeconomics, food insecurity, dietary intake and sunlight exposure will be collected by using a set of questionnaires. The blood sample for measuring serum 25 (OH) D will be taken the same day as questionnaires were filled.

The second stage: The data collection process will be performed in few stages. The first stage will include of contact with health centres in Karaj city to identify the older adults for both groups; intervention and control. Consent will be obtained from those who will eligible. Anthropometric measurement (height, weight, body mass index, and waist circumference), blood pressure measurement, blood taking and three-day food record will be obtained during baseline from all study respondents in the intervention and control groups.

Inclusion Criteria:

• Food insecure,
• Have fit criteria of metabolic syndrome; (WC>90 cm), obesity (BMI≥30 kg/m2), diabetes (FBS>100 mg/dl), high blood pressure (systolic >135 mmHg and diastolic >85 mmHg) and dyslipidaemia (LDL≥ 240 mg/dl, HDL<40 mg/dl, TC≥ 160 mg/dl; TG≥ 200 mg/dl),
• Vitamin D deficient; serum 25(OH) D level <30 ng/ml,
• No use of vitamin D supplementation before 60 days,

Exclusion Criteria:

• An inability or unwillingness to participate,
• Those who are already taking any type of vitamin D supplements,
• Individuals with a history of allergy,
• Those subjects with serious medical condition such as cancer, heart attack, stroke, and etc.,
• Illness that required corticosteroids or insulin,
• Drugs are known to influence vitamin D level; steroids, anti-acids, oestrogen,
• People with conditions that contradict vitamin D supplementation, for example, a history of hypercalcaemia, hepatic disease or renal stones, sarcoidosis, or malignancy,

Aged from 60 to 80 years old,