It is a two-year longitudinal effectiveness study. A comparative study with a case-control design. Study will be conducted in Pune city. A total of up to 100 families (50 families per group) will be recruited. The test group will consist of families consuming fortified milk and oil and the control group will consist of families consuming non fortified milk and oil. Individuals between the age 5-18 years, 18-50 years and more than 50 years will be enrolled. Families which intend to stay in the city for the next 2 years, willing to continue with the same brand of milk and oil for the next 2 years, children living with their biological parents and families willing to sign consent form, will be enrolled in the study. Individuals having chronic illnesses likely to affect vitamin D concentrations and those allergic to milk will be excluded.

Study design: A two-year longitudinal effectiveness study Sample selection: Hundred families will be selected for this study, 50 in each group.

For the test group, people/families buying the standardized milk habitually will be identified and offered the study, an ethics approval would be obtained before commencing the study. After a consent is signed, a home visit will be made and family will be given information about the study.

Individuals from families who consume standardized fortified milk + fortified oil will be offered the study. The control group will consist of families consuming unfortified milk and oil. Thus, families habitually consuming unfortified milk and oil (from 'ghanas') will be offered the study.

Inclusion Criteria: Age between 5 to 80 years at the time of enrolment, Intention to stay in the city for the next two years, Families willing to continue with same brand of oil and milk for next two years after enrolment, Children living with their biological mothers/parents, Families willing to sign a consent form.

Exclusion Criteria: History of illness involving calcium or bone metabolism, including stones of the urinary tract, Currently taking vitamin D supplements as treatment of any disease, Receiving immunosuppressive therapy (oral corticosteroids, chemotherapy) during the previous year, Known history of lactose intolerance or other contra-indications or a version to milk intake, Known hypercalcemia or hypercalciuria, Diabetes mellitus or past/current history of renal stones, and any known systemic, endocrine or metabolic disorder, Medications known to interact with vitamin D metabolism (steroids, thiazide diuretics, phenytoin, phenobarbitone, and antitubercular drugs), Hypersensitivity or allergy to any of the components used in nonfortified or fortified milk or oil, Any other reason which in the opinion of a Principal Investigator would interfere with the study shall be excluded.

Individuals between the age 5 - 80 years will be enrolled.

Research data will be shared by keeping names and other information of participant confidential.