Over the past decade, there is growing evidence that Vitamin D deficiency has now grown into a pandemic. Prevalence of vitamin D deficiency in India is observed to be in more than 30% population, statusbeing poor in school children, pregnant women and large cities. 

Vitamin D is a unique vitamin as it not only can be ingested in the diet as cholecalciferol (vitamin D3) or ergocalciferol (vitamin D2) but it can also be synthesized in the skin when there is adequate sunlight exposure. The role of vitamin D was earlier restricted to skeletal diseases and bone health. Recently its many other functions have been explored and vitamin D has also been linked with several other conditions such as colorectal cancer, diabetes mellitus, multiple sclerosis, cardiovascular disease, obesity, NALFD, etc. Also, there is emerging evidence of a direct role for vitamin D in regulation of immune function. 

In the prevalence studies conducted for hypovitaminosis D, women have often been found to have lower levels of 25(OH)D levels than men. Hypovitaminosis D in women is of a particular concern in the childbearing age as the status of vitamin D during pregnancy in the mother is an important factor for the determination of the vitamin D status in the child. 

Fortification of staple foods was a strategy adopted to achieve vitamin D sufficiency but unfortunately even in advanced countries like USA and Canadathese strategies have been found to be only partially effective and have largely failed to attain vitamin D sufficiency. 

Among the factors that affect Vitamin D levels, the important ones are skin synthesis and dietary intake. It is interesting to note that in spite of being a deficiency disorder, its prevalence is more in obese population. Vitamin D is a fat-soluble vitamin and hence it can move into adipose tissue which can lead to a drop in serum levels. Obesity thus has effects on vitamin D bioavailability. Meta-analysis by Santos et al revealed that vitamin D deficiency was 35% higher in obese individuals. 

The correlation between the triad of obesity, NAFLD and hypovitaminosis D has been investigated and researched by a number of researchers. However, the role that digestion plays in vitamin D absorption, the status of liver health, quality of bile necessary for proper absorption of fat soluble nutrients like vitamin D has not yet been explored. Vitamin D absorption and its possible link to impaired fat metabolism in obesity and NAFLD could be the cause of hypovitaminosis D in obese females. With this background, the current study aims to evaluate effect of therapeutic diet in improving vitamin D levels in obese females with NAFLD.