Periodontal disease is an infectious disease caused by bacterial infection and can be treated and prevented by the elimination of bacterial plaque in the adequately nourished individual. Vitamin D is crucial for systemic health; nevertheless, its deficiency is highly prevalent, present in 30‑ 50% of the general population. Evidence has demonstrated that vitamin D deficiency may place subjects at risk for not only infectious and chronic inflammatory diseases like periodontitis but also breast cancer. Through its effect on bone and mineral metabolism, innate immunity, and several vitamin D receptor gene polymorphisms, vitamin D has been reported to be associated with the periodontal disease. Historically, periodontal disease was seen as an inflammatory disease with little link to nutrition, and many early epidemiological studies failed to show associations between nutritional status and periodontal disease. This paper systematically reviewed published literature on possible associations between different nutrient deficiencies, periodontal disease and breast cancer. Overall, the studies included were limited due to restricted selection and information bias. I. Introduction Periodontal disease is multifactorial disease initiated by bacterial infection leading to response by the host. Periodontal disease involves complex interactions of host defense, bacteria, and virus. Periodontal disease is initiated by biofilm of bacteria on the teeth which triggers an immune-inflammatory response in the adjacent host tissues. (1) Numerous oral bacterial species have been associated with periodontal disease.(2)Hallmarks of this disease are bone loss and an inflammatory, immune reaction. Vitamin D plays role in both calcium and bone homeostasis as well as in the immune function. Vitamin D and calcium deficiencies lead to bone loss and increased inflammation, both well-known symptoms of periodontal disease.Susceptibility to periodontal disease varies among patients as displayed by their onset, extent, and severity of the disease.(3) Carcinogenesis has been described as a multistep process and these steps reflect genetic alterations that drive the progressive transformation of normal human cells into highly malignant derivatives.(4) A history of low degree of chronic inflammation, such as that seen in periodontal disease, is involved in carcinogenesis, and that the incidence of breast cancer would be associated with periodontal disease and characteristic tooth loss. A few earlier studies have reported an association between periodontitis and cancer.(5) The relationship between the coincidence oftheoccurrence of tumors at particular latitudes andthe vitamin D deficiency has for many years beenthe subject of numerous research studies. The discoverythat most tissues have receptors for the vitaminD was breakthrough in understanding therole of the vitamin D in the mechanism of tumor development. The research showed that the vitaminD, by increasing the tissue differentiation andpromoting the apoptosis, reduces the formation of metastases and the angiogenesis.(6) The presence of different alleles for the VDR gene is responsiblefor different risk of tumor formation.