Traditionally, calcium and vitamin D are treated as partners crucial for bone health. In the human body calcium is located mostly in the skeleton, only 1–2% is present in body fluids and this part is metabolically active. Serum calcium concentration is closely regulated within a narrow physiological range [1]. However, calcium is responsible not only for bone mineralization but also for muscular and neural conductivity and blood coagulation [1]. Vitamin D is necessary for calcium absorption, through amplification of calbindin synthesis, it is also involved in the regulation of parathyroid hormone synthesis [1, 2]. Recently, the pleiotropic effects of vitamin D have become the subject of interest [1, 2]; potential extraskeletal benefits of vitamin D intake include lower cardiovascular morbidity and mortality, reduced risk of diabetes mellitus, breast and colon cancer, multiple sclerosis, allergy, asthma and cognitive illness [1, 2, 3]. Calcium and vitamin D deficiency may lead to secondary hyperparathyroidism which results in the development of rickets and low peak bone mass in children and processes of osteomalacia and osteoporosis in adults [2]. Low vitamin D status in women is associated with impaired fertility [4], adverse pregnancy outcomes, such as miscarriage, preeclampsia and preterm birth, development of gestational diabetes and bacterial vaginosis [4, 5]. Vitamin D deficiency in pregnant women may affect their offspring, because there is a strong correlation between maternal and cord blood 25(OH)D and newborns have inadequate vitamin D storage to draw on in early life [6]. Vitamin D affects more than 3,000 genes, many of which have a role to play in foetal development [7], supporting hypothesis on the role of vitamin D in foetal programming, influencing the genomic programming of foetal and neonatal development, and subsequent disease risk of respiratory infections and asthma, type-1 diabetes and schizophrenia in both childhood and adult life [8, 9]. Rickets, low bone mineral density and reduced postnatal linear growth and weight gain may also occur, particularly if the postnatal supplementation of vitamin D is not sufficient [9]. Diet is the main source of calcium for humans and dairy products are the richest in calcium. On the contrary, a diet that includes fatty fish, beef liver and egg yolk provides only about 10% of vitamin D demand. Most vitamin D comes from skin synthesis.