Vitamin D Deficiency in Children and Adults

**3**

**Chapter 1**

**Abstract**

research criteria.

**1. Introduction**

rickets [2].

**2. Function of vitamin D**

**2.1 Vitamin D and bone health**

vitamin D during the past two decades [5].

Saudi Arabia

*Fawzi F. Bokhari and Mai Albaik*

Vitamin D and Its Deficiency in

Vitamin D is a hot topic that has attracted attention over the past 10 years, especially since a large proportion of people suffer from this nutrient deficiency. Vitamin D deficiency is estimated to be about 1 billion people all over the world and 50% in Asia and the Middle East. Saudi Arabia has also demonstrated a high prevalence of vitamin D deficiency among healthy Saudi individuals. This chapter provides, in detail, a clear and understandable identification of vitamin D, its function, source, synthesis, metabolism, status, and deficiency. The chapter also focuses on studying vitamin D deficiency in Saudi Arabia based on PubMed's initial

Vitamin D, "sunshine" vitamin, is a vital topic that has attracted great attention of many researchers and the public over the past decades, because a large proportion of the world's population is deficient in this nutritious element [1]. Vitamin D was first discovered at the beginning of the twentieth century in children with

Vitamin D is a prohormone steroid and belongs to the fat-soluble vitamins. It is responsible for endocrine, paracrine, and autocrine functions [1]. Vitamin D is also essential for calcium absorption, bone mineralization, calcium and phosphorus homeostasis, hormonal release, nerve conduction, and neuromuscular function [3, 4].

Vitamin D is known for its crucial role in bone health about a century ago. However, it has also demonstrated its role and effectiveness in extra-skeletal roles of

Vitamin D regulates physiological functions by controlling the metabolism of calcium and phosphates, stimulates growth, and promotes the necessary remodeling of bones and teeth [6]. Vitamin D deficiency is often associated with bone disorders (such as rickets, osteomalacia, and osteoporosis); when serum calcium decreases, the thyroid gland immediately releases parathyroid hormone (PTH),

**Keywords:** vitamin D, function, synthesis, deficiency, Saudi Arabia
