Effects of bariatric surgery on bone metabolism: focusing on vitamin D

Abstract

The main goal of bariatric surgery is weight loss due to fundamental differential changes in the anatomical and physiological characteristics of the gastrointestinal tract. At the same time, one of the most frequent complications of obesity surgery, especially operations associated with malabsorption, is vitamin D deficiency. Patients with obesity initially have a wide range of predisposing factors for metabolic diseases of the skeleton due to lifestyle problems. Nutrient deficiencies with high-calorie diets and a sedentary lifestyle with a tendency to wear clothing that covers most of the skin — reduces serum 25 (OH) D levels. In addition, the situation is aggravated by a decrease in the bioavailability of 25 (OH) D due to its sequestration in adipose tissue and its complete inaccessibility to the central blood flow. The consequences of bariatric surgery — a decrease in the amount of skin and malabsorption can aggravate the existing deficiency. As a result of a decrease in the level of 25 (OH) D and subsequent hypocalcemia and secondary hyperparathyroidism, negatively affect the state of bone health. The presented literature review is devoted to the problems of obesity surgery and vitamin D deficiency. The main focus is on bone metabolism associated with bariatric surgery, the causes of pre and postoperative vitamin D deficiency are discussed, and recommendations for its treatment after obesity surgery are given.