Micronutrient status in obese patients: A narrative review

Obesity is a violation of carbohydrate and fat metabolism, which further affects the micronutrient status. The volume of distribution of lipophilic substances (including fat-soluble vitamins) also increases in proportion to fat mass. To date, there is much evidence that obese people have lower serum levels of vitamins A and D. Moreover, obesity leads to a decrease in vitamin D endogenous synthesis. The developed vitamins A and D deficiency aggravates carbohydrate and fat metabolism. A vicious circle forms. Obesity is also associated with lower concentrations of water-soluble vitamins. People with an increased BMI often face thiamine, folate, and ascorbic acid deficiency. Firstly, the excretion of these vitamins increases because of their evaluated expenditure. Secondly, the diet of obese patients often lacks vegetables and fruits, which results in reduced intake of folic and ascorbic acids. Obese people are at greater risk of developing zinc, manganese, magnesium, chromium, and vanadium deficiency. This is due to the increased need for these elements in obesity because they are involved in carbohydrate and fat metabolism. Moreover, the nutritional intake of these micro- and trace elements is also often reduced in people who consume not enough plant foods. The existing recommended dietary allowances for micronutrients are standard, but it seems necessary to develop specific norms for patients with obesity on different stages. The assessment of micronutrient supply in obese patients is challenging. It's not fully understood how vitamins, macro- and trace elements serum levels reflect their status in the organism considering the significantly changed nutrient kinetics of obese patients compared to the average population. © 2020 Elsevier Ltd