Relação Entre Obesidade e Deficiências Micronutrientes na COVID-19

Relationship between obesity and low levels of micronutrients among elderly patients infected by SARS-CoV-2

Author 

Thiago José Martins Gonçalves, MD

Affiliation/Institution

Division of Nutrology and Clinical Nutrition, Sancta Maggiore Hospital, Prevent Senior Private Health Operator, São Paulo, Brazil

Running Title

Micronutrients and Obesity in COVID-19

Correspondent author

Thiago José Martins Gonçalves, MD

e-mail: thiagojmg@yahoo.com.br

Lourenço Marques, 158 - Vila Olímpia, São Paulo – SP Brazil

ZIP CODE: 04547-100

Phone: +55 11 976058393

Abstract

        The pandemic caused by 2019 novel coronavirus disease (COVID-19) emerged in Wuhan province, China, in December 2019, and has caused infections with varied clinical presentations, ranging from asymptomatic patients, mild flu syndrome to severe respiratory failure. Elderly individuals are part of the highest risk group for infection. In addition, it can be seen that many of elderly are obese and have multiple clinical comorbidities such as hypertension, diabetes and heart disease. Aging and obesity reduce levels of circulating micronutrients both due to the lower absorption of these nutrients by the digestive tract and the high consumption of some micronutrients due to the oxidative stress of the obese patient. Low levels of micronutrients among obese elderly people can aggravate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the disease may progress to orotracheal intubation and the need for mechanical ventilatory support. This mini review will show especially the relationship between low levels of vitamin D and zinc among elderly patients with obesity hospitalized with COVID-19.

Keywords

obesity; micronutrients; elderly; COVID-19; SARS-CoV-2

Introduction

        In early December 2019, the fast propagation of a novel coronavirus broke out in Wuhan, Hubei, China, and caused a highly infectious serious acute respiratory syndrome named coronavirus disease 2019 (COVID-19) (1). COVID-19 causes high morbidity and mortality worldwide, and the World Health Organization (WHO) officially declared it a pandemic in March 2020.

        Obesity is very popular in most countries, especially in the United States with the incidence higher than 40% (2). It may lead to diabetes and heart disease, which are all associated with susceptibility or higher mortality of COVID-19. These remind us that obesity may be closely related to the aggravation of COVID-19. Obesity has been described as an independent predisposition factor for severe pulmonary infection (2). Moreover, abdominal obesity is associated with impaired ventilation of the base of the lungs, resulting in reduced oxygen saturation of blood. Furthermore, the abnormal secretion of adipokines and cytokines like TNF-alpha and interferon characterize a chronic low-grade inflammation characteristic of abdominal obesity, which may impair immune response and have effects on the lung parenchyma (3). Exploring the relationship between obesity and the severity of the disease is therefore of major clinical importance.

        Furthermore, obesity could lead to severe conditions of COVID-19 in several possible ways such as: metabolic syndrome could cause damage to organs;  increased expression of angiotensin converting enzyme-2 (ACE2), which would bind to the virus protein firmly and make adipose tissue a portal for virus invasion; state of overactivated inflammation and immune response, which may induce the excessive inflammatory response and immune exhaustion in COVID-19; obesity has increased abdominal pressure, limited chest expansion and movement, and insufficient respiratory compensatory function (4,5).

        Obesity also induced inflammation and insulin resistance in adipose tissue can further complicate the COVID-19. The resistance and the lipolytic effects of catecholamines and natriuretic peptide in obese patients mediated by a low amount of beta-2 adrenergic receptors in adipocytes can lead to a reduction in the release of micronutrients stored in adipose tissue (6).

        Clinical and subclinical micronutrient deficiencies common in older adults especially with obesity are known to contribute to decreased immune function and age-related diseases, implying that nutritional management is essential to reduce the risk of severe infection. In view of a lack of clinical data on preventive and/or therapeutic efficiency of the nutritive adequacy especially of zinc and vitamin D in COVID-19, this mini review aims to discuss the relationship between obesity and low levels  of micronutrients among elderly patients infected by severe acute respiratory syndrome (SARS-CoV-2) and the role of these micronutrients in the protection against bronchopulmonary infections, as well as the existing indications of their impact on COVID-19.  

Discussion

        With the COVID-19 pandemic, nutrition is currently being discussed not only as a game changer for world health, but also when the nutrition is inadequate, as a potential source and reservoir for the emergence of viruses and development multi-resistant bacteria (7). An optimized nutritional status can have a range of effects on the activation of the immune system. A diet rich in proteins of high biological value, vitamins and minerals, such as lean meats, fruits, vegetables, legumes, nuts and olive oil, can have an influence on minor susceptibility to infectious diseases (8).

        Recent studies have shown that low levels of micronutrients such as vitamin D and zinc, especially among elderly patients with obesity, have a greater potential in viral respiratory infections in previous deficient populations. Although the nutritional status of patients with COVID-19 has not yet been adequately studied, there is preliminary evidence that these disorders are associated with worse disease progression and outbreak, probably associated with a greater susceptibility to infection (8,9).

Vitamin D

        Vitamin D is a lipophilic hormone playing a key role in bone metabolism and calcium homeostasis, mainly acting by binding the vitamin D receptor (VDR), whose distribution involves almost all human tissues and cells. Recent data have also demonstrated potential modulation of extra-skeletal effects such as the immune system, cardiovascular diseases, insulin resistance and type 2 diabetes, conditions commonly linked with obesity (10).

        Hypovitaminosis D is a common condition among elderly patients with obesity. Worldwide data show that 5% - 25% of the independent elderly population and 60 - 80% of institutionalized patients are deficient or insufficient in vitamin D (11). Epidemiological studies reported that vitamin D deficiency represents an increasingly widespread phenomenon in various populations. Vitamin D deficiency is considered a clinical syndrome determined by low circulating levels of 25-hydroxyvitamin D (25-OHD), which is the biologically inactive intermediate and represents the predominant circulating form. Different mechanisms have been hypothesized to explain the association between hypovitaminosis D and elderly patients with obesity, including lower dietary intake of vitamin D, lesser skin exposure to sunlight, due to less outdoor physical activity, decreased intestinal absorption, impaired hydroxylation in adipose tissue and 25-OHD accumulation in fat (10,11).

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