Coronavirus disease 2019 (COVID-19) is an acute respiratory disease associated with severe systemic inflammation. The optimal status of vitamins and microelements is considered crucial for the proper functioning of the immune system and necessary for successful recovery. Most patients with respiratory distress in COVID-19 are vitamin and microelement deficient, with vitamin D and Se deficiency being the most common. Anyway, various micronutrient supplements are widely and arbitrarily used for prevention or in the treatment of COVID-19. We aimed to summarise current knowledge about molecular and physiological mechanisms of vitamins (D, A, C, B6, B9 and B12) and microelements (Se, Zn, Cu and Fe) involved in the immune system regulation in consideration with COVID-19 pathogenesis, as well as recent findings related to their usage and effects in the prevention and treatment of COVID-19. In the early course of the pandemic, several, mainly observational, studies reported an association of some micronutrients, such as vitamin C, D and Zn, with severity reduction and survival improvement. Still, emerging randomised controlled trials showed no effect of vitamin D on hospitalisation length and no effect of vitamin C and Zn on symptom reduction. Up to date, there is evidence neither for nor against the use of micronutrients in the treatment of COVID-19. The doses that exceed the recommended for the general population and age group should not be used, except in clinical trials. Benefits of supplementation are primarily expected in populations prone to micronutrient deficiencies, who are, as well, at a higher risk of worse outcomes in COVID-19.

The grain of modern wheat cultivars has a significantly lower mineral content, including the content of copper, iron, magnesium, manganese, phosphorous, selenium and zinc. For this reason cereal breeders, are constantly searching for new genetic sources of minerals that are essential in human nutrition. Triticum polonicum, which is grown on a small scale in Spain, southern Italy, Algeria, Ethiopia and warm regions of Asia, deserves special attention in this context. The micronutrient and macronutrient content of T. polonicum versus T. durum and T. aestivum was compared in this study. Polish wheat grain was characterized by the significantly highest content of phosphorus (4.55 g/kg), sulphur (1.82 g/kg), magnesium (1.42 g/kg), zinc (49.5 mg/kg), iron (39.1 mg/kg) and boron (0.56 mg/kg) as well as a low content of aluminium (only 1.04 mg/kg). The macronutrient profile of most T. polonicum lines differed completely from that of common wheat and durum wheat. The principal component analysis supported discrimination of seven Polish wheat lines with a particularly beneficial micronutrient profile (P2, P3, P5, P7, P9, P22 and P25). These lines were characterized by the highest content of copper, iron and zinc, as well as the lowest concentrations of strontium, aluminium and barium which are undesirable in food products. The above lines can be potentially applied as source materials for breeding new wheat varieties. The results of this study indicate that Polish wheat could be used in genetic biofortification of durum wheat and common wheat.

The levels of essential microelements in poultry feed must be high enough to satisfy the birds' requirements, yet low enough to ensure the safety of both animal feed and meat and eggs for human nutrition. The essential role of vanadium (V), chromium (Cr) and nickel (Ni) in poultry nutrition is still under investigation, while their toxicity was well established a long time ago. Even though some feeds might represent a potential source of harmful amounts of microelements, the combination of relevant quality control programs in the animal feed industry, as well as the application of good production practices and the adequate education of nutritionists can substantially reduce the risks associated with overfeeding such minerals. The aim of this review is to give an overview of the role, importance and needs of poultry for V, Cr and Ni.

The objective of this review is to update and discuss the current findings from studies with laying hens on dietary factors that can beneficially affect eggshell quality, with special emphasis on microelements and feed additives. The crucial importance of dietary calcium, phosphorus and vitamin D3 levels and sources for eggshell quality has been well documented in scientific literature. Many recent studies regarding the effect of nutrition on eggshell parameters have focussed on dietary micromineral levels and sources. There has been also growing interest in the influence of feed additives on the improvement of intestinal health and mineral availability. The results of the experiments presented here demonstrate that efficacy of layer diet supplementation with microelements and feed additives is not consistent, however findings of several trials indicate, that eggshell quality may be positively affected in certain conditions by optimal dietary level and form of manganese, as well as by the addition of pre- and probiotics, organic acids, and herb extracts.