Neonatal vitamin A deficiency and its impact on acute respiratory infections among preschool Inuit children

Dietary patterns and micronutrients in respiratory infections including COVID-19: a narrative review

BACKGROUND

COVID-19 is a pandemic caused by nCoV-2019, a new beta-coronavirus from Wuhan, China, that mainly affects the respiratory system and can be modulated by nutrition.

METHODS

This review aims to summarize the current literature on the association between dietary intake and serum levels of micronutrients, malnutrition, and dietary patterns and respiratory infections, including flu, pneumonia, and acute respiratory syndrome, with a focus on COVID-19. We searched for relevant articles in various databases and selected those that met our inclusion criteria.

RESULTS

Some studies suggest that dietary patterns, malnutrition, and certain nutrients such as vitamins D, E, A, iron, zinc, selenium, magnesium, omega-3 fatty acids, and fiber may have a significant role in preventing respiratory diseases, alleviating symptoms, and lowering mortality rates. However, the evidence is not consistent and conclusive, and more research is needed to clarify the mechanisms and the optimal doses of these dietary components. The impact of omega-3 and fiber on respiratory diseases has been mainly studied in children and adults, respectively, and few studies have examined the effect of dietary components on COVID-19 prevention, with a greater focus on vitamin D.

CONCLUSION

This review highlights the potential of nutrition as a modifiable factor in the prevention and management of respiratory infections and suggests some directions for future research. However, it also acknowledges the limitations of the existing literature, such as the heterogeneity of the study designs, populations, interventions, and outcomes, and the difficulty of isolating the effects of single nutrients from the complex interactions of the whole diet.

Under five children's acute respiratory infection dropped significantly in Bangladesh: an evidence from Bangladesh demographic and health survey (BDHS), 1996-2018

AIM

This study aims to systematically identify and review the most significant risk factors and the trends that follow Acute Respiratory Infection (ARI) among children under five in Bangladesh.

METHODS

A total of 6863 under-five children were eligible for our analysis, retrieved from Bangladesh Demographic and Health Survey, 2014. ARI cases were defined if a child experienced of coughing with short and rapid breathing at the chest that occurred during two weeks prior to the study. Logistic regression and systematic review methods were appraised to explore the various risk factors involving ARI in Bangladesh. Furthermore, a trend analysis was performed to overlook the historical trend of ARI prevalence and affiliated determinants from 1996/97 to 2017/18 in Bangladesh.

RESULTS

Over the past two decades, Bangladesh experienced a significant drop in ARI prevalence from 12.8% in 1996 to only 3.0% in 2018. The cross-sectional findings revealed that boys (OR=1.35, 95% CI: 1.03-1.78), stunted children (OR=1.35, 95% CI: 1.03-1.78) and mothers with primary or no education (OR=2.53, 95% CI: 1.43-4.90) and secondary education (OR=1.77, 95% CI: 1.00-3.44) has the higher odds of ARI than their counterparts.

CONCLUSION

ARI prevalence significantly declined in Bangladesh while boys, stunted children and uneducated or primary educated mothers were identified as potential risk factors.

Nutritional approach for increasing public health during pandemic of COVID-19: A comprehensive review of antiviral nutrients and nutraceuticals

Background: The novel coronavirus (COVID-19) is considered as the most life-threatening pandemic disease during the last decade. The individual nutritional status, though usually ignored in the management of COVID-19, plays a critical role in the immune function and pathogenesis of infection. Accordingly, the present review article aimed to report the effects of nutrients and nutraceuticals on respiratory viral infections including COVID-19, with a focus on their mechanisms of action. Methods: Studies were identified via systematic searches of the databases including PubMed/ MEDLINE, ScienceDirect, Scopus, and Google Scholar from 2000 until April 2020, using keywords. All relevant clinical and experimental studies published in English were included. Results: Protein-energy malnutrition (PEM) is common in severe respiratory infections and should be considered in the management of COVID-19 patients. On the other hand, obesity can be accompanied by decreasing the host immunity. Therefore, increasing physical activity at home and a slight caloric restriction with adequate intake of micronutrients and nutraceuticals are simple aids to boost host immunity and decrease the clinical manifestations of COVID-19. Conclusion: The most important nutrients which can be considered for COVID-19 management are vitamin D, vitamin C, vitamin A, folate, zinc, and probiotics. Their adequacy should be provided through dietary intake or appropriate supplementation. Moreover, adequate intake of some other dietary agents including vitamin E, magnesium, selenium, alpha linolenic acid and phytochemicals are required to maintain the host immunity.

[Serum level of vitamin A in children with pneumonia aged less than 3 years]

OBJECTIVE

To investigate the association of the serum level of vitamin A (VA) with the severity of pneumonia and recurrent respiratory infection (RRI) within one year after treatment in children with pneumonia, and to provide a basis for serum VA level used as an index for judgment of the condition of pneumonia and prediction of the risk of recurrent respiratory infection.

METHODS

A total of 88 children with pneumonia aged less than 3 years were enrolled as study subjects. Serum VA level was measured on admission, and the development of RRI was followed up by telephone within 1 year after discharge.

RESULTS

The children with pneumonia showed a reduction in the serum level of VA (0.8±0.3 μmol/L). The severe pneumonia group had a significantly lower serum level of VA than the mild pneumonia group (0.7±0.3 μmol/L vs 0.9±0.3 μmol/L; P<0.05), as well as a significantly higher detection rate of vitamin A deficiency (VAD) than the mild pneumonia group (63% vs 28%; P<0.05). The children were followed up for 1 year. The VAD-pneumonia group showed a significantly higher incidence of RRI than the normal VA-pneumonia group (49% vs 18%; P<0.05), while there were no significant differences in the incidence of RRI between the suspected subclinical vitamin A deficiency (SSVAD)-pneumonia group and the normal VA-pneumonia group, as well as between the VAD-pneumonia group and the SSVAD-pneumonia group (P>0.05).

CONCLUSIONS

Children with pneumonia often have a low level of VA, and the level of VA is associated with the severity of pneumonia and the development of RRI afterwards.

[Serum level of vitamin A in children with pneumonia aged less than 3 years]

OBJECTIVE

To investigate the association of the serum level of vitamin A (VA) with the severity of pneumonia and recurrent respiratory infection (RRI) within one year after treatment in children with pneumonia, and to provide a basis for serum VA level used as an index for judgment of the condition of pneumonia and prediction of the risk of recurrent respiratory infection.

METHODS

A total of 88 children with pneumonia aged less than 3 years were enrolled as study subjects. Serum VA level was measured on admission, and the development of RRI was followed up by telephone within 1 year after discharge.

RESULTS

The children with pneumonia showed a reduction in the serum level of VA (0.8±0.3 μmol/L). The severe pneumonia group had a significantly lower serum level of VA than the mild pneumonia group (0.7±0.3 μmol/L vs 0.9±0.3 μmol/L; P<0.05), as well as a significantly higher detection rate of vitamin A deficiency (VAD) than the mild pneumonia group (63% vs 28%; P<0.05). The children were followed up for 1 year. The VAD-pneumonia group showed a significantly higher incidence of RRI than the normal VA-pneumonia group (49% vs 18%; P<0.05), while there were no significant differences in the incidence of RRI between the suspected subclinical vitamin A deficiency (SSVAD)-pneumonia group and the normal VA-pneumonia group, as well as between the VAD-pneumonia group and the SSVAD-pneumonia group (P>0.05).

CONCLUSIONS

Children with pneumonia often have a low level of VA, and the level of VA is associated with the severity of pneumonia and the development of RRI afterwards.

Leukocyte homing, fate, and function are controlled by retinoic acid

Although vitamin A was recognized as an "anti-infective vitamin" over 90 years ago, the mechanism of how vitamin A regulates immunity is only beginning to be understood. Early studies which focused on the immune responses in vitamin A-deficient (VAD) animals clearly demonstrated compromised immunity and consequently increased susceptibility to infectious disease. The active form of vitamin A, retinoic acid (RA), has been shown to have a profound impact on the homing and differentiation of leukocytes. Both pharmacological and genetic approaches have been applied to the understanding of how RA regulates the development and differentiation of various immune cell subsets, and how RA influences the development of immunity versus tolerance. These studies clearly show that RA profoundly impacts on cell- and humoral-mediated immunity. In this review, the early findings on the complex relationship between VAD and immunity are discussed as well as vitamin A metabolism and signaling within hematopoietic cells. Particular attention is focused on how RA impacts on T-cell lineage commitment and plasticity in various diseases.

Dissecting the role of retinoic acid receptor isoforms in the CD8 response to infection

Vitamin A deficiency leads to increased susceptibility to a spectrum of infectious diseases. The studies presented dissect the intrinsic role of each of the retinoic acid receptor (RAR) isoforms in the clonal expansion, differentiation, and survival of pathogen-specific CD8 T cells in vivo. The data show that RARα is required for the expression of gut-homing receptors on CD8(+) T cells and survival of CD8(+) T cells in vitro. Furthermore, RARα is essential for survival of CD8(+) T cells in vivo following Listeria monocytogenes infection. In contrast, RARβ deletion leads to modest deficiency in Ag-specific CD8(+) T cell expansion during infection. The defective survival of RARα-deficient CD8(+) T cells leads to a deficiency in control of L. monocytogenes expansion in the spleen. To our knowledge, these are the first comparative studies of the role of RAR isoforms in CD8(+) T cell immunity.

In utero and lactational exposure to a mixture of environmental contaminants detected in Canadian Arctic human populations alters retinoid levels in rat offspring with low margins of exposure

Arctic inhabitants are highly exposed to persistent organic pollutants (POP), which may produce adverse health effects. This study characterized alterations in tissue retinoid (vitamin A) levels in rat offspring and their dams following in utero and lactational exposure to the Northern Contaminant Mixture (NCM), a mixture of 27 contaminants including polychlorinated biphenyls (PCB), organochlorine (OC) pesticides, and methylmercury (MeHg), present in maternal blood of the Canadian Arctic Inuit population. Further, effect levels for retinoid system alterations and other endpoints were compared to the Arctic Inuit population exposure and their interrelationships were assessed. Sprague-Dawley rat dams were dosed with NCM from gestational day 1 to postnatal day (PND) 23. Livers, kidneys and serum were obtained from offspring on PND35, PND77, and PND350 and their dams on PND30 for analysis of tissue retinoid levels, hepatic cytochrome P-450 (CYP) enzymes, and serum thyroid hormones. Benchmark doses were established for all endpoints, and a partial least-squares regression analysis was performed for NCM treatment, hepatic retinoid levels, CYP enzyme induction, and thyroid hormone levels, as well as body and liver weights. Hepatic retinoid levels were sensitive endpoints, with the most pronounced effects at PND35 though still apparent at PND350. The effects on tissue retinoid levels and changes in CYP enzyme activities, body and liver weights, and thyroid hormone levels were associated and likely driven by dioxin-like compounds in the mixture. Low margins of exposure were observed for all retinoid endpoints at PND35. These findings are important for health risk assessment of Canadian Arctic populations and further support the use of retinoid system analyses in testing of endocrine-system-modulating compounds.

A decade of research in Inuit children, youth, and maternal health in Canada: areas of concentrations and scarcities

Inuit Canadians are on average about 20 years younger and have a 10-year lower life expectancy than other Canadians. While there have been improvements in Inuit health status over time, significant health disparities still remain. This paper will review the peer-reviewed literature related to Inuit child, youth, and maternal health between 2000 and 2010, investigate which thematic areas were examined, and determine what proportion of the research is related to each group. Establishing areas of research concentrations and scarcities may help direct future research where it is needed. We followed a systematic literature review and employed peer-reviewed research literature on child, youth, and maternal health which were selected from 3 sources, MEDLINE, CINAHL, and the Circumpolar Health Bibliographic Database. The resulting references were read, and summarized according to population group and thematic area. The thematic areas that emerged by frequency were: infectious disease; environment/environmental exposures; nutrition; birth outcomes; tobacco; chronic disease; health care; policy, human resources; interventions/programming; social determinants of health; mental health and wellbeing; genetics; injury; and dental health. The 72 papers that met the inclusion criteria were not mutually exclusive with respect to group studied. Fifty-nine papers (82%) concerned child health, 24 papers (33%) youth health, and 58 papers (81%) maternal health. The review documented high incidences of illness and significant public health problems; however, in the context of these issues, opportunities to develop research that could directly enhance health outcomes are explored.

Vitamin A deficiency induces fluid hyposecretion from the airway submucosal glands of mice

Vitamin A deficiency (VAD) alters the phenotype of airway epithelium and attenuates the epithelial defense system, and many studies have reported the association of VAD with respiratory disease. In this study, we investigated changes in submucosal glands (SMG) in a mouse model of VAD. C57BL/6 mice were fed a vitamin A-devoid diet and the others were fed a control diet (1.2 mg retinol/kg). The areas of serous and mucous cells of SMG were measured in 4-, 8-, and 20-wk-old male mice. The volume and lysozyme concentration of glandular secretions were also measured. The 2 groups did not differ in body weight or general morbidity at 3-10 wk of age, although serum retinol concentrations were greater in the control mice than in the VAD mice after 4 wk. Upon histological evaluation, we found that the areal ratio of serous cells:total SMG cells was significantly lower after 8 wk in the VAD mice compared with the control mice, although the total area of SMG did not differ between groups throughout the 20-wk experiment. The number of secretory bubbles did not differ between the groups, but total secretion volume was reduced by 35% in 8-wk-old VAD mice compared with controls. Furthermore, the concentration of lysozyme in secretions from 8-wk-old VAD mice was also less than in controls, compounding the effect of diminished secretion volume. In this study, we found serous cell hypotrophy/hypoplasia and dysfunction in VAD mice, which may contribute to the susceptibility to airway infection linked to VAD.

Climate change and environmental impacts on maternal and newborn health with focus on Arctic populations

BACKGROUND

In 2007, the Intergovernmental Panel on Climate Change (IPCC) presented a report on global warming and the impact of human activities on global warming. Later the Lancet commission identified six ways human health could be affected. Among these were not environmental factors which are also believed to be important for human health. In this paper we therefore focus on environmental factors, climate change and the predicted effects on maternal and newborn health. Arctic issues are discussed specifically considering their exposure and sensitivity to long range transported contaminants.

METHODS

Considering that the different parts of pregnancy are particularly sensitive time periods for the effects of environmental exposure, this review focuses on the impacts on maternal and newborn health. Environmental stressors known to affects human health and how these will change with the predicted climate change are addressed. Air pollution and food security are crucial issues for the pregnant population in a changing climate, especially indoor climate and food security in Arctic areas.

RESULTS

The total number of environmental factors is today responsible for a large number of the global deaths, especially in young children. Climate change will most likely lead to an increase in this number. Exposure to the different environmental stressors especially air pollution will in most parts of the world increase with climate change, even though some areas might face lower exposure. Populations at risk today are believed to be most heavily affected. As for the persistent organic pollutants a warming climate leads to a remobilisation and a possible increase in food chain exposure in the Arctic and thus increased risk for Arctic populations. This is especially the case for mercury. The perspective for the next generations will be closely connected to the expected temperature changes; changes in housing conditions; changes in exposure patterns; predicted increased exposure to Mercury because of increased emissions and increased biological availability.

CONCLUSIONS

A number of environmental stressors are predicted to increase with climate change and increasingly affecting human health. Efforts should be put on reducing risk for the next generation, thus global politics and research effort should focus on maternal and newborn health.

Environmental contaminants and human health in the Canadian Arctic

The third Canadian Arctic Human Health Assessment conducted under the Canadian Northern Contaminants Program (NCP), in association with the circumpolar Arctic Monitoring and Assessment Programme (AMAP), addresses concerns about possible adverse health effects in individuals exposed to environmental contaminants through a diet containing country foods. The objectives here are to: 1) provide data on changes in human contaminant concentrations and exposure among Canadian Arctic peoples; 2) identify new contaminants of concern; 3) discuss possible health effects; 4) outline risk communication about contaminants in country food; and 5) identify knowledge gaps for future contaminant research and monitoring. The nutritional and cultural benefits of country foods are substantial; however, some dietary studies suggest declines in the amount of country foods being consumed. Significant declines were found for most contaminants in maternal blood over the last 10 years within all three Arctic regions studied. Inuit continue to have the highest levels of almost all persistent organic pollutants (POPs) and metals among the ethnic groups studied. A greater proportion of people in the East exceed Health Canada's guidelines for PCBs and mercury, although the proportion of mothers exceeding these guidelines has decreased since the previous assessment. Further monitoring and research are required to assess trends and health effects of emerging contaminants. Infant development studies have shown possible subtle effects of prenatal exposure to heavy metals and some POPs on immune system function and neurodevelopment. New data suggest important beneficial effects on brain development for Inuit infants from some country food nutrients. The most successful risk communication processes balance the risks and benefits of a diet of country food through input from a variety of regional experts and the community, to incorporate the many socio-cultural and economic factors to arrive at a risk management decision that will be the most beneficial in Arctic communities.

Impact of maternal vitamin A supplementation on the mother-infant pair in Brazil

BACKGROUND/OBJECTIVES

Vitamin A deficiency (VAD) is a major public health problem. The supplementation of lactating women could be an effective strategy to combat it. The objective of this study was to assess the impact of maternal vitamin A supplementation on the mother-infant pair.

SUBJECTS/METHODS

This was a double blind, placebo-controlled randomized clinical assay in which 33 women received 200 000 IU of vitamin A and 33 women received soy oil between 20th and 30th postpartum days. Maternal blood and milk samples were collected immediately before supplementation and 3 months after delivery, when blood was also collected from the babies. Retinol concentrations 0.70 μmol/l in serum and 1.05 μmol/l in milk were considered to indicate VAD.

RESULTS

Increase in serum retinol level was observed in the supplemented group compared with the pre-supplementation levels (1.05 and 1.17 μmol/l, respectively; P=0.026) and to the post-supplementation levels of the control group (1.02 μmol/l; P=0.032). Reduction in breast milk retinol was observed in the control group compared with the pre-supplementation levels (1.93 and 1.34 μmol/l, respectively; P<0.0001) and to the post-supplementation levels of the supplemented group (1.56 μmol/l; P=0.0003). There was significant difference in the prevalence of VAD in breast milk after supplementation, 55.6% (15/27) in the control group and 16.1% (5/31) in the supplemented group (P=0.002). VAD was present in 66.1% (39/59) of infants, with mean serum retinol levels of 0.64±0.30 μmol/l in the control group and of 0.69±0.26 μmol/l in the supplemented group.

CONCLUSIONS

Supplementation had a positive impact on maternal vitamin A status. No effect on infant status was detectable 2 months after supplementation with a single dose.