The Role of Diet and Specific Nutrients during the COVID-19 Pandemic: What Have We Learned over the Last Three Years?

Nutrients and diets have an important impact on our immune system and infection risk and a huge number of papers have been published dealing with various aspects of nutrition in relation to SARS-CoV-2 infection risk or COVID-19 severity. This narrative review aims to give an update on this association and tries to summarize some of the most important findings after three years of pandemic. The analysis of major studies and systematic reviews leads to the conclusion that a healthy plant-based diet reduces the risks for SARS-CoV-2 infection and especially COVID-19 severity. Regarding micronutrients, vitamin D is to the fore, but also zinc, vitamin C and, to some extent, selenium may play a role in COVID-19. Furthermore, omega-3-fatty acids with their anti-inflammatory effects also deserve attention. Therefore, a major aim of societal nutritional efforts in future should be to foster a high quality plant-based diet, which not only exerts beneficial effects on the immune system but also reduces the risk for non-communicable diseases such as type 2 diabetes or obesity which are also primary risk factors for worse COVID-19 outcomes. Another aim should be to focus on a good supply of critical immune-effective nutrients, such as vitamin D and zinc.

Selenium, Zinc, and Manganese Status in Pregnant Women and Its Relation to Maternal and Child Complications.

Micronutrients, as essential components of prenatal care, are important to reduce the risk for maternal and child morbidity and mortality by lowering pregnancy-related complications. The present study aimed to investigate the status of the trace elements, i.e., selenium, zinc, and manganese in pregnant and non-pregnant women from a developing country and to evaluate its relationship with maternal and child complications. Selenium, zinc, and manganese concentrations were measured in the blood serum of 80 pregnant women and compared with 40 non-pregnant healthy controls. The quantitative analyses of trace elements were performed by using the inductively coupled plasma-optical emission spectrometry (ICP-OES) method. The information about the dietary habits of the study participants was recorded by using a food frequency questionnaire. The results showed significant lower selenium and zinc levels in pregnant women as compared to the controls (2.26 ± 1.09 vs. 2.76 ± 1.15 µmol/L, p = 0.031; 21.86 ± 7.21 vs. 29.54 ± 7.62 µmol/L, p < 0.001) respectively, with no difference in manganese concentrations (1.40 ± 0.09 vs.1.38 ± 0.09 log10 nmol/L, p = 0.365). Regarding maternal and child complications, higher manganese levels were associated with an increased odds ratio for maternal complications (OR = 3.175, CI (95%) 1.631-6.181; p = 0.038). Consumption of dairy products was associated with lower selenium and manganese values. Pregnant women showed a lower serum selenium and zinc status, and in addition elevated serum manganese concentrations, which might be associated with a higher risk for maternal pregnancy/birth complications, although more studies are necessary to evaluate this association.

Maternal and neonatal outcomes related to iron supplementation or iron status: a summary of meta-analyses.

BACKGROUND: Iron deficiency is the most abundant nutritional deficiency in the world and is discussed to be associated with adverse pregnancy outcomes. The objective of this review was to perform an umbrella summary of meta-analyses to evaluate the effects and associations of iron supplementation or iron status on maternal and birth/neonatal outcomes. METHODS: A literature search was conducted on PubMed and Scopus by two reviewers without temporal restriction. Systematic reviews and meta-analyses of studies evaluating (1) the effects of multimicronutrient compared to iron + folic acid supplementations on maternal and birth/neonatal outcomes (2), the association of dietary iron intake or hemoglobin or ferritin status regarding the risk for maternal (gestational diabetes mellitus (GDM)) and birth/neonatal outcomes, and (3) the effects of iron supplementation on pregnancy and birth/neonatal outcomes, were included in this review. RESULTS: Overall, 16 meta-analyses were included. Multimicronutrient supplements had significant risk reducing effects on low birth weight and small for gestational age compared to iron/folic acid supplements as controls. Furthermore, most of the meta-analyses showed that higher levels of hemoglobin or ferritin increased the risk for GDM. On the other hand, maternal anemia (low hemoglobin levels) was associated with adverse birth/neonatal outcomes. Finally, iron supplementation reduced the risk of iron deficiency and iron deficiency anemia and had some risk reducing effects on low birth weight newborns. CONCLUSIONS: Our summary of meta-analyses showed that multimicronutrient supplementation had beneficial effects on some neonatal outcomes. Furthermore, higher ferritin levels seem to increase the risk for GDM whereas maternal anemia was associated with adverse birth/neonatal outcomes.

Comparison of rest-break interventions during a mentally demanding task.

Research is scarce on ways to enhance the effect of rest breaks during mentally demanding tasks. The present study investigated the effectiveness of two rest-break interventions on well-being during an academic lecture. Sixty-six students (53 females, mean age 22.5 years) enrolled in two different university classes of 4-hr duration participated in the study. Two measures of well-being (fatigue and vigor) were assessed immediately before, after, and 20 minutes after the break. A control condition without a break as well as an unstructured break was compared with breaks either encompassing physical activity or a relaxation exercise. Compared with the nonbreak condition, the unstructured rest break led to an increase in vigor, the exercise break as well as the relaxation break both to an increase in vigor and a decrease in fatigue at 20-min post break. Compared with the unstructured break, exercise led to an (additional) increase in vigor and relaxation to an (additional) decrease in fatigue at 20-min post break. Thus, the effects of rest breaks during mentally demanding tasks can be enhanced by engaging in physical activity or relaxation exercises, with effects lasting at least as long as 20 min into the continuation of the task.

Impact of Salt Intake on the Pathogenesis and Treatment of Hypertension.

Excessive dietary salt (sodium chloride) intake is associated with an increased risk for hypertension, which in turn is especially a major risk factor for stroke and other cardiovascular pathologies, but also kidney diseases. Besides, high salt intake or preference for salty food is discussed to be positive associated with stomach cancer, and according to recent studies probably also obesity risk. On the other hand a reduction of dietary salt intake leads to a considerable reduction in blood pressure, especially in hypertensive patients but to a lesser extent also in normotensives as several meta-analyses of interventional studies have shown. Various mechanisms for salt-dependent hypertension have been put forward including volume expansion, modified renal functions and disorders in sodium balance, impaired reaction of the renin-angiotensin-aldosterone-system and the associated receptors, central stimulation of the activity of the sympathetic nervous system, and possibly also inflammatory processes.Not every person reacts to changes in dietary salt intake with alterations in blood pressure, dividing people in salt sensitive and insensitive groups. It is estimated that about 50-60 % of hypertensives are salt sensitive. In addition to genetic polymorphisms, salt sensitivity is increased in aging, in black people, and in persons with metabolic syndrome or obesity. However, although mechanisms of salt-dependent hypertensive effects are increasingly known, more research on measurement, storage and kinetics of sodium, on physiological properties, and genetic determinants of salt sensitivity are necessary to harden the basis for salt reduction recommendations.Currently estimated dietary intake of salt is about 9-12 g per day in most countries of the world. These amounts are significantly above the WHO recommended level of less than 5 g salt per day. According to recent research results a moderate reduction of daily salt intake from current intakes to 5-6 g can reduce morbidity rates. Potential risks of salt reduction, like suboptimal iodine supply, are limited and manageable. Concomitant to salt reduction, potassium intake by higher intake of fruits and vegetables should be optimised, since several studies have provided evidence that potassium rich diets or interventions with potassium can lower blood pressure, especially in hypertensives.In addition to dietary assessment the gold standard for measuring salt intake is the analysis of sodium excretion in the 24 h urine. Spot urine samples are appropriate alternatives for monitoring sodium intake. A weakness of dietary evaluations is that the salt content of many foods is not precisely known and information in nutrient databases are limited. A certain limitation of the urine assessment is that dietary sources contributing to salt intake cannot be identified.Salt reduction strategies include nutritional education, improving environmental conditions (by product reformulation and optimization of communal catering) up to mandatory nutrition labeling and regulated nutrition/health claims, as well as legislated changes in the form of taxation.Regarding dietary interventions for the reduction of blood pressure the Dietary Approaches to Stop Hypertension (DASH) diet can be recommended. In addition, body weight should be normalized in overweight and obese people (BMI less than 25 kg/m2), salt intake should not exceed 5 g/day according to WHO recommendations (<2 g sodium/day), no more than 1.5 g sodium/d in blacks, middle- and older-aged persons, and individuals with hypertension, diabetes, or chronic kidney disease, intake of potassium (~4.7 g/day) should be increased and alcohol consumption limited. In addition, regular physical activity (endurance, dynamic resistance, and isometric resistance training) is very important.

Initial evidence for the link between activities and health: Associations between a balance of activities, functioning and serum levels of cytokines and C-reactive protein.

Growing evidence shows interrelations of psychological factors, neurological and immunological processes. Therefore, constructs like a balance of activities, the so called "occupational balance", could also have biological correlates. The aim of this study was to investigate potential associations between occupational balance, functioning, cytokines and C-reactive protein (CRP) in patients suffering from a chronic inflammatory disease like rheumatoid arthritis (RA) and healthy people. Moreover, we wanted to explore potential differences in gender and employment status. A descriptive study in patients with RA and healthy people was conducted using the Occupational Balance-Questionnaire (OB-Quest) and the Short-Form 36 Health Survey (SF-36). Serum levels of cytokines, such as interleukin 6 (IL-6) and 8 (IL-8), interferon alpha (INFα), tumour necrosis factor alpha (TNFα), rheumatoid factor (RF) and of CRP were measured. Descriptive statistics, as well as Mann-Whitney U tests and Spearmen's rank correlation coefficients (rs) were calculated. One-hundred-thirty-two patients with RA and 76 healthy people participated. Occupational balance was associated with functioning, cytokines and CRP. The strongest associations were identified in the unemployed healthy-people sample with cytokines and CRP being within the normal range. For example, the OB-Quest item challenging activities was associated with IL-8 (rs=-0.63, p=0.04) and the SF-36 sub-scale bodily pain was associated with IFNα (rs=-0.69, p=0.02). The items rest and sleep (rs=-0.71, p=0.01) and variety of different activities (rs=-0.74, p<0.01) correlated with the SF-36 sub-scale social functioning. Employed and unemployed people differed in their age and CRP levels. Additionally, gender differences were found in two OB-Quest items in that fewer women were able to adapt their activities to changing living conditions and fewer men were overstressed. In conclusion, we found preliminary biological evidence for the link between occupation and health in that the concepts encompassed in the construct of occupational balance were associated with functioning, cytokines and CRP.

A combination of resveratrol and melatonin exerts chemopreventive effects in N-methyl-N-nitrosourea-induced rat mammary carcinogenesis.

The neurohormone melatonin is primarily involved in the regulation of circadian rhythms, but also acts as an antioxidant and anticarcinogenic agent, especially in breast cancer. Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a widely known polyphenolic agent from red wine, which has been shown to exert antioxidant, anti-inflammatory and anticarcinogenic effects. The objective of this study was therefore to investigate the effects of melatonin in combination with resveratrol in a rat model of experimental mammary carcinogenesis. Female Sprague-Dawley rats aged 31 days were used in the experiment. Mammary carcinogenesis was induced by N-methyl-N-nitrosourea (NMU), which was administered in two intraperitoneal doses (50 mg/kg of body weight). Chemoprevention with resveratrol and melatonin started 2 weeks before the first dose of NMU and lasted until the end of the experiment. The basic parameters evaluated were: tumour incidence, latency period, tumour frequency per group and tumour volume. In addition, oestrogen receptors ERα and ERß, melatonin receptor MT1, proliferating cell nuclear antigen and vascular endothelial growth factor were determined by immunohistochemical staining. The combination of resveratrol and melatonin reduced tumour incidence by approximately 17% and significantly decreased the quantity of invasive and in-situ carcinomas. Food intake declined in the second and seventh weeks after the administration of carcinogen. Resveratrol in combination with melatonin returned food intake to the level of intact controls. Resveratrol in combination with melatonin has some protective effects on NMU-induced rodent breast cancer. Further studies are necessary to confirm these effects of this promising combination.

Combined inpatient rehabilitation and spa therapy for breast cancer patients: effects on quality of life and CA 15-3.

The present study investigated the changes of quality of life, mood, and the tumor marker CA 15-3 associated with a 3-week inpatient breast cancer rehabilitation program incorporating spa therapy. One hundred forty-nine women, 32 to 82 years, participated in the study 3 to 72 months after breast cancer surgery. Quality of life (QoL, EORTC QLQ-C30), anxiety, and depression (HADS) were measured 2 weeks before, at the end, and 6 months after rehabilitation; CA 15-3 at the beginning, end, and at 6 months follow-up. Patients received an individualized rehabilitation program incorporating manual lymph drainage, exercise therapy, massages, psychological counseling, relaxation training, carbon dioxide baths, and mud packs. Quality of life and mood improved significantly, the greatest short-term improvements found for mood-related aspects of quality of life, the most lasting improvements found for physical complaints (eg, fatigue). Also, the tumor marker CA 15-3 declined significantly to follow-up. Patient characteristics, as well as the time since surgery, moderated rehabilitation outcome to a limited extent. Older patients, nonobese patients, patients with a greater lymphedema, and patients with an active coping style showed slightly greater improvements. Hot mud packs inducing hyperthermia did not affect CA 15-3. In conclusion, the combination of inpatient rehabilitation with spa therapy provides a promising approach for breast cancer rehabilitation.

Improving homocysteine levels through balneotherapy: effects of sulphur baths.

BACKGROUND: Plasma homocysteine (tHcy) is a risk factor for cardio-vascular diseases. Furthermore it has been associated with antioxidative status. Additionally balneotherapeutic sulphur baths have been shown to influence antioxidative status. METHODS: 40 patients with degenerative osteoarthrosis were randomised into two equal groups, a treatment group, receiving stationary spa therapy plus daily sulphur baths (sulphur group) and a control group receiving spa therapy alone (control group). Blood tHcy levels and urinary 8-OHdG (an indicator for oxidative stress) were measured at the beginning and the end of spa therapy. RESULTS: tHcy (micromol/l) was significantly reduced from 11.41 (+/-2.91) to 10.55 (+/-2.28) in the sulphur group (p=0.016) and rose insignificantly from 12.93 (+/-2.28) to 13.80 (+/-3.87) in the control group. 8-OHdG (ng 8-OHdG/mg creatinine) declined from 18.00 (+/-18.28) to 11.16 (+/-5.33) in the sulphur group (n.s.) and from 17.91 (+/-5.87) to 18.17 (+/-5.70) in the control group (n.s.). Differences between the two groups showed significant effects of sulphur baths for tHcy (p=0.006) but not for 8-OHdG (p=0.106). CONCLUSIONS: Sulphur baths exert beneficial effects on plasma tHcyt whereas effects on 8-OHdG seem to be unlikely.

Toxic and biochemical effects of zinc in Caco-2 cells.

Zinc (in relatively high concentrations) can be toxic to intestinal cells. The aim of the present study was to quanitfy cellular injury in preconfluent, colonic cancerous cells and in postconfluent, differentiating human intestinal Caco-2 cells. Cellular damage was measured by using cell proliferation, lactate dehydrogenase (LDH)-release, and apoptosis studies. Furthermore, the activities of the major antioxidative enzymes [superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase] and differentiation markers (alkaline phosphatase and aminopeptidase-N) were determined after exposure of the cells to increasing amounts of zinc sulfate. Proliferation and viability decreased in a concentration-dependent manner. A noticeable increase of LDH-release correlated to cell rounding and detachment at relatively high zinc levels (200 muM) was observed in both groups of cells. Above 100 muM of zinc, significant apoptotic activity was found in the preconfluent cells. Zinc supplementation did not alter SOD activities. However, GPx and, in part, catalase activities tended to be higher in zinc-treated cells (nevertheless the results were not significant). Differentiation markers were noticeably induced by increasing amounts of zinc, especially in the preconfluent cells. In conclusion, we suggest that the susceptibility to zinc induced damage is equal in both confluentation groups of Caco-2 cells. Risk assessment for high concentrations seems recommendable.

Contribution of individual spa therapies in the treatment of chronic pain.

OBJECTIVES: The aim of the present study was to evaluate the contribution of individual spa therapies administered during a period of 3 weeks on measures of well being and pain in a sample of patients with chronic back pain. DESIGN: One hundred fifty-three patients with chronic back pain undergoing inpatient spa therapy in Bad Tatzmannsdorf, Austria, participated in the study. According to the prescription of their spa physician, patients underwent two or more of the following treatments: mud packs, carbon dioxide baths, massages, exercise therapies, spinal traction, and electrotherapy. The outcome measures were general pain, back pain, negative mood, and health satisfaction. Regression analyses were conducted to predict the 4 outcome measures at the end of spa therapy and at 6 weeks' follow-up for all therapies applied. The pretreatment outcome measure, age, and sex were controlled for by entering them into the analysis. RESULTS: Patients showed significant improvements in all 4 outcome measures. The prediction of improvement was generally small: only 1% to 11% of the change of the outcome measures could be explained by the type and number of therapies received. On a short-term basis, mud packs and exercise were found to be associated with a greater improvement in mood, whereas a greater frequency of massage therapy and carbon dioxide baths was associated with a smaller improvement in health satisfaction. On a long-term basis, exercise therapy and spinal traction were associated with a greater reduction in back pain. CONCLUSIONS: The results indicate that, in addition to the individual therapies, other factors relating to spa therapy as a whole must contribute to overall treatment outcome. In addition, the results support the efficacy of exercise therapy for chronic back pain.

Seasonal variation in effect of spa therapy on chronic pain.

This study sought to investigate whether the effects of spa therapy are subject to seasonal variation as suggested by conventional spa therapy research. A total of 268 female (age 31-90 yr) and 119 male (age 35-85 yr) patients with noninflammatory chronic pain were studied. Patients stayed at an Austrian spa for 3 wk and received 2-4 treatments per day, including mudpacks, massages, and exercise therapy. In different groups of patients for 2 yr, pain (self-assessed by questionnaire and Likert scales) and associated variables (mood, fatigue) were measured at the beginning, end, and 6 wk after spa therapy. Data were analyzed by multivariate analysis of covariance controlling for possible group differences between seasons and cosinor analysis. The effect of spa therapy on pain was seasonally dependent; short-term decrease of pain was best between April and June and medium-term decrease of pain was best between October and November, with a second minor peak in fall and spring, respectively. The magnitude of the seasonal variation was greater for back (approximately 30%) than for joint (approximately 20%) pain. Positive mood also improved most between April and June. The observed semi-annual variations of pain do not correspond to the well-known annual change in many physiological and psychological variables. The results suggest that the effects of spa therapy and possibly other related treatments, such as physical and alternative therapies, are subject to seasonal variation.