The coronavirus-disease 2019 (COVID-19) was announced as a global pandemic by the World Health Organization. Challenges arise concerning how to optimally support the immune system in the general population, especially under self-confinement. An optimal immune response depends on an adequate diet and nutrition in order to keep infection at bay. For example, sufficient protein intake is crucial for optimal antibody production. Low micronutrient status, such as of vitamin A or zinc, has been associated with increased infection risk. Frequently, poor nutrient status is associated with inflammation and oxidative stress, which in turn can impact the immune system. Dietary constituents with especially high anti-inflammatory and antioxidant capacity include vitamin C, vitamin E, and phytochemicals such as carotenoids and polyphenols. Several of these can interact with transcription factors such as NF-kB and Nrf-2, related to anti-inflammatory and antioxidant effects, respectively. Vitamin D in particular may perturb viral cellular infection via interacting with cell entry receptors (angiotensin converting enzyme 2), ACE2. Dietary fiber, fermented by the gut microbiota into short-chain fatty acids, has also been shown to produce anti-inflammatory effects. In this review, we highlight the importance of an optimal status of relevant nutrients to effectively reduce inflammation and oxidative stress, thereby strengthening the immune system during the COVID-19 crisis.

Strengthening the Immune System and Reducing Inflammation and Oxidative Stress through Diet and Nutrition: Considerations during the COVID-19 Crisis.

Plant foods are rich in phenolic compounds (PCs) that display multifaceted bioactions in health promotion and disease prevention. To exert their bioactivity, they must be delivered to and absorbed in the gastrointestinal (GI) tract, transported in circulation, and reach the target tissues. During the journey from ingestion to target tissues and final excretion, PCs are subjected to modifications by many factors during their absorption, deposition, metabolism and excretion (ADME) and consequently their bioefficacy may be modified. Consistent with all nutrients in foods, PCs must first be released from the food matrix through mechanical, chemical, and enzymatic forces to facilitate absorption along the GI tract, particularly in the upper small intestine section. Further, glycosylation of PCs directs the route of their absorption with glycones being transported through active transportation and aglycones through passive diffusion. After enteral absorption, the majority of PCs are extensively transformed by the detoxification system in enterocytes and liver for excretion in bile, feces, and urine. The journey of PCs from consumption to excretion appears to be comparable to many synthetic medications, but with some dissimilarities in their fate and bioactivity after phase I and II metabolism. The overall bioavailability of PCs is determined mainly by chemical characteristics, bioaccessibility, and ADME. In this review, factors accounting for variation in PCs bioavailability are discussed because this information is crucial for validation of the health benefits of PCs and their mechanism of action.

Phenolic compounds: their journey after intake

https://pubs.rsc.org/en/content/articlepdf/2017/NP/C7NP00030H

Chlorogenic acids and the acyl-quinic acids: discovery, biosynthesis, bioavailability and bioactivity

Polyphenols are secondary plant metabolites which have been shown to exert antioxidative and antiinflamma tory effects in cell culture, rodent and human studies. Based on the fact that conditions of oxidative stress and inflammation are highly relevant in farm animals, polyphenols are considered as promising feed additives in the nutrition of farm animals. However, in contrast to many studies existing with model animals and humans, potential antioxidative and antiinflammatory effects of polyphenols have been less investigated in farm animals so far. This review aims to give an overview about potential antioxidative and antiinflammatory effects in farm animals. The first part of the review highlights the occurrence and the consequences of oxidative stress and inflammation on animal health and performance. The second part of the review deals with bioavailability and metabolism of polyphenols in farm animals. The third and main part of the review presents an overview of the findings from studies which investigated the effects of polyphenols of various plant sources in pigs, poultry and cattle, with particular consideration of effects on the antioxidant system and inflammation.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/jpn.12579

Potential of plant polyphenols to combat oxidative stress and inflammatory processes in farm animals

Inflammation aims to restore tissue homeostasis after injury or infection. Age-related decline of tissue homeostasis causes a physiological low-grade chronic inflammatory phenotype known as inflammaging that is involved in many age-related diseases. Activation of tryptophan (Trp) metabolism along the kynurenine (Kyn) pathway prevents hyperinflammation and induces long-term immune tolerance. Systemic Trp and Kyn levels change upon aging and in age-related diseases. Moreover, modulation of Trp metabolism can either aggravate or prevent inflammaging-related diseases. In this review, we discuss how age-related Kyn/Trp activation is necessary to control inflammaging and alters the functioning of other metabolic faiths of Trp including Kyn metabolites, microbiota-derived indoles and nicotinamide adenine dinucleotide (NAD+). We explore the potential of the Kyn/Trp ratio as a biomarker of inflammaging and discuss how intervening in Trp metabolism might extend health- and lifespan.

/pdf/tryptophan-metabolism-in-inflammaging-from-biomarker-to-25e22k2tjs.pdf

Tryptophan Metabolism in Inflammaging: From Biomarker to Therapeutic Target

Time-dependent fermentation of different structural units of commercial pectins with intestinal bacteria.

Hintergrund: Der Apfel (Malus × domestica Borkh) ist die am meisten produzierte und konsumierte Frucht Deutschlands [1]. Die Vielfalt an hochwertigen Sorten wird standig durch Neuzuchtungen erweitert, um die Anforderungen von Produzenten und Konsumenten zu erfullen. Ein wichtiges Zuchtungskriterium ist z.B. die Pathogenresistenz [2]. Umfassende Inhaltsstoffanalysen sind erforderlich, um die Qualitatsunterschiede zwischen Sorten hinsichtlich Geschmack, Lagerfahigkeit und Resistenzen gegenuber Schaderregern zu verstehen. Bisherige Sortenvergleichsstudien betrachten jedoch meist nur einzelne Substanzklassen, z.B. Polyphenole [3]. Daher wurde im Rahmen dieser Arbeit eine umfassende Charakterisierung der Metabolitenprofile von 14 uberwiegend neugezuchteten Apfelsorten mittels GC×GCMSund GC-MS-Analysen durchgefuhrt.

/pdf/vergleich-von-herkommlichen-und-neugezuchteten-apfelsorten-3afcp0wo6x.pdf

Vergleich von herkömmlichen und neugezüchteten Apfelsorten mithilfe ungerichteter, GC-basierter Metabolomanalysen

Soil salinity is progressively impacting agriculture, including viticulture. Identification of genetic factors rendering grapevine (Vitis vinifera L.) resilient that can be introgressed into commercial varieties is necessary for safeguarding viticulture against the consequences of global climate change. To gain insight into the physiological and metabolic responses enabling salt tolerance, we compared a salt-tolerant accession of Vitis sylvestris from Tunisia, 'Tebaba', with '1103 Paulsen' rootstock widely used in the Mediterranean. Salt stress was slowly increased, simulating the situation of an irrigated vineyard. We determined that 'Tebaba' does not sequester sodium in the root but can cope with salinity through robust redox homeostasis. This is linked with re-channelling of metabolic pathways towards antioxidants and compatible osmolytes, buffering photosynthesis, such that cell-wall breakdown can be avoided. We propose that salt tolerance of this wild grapevine cannot be attributed to a single genetic factor but emerges from favorable metabolic fluxes that are mutually supportive. We suggest that introgression of 'Tebaba' into commercial varieties is preferred over the use of 'Tebaba' as a rootstock for improving salt tolerance in grapevine.

Christoph H. Weinert

Papers

Time-dependent fermentation of different structural units of commercial pectins with intestinal bacteria.

Vergleich von herkömmlichen und neugezüchteten Apfelsorten mithilfe ungerichteter, GC-basierter Metabolomanalysen

A Tunisian Wild Grape Leads to Metabolic Fingerprints of Salt Tolerance.