Jan Frank

University of Hohenheim · Institute of Nutritional Sciences

Scope Prenylated chalcones and flavonoids are found in many plants and are believed to have beneficial effects on health when consumed. Xanthohumol is present in beer and likely the most consumed prenylated chalcone, but poorly absorbed and rapidly metabolized and excreted, thus limiting its bioavailability. Micellar formulations of phytochemicals...

Beans (Phaseolus vulgaris L.) are a traditional food in Chile. This work aimed to determine the chemical composition, antioxidant capacity, and enzyme inhibition effect of secondary metabolites-enriched extracts (SMEE) of thirteen Chilean bean landraces before and after boiling. The SMEE composition was assessed by HPLC-DAD-MS/MS, and the main comp...

The fruits of Rosa pimpinellifolia are rich sources of (poly)phenols, however they are underutilized due to the limited information available. The influence of the pressure, temperature, and co-solvent concentration (aqueous ethanol) of the supercritical carbon dioxide extraction (SCO2-aqEtOH) on the extraction yield, total phenolic-, total anthocy...

Globally, the prevalence of anemia among children during the period of complementary feeding is high. A cross-sectional, mixed-methods study was conducted to examine the main determinants of anemia among Syrian refugee children aged 6 to 23 months (n = 215) and to illuminate the knowledge, attitudes and perceptions of their mothers and Lebanese hea...

Background Bread is a major source of grain-derived carbohydrates worldwide. High intakes of refined grains, low in dietary fiber and high in glycemic index, are linked with increased risk for type 2 diabetes mellitus (T2DM) and other chronic diseases. Hence, improvements of the composition of bread could influence population health. Objective Thi...

Dietary supplements that promote healthy aging are mostly warranted in an aging society. Because of age-related risks, anti-inflammatory and anti-oxidative agents such as mi-croalgae are potential candidates for intervention. In a randomized controlled trial, we tested Phaeodactylum tricornutum (PT), a microalgae rich in eicosapentaenoic acid (EPA)...

Syrian refugees in Lebanon are facing vulnerabilities that are affecting their food insecurity levels. The objectives of this study were to measure dietary diversity, food insecurity (FI), and mental health status of Syrian refugee mothers in Lebanon and to explore its associations with their anemia and nutritional status. A cross-sectional study w...

The objective was to describe infant feeding practices, nutrition and related health aspects of infants under six months among Syrian refugees in Greater Beirut, Lebanon. A cross-sectional study was conducted among Syrian refugee mothers with infants under six months in July–October 2018 (N = 114). Additionally, eleven focus group discussions were...

Scope: 20-hydroxyecdysone (20E) is the main phytochemical present in the fresh arils of Prumnopitys andina. 20E was reported to have anabolic effects by modulation of gene transcription by interaction with nuclear receptors. Our aim was to evaluate in vitro bioaccessibility, transepithelial transport of 20E and the capacity of P. andina fruit extr...

In this work, pressurized hot water extraction (PHWE) of hydrophilic polyphenols from black rosehip fruit was maximized using response surface methodology for simultaneous optimization in terms of extraction yield, total antioxidant capacity, total (poly)phenols, catechin, total monomeric anthocyanins, and cyanidin-3-O-glucoside. Extraction paramet...

The objective is to describe infant feeding practices and the nutritional status of infants under six months among Syrian refugees in Greater Beirut, Lebanon. A cross-sectional study was conducted among Syrian refugee mothers with children under five years (July-October 2018), mothers with infants under six months were included in the analysis (n=1...

Scope: Preclinical models have demonstrated the anti-inflammatory and lipid-lowering effects of curcumin. Innovative formulations have been developed to overcome the poor bioavailability of native curcumin. The study hypothesizes that the bioavailability of micellar curcumin is superior to native curcumin and investigates the potential anti-inflam...

Recent studies suggest that a diet rich in sugars significantly affects the gut microbiota. Adverse metabolic effects of sugars may partly be mediated by alterations of gut microbiota and gut health parameters, but experimental evidence is lacking. Therefore, we investigated the effects of high intake of fructose or galactose, with/without fructool...

Inadequate consumption of micronutrient-dense and protein-rich foods such as vegetables, legumes and meat is an important contributing cause for anemia and deficiencies of vitamin A and iron in rural communities of Tanzania and Mozambique. A cross-sectional study was conducted to assess the nutritional status (anthropometrics and hemoglobin) and di...

Background Urinary metabolites of vitamin E, i.e., α- and γ-carboxyethyl hydroxychroman (α- and γ-CEHC), have gained increasing attention and have been proposed as novel biomarkers of vitamin E intake and status. However, there are insufficient data on the relationship of plasma α-tocopherol and γ-tocopherol and dietary vitamin E intake with 24 h u...

Objectives A high intake of sugars is associated with adverse metabolic effects in animal models and humans. However, little is known about the potential of simultaneously ingested dietary fibers to attenuate the negative effects of sugars. The current study thus aimed to investigate the effects of high intakes of fructose or galactose with or with...

Über ein Viertel der Bevölkerung in Deutschland nimmt regelmäßig Nahrungsergänzungsmittel ein, von denen wiederum 11% Vitamin E enthalten [1]. Diese Supplemente können bis zu 1000 I.E. pro Dosis enthalten, was ca. 60-mal höher ist als die empfohlenen 16–22 I.E. pro Tag [2]. Da gerade ältere Menschen häufig Medikamente einnehmen müssen, sind möglich...

Mesenchymal stem cells (MSC) have many roles that are important for the body’s proper functioning. When the MSC pool is damaged, it is often correlated with impaired development or health of the organism. MSC are known for their anti-inflammatory, immunomodulatory and trophic characteristics that play an important role in the physiological homeosta...

Background: Local leafy vegetables are gaining attention as affordable sources of micronutrients, including vitamins, pro-vitamin carotenoids, and other bioactive compounds. Stinging nettles (Urtica spp.) are used as source of fibers, herbal medicine, and food. However, despite the relatively wide geographical spread of Urtica leptophylla on the A...

(1) Background: Mitochondria are the cells' main source of energy. Mitochondrial dysfunction represents a key hallmark of aging and is linked to the development of Alzheimer's disease (AD). Maintaining mitochondrial function might contribute to healthy aging and the prevention of AD. The Mediterranean diet, including walnuts, seems to prevent age-r...

Hop prenylated flavonoids have been investigated for their in vivo activities due to their broad spectrum of positive health effects. Previous studies on the metabolism of xanthohumol using untargeted methods have found that it is first degraded into 8-prenylnaringenin and 6-prenylnaringenin, by spontaneous cyclisation into isoxanthohumol, and subs...

Grass silage is barely used in intensive beef production, but it is unclear if its lower energy supply compared to maize-silage feeding really impairs growth performance. Diets with 100, 300, 500 or 750 g grass silage/kg dry matter replacing maize silage and concentrate were tested with or without dried corn-cob mix (CCM). Performance, carcass and...

Uptake into intestinal cells and intracellular distribution into metabolically competent organelles, such as the endoplasmic reticulum, are important processes potentially limiting the bioavailability of xenobiotics. The incorporation of curcumin into polysorbate 80 micelles improves its naturally low oral bioavailability in humans. Here, we invest...

11′-α-Tocomonoenol (11′-αT1) is structurally related to vitamin E and has been quantified in the microalgae Tetraselmis sp. and Nannochloropsis oceanica. However, it is not known whether 11′-αT1 is present in other microalgae independent of species and origin. The aim of this study was to analyze the tocochromanol profiles of Chlorella sorokiniana,...

Study on the Dietary Diversity, and Nutritional Status of Mother child Pairs by Season in Enset Cultivating Areas of Southern Ethiopia

Phytic acid, the main storage form of phosphate in maize (Zea mays L.) grains, is known as antinutrient due to its chelating properties but may also prevent oxidation. Thus, the impact of phytic acid on the degradation of tocochromanols, carotenoids, fatty acids, and oxidation products in maize during cooking and subsequent in vitro digestion was e...

Xanthohumol is the main prenylflavonoid in hops and has been associated with a wide range of health benefits, due to its anti-inflammatory, anti-oxidative, and cancer-preventive properties. Increasing evidence suggests that xanthohumol positively affects biomarkers associated with metabolic syndrome and cardiovascular diseases (CVDs). This review s...

The microalgae Phaeodactylum tricornutum (PT) contains valuable nutrients such as proteins, polyunsaturated omega-3 fatty acids (n-3 PUFA), particularly eicosapentaenoic acid (EPA) and some docosahexaenoic acid (DHA), carotenoids such as fucoxanthin (FX), and beta-glucans, which may confer health benefits. In a randomized intervention trial involvi...

α-Tocomonoenols are vitamin E-derivatives with a single double-bond in the tocochromanol sidechain. Currently, two congeners are known: 11'-α-tocomonoenol and 12'-α-tocomonoenol, the later better known as “marine-derived tocopherol” (MDT). Information regarding their presence in photosynthetic aquatic organisms is scarce. We thus determined vitamin...

Commercially produced complementary foods are inaccessible to rural households in Ethiopia. This study aimed to optimize the nutritional and functional properties of local complementary foods using flours of the following locally available crops: maize, red kidney bean, kocho, and pumpkin fruit. Ten formulations were generated using a customized mi...

Self-rated health (SRH) is associated with higher risk of death. Since low plasma levels of fat-soluble vitamins are related to mortality, we aimed to assess whether plasma concentrations of vitamins A, D and E were associated with SRH in the MARK-AGE study. We included 3158 participants (52% female) aged between 35–75 years. Cross-sectional data w...

The biological activities of curcumin in humans, including its antioxidative and anti-inflammatory functions, are limited by its naturally low bioavailability. Different formulation strategies have been developed, but the uptake of curcumin from these galenic formulations into and efflux from intestinal cells, which may be critical processes limiti...

Contrary to the major vitamin E congener α-tocopherol, which carries a saturated sidechain, and α-tocotrienol, with a threefold unsaturated sidechain, little is known about the intracellular fate of α-tocomonoenol, a minor vitamin E derivative with a single double bond in C11′-position of the sidechain. We hypothesized that, due to structural simil...

Scope: Different mechanistic approaches to improve the low oral bioavailability of curcumin have been developed, but not yet directly compared in humans. Methods and results: In a randomized, double-blind, cross-over trial with 12 healthy adults, the 24 h pharmacokinetics of a single dose of 207 mg curcumin is compared from the following formula...

Resveratrol, a natural plant phytoalexin, is produced in response to fungal infection or− UV irradiation. It exists as an isomeric pair with cis- and trans-conformation. Whereas multiple physiological effects of the trans-form, including a pronounced anti-tumoral activity, are nowadays elucidated, much less knowledge exists concerning the cis-isome...

The increasing prevalence of overweight/obesity may already have reached the farmers in Tanzania and Mozambique. Here, the measurement of the mid-upper-arm-circumference (MUAC) could become a simple and sensitive tool for early detection of at-risk groups of overweight as well as underweight. Body Mass Index (BMI) and MUAC of female and male farmer...

Berries are rich food sources of potentially health-beneficial (poly)phenols. However, they may undergo chemical modifications during gastrointestinal digestion. The effect of simulated gastrointestinal digestion on the content and composition of secondary metabolites from Gaultheria phillyreifolia and G. poeppigii berries was studied. The influenc...

Grains of three specialty maize varieties and one conventional maize variety cultivated in China were collected and dissected to obtain the germ, endosperm, and pericarp fraction, and then determined for distribution pattern of phosphorus, carotenoids, and tocochromanols. The results showed that phytochemical contents varied significantly among dif...

The objective was to assess the prevalence of anemia and nutritional status of mothers and children under five years among Syrian refugees in Lebanon and to identify nutritional deficiencies among pregnant, lactating, and non-pregnant non-lactating (NPNLM) mothers. A cross-sectional study was conducted among Syrian refugee mothers with children und...

Bitter acids are produced in the glands of the female inflorescence of hop and cause the characteristic bitter taste of most beer styles. The bitter acid biosynthesis is an enzymatic process in which three enzymes are mainly responsible for bitter acid production: valerophenone synthase (VPS) and prenyltransferases 1 and 2 (PT1 and PT2). PT1 is, in...

Acrocomia aculeata is a promising crop for agroforestry systems in subtropical regions and investigated as an alternative to oil palm. Since significant regional differences in morphology and chemical composition have been reported for Acrocomia fruits, we aimed to determine the vitamin E profiles of Costa Rican Acrocomia aculeata from three differ...

The present demographic changes toward an aging society caused a rise in the number of senior citizens and the incidence and burden of age-related diseases (such as cardiovascular diseases [CVD], cancer, nonalcoholic fatty liver disease [NAFLD], diabetes mellitus, and dementia), of which nearly half is attributable to the population ≥60 years of ag...

Epidemiological studies frequently rely on a single biomarker measurement to assess the relationship between antioxidant status and diseases. This bears an inherent risk for misclassification, if the respective biomarker has a high intra-individual variability. The present study investigates the intra-individual variation and reliability of enzymat...

Phosphate is a limiting plant nutrient and essential for corn growth and development. Thus, the impact of phosphate fertilization, location, and the variety of modern corn (Zea mays L.) hybrids on the profiles of fatty acids, carotenoids, and tocochromanols (vitamin E) was assessed in corn grains. Eight different corn hybrids were grown with (52.9...

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in Western nations and characterized by excessive accumulation of lipids in the liver. In this narrative review, we summarize the evidence from human trials that free radical-induced oxidation of macromolecules, in particular of lipids, is a characteristic feature of NAFLD...

Scope A high fructose and galactose intake have shown adverse metabolic effects in animal models and in humans, but it is yet unknown if addition of fermentable dietary fiber could mitigate such effects. This study investigated the effects of high intakes of fructose and galactose, with/without added fructooligosaccharides (FOS), on metabolic facto...

The effects of single and twofold continuous pressure change technology (PCT) applications on the volatiles and sensory characteristics of pineapple juice were studied. Fresh and thermally pasteurised juices were additionally characterised. 128 volatiles were tentatively assigned in the four juices. Thermal pasteurisation and a single PCT treatment...

Tocomonoenols are vitamin E derivatives present in foods with a single double bond at carbon 11' in the sidechain. The α-tocopherol transfer protein (TTP) is required for the maintenance of normal α-tocopherol (αT) concentrations. Its role in the tissue distribution of α-11′-tocomonoenol (αT1) is unknown. We investigated the tissue distribution of...

Due to increased global demand for vegetable oils, diversification of the supply chain with sustainable sources is necessary. Acrocomia aculeata has recently gained attention as a multi-purpose, sustainable crop for oil production. However, the information necessary for effective selection of promising varieties for agricultural production is lacki...

A comprehensive study using continuous pressure change technology (PCT) for the non-thermal processing of fresh pineapple juice on pilot scale was conducted (1 L/min, 50 MPa, argon, 3 min, <35 °C). The immediate effects of a single and a twofold PCT treatment on the most important quality parameters were examined and compared with those of fresh an...

Coconut antimicrobial peptide-1 (CnAMP1) is a naturally occurring bioactive peptide from green coconut water (Cocos nucifera L.). Although biological activities have been reported, the physiological relevance of these reports remains elusive as it is unknown if CnAMP1 is taken up into intestinal cells. To address this open question, we investigated...

Background: Maternal undernutrition is a pervasive health problem among Ethiopian mothers. This study aims at identifying the level of maternal undernutrition and its associated factors in Kilte Awaleo-Health and Demographic Surveillance Site (KA-HDSS), Tigray region, Ethiopia. Methods: Nutritional status of 2260 lactating mothers was evaluated...

The effect of pulsed light (PL) on numerous important quality characteristics of pineapple juice was studied and compared with untreated and thermally pasteurised samples. The laboratory scale PL batch system used was operated with each three different voltages (1.8, 2.1, and 2.4 kV) and numbers of pulses (47, 94, and 187). Treatments with 2.4 kV a...

Introduction: Micronutrient deficiencies and malnutrition during the first 1000 days of life can have lifelong effects on the physical and cognitive development of the child. Lebanon, host of the world's highest per capita number of refugees, is becoming increasingly vulnerable to micronutrient deficiencies and facing a protracted crisis. Up-to-dat...

Colorectal cancer (CRC) is one of the most common cancers and preventive strategies based on natural compounds are highly desirable. Curcumin, the principal bioactive compound in Curcuma longa, was described to have multiple beneficial health effects. A drawback, however, is the low bioavailability due to its insolubility in water. Here, we studied...

Background Xanthohumol is known to exert anti-inflammatory properties but has poor oral bioavailability. Using advanced micellization technology, it has been possible to markedly enhance its bioavailability. Purpose In the present study, we compared the chronic anti-inflammatory activities of native and micellar xanthohumol in the rat adjuvant art...

Whole fruit and vegetable consumption is universally promoted as healthy, to a large extent due to their high contents of phytochemicals, including phenolics and dietary fibre. The major fibre in fruits and vegetables, pectin, however also decreases the bioavailability of phenolics and carotenoids. While ascorbic acid, sucrose and olive oil lipids...