Key Research Interests and Expertise

Selected projects

Nutritional evaluation of a legume-rich diet in a dietary pattern approach (Planetary Health Concept) and in comparison to a Western dietary pattern in subjects at risk for cardiovascular and neurodegenerative diseases (BMEL/BLE, LeguPlan)

The aim of this research project is the nutritional evaluation of the acute and chronic effects of a legume-rich diet in a dietary pattern approach (Planetary Health Diet Concept), compared to a Western diet, in individuals with risk factors for cardiovascular and neurodegenerative diseases. The research project includes two human intervention studies. The first study aims to determine whether a legume-rich, plant-based meal can already have acute positive effects on the magnitude and duration of postprandial metabolic processes, by assessing a wide range of physiological parameters as well as neuropsychological outcome measures. The second study will examine the longer-term effects of a legume-rich, plant-based diet compared to a Western dietary pattern. Study variables of this intervention are cardiovascular and metabolic parameters, as well as biomarkers of neurodegeneration and neuropsychological targets.

LeguPlan is carried out in collaboration with the University Hospital Bonn, the German Center for Neurodegenerative Diseases (DZNE, Bonn), the University Hospital Cologne, Paderborn University and Friedrich Schiller University Jena.

BMEL/BLE FKZ: 2822EPS008

ClinicalTrials.gov Identifiers: NCT06270901 and NCT06700954

Nutritional evaluation of plant proteins and protein ingredients in the context of nutritional intervention studies (BMBF, AlProPlant)

The aim of this research project is the nutritional evaluation of the influence of plant proteins or protein ingredients (e.g. concentrate, isolate, texturate) on postprandial metabolic responses in metabolically healthy men and women. The research project includes two human intervention studies. Using pea as an example, the first study compares the “digestibility“, availability (including plasma profiles of individual amino acids), and acceptability/tolerability of plant protein components with different degrees of processing. In the second study, physiological effects (e.g., parameters of lipid and glucose metabolism, hunger- and satiety-associated hormones) of the pea protein will be compared with the physiological effects of other protein sources (e.g., poultry, gluten).

AlProPlant is carried out in collaboration with the University Hospital Bonn, the Technical University of Munich, the Friedrich Schiller University Jena and the Fraunhofer IVV Freising.

The research project is conducted and funded within the Innovation Space NewFoodSystems (https://newfoodsystems.de/).

BMBF FKZ: 031B1366

ClinicalTrials.gov Identifiers: NCT06155656 and NCT06618729

Influence of ambient temperature on resting energy expenditure of healthy adults

Resting energy expenditure is defined as the energy required to maintain metabolism and body functions. Several determinants of resting energy expenditure are known, such as body height, body weight, body composition and age. The aim of this human intervention study is to investigate the influence of ambient temperature on the resting energy expenditure of healthy adults. In this context, the resting energy expenditure is measured for each participant at different ambient temperatures (from 18 to 38°C) via respiratory gas analysis. During this time body core- and surface temperature are assessed, as well as body composition via bioelectrical impedance analysis.

The research project is carried out in collaboration with the University Hospital Bonn and the German Aerospace Center (DLR).

ClinicalTrials.gov Identifier: NCT05505240

Plasma appearance of xanthohumol and its effects on resting energy expenditure in healthy adults

Xanthohumol is a secondary plant compound found in hops that has been attributed with various health-promoting properties, especially in animal model studies. The aim of this human intervention study is to investigate the bioavailability of xanthohumol in healthy men and women. In this context, the rate and extend of the plasma appearance of native xanthohumol and xanthohumol integrated into micelles is investigated. In an observational period of 24 hours, xanthohumol and its major metabolites are analyzed in plasma. In a subsequent human intervention study in healthy women, the effects of xanthohumol on resting energy expenditure and substrate oxidation are investigated during an observational period of 3 hours via respiratory gas analysis.

The research project is carried out in collaboration with the University Hospital Bonn, the University of Hohenheim and AQUANOVA AG.

ClinicalTrials.gov Identifiers: NCT05524714 and NCT05711212

Effects of canola oil and coconut oil on postprandial metabolism in older adults with increased cardiometabolic risk

The aim of this human intervention study is to investigate the postprandial effects of fat content and fatty acid composition of mixed meals on parameters associated with cardiometabolic and neurodegenerative diseases in older adults. In this context, subjects consume four breakfast meals with 25 or 50 g of either canola oil (primarily unsaturated fatty acids) or coconut oil (primarily saturated fatty acids). In a postprandial period of 6 hours, parameters of lipid metabolism (e.g., plasma triglycerides), glucose metabolism (e.g., plasma glucose, serum insulin), as well as markers of inflammation (e.g., IL-6), vascular system (e.g., pulse wave velocity) and antioxidant system (e.g., trolox equivalent antioxidative capacity) are analyzed. Furthermore, fatty acid profile, neuropsychologic parameters (e.g., attention, memory) and satiety-associated hormones (e.g., Ghrelin) are assessed.

The research project is funded by the Union for the Promotion of Oil and Protein Plants (UFOP, Germany) and is carried out in collaboration with the University Hospital Bonn and the German Center for Neurodegernerative Diseases (DZNE, Bonn).

ClinicalTrials.gov ID: NCT05208346

Acute effects of different meals on postprandial metabolism in elderly men and women with a risk phenotype for cardiovascular diseases

There is increasing evidence that the postprandial state is an important contributing factor to chronic diseases. The postprandial situation is generally characterized by hyperlipemia, hyperglycaemia/insulinaemia, and associated events such as low-grade oxidative stress and inflammation. The physiology and pathophysiology of the postprandial responses are influenced by nutrient-independent (e.g., metabolic diseases) and nutrient-dependent (e.g., energy content of a meal) factors. The aim of this research project was to systematically investigate the effects of different meals on postprandial metabolic events and to identify dietary, physiological and genetic determinants of postprandial reactions.

The research project was carried out in collaboration with the University Hospital Bonn and the University Hospital Cologne.

The research project was conducted and funded within the project “Diet-Body-Brain”.

BMBF FKZ: 01EA1372D

DRKS-ID: DRKS00009861

Schönknecht YB, Crommen S, Stoffel-Wagner B, Coenen M, Fimmers R, Stehle P, Egert S: Influence of a proinflammatory state on postprandial outcomes in elderly subjects with a risk phenotype for cardiometabolic diseases. European Journal of Nutrition 2022; 61(6):3077-3083

Schönknecht YB, Crommen S, Stoffel-Wagner B, Coenen M, Fimmers R, Stehle P, Ramirez A, Egert S: APOE ɛ4 is associated with postprandial inflammation in older adults with metabolic syndrome traits. Nutrients 2021; Nov 2;13(11):3924

Schönknecht YB, Crommen S, Stoffel-Wagner B, Coenen M, Fimmers R, Holst JJ, Simon MC, Stehle P, Egert S: Acute effects of three different meal patterns on postprandial metab-olism in older individuals with a risk phenotype for cardiometabolic diseases: a randomized controlled crossover trial. Molecular Nutrition and Food Research 2020; Mar 29;e1901035

Acute impact of dietary pattern and walking on postprandial metabolism, attention, and mood in older adults with a cardiovascular disease risk phenotype

Attenuating the postprandial stress response and its associated inflammatory and endothelial events through specific nutritional and lifestyle interventions seems to be a promising and important approach to decrease the susceptibility to the development of cardiovascular diseases in the long term. This might be particularly relevant in individuals already at increased risk to develop cardiovascular or neurodegenerative complications (e.g., individuals with metabolic syndrome). This research project followed a holistic approach and examined the effects of meal composition and moderate physical activity on postprandial events in older subjects with increased risk for the development of cardiovascular and neurodegenerative diseases.

The research project was carried out in collaboration with the University Hospital Bonn, the German Center for Neurodegernerative Diseases (DZNE, Bonn), Healthy Campus Bonn, University Sports Bonn and the German Sport University Cologne.

DRKS-ID: DRKS00012409

Diekmann C, Wagner M, Huber H, Preuß M, Preuß P, Predel HG, Stoffel-Wagner B, Fimmers R, Stehle P, Egert S: Acute Impact of Dietary Pattern and Walking on Postprandial Attention, Mood, and Satiety in Older Adults: A Randomized Crossover Trial. Nutrients. 2019 Sep 26;11(10). pii: E2294. doi: 10.3390/nu11102294

Diekmann C, Huber H, Preuß M, Preuß P, Predel HG, Stoffel-Wagner B, Fimmers R, Stehle P, Egert S: Moderate postmeal walking has no beneficial effects over resting on postprandial lipemia, glycemia, insulinemia, and selected oxidative and inflammatory parameters in older adults with a cardiovascular disease risk phenotype: A randomized crossover trial. Journal of Nutrition. 2019 Nov 1;149(11):1930-1941. doi: 10.1093/jn/nxz14

Human intervention study to examine interactions between alpha-linolenic acid and quercetin

Increased dietary intake and tissue status of the long-chain n-3 PUFAs, EPA and DHA, is associated with cardiovascular benefits. Epidemiological and animal studies suggest that concomitant nutritive intake of flavonoids may increase the conversion of α-linolenic acid (ALA) to longer-chain n-3 fatty acids EPA and DHA. This research project investigated the effects of increased ALA intake on fatty acid composition of serum phospholipids and erythrocytes in metabolically healthy men and women and whether fatty acid profiles and ALA conversion were affected by regular quercetin intake or sex. In addition, the potential independent and additive effects of plant ALA and quercetin on markers of cardiovascular disease risk (e.g., blood pressure, lipid and glucose metabolism, inflammation) were studied.

The research project was funded by the Union for the Promotion of Oil and Protein Plants (UFOP, Germany) and was carried out in collaboration with the University Hospital Bonn, Kiel University and the Johannes Gutenberg University Mainz.

DRKS-ID: DRKS00005076

Burak C, Wolffram S, Zur B, Langguth P, Fimmers R, Alteheld B, Stehle P, Egert S: Effect of alpha-linolenic acid in combination with the flavonol quercetin on markers of cardiovascular disease risk in healthy, non-obese adults: a randomized double-blinded placebo-controlled crossover trial. Nutrition 2019 Feb;58:47-56.

Burak C, Wolffram S, Zur B, Langguth P, Fimmers R, Alteheld B, Stehle P, Egert S: Effect of alpha-linolenic acid supplementation in combination with quercetin and conversion to n-3 long-chain polyunsaturated fatty acids in humans: a randomized double-blinded placebo-controlled crossover trial. British Journal of Nutrition 2017 Mar;117(5):698-711.

Effects of quercetin on blood pressure and endothelial function in subjects with a high CVD risk phenotype

Quercetin is one of the most abundant flavonol in the Western European diet. The aim of this project was to investigate the effects of dietary quercetin supplementation on blood pressure parameters, direct and indirect biomarkers of endothelial function, as well as biomarkers of oxidation and inflammation in patients with components of a metabolic syndrome. To this end, a double-blinded, placebo-controlled crossover trial in overweight men and women was conducted. The study was supported by Grant No. EG292/3-1 of the German Research Foundation (DFG).

The research project was carried out in collaboration with the University Hospital Bonn, Kiel University and Johannes Gutenberg University Mainz.

DRKS-ID: DRKS00000555

Brüll V, Burak C, Stoffel-Wagner B, Wolffram S, Nickenig G, Müller C, Langguth P, Alteheld B, Stehle P, Egert S: Acute intake of quercetin does not influence postprandial blood pressure and endothelial function in overweight-to-obese adults with hypertension in a randomized double-blinded placebo-controlled crossover trial. European Journal of Nutrition 2017; 56(3): 1347-1357.

Brüll V, Burak C, Stoffel-Wagner B, Wolffram S, Nickenig G, Müller C, Langguth P, Alteheld B, Stehle P, Egert S: No effects of quercetin on serum leptin and adiponectin concentrations in overweight-to-obese patients with hypertension: a randomized double-blinded placebo-controlled crossover trial. European Journal of Nutrition 2017; 56(7):2265-2275.

Brüll V, Burak C, Stoffel-Wagner B, Wolffram S, Nickenig G, Müller C, Langguth P, Alteheld B, Fimmers R, Naaf S, Zimmermann BF, Stehle P, Egert S: Effects of a quercetin-rich onion skin extract on 24 h ambulatory blood pressure and endothelial function in overweight-to-obese patients with (pre-)hypertension: a randomised double-blinded placebo-controlled crossover trial. British Journal of Nutrition 2015; 114(8):1263-77.

Bioavailability of quercetin in healthy men and women

The flavonol quercetin is one of the major flavonoids found in edible plants. The bioavailability of quercetin in humans may be influenced by the food matrix in which it is consumed as well as by its chemical and physical form. The objective of this study was to investigate the systemic availability of quercetin aglycone from hard capsules filled with onion skin extract powder and from hard capsules filled with pure quercetin dihydrate in metabolically healthy normal-weight men and women. A secondary objective was to examine potential sex-specific differences in the bioavailability of quercetin.

The research project was carried out in collaboration with the University Hospital Bonn, Kiel University and Johannes Gutenberg University Mainz.

DRKS-ID: DRKS00004350

Burak C, Brüll V, Langguth P, Zimmermann BZ, Stoffel-Wagner B, Sausen U, Stehle P, Wolffram S, Egert S: Higher plasma quercetin levels following oral administration of an onion skin extract compared with pure quercetin dihydrate in humans. European Journal of Nutrition 2017 Feb;56(1):343-353