Month: October 2019

Interactive effects of the rootstock and the deficit irrigation technique on wine composition, nutraceutical potential, aromatic profile, and sensory attributes under semiarid and water limiting conditions

By Pascual Romero and Josefa Navarro

According to the climate projections for the middle of this century (2040-2070), it will be in semiarid regions of southern Europe (e.g., SE Spain) where viticulture will need to make the greatest adaptation to climate change (CC), with greater costs to maintain quality and productivity, since they are going to experience more severe water stress and impacts of greater magnitude than other winegrowing areas (Guiot and Cramer, 2016; Resco et al., 2016).
The predicted increase in the evapotranspiration and water needs of the vine as a result of CC will make necessary the application of irrigation water to maintain the sustainability of vineyards and to prevent severe water stress in many winegrowing Mediterranean regions, such as southern Spain (Resco et al., 2016). This future scenario, with more recurrent drought phenomena and heatwaves, will make it more necessary to apply efficient deficit irrigation (DI) strategies and techniques as an adaptation to CC, because the water resources will be increasingly limiting. However, to maintain the long-term sustainability of the vineyards, until the year 2050 and beyond, it will be necessary to apply additional adaptation measures, besides irrigation (Fraga et al., 2018).
To face the risks associated with CC and to achieve environmentally sustainable viticulture, the vine genetic diversity should be taken advantage of to increase the diversity of vineyards and overcome the threats of CC (Wolkovich et al., 2018). In a recent study, we evaluated the interactive effects of the irrigation method (RDI and PRI) and rootstock (invigorating and non-invigorating) on global Monastrell berry and wine quality (Romero et al., 2018, 2019). To achieve this, field-grown mature Monastrell grapevines grafted on five different rootstocks (140Ru, 1103P, 41B, 110R, 161-49C) were subjected to regulated deficit irrigation (RDI) and partial root zone irrigation (PRI) in a semiarid region in SE Spain (D.O. Bullas, Region of Murcia) (Figure 1). The main goal was to analyse the effects of the rootstock (R), irrigation method (IM), and their interaction (R x IM) on the final wine composition, volatile aromatic profile, and wine sensory attributes (Romero et al., 2019). We analysed, over three years, the technological, phenolic, metabolomics-nutraceutical, and aromatic composition of the wines from the different rootstock x irrigation method combinations (R x IM) studied. In addition, a sensory analysis of the wines by panels of expert and consumer tasters was carried out in order to relate the final wine chemical composition and quality characteristics to the sensory attributes, taster preferences, and scores of the wines.

Figure 1. Experimental vineyard, with mature Monastrell grapevines grafted onto different rootstocks in SE Spain (Bullas).

The application of low annual water volumes (85-90 mm year−1) to low vigorous rootstocks (161-49C, 110R) was reflected in wines with higher contents of polyphenolics and alcohol, a higher wine quality index (QIwine), enhanced levels of health-promoting bioactive compounds (flavonols, malvidins) (Table 1), and better organoleptic perception compared to other rootstocks (Romero et al., 2019) (Figure 2). These wines also had lower concentration of aromatic compounds (alcohols and esters). The 140Ru wines, although having a lower polyphenolic concentration and worse color, were also among those rated most highly and preferred by the tasters (Figure 2). These wines had a high content of lactic acid and amino acids, higher tartaric/malic and anthocyanins/tannins ratios and a low concentration of aromatic compounds. Future studies will focuss in the optimization of a specific lower-water volume DI strategy for this vigorous and drought-tolerant rootstock, in order to control the excess vigor and yield and enhance Monratrell berry/wine quality in 140Ru.

Table 1. Mean values of the concentrations of several derivatives of anthocyanins and flavonols in wines after alcoholic fermentation, for each rootstock (R), irrigation method (IM), and year, and the interaction (R x IM). The data are from two years (2014 and 2015)..

Figure 2. Number of positive and negative sensory attributes in the wines from different rootstocks, as reported by professional tasters during the sensory analysis. Average values over three years (2014-1026). The vertical bars filled with black oblique lines represent the results of the sum of the positive and negatives attributes. Among the positive attributes reported for wines from rootstock 140Ru by the panelists stand out: middle-upper color layer, violet edge, unctuous, structured, fresh, with ripe black-red fruit, cherries, plums, good acidity, good entry in the mouth, intense, persistent, and long aftertaste. Besides, among the positive attributes reported for the wines from rootstock 161-49C stand out: vivid color, high chromatic intensity, high color intensity, violet edge, fresh, red-black fruit, overripe fruit, peach, pear, intense, expressive, aromatic, persistent, balsamic, and good acidity.

In contrast, 1103P and 41B wines had lower polyphenolic content-nutraceutical value, lower QIwine, tartaric/malic and anthocyanins/tannins ratios, more aromatic compounds, abundant green-vegetable/astringent notes, and more defect-causing compounds. In addition, these wines were also the worst rated in the sensory analysis. Significant positive correlations between the polyphenolic content and alcoholic degree and the score in the wine sensory analysis indicated that the greater the polyphenolic and alcohol contents in the wine, the better valued and more preferred by the tasters it was. PRI method improved wine quality and organoleptic perception for low vigor rootstocks (especially 161-49C), compared to RDI. These wines showed darker color, higher sugar content and nutraceutical potential as well as better sensory perception compared to other rootstock-IM combinations. In contrast, for high vigor rootstocks (1103P, 140Ru), RDI was more beneficial for wine composition, global quality, and sensory perception. Overall, the PRI method also increased the presence of some volatile unpleasant alcohols in the wines. PCA-cluster analysis also showed that 161-49C PRI wines were clearly differentiated from the other rootstock-IM combinations, mainly for their best quality (higher QIwine) and alcohol (PC3) (Figure 3). In contrast, 41B PRI wines were also differentiated (for PC2 and PC3), mainly for their worst quality: higher tannins content, lower QIwine and alcohol and worse sensory evaluation. We recommend the use of low vigor rootstocks (161-49C and R110) and DI techniques with small water volumes to improve Monastrell wine quality and nutraceutical potential, and as a measure to adapt vineyards to climate change under semiarid and water limiting conditions.

Read more about this study at https://doi.org/10.1016/j.agwat.2019.105733

Figure 3. Principal component analysis store plot of factorial weight of the main variables of each component (left), factorial stores of different combinations (rootstock x irrigation method) and groupings made from cluster analysis taking into account each component (right). In different colors the results for each component are shown (red, PC1, green, PC 2 and blue, PC3). Data from three years (2014-2016).

Dr. Pascual Romero is biologist (Murcia University) and he is specialist in soil-plant water relations and stress physiology and he is an expert in the application of several deficit irrigation techniques and strategies in different woody crops, such as almonds, peaches, citrus trees and winegrapes.

Dr. Navarro, degree and PhD in Chemistry at the University of Murcia. During her PhD, carried out at the Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC) in Murcia (Spain), she acquired wide experience in the behaviour of plants under abiotic stress. In 2002, she joined the Irrigation and Stress Physiology Group at the Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA) as researcher. Her research interest focus on the agronomical and physiological responses of plants under saline and drought stresses. Currently, her research is focused into the study of different methodologies, technologies and strategies in order to improve the water use efficiency in plants, and the use of waters of different qualities and quantities for plant irrigation. She is working on multiple projects that include from more agronomic to physiological, nutritional, or more basic aspects related with the fruit quality mainly of citrus and wine grape.
She has participated as scientific responsible and team member of numerous research projects. Her research activity is documented by the publication of large amount of articles in scientific peer-reviewed journals, participation in numerous national and international conferences with posters and oral presentations. She is the reviewer of several international scientific journals, research projects, PhD theses co-supervision of master and bachelor students, assistance in practical lessons and seminars. The h-index is equal to 19, and the total citations are 1,039 (22/10/2019). Web of Science ResearcherID Q-6256-2016. ORCID 0000-0002-8811-4576

References

Fraga, H., García de Cortazar-Atauri, I., Santos, J.A. (2018). Viticultural irrigation demands under climate change scenarios in Portugal. Agri. Water Manag. 196, 66-74.

Guiot, J., and Cramer, W. (2016). Climate change: The 2015 Paris agreement thresholds and Mediterranean basin ecosystems. Science 354, 465-468.

Resco, P., Iglesias, A., Bardají, I., and Sotés, V. (2016). Exploring adaptation choices for grapevine regions in Spain. Reg. Environ. Change 16, 979-993.

Romero, P., Botía, P., and Navarro, J.M. (2018). Selecting rootstocks to improve vine performance and vineyard sustainability in deficit irrigated Monastrell grapevines under semiarid conditions. Agric. Water Manag. 209, 73-93.

Romero, P. , Botía, P., del Amor, F.M., Gil-Muñoz, R., Flores, P., Navarro, J.M. (2019). Interactive effects of the rootstock and the deficit irrigation technique on wine composition, nutraceutical potential,  aromatic profile, and sensory attributes under semiarid and water limiting conditions.

Wolkovich, E.M., García de Cortazar-Atauri, I., Morales-castilla I., Nicholas K.A., and Lacombe T. (2018). From Pinot to Xinomavro in the world´s future wine-growing regions. Nat. Clim. Change 8, 29-37.

Posted by in Viticulture

How natural do you perceive this wine?

By Cornelia Staub

The naturalness trend
Dining out in one of Zurich’s hip new restaurants, I found in the wine list what I normally found on the menu and indicate a vegetarian dish: a little green leaf. The legend explained that these wines are natural wines. What long could be observed in the food sector is becoming a thing in the wine sector too, and often leads to emotional discussions among consumers, producers, and other actors in this field. To this day, there is no one definition of what natural is. Neither for food, nor for wine. Research in the field of food and consumer behavior brings to mind that what counts at the end is not necessarily what could be considered as reasonable or justifiable but what consumers perceive, whether that may be understandable, or not. Is a cookie more natural just because the packaging is green? Of course not, but it’s highly likely consumers will perceive it that way.

To add to the research about naturalness and the discussions of what winemakers should be allowed or not allowed to do to call their wines natural1, we conducted a study to find out, what do consumers think: when is wine natural and when is it not. More specifically, how and where can a wine be produced and packaged in order to be perceived as particularly natural?

1Note, that a ‘common’ interpretation of natural is a wine from organic or biodynamic farming with as few manipulations as possible including spontaneous fermentation instead of adding lab-produced yeast-strains.

What we did
In our study we compared Swiss and Australian consumers using an online survey. We found that naturalness is strongly linked to tradition. Traditional practices such as aging in oak barrels or the use of an oak cork for ceiling were regarded as the most natural practices. Also, the origin seems to be important. Wine from an Old-World producing country were perceived much more natural than wines from the New World, even by Australian participants. Less surprising, since similar results were found for food, organically produced wine was perceived to be more natural than wines from conventional farming. Moreover, it was found that consumers seem to make a difference in the degree of processing that a wine undergoes. A simple practice such as aging in an oak barrel or steel tank is perceived to be much more natural than processes that induce a physical change in the product such as a filtering, and even more natural than processes that induce a chemical manipulation of the wine such as enzymes or the addition of acids.
Interestingly, it was the practices that are prevalent in winemaking that are perceived as being the least natural such as the addition of sulfites, sugar or acids, or clearing agents like charcoal or gelatin.

What’s next
Our findings are not a claim for defining when a wine is allowed to be called natural and when it is not. However, the results show that consumers’ perceptions about whether what they consume is natural or not may not meet the established practices in winemaking. Therefore, a new approach towards how to produce a wine forgoing the use of chemicals and many potentially quality enhancing machines and techniques may be justified.
Many traditional wine drinkers disregard the oftentimes young winemakers of their self-proclaimed natural wines. However, one may keep in mind that it needs a determined enthusiast and a good amount of risk friendliness to produce what they consider a natural wine. Because whether it’s natural or not, what consumers won’t compromise on, is the taste. Consumers’ worries about a product’s naturalness may not always be understandable, not always reasonable, but should certainly not be neglected. Because last but not least it’s them who take the decision buy or not to buy.

 

See more about this studu at: https://doi.org/10.1016/j.foodqual.2019.103752

 

Cornelia Staub holds a Master in Agronomy from ETH Zürich (2018) and is currently doing a PhD in the Group of Consumer Behavior at ETH Zürich. In between and besides her studies, she worked for companies in different fields of food and agricultural products both in Switzerland an abroad, such as in dairy trading (China, Thailand), large-scale vegetable production and trading, aquaponics (France), and more recently in the wine sector, both in production and trading. In her research she focuses on the perception of wine by consumers and the influence on their purchasing behavior. Her particular interest lies in the influence of wine knowledge on perception and behavior, as well as cross-country comparisons. Besides her work as a researcher, she is engaged in consulting of a wine start-up.

Posted by in Enology

Mass spectrometry-based metabolomics in grapevine and wine fingerprinting

By Marta Sousa Silva and Carlos Cordeiro

In the omics universe, the metabolome are the biochemical products that arise from cellular processes and is the final response of a biological system to environmental or genetic changes. Being highly dynamic and time-dependent, metabolomes are exquisitely complex (Aretz and Meierhofer, 2016). In plants, it is predicted that more than 200,000 metabolites are involved in physiological processes, in controlling plant growth and development and plant responses to environmental changes or biotic stresses (Fiehn, 2002). Besides their importance for plant physiology, there is a wide range of compounds with high nutritional value, organoleptic properties and potential human health benefits, which is particularly relevant in crop plants. Due to its economic importance in the wine industry, grapevine (Vitis vinifera L.) is one of the most important fruit plants cultivated worldwide. The characterization of the grapevine’s metabolome is essential to understand its physiology, its response to stress conditions, improve resistance to pathogens, increase productivity, quality and assess food safety. Concerning wine, one of the most widely appreciated drinks worldwide, its metabolome results from a complex process, involving grapes, yeast, bacteria, terroir effects and its ageing in wooden barrels. Wine metabolome fingerprint tells the story of its origin, production and quality. Its characterization is of paramount importance for quality control, authenticity and quality improvement. Wine metabolome characterization remains one the greatest challenges of analytical chemistry and biochemistry that challenges all conventional approaches to metabolomics. Indeed, metabolome characterization is often achieved through integrated analytical technologies such as nuclear magnetic resonance spectroscopy (NMR) and a combination of different mass spectrometry (MS)-based methods. Over the last five years, MS-based metabolomics superseded NMR-based metabolomics, because of its higher sensitivity, selectivity, number of compounds detected and identified, as well as the ability to perform very high-throughput assays (Markley et al, 2017; Sousa Silva et al, 2019). Typical MS-based metabolomics experiments are performed using liquid (LC) or gas (GC) chromatography coupled to MS instruments. The choice for one or both technologies depends on the chemical characteristics of the molecules of interest and the sensitivity and speed of the instrument, often resulting in the identification of dozens to hundreds of compounds (Boccard et al, 2010).

Figure 1. Grapevine, grapes and wine. Mass spectrum from grapevine leaves obtained by FT-ICR mass spectrometry at Laboratório de FT-ICR e Espectrometria de Massa Estrutural – Ciências, Universidade de Lisboa.

LC-MS and GC-MS technologies have been widely used in grapevine’s metabolic profiling, mainly in a targeted approach for the characterization of specific classes of secondary metabolites from grapes, leaves and stems (Anesi et al, 2015; Billet et al, 2018; Monagas et al, 2006; Souquet et al, 2000). These studies pointed out grapevine as a potential source of bioactive ingredients with antioxidant properties, paved the way to grapevine genotype discrimination based on a small picture of their metabolism, and confirmed the terroir effect in the grape’s metabolic profile, from the same grapevine cultivar. In wine analysis by LC- or GC-MS, the main target are phenolic compounds, as they contribute to the colour, astringency, bitterness and aroma of wine, sugars and aminoacids (Cuadros-Inostroza et al, 2016; Monagas et al, 2007; Rubert et al, 2014). Despite these promising results, only small subset of these metabolomes was uncovered.
The analysis of extremely complex samples calls for disruptive analytical techniques, able to provide extreme resolution to resolve tens of thousands of individual compounds in very high-throughput assays, without the need for time-consuming chromatographic separation. At present, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) provides the ultra-highest mass resolution available, with the latest instrument developed (Bruker Daltonics) able to exceed 20 million resolution. This technology is bringing grapevine and wine research to a higher level. In our group, we have been developing methods for metabolite extraction from grapevine leaves compatible with direct infusion-FTICR-MS-based metabolomics (Maia et al, 2016), capable to identify thousands of chemical species in a few minutes, to perform a thorough metabolome characterization of grapevine leaves, validating their valorisation as a source of bioactive compounds with high nutritional and nutraceutical value (Maia et al, 2019). Grapes and their corresponding wines are also discriminated based on their chemical fingerprints, and the effect of the terroir in their composition was confirmed to an unprecedent depth (Roullier-Gall et al, 2014a; Roullier-Gall et al, 2014b). And, although it is possible to characterize ten years of wine bottle ageing through its chemical profile (Karbowiak et al, 2019), only FT-ICR-MS uncovered the comprehensive chemical signatures still present in 170-year-old champagne bottles recovered from the Baltic Sea (Jeandet et al, 2015). This work contributed to the knowledge of the winemaking process used in Champagne at mid-19th century, giving an invaluable input for the World’s cultural heritage. FT-ICR-MS is thus poised to revolutionise our understanding of wine, from grapevine to glass.

Acknowledgments

We acknowledge the support from projects PTDC/BAA-MOL/28675/2017 and CEECIND/02246/2017 (to MS) from Fundação para a Ciência e Tecnologia (Portugal), from the Portuguese Mass Spectrometry Network (LISBOA-01-0145-FEDER-022125) and the Project EU_FT-ICR_MS, funded by the Europe and Union's Horizon 2020 research and innovation programme under grant agreement no. 731077.

Marta Sousa Silva

Principal Researcher (CEEC-FCT) at Laboratório de FT-ICR e Espectrometria de Massa Estrutural – Ciências, Universidade de Lisboa (http://ft-icr.rd.ciencias.ulisboa.pt/). Science Manager of the Portuguese Centre in the European FT-ICR MS consortium (http://www.eu-fticr-ms.eu/). Member of the Steering Committee of the Portuguese Mass Spectrometry Network (RNEM) and Expert in the Groups “Analytical Methods” and “Viticulture” of the National Commission of the International Organization of Vine and Wine (Comissão Nacional da Organização Internacional da Vinha e do Vinho, CNOIV). Molecular Biologist, research focused in metabolomics and metabolic pathway analysis.
https://orcid.org/0000-0002-3080-9682

Carlos Cordeiro

Associate Professor with Habilitation at Faculdade de Ciências da Universidade de Lisboa. Director of the Laboratório de FT-ICR e Espectrometria de Massa Estrutural – Ciências (http://ft-icr.rd.ciencias.ulisboa.pt/), Vice-Coordinator of the Portuguese Mass Spectrometry Network (RNEM), PI of the Portuguese Center in the European FT-ICR MS consortium (http://www.eu-fticr-ms.eu/). Expert in the Group “Analytical Methods” of the National Commission of the International Organization of Vine and Wine (Comissão Nacional da Organização Internacional da Vinha e do Vinho, CNOIV). Experience in analytical biochemistry, chromatography and mass spectrometry, FT-ICR-MS and native MS, introducing both technologies in Portugal.
http://orcid.org/0000-0001-6327-8606

References
Anesi, A; Stocchero, M; Dal Santo, S; Commisso, M; Zenoni, S; Ceoldo, S; Tornielli, G; Siebert, TE; Herderich, M; Pezzotti, M; Guzzo, F (2015) Towards a scientific interpretation of the terroir concept: plasticity of the grape berry metabolome. BMC PLANT BIOLOGY 15, 191. Doi 10.1186/s12870-015-0584-4
Aretz, I; Meierhofer, D (2016) Advantages and Pitfalls of Mass Spectrometry Based Metabolome Profiling in Systems Biology. INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES 17 (5), 632. Doi 10.3390/ijms17050632
Billet, K; Houille, B; de Bernonville, TD; Besseau, S; Oudin, A; Courdavault, V; Delanoue, G; Guerin, L; Clastre, M; Giglioli-Guivarch, N; Lanoue, A (2018) Field-Based Metabolomics of Vitis vinifera L. Stems Provides New Insights for Genotype Discrimination and Polyphenol Metabolism Structuring. FRONTIERS IN PLANT SCIENCE 9, 798. Doi 10.3389/fpls.2018.00798
Boccard, J; Veuthey, J-L; Rudaz, S (2010) Knowledge discovery in metabolomics: An overview of MS data handling. JOURNAL OF SEPARATION SCIENCE 33 (3), 290-304. Doi 10.1002/jssc.200900609
Cuadros-Inostroza, Al; Ruiz-Lara, S; Gonzalez, E; Eckardt, A; Willmitzer, L; Pena-Cortes, H (2016) GC-MS metabolic profiling of Cabernet Sauvignon and Merlot cultivars during grapevine berry development and network analysis reveals a stage- and cultivar-dependent connectivity of primary metabolites. METABOLOMICS 12 (2), 39. Doi 10.1007/s11306-015-0927-z
Fiehn, O (2002) Metabolomics - the link between genotypes and phenotypes. PLANT MOLECULAR BIOLOGY 48 (1-2), 155-171. Doi 10.1023/A:1013713905833
Karbowiak, T; Crouvisier-Urion, K; Lagorce, A; Ballester, J; Geoffroy, A; Roullier-Gall, C; Chanut, J; Gougeon, RD; Schmitt-Kopplin, P; Bellat, JP (2019) Wine aging: a bottleneck story. NPJ SCIENCE OF FOOD 3, 14. Doi 10.1038/s41538-019-0045-9
Maia, M; Monteiro, F; Sebastiana, M; Marques, AP; Ferreira, AEN; Ponces Freire, A; Cordeiro, C; Figueiredo, A; Sousa Silva, M (2016) Metabolite extraction for high-throughput FTICR-MS-based metabolomics in grapevine. EUPA OPEN PROTEOMICS 12, 4-9. Doi 10.1016/j.euprot.2016.03.002
Maia, M; Ferreira, AEN; Laureano, G; Marques, AP; Torres, VM; Silva, AB; Matos, AR; Cordeiro, C; Figueiredo, A; Sousa Silva, M (2019) Vitis vinifera 'Pinot noir' leaves as a source of bioactive nutraceutical compounds. FOOD & FUNCTION 10 (7), 3822-3827. Doi 10.1039/c8fo02328j
Markley, JL; Bruschweiler, R; Edison, AS; Eghbalnia, HR; Powers, R; Raftery, D; Wishart, DS (2017) The future of NMR-based metabolomics. CURRENT OPINION IN BIOTECHNOLOGY 43, 34-40. Doi 10.1016/j.copbio.2016.08.001
Monagas, M; Bartolome, B; Gomez-Cordoves, C (2005) Updated knowledge about the presence of phenolic compounds in wine. CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION 45 (2), 85-118. Doi 10.1080/10408690490911710
Monagas, M; Hernandez-Ledesma, B; Gomez-Cordoves, C; Bartolome, B (2006) Commercial dietary ingredients from Vitis vinifera L. leaves and grape skins: Antioxidant and chemical characterization. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 54 (2), 319-327. Doi 10.1021/jf051807j
Roullier-Gall, C; Boutegrabet, L; Gougeon, RD; Schmitt-Kopplin, P (2014) A grape and wine chemodiversity comparison of different appellations in Burgundy: Vintage vs terroir effects. FOOD CHEMISTRY 152, 100-107. Doi 10.1016/j.foodchem.2013.11.056
Roullier-Gall, C; Lucio, M; Noret, L; Schmitt-Kopplin, P; Gougeon, RD (2014) How Subtle Is the “Terroir” Effect? Chemistry-Related Signatures of Two Climats de Bourgogne. PLOS ONE 9 (5), e97615. Doi 10.1371/journal.pone.0097615
Rubert, J; Lacina, O; Fauhl-Hassek, C; Hajslova, J (2014) Metabolic fingerprinting based on high-resolution tandem mass spectrometry: a reliable tool for wine authentication? ANALYTICAL AND BIOANALYTICAL CHEMISTRY 406 (27), 6791-6803. Doi 10.1007/s00216-014-7864-y
Sousa Silva, M; Cordeiro, C; Roessner, U; Figueiredo, A (2019) Editorial: Metabolomics in Crop Research-Current and Emerging Methodologies. FRONTIERS IN PLANT SCIENCE 10, 1013. Doi 10.3389/fpls.2019.01013
Souquet, JM; Labarbe, B; Le Guerneve, C; Cheynier, V; Moutounet, M (2000) Phenolic composition of grape stems. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 48 (4), 1076-1080. Doi 10.1021/jf991171u

Posted by in Chemistry, Viticulture

Alcohol use in fatty liver disease

By Fredrik Åberg

Fatty liver disease (FLD), the accumulation of fat in liver cells, presently affects around 25% of adults (1). Of these, one fifth suffer from the more severe form of FLD, namely steatohepatitis, which over time can progress to liver cirrhosis, liver cancer and end-stage liver disease.
FLD is most often associated with abdominal obesity, insulin resistance, and the metabolic syndrome (non-alcoholic fatty liver disease, NAFLD). Other causes of FLD include hazardous alcohol consumption, genetics, certain medications, parenteral nutrition and viral hepatitis.
Alcohol intake of less than 30 grams of pure ethanol among men or less than 20 grams among women is generally not considered to cause liver fat accumulation, but the effects of such light-moderate alcohol use on the background of pre-existing obesity-related FLD are controversial.
Numerous studies on individuals with NAFLD have shown an association between light-moderate alcohol consumption, particularly wine, and milder liver disease compared to total alcohol abstinence (2-4). It has been suggested that the beneficial effects of light alcohol use on insulin sensitivity can lead to a reduction in the amount of fat in the liver. However, the hepatotoxic effects of alcohol are not limited to simple fat accumulation alone, and there is conflicting clinical evidence on the effects on the liver of light-moderate alcohol consumption. Studies reporting liver-protective effects of alcohol are limited by a number of potential biases. For instance, they have been conducted mainly in cross-sectional settings (exposure and outcome variables are measured simultaneously), with insufficient adjustment for confounding factors such as lifestyle, socioeconomic status, and co-morbidity, and the outcome variables used in these studies most often represent surrogate markers such as steatosis or liver enzymes. People with previous drinking who later stopped drinking (current abstainers) are often not separated from lifetime abstainers. In addition, underestimation of alcohol intake is particularly common among people who already know they have liver disease (cross-sectional studies).
In a recent longitudinal Finnish study, we were able to overcome many of these limitations of earlier studies (5). Combining data from the Finnish FINRISK 1992-2012 and Health 2000 population surveys with data from national mandatory registers for hospitalizations, cancer and death related to liver disease enabled analyzes on the effects of alcohol use on the risk of incident advanced clinical liver disease. We excluded persons who consumed> 50 grams of alcohol per day, current abstainers, and those with viral hepatitis (at baseline or during follow-up) or baseline severe liver disease. Analyzes were adjusted for various risk factors, lifestyle factors and socioeconomic status.

In the combined cohort of the more than 27,000 persons, 8345 had NAFLD at baseline (defined as a Fatty Liver Index > 60). We found no liver-beneficial effects of light-moderate alcohol intake. On the contrary, even low alcohol consumption increased the risk of advanced liver disease. Among persons with NAFLD, a daily intake of 10 to 19 grams of any type of alcohol doubled the risk of advanced liver disease compared to non-drinkers. A similar risk increase was seen already at alcohol intake of less than 10 grams per day when the consumption was in the form of non-wine beverages. In contrast, wine drinking with total average intake of less than 25 grams per day of ethanol did not significantly raise the risk of advanced liver disease.

 

In: Christopher D. Byrne, Giovanni Targher (2015). NAFLD: A multisystem disease. Journal of Hepatology, Volume 62, Issue 1, Supplement, S47-S64.

Regarding the risk for cardiovascular disease (CVD), we found a tendency towards reduced risk with light-moderate alcohol intake even after multiple adjustments. This was sensitive to beverage type with a larger risk reduction seen in preferential wine drinkers than preferential beer or spirits drinkers. In contrast, light drinking raised the risk for cancer, without any clear effect modification from the fraction of wine. We found a J-shaped relationship between alcohol use and all-cause mortality with a maximal risk reduction of 21% at alcohol intake of 0-9 g/day in the fully adjusted model. Larger risk reductions for death were again seen in preferential wine drinkers than in non-wine drinkers. Alcohol intake above 30 g/day was associated with increased mortality. The J-shaped relationship between alcohol and mortality was only evident in never smokers, suggesting that smoking modifies the relationship between alcohol and risk of death.
Taken together, among non-smokers with NAFLD, the absolute risk increases for liver cirrhosis conferred by drinking 1-2 standard glasses of wine per day seems minimal, so this may not need to be prohibited in the average individual with NAFLD without advanced liver fibrosis. In NAFLD with advanced liver fibrosis or particular risk for progressive liver disease, however, complete alcohol abstinence seems warranted. The clinical implications of the J-shaped association between alcohol and incident CVD and death in never smokers remain unclear, and needs to be balanced against an increased risk for cancers. From a holistic point of view, there are more effective and safer means to reduce CVD risk than by alcohol use, and given the elevated risk estimates for advanced liver disease and cancer in general, light-moderate alcohol drinking cannot be encouraged in people with NAFLD.

Fredrik Åberg
Email: fredrik.aberg@hus.fi
PERSONAL DATA
Name Fredrik Oskar Åberg
Date of birth 14.03.1981
EDUCATION
2018 Helsinki University, Faculty of Medicine, Adjunct professor (docent)
2015 Helsinki University, Faculty of Medicine, Specialist in gastroenterology
2010 Helsinki University, Faculty of Medicine, Doctor of medical sciences (PhD)
2007 Helsinki University, Faculty of Medicine, Licentiate of medicine
2000 Brändö Gymnasium, higher school certificate
WORK EXPERIENCE
08/2017 – Sahlgrenska university hospital (Sweden), Transplant Institute
10/2015 – HUCS Meilahti hospital, Transplantation and Liver Surgery Clinic
04/2013 – 10/2015 HUCS Meilahti hospital, Deparment of Gastroenterology
01/2013 – 03/2013 HUCS Meilahti hospital, Transplantation and Liver Surgery clinic
01/2012 – 12/2012 HUS Maria (Malm) hospital, Department of Internal medicine
12/2009 – 01/2012 Diacor, Helsinki, General medicine
2007 - 2010 HUS Porvoo Hospital, Porvoo, Department of Internal medicine
02/2008 – 12/2008 Porvoo Health Center, General medicine
06-08/2006 HUS Tammisaari Hospital, Department of Emergency medicine
06-08/2005 HUCS Surgical Hospital, Department of Anaesthesiology

ADDITIONAL ACTIVITES
2015 - Finland’s representative in United European Gastroenterology (UEG) “Friends of
Young Talent Group”
2014 - 2016 Research foundation for gastrointestinal diseases, commissioner
2015 - 2017 Finland’s representative in Scandiatransplant Association
2014 - 2015 HUCS Endoscopy team, member and Department of Gastroenterology team, member
01/2002 - Medicinarklubben Thorax r.f. (student organisation for medical students)
INVITED TALKS AT INTERNATIONAL MEETINGS: 4 times (ILTS, British Transplant
Society, Astellas Network Meeting, Nordic Hemophilia days, Nordic Liver Transplant
Group 25yr Anniversary Symposium)
INVITED TALKS AT NATIONAL MEETINGS: 37 times
ORAL ABSTRACT PRESENTATIONS: 13 times at key international meetings including EASL
International Liver Congress’ grand session, ILTS, ESOT, TTS, STS, ELITA
REVIEWER FOR MANUSCRIPTS IN PEER-REVIEWED JOURNALS
52 reviews in 25 different journals, including Gastroenterology, Hepatology, American
Journal of Transplantation, Liver International, Liver Transplantation
Ongoing reviewer for Centre for Evidence in Transplantation, Transplant Library
INTERNATIONAL AWARDS
EASL travel grant 2013
EASL International Liver Congress travel and abstract award 2017 and oral
presentation at Grand Session
Finnish nominee for UEG Rising star award 2018 and 2019
RESEARCH GRANTS
Mary och Georg Ehrnrooth foundation (2009, 2017, 2018), Stockmann foundation (2016), Finska
Läkaresällskapet (2009, 2014, 2015, 2016, 2017, 2018), Finnish-Norwegian medical society (2014,
2017), Liv och Hälsa foundation (2007, 2008, 2009, 2010, 2016, 2017), Perklen foundation (2009,
2014), Scandiatransplant (2012), Maud Kuistila memorial fund (2009), Biomedicum foundation
(2009), Finnish transplantation society (2008)
OTHER: GCP training PharmaSchool certificate 23.8.2016

References

  1. Younossi ZM. J Hepatol. 2019;70(3):531-544
  2. Moriya A et al. Aliment Pharmacol Ther. 2011;33(3):378-388
  3. Dunn W et al. J Hepatol. 2012;57(2):384-391
  4. Mitchell T et al. Am J Gastroenterol. 2018;113(10):1484-1493
  5. Åberg F et al. Hepatology. 2019 Jul 19 (Epub ahead of print)
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