Global warming has many known effects on sea level rise, extreme weather conditions, ice sheets, and even general human activities, one of them being agriculture. What is not as established is how exactly it is impacting viniculture and its health research potential. Grapes, though hardy, are sensitive to increases in temperature, and this is beginning to show in harvests (Roman 2026). Notably, global warming leads to more sugar formation in grapes because of quicker ripening, but also fewer secondary compounds are produced (Chrobak and Zimmer 2022). These compounds include anthocyanins (ACNs), which are polyphenol pigment compounds that give grapes their colours (n.a. 2022). Polyphenols in grapes are susceptible to oxidation, or losing electrons, due to their unsaturated double bonds and hydroxyls, so ACNs are notable antioxidants (Graham 2021). However, their colour stability is reduced because they can break down under heat. Global warming, and variation in day-night temperatures have a strong influence on berry metabolites like ACN by repressing ACN-regulating genes (Shah et al. 2021). Heat has been shown to repress ACN biosynthesis regulators, such as VviMYBA1 and downstream regulating genes such as VviCHI, VviUFGT, VviDFR, VviF3H2, and VviLDOX, which means reduced ACN levels (Shah et al. 2021).
ACN consumption is linked to reduced risk of cardiovascular disease (CVD), specifically ischemic heart disease (IHD), a condition characterised by oxidative stress-caused chronic inflammation (Kibel et al. 2020; Valaitienė and Laučytė-Cibulskienė 2024). This is because of its anti-inflammatory, antioxidant, and lipid-lowering properties (Vendrame and Klimis-Zacas 2019). However, epidemiological data shows a link between ACNs and BP regulation, specifically an inverse association between ACNs and CVD, and an inverse association between ACN intake and hypertension (Vendrame and Klimis-Zacas 2019). ACNs in vitro and in vivo are protective against ischemia/reperfusion-induced injury because they can remove reactive oxygen species (ROS) by direct scavenging, induction of enzymes responsible for ROS removal, chelation of metal ions needed to generate ROS or modulation of ROS forming enzymes such as xanthine oxidase and others (Liobikas et al. 2016). This antioxidant property is dependent on ring orientation, because its structure allows ACN to donate a H+ atom from its hydroxyl to a free radical (Graham 2021; Liobikas et al. 2016). ACNs can also reduce oxidative stress in cells by modifying mitochondrial respiration, which results in the slight uncoupling of oxidative phosphorylation. This causes attenuation of mitochondrial ROS generation, which potentially prevents CVD because ROS negatively affect myocardial calcium movement. This leads to arrhythmias, or irregular heartbeats, and thus cardiac remodelling through apoptosis and necrosis of tissue (Liobikas et al. 2016). So, tissue damage of the heart leads to ischemic heart disease, a form of CVD, through oxidative stress.
Now, here’s the big picture: as the Earth continues to warm up, grape chemistry is altered because there are lower levels of ACNs available in red wines after the fermentation process. This means the final red wine product is no longer viable as a potential antioxidant-rich libation. Colour stability is also greatly lessened, and red wines lose a lot of their shelf stability and appeal. Note that CVD is accountable for 32% of global deaths, with up to 19.8 million deaths annually, of which 85% are attributed to IHD and stroke (WHO 2025). Sure, red wine isn’t a treatment or management option for IHD, but there is undeniable evidence showing that light/moderate red wine consumption can help reduce the risk of IHD (Choleva et al. 2022; Liobikas et al. 2016; Vendrame and Klimis-Zacas 2019), which means that this topic has been, and will continue to be, heavily researched in being beneficial against CVD.
However, all hope isn’t lost yet: winemakers are finding new ways to combat global warming and maintain the quality and quantity of viticulture. Those we’ve heard about within Ontario include the relocation of vineyards to higher altitudes for cooler temps, frost damage prevention, and earlier harvests (Roman 2026). However, there exist other strategies employed by winemakers around the world, such as using new hardier cultivars, or irrigation – bringing in fruits from outside a certain region – in order to have grape varietals that are less susceptible to changes in phenolic compound ratios throughout the vinification process (Stavins et al. 2025). If successful, this would mean ACNs in red wine grapes would remain virtually untouched, and their antioxidant properties would remain intact. So, fear not wine moms – you may drink in moderation and keep heart disease at bay for a long time still.
References
4 Health Benefits of Anthocyanins. (2022, June 2). Cleveland Clinic. https://health.clevelandclinic.org/anthocyanins
Choleva, M., Argyrou, C., Detopoulou, M., Donta, M.-E., Gerogianni, A., Moustou, E., Papaemmanouil, A., Skitsa, C., Kolovou, G., Kalogeropoulos, P., & Fragopoulou, E. (2022). Effect of Moderate Wine Consumption on Oxidative Stress Markers in Coronary Heart Disease Patients. Nutrients, 14(7), 1377. https://doi.org/10.3390/nu14071377
Chrobak, U., & Zimmer, K. (2022, September 12). How climate change is tweaking the taste of wine. BBC. https://www.bbc.com/future/article/20220825-how-climate-change-affects-wine
Graham, K. (2021, March 9). 1.15: Wine. Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Biological_Chemistry/Fermentation_in_Food_Chemistry_(Graham)/01%3A_Modules/1.15%3A_Wine
Kibel, A., Lukinac, A. M., Dambic, V., Juric, I., & Selthofer-Relatic, K. (2020a). Oxidative Stress in Ischemic Heart Disease. Oxidative Medicine and Cellular Longevity, 2020, 6627144. https://doi.org/10.1155/2020/6627144
Kibel, A., Lukinac, A. M., Dambic, V., Juric, I., & Selthofer-Relatic, K. (2020b). Oxidative Stress in Ischemic Heart Disease. Oxidative Medicine and Cellular Longevity, 2020, 6627144. https://doi.org/10.1155/2020/6627144
Liobikas, J., Skemiene, K., Trumbeckaite, S., & Borutaite, V. (2016). Anthocyanins in cardioprotection: A path through mitochondria. Pharmacological Research, Countries in Focus: Pharmacology in the Baltic States, 113, 808–815. https://doi.org/10.1016/j.phrs.2016.03.036
Shah, M., Rafique, R., Rafique, T., Naseer, M., Khalil, U., & Rafique, R. (2021). Effect of Climate Change on Polyphenols Accumulation in Grapevine. https://doi.org/10.5772/intechopen.99779
Stavins, R. N., Catena, L., Forrestel, E., Rivail, J.-B., Sahn, M., & Sumner, D. A. (2025). Global Climate Change and Wine Production: Industry and Academic Perspectives. Harvard Data Science Review, 7(1). https://doi.org/10.1162/99608f92.a17caeae
Valaitienė, J., & Laučytė-Cibulskienė, A. (2024). Oxidative Stress and Its Biomarkers in Cardiovascular Diseases. Artery Research, 30(1), 18. https://doi.org/10.1007/s44200-024-00062-8
Vendrame, S., & Klimis-Zacas, D. (2019). Potential Factors Influencing the Effects of Anthocyanins on Blood Pressure Regulation in Humans: A Review. Nutrients, 11(6), 1431. https://doi.org/10.3390/nu11061431
WHO. (2025, July 31). Cardiovascular diseases (CVDs). https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds)
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