Beyond Caffeine: Unpacking the Sleep Saboteurs in Your Coffee and Tea

Question: What are some common, everyday additions to coffee or tea that might be hindering my sleep quality?

The Sweetening Secret of Sleeplessness

It’s widely acknowledged that caffeine, the primary stimulant in coffee and tea, can interfere with sleep [6, 7]. However, the journey to a restful night doesn’t end with the base beverage. Many everyday additions, often considered benign, can contribute to poor sleep quality. Perhaps the most prevalent culprits are added sugars and artificial sweeteners. Consuming sugary beverages, especially close to bedtime, can lead to fluctuations in blood sugar levels. A rapid rise followed by a crash can trigger the release of stress hormones like cortisol and adrenaline, making it harder to fall asleep and stay asleep [8]. While artificial sweeteners are often positioned as healthier alternatives, some research suggests they may also negatively impact sleep. The precise mechanisms are still under investigation, but potential pathways include alterations in gut microbiota, which can influence neurotransmitter production and overall sleep architecture [8].

Dairy Dilemmas and Digestive Disruptions

For many, a splash of milk or cream is an essential part of their morning ritual or evening wind-down. However, for individuals sensitive to lactose or dairy in general, these additions can be problematic. Digestion itself requires energy, and consuming heavy or difficult-to-digest ingredients close to bedtime can keep the body in a more active state, hindering the transition to sleep [8]. This is particularly true for those with digestive sensitivities, where the consumption of dairy could lead to discomfort, bloating, or other gastrointestinal issues that disrupt sleep [8]. While some studies focus on the overall beverage consumption and its association with sleep, the specific impact of common additives like dairy warrants attention for those struggling with sleep quality [8].

Beyond the Basics: Exploring Less Common Additives

While sugars, sweeteners, and dairy are frequent flyers in coffee and tea cups, other less obvious additives might also play a role. For instance, flavorings and syrups, often packed with sugar and artificial ingredients, can have a cumulative negative effect. Some research has explored the volatile compounds in coffee, which contribute to its aroma and flavor profile [3]. While these are inherent to the coffee itself, the extensive use of artificial flavorings in many coffee-based drinks introduces a different set of chemical compounds that haven’t been extensively studied for their impact on sleep. Similarly, the processing of coffee grounds, and the potential for residues from these processes, has been investigated in the context of material science [2]. While not direct beverage additives, these explorations highlight the complex composition of coffee that could, in less obvious ways, influence physiological responses.

Considering the Source: Coffee and Tea Varieties

While the focus has been on what we add, the coffee or tea itself, and its inherent properties, can also matter. Different coffee species, such as Arabica and Robusta, have varying chemical compositions, including lipid content which can affect foam stability in espresso [1]. While this is more related to the texture of the coffee, the underlying compounds and processing methods, such as fermentation protocols, are known to influence volatile compounds and, by extension, flavor and potentially physiological effects [3]. Similarly, the type of tea consumed can have varying impacts. Research indicates that sleep quality can mediate the association between tea consumption and symptom duration, suggesting that different tea types might have differential effects on sleep [7].

A Wake-Up Call for Your Bedtime Beverage

While caffeine is a well-known sleep disruptor, the common additions to our beloved coffee and tea—from sugars and artificial sweeteners to dairy and artificial flavorings—can also be quietly undermining our sleep. Paying attention to what goes into your cup, especially in the hours leading up to bedtime, is crucial for cultivating better sleep hygiene. By making mindful choices about these additions, you can enjoy your favorite warm beverages without sacrificing a night of restorative sleep.

References

[1] — Ernesto Illy, Luciano Navarini — Neglected Food Bubbles: The Espresso Coffee Foam. — 2011-Sep — https://pubmed.ncbi.nlm.nih.gov/21892345/ [2] — Magdalena Zdanowicz, Marta Rokosa, Magdalena Pieczykolan, Adrian Krzysztof Antosik, Katarzyna Skórczewska — Biocomposites Based on Wheat Flour with Urea-Based Eutectic Plasticizer and Spent Coffee Grounds: Preparation, Physicochemical Characterization, and Study of Their Influence on Plant Growth. — 2024-Mar-06 — https://pubmed.ncbi.nlm.nih.gov/38473683/ [3] — Gustavo Galarza, Jorge G Figueroa — Volatile Compound Characterization of Coffee ( — 2022-Mar-21 — https://pubmed.ncbi.nlm.nih.gov/35335365/ [4] — Katarína Poláková, Alica Bobková, Alžbeta Demianová, Marek Bobko, Judita Lidiková, Lukáš Jurčaga, Ľubomír Belej, Andrea Mesárošová, Melina Korčok, Tomáš Tóth — Quality Attributes and Sensory Acceptance of Different Botanical Coffee Co-Products. — 2023-Jul-11 — https://pubmed.ncbi.nlm.nih.gov/37509767/ [5] — Rongsuo Hu, Fei Xu, Liyan Zhao, Wenjiang Dong, Xingyuan Xiao, Xiao Chen — Comparative Evaluation of Flavor and Sensory Quality of Coffee Pulp Wines. — 2024-Jun-27 — https://pubmed.ncbi.nlm.nih.gov/38999011/ [6] — Aruna Raju, Madhavan Chandran, Jean Fredrick — Excessive day time sleepiness, poor sleep quality, and their association to caffeine consumption among young Informational Technology professionals. — 2025 — https://pubmed.ncbi.nlm.nih.gov/40861136/ [7] — Yuxin Fan, Yaonan Zhu, Yunyu Wang, Jun Jiang, Shaopeng Yang, Jie Lu, Qinghua Ma, Hong Zhu — Sleep quality mediates the association between tea consumption and duration of COVID-19-related symptoms in middle-aged and elderly adults (aged 50 and above). — 2025 — https://pubmed.ncbi.nlm.nih.gov/40881360/ [8] — Lydi-Anne Vézina-Im, Dominique Beaulieu, Stéphane Turcotte, Anne-Frédérique Turcotte, Joannie Delisle-Martel, Valérie Labbé, Lily Lessard, Mariane Gingras — Association between Beverage Consumption and Sleep Quality in Adolescents. — 2024-Jan-18 — https://pubmed.ncbi.nlm.nih.gov/38257178/