The Nightcap Conundrum: Dairy Delights vs. Dark Roast Dilemmas for Sleep

[1] — Ernesto Illy, Luciano Navarini — Neglected Food Bubbles: “The Espresso Coffee Foam. — 2011-Sep — https://pubmed.ncbi.nlm.nih.gov/21892345/" [2] — Gustavo Galarza, Jorge G Figueroa — Volatile Compound Characterization of Coffee ( — 2022-Mar-21 — https: “//pubmed.ncbi.nlm.nih.gov/35335365/” [3] — Faguang Hu, Haohao Yu, Xingfei Fu, Zhongxian Li, Wenjiang Dong, Guiping Li, Yanan Li, Yaqi Li, Bingqing Qu, Xiaofei Bi — Characterization of volatile compounds and microbial diversity of Arabica coffee in honey processing method based on different mucilage retention treatments. — 2025-Jan — https: “//pubmed.ncbi.nlm.nih.gov/39974542/” [4] — 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/” [5] — Samuel Awlachew, Assefa Desalew, Usmael Jibro, Abera Kenay Tura — Pregnant women’s sleep quality and its associated factors among antenatal care attendants in Bahir Dar City, Northwest Ethiopia. — 2025-May-04 — https: “//pubmed.ncbi.nlm.nih.gov/40320398/” [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/”

Question: How do dairy additives versus black coffee influence late-evening sleepiness or insomnia risk?

The Nightcap Conundrum: Dairy Delights vs. Dark Roast Dilemmas for Sleep

The lure of a late-night beverage is a common comfort for many, but when it comes to winding down, the choices can significantly impact our ability to drift off peacefully. Specifically, the question arises: how do dairy additives in drinks and plain black coffee stack up when it comes to influencing late-evening sleepiness or the risk of insomnia? While research directly comparing these two specific scenarios is limited, we can draw insights from studies on caffeine consumption and beverage habits to understand their potential effects.

Caffeine’s Wakeful Embrace

Black coffee, a staple for many, is renowned for its caffeine content, a stimulant that directly affects our central nervous system. Caffeine works by blocking adenosine, a neurotransmitter that promotes relaxation and sleepiness. By inhibiting adenosine, caffeine can lead to increased alertness and, consequently, a reduced sensation of sleepiness [6]. This is particularly relevant in the late evening, when our bodies are naturally preparing for rest. Studies have shown a link between caffeine consumption and poorer sleep quality, with some individuals experiencing increased difficulty falling asleep or maintaining sleep [4]. For young IT professionals, for instance, excessive daytime sleepiness has been associated with caffeine consumption, suggesting a potential disruption to their sleep-wake cycle [6].

While the precise mechanisms of how coffee compounds influence sleep beyond caffeine are still being explored, the volatile compounds present in coffee are a subject of scientific interest. Research has focused on characterizing these compounds, with some studies indicating that fermentation protocols can positively influence acidity and volatile compound concentrations [2]. However, the direct impact of these specific volatile compounds on late-evening sleepiness remains an area requiring further investigation. Similarly, the characteristics of coffee foam, such as lipid content in espresso, are studied for their impact on texture rather than their direct influence on sleep [1].

The Dairy Dilemma: A Calming Embrace?

Dairy products, on the other hand, are often associated with promoting sleep. This is largely attributed to their tryptophan content, an amino acid that the body uses to produce serotonin and melatonin – hormones crucial for regulating sleep and mood. While research specifically isolating the sleep effects of dairy additives in beverages versus black coffee is scarce, the general properties of dairy suggest a potentially different impact. Consuming milk, for example, has historically been considered a sleep aid, possibly due to the combination of tryptophan and the psychological comfort of a warm beverage [5]. However, it’s important to note that the concentration of sleep-promoting compounds in a typical dairy additive might be significantly lower than in a glass of milk, and the overall beverage matrix matters.

The provided references do not offer direct evidence on how dairy additives, when introduced into other beverages, influence sleep. However, understanding the potential impact of dairy itself, as highlighted by the association of certain factors with sleep quality in specific populations, provides a contextual framework. For instance, research on pregnant women identified older maternal age and the third trimester as factors associated with poor sleep quality [5], but did not specifically link dairy consumption to either improved or worsened sleep.

Unpacking the Nuances and Future Directions

The influence of beverages on sleep is a multifaceted issue. While black coffee, due to its caffeine, is more likely to contribute to alertness and potentially insomnia if consumed late in the evening [4, 6], the role of dairy additives is less clear and likely depends on their composition and quantity. If the dairy additive primarily contributes components like tryptophan or offers a soothing texture, it might lean towards a neutral or even mildly beneficial effect on sleep initiation compared to the stimulating effects of caffeine. Conversely, if the additive is part of a high-sugar beverage, the overall impact could be negative, as sugar-sweetened coffee has been linked to poorer sleep quality [4].

It’s crucial to acknowledge that individual responses to caffeine and other beverage components can vary significantly based on genetics, tolerance, and overall health. Furthermore, the specific processing methods of coffee, such as fermentation treatments, can alter its chemical composition [2], though their direct sleep-related outcomes are not detailed in the provided sources.

Conclusion

In the late-evening beverage arena, black coffee, primarily due to its caffeine content, presents a clearer potential for disrupting sleep and increasing insomnia risk compared to beverages with dairy additives. While specific research directly comparing dairy additives to black coffee on sleep is limited, the known stimulant properties of caffeine in coffee are well-established as a factor that can interfere with sleep [4, 6]. Dairy products, on the other hand, are generally associated with sleep-promoting compounds like tryptophan. However, the actual impact of dairy additives would likely depend on their specific formulation and the overall composition of the beverage they are incorporated into.