A recent study published in The Lancet eBioMedicine has shed light on a potential link between certain foods and excessive daytime sleepiness, a persistent feeling of fatigue that can interfere with daily activities. While factors like adequate sleep, exercise, and hydration are crucial, diet may also play a significant role. The research identified specific molecules in the blood, or metabolites, that are associated with this mid-day slump.

Researchers analyzed data from 877 metabolites, derived from blood samples of 6,000 participants in the Hispanic Community Health Study/Study of Latinos, alongside questionnaire data on daytime sleepiness. The study pinpointed seven metabolites linked to excessive daytime sleepiness, with two strongly associated with particular foods. Tyramine, found in fermented and overripe foods such such as aged cheeses, tofu, kimchi, and salami, and sphingomyelins, present in eggs, milk, and meat, were closely linked to increased sleepiness. Conversely, key nutrients like omega-3 and omega-6 fatty acids, commonly found in the Mediterranean diet, were associated with reduced sleepiness. Scott Keatley, RD, co-owner of Keatley Medical Nutrition Therapy, notes that omega-3-rich foods include salmon, walnuts, and flax, while seeds and nuts are good sources of omega-6s.

While the study identified associations rather than direct causation, experts offer explanations. Keatley suggests that foods high in tyramine, especially fermented ones, can disrupt neurotransmitters like serotonin and melatonin, which are essential for regulating sleep and wake cycles, potentially leading to increased grogginess. On the other hand, omega-3 and omega-6 fatty acids "appear protective because they support melatonin production and stabilize circadian rhythms," according to Keatley, thereby improving sleep efficiency and hormone regulation.

However, beating daytime sleepiness isn't as simple as swapping one food for another. Keri Gans, RDN, author of The Small Change Diet, emphasizes that it's more about overall eating patterns, combined with other critical factors such as sleep habits, hydration, stress management, physical activity, and medications. Jessica Cording, RD, author of The Little Book of Game-Changers, advises focusing on maintaining stable blood sugar levels. Foods that cause rapid blood sugar spikes followed by crashes can lead to feelings of sleepiness. It's important to note that tyramine-containing foods are not inherently detrimental to blood sugar, and foods rich in omega-3s and omega-6s often contribute to blood sugar stability.

To promote stable blood sugar and combat daytime sleepiness, Cording recommends incorporating protein, healthy fats, and complex carbohydrates into every meal and snack. Additionally, staying well-hydrated by drinking plenty of water and consuming hydrating foods like watermelon, berries, or bell peppers is crucial, as dehydration can also cause sluggishness. Keatley also suggests avoiding large meals during the day, which can cause significant blood sugar fluctuations. Instead, opt for smaller, balanced meals and snacks that combine protein, fiber-rich carbohydrates, and healthy fats to maintain sustained energy and alertness throughout the day. If changing dietary habits doesn't alleviate excessive sleepiness, consulting a healthcare provider is recommended to rule out other potential causes.