Scott Tindal, Co-Founder and the Chief Nutrition Officer of US based company Fuelin reviews the role of sleep and diet on health, and the effect of diet on sleep duration and quality. 
 
Have you ever considered what you eat could have a profound effect on how you sleep? It seems funny to pose the question, yet for so many, the thought has not crossed their minds.  

Recently, Fuelin was sent an update from a current athlete that her consumption of vegetables 45 times over 90 days had been acknowledged by Whoop.  The company suggested that this intake of vegetables appeared to be having a positive effect on her REM sleep duration.  

Does sleep and diet impact health? 
There is no doubt that nutrition is playing a large role in this health crisis with overconsumption of calories and ultra-processed foods driving the problem to breaking point. Higher consumption of fruit and vegetables is positively associated with reduced mortality and better health outcomes in humans. Simple measures to increase vegetable and fruit intake daily can have a profound impact on body mass, fat mass and overall health. 

Improved sleep quality and optimal duration also have a positive impact on human health in terms of risk of diseases such as cancer, cardiovascular disease, diabetes and cognitive decline. (3-5). The mention of optimal sleep duration is important as it is not always the case of more sleep is better. In fact, sleep duration beyond 9 hours daily has been inversely associated with increased mortality. (6) That means, too much sleep resulted in an increased risk of death. In this particular study, a 33% increase! Insufficient sleep is associated with increased caloric consumption, poor dietary habits, and obesity. Along with insufficient sleep results in increased snacking and the number of meals consumed per day (7). 
 
Does nutrition impact sleep? 
The obvious question on your lips is “If sleep (quality + duration) and vegetable/fruit intake affect health, does fruit & vegetable intake affect sleep? The follow-up to this would be “Is the impact positive or negative?”  
 
A recent systematic review investigated the role of diet and its impact on sleep. Their conclusion, based on the available evidence is that consumption of “healthy foods” mostly refers to the Mediterranean Diet (MedDiet) with high consumption of fruit and vegetables, was associated with better sleep quality (10). Adherence to the diet was associated with a reduction in variability in sleep hours per night (<2hrs) along with the improved quality of sleep in several of the prospective studies. Better adherence to the MedDiet was also associated with reduced sleep issues and improved total duration of 6-7 hours per night.   
 
The role of inflammation in the diet has been investigated and put forward as a possible reason for differences in sleep quality. Researchers found that individuals with higher adherence to a pro-inflammatory diet were more likely to have worse sleep quality. In other words, those that ate a diet high in processed and ultra-processed foods with minimal fruit and vegetables had worse sleep quality. (11) 

The reason why diets such as the MedDiet could have a positive impact on sleep is due to these types of diets contain foods with higher amounts of tryptophan. It is an essential amino acid found mostly in animal products, such as beef, lamb, pork, poultry, and dairy, as well as in nuts and seeds, whole grains, and legumes. (1) The body uses tryptophan to help make melatonin and serotonin. Melatonin helps regulate the sleep-wake cycle, and serotonin is thought to help regulate appetite, sleep, mood, and pain. 

The bigger picture. 
The bidirectional nature of the relationship between sleep and diet is acknowledged however the research investigating the impact of diet on sleep is lacking compared to that of sleep and its impact on diet. That being said, a growing body of evidence highlights the role of nutrition in influencing sleep quality and duration. More importantly, the quality of nutrition plays an important role in having a positive effect on health and specifically, sleep. Inflammation in the body is linked to poor sleep quality, increased sleep quantity (hours >9), cognitive issues and other chronic diseases including heart disease, metabolic syndrome and cancer. These inflammatory markers are often seen with highly processed food consumption combined with a lack of daily vegetables, fruits and grains. Consuming between 5 to 7 serves of fruits and vegetables has been shown to reduce the likelihood of poor-quality sleep (15).  

Final Thoughts. 
The studies investigating nutrition and its effect on sleep are still in their infancy. In saying that, common sense should be applied to what we are seeing as a society. It is clear that a diet consisting of processed, ultra-processed, high-caloric density foods is resulting in negative consequences on health.  
 
The impact that this type of diet has on sleep as an aspect of that individual’s health also appears to be negative. With so much focus on sleep at present and the tracking of metrics related to sleep, it is interesting that so little attention is being focused on what we are eating.  
 
The focus is so often on the mind from a stress perspective. A constant and consistent reinforcement message by apps and social media to be mindful and meditate more. Perhaps a shift is required? Be mindful yes. Be mindful of what goes on your plate and into your mouth.  
 
Why not be aggressive and impactful with challenging yourself to increasing your intake of vegetables and fruits to a minimum of 5-7 serves per day. This simple act could have you getting the optimal 7-9 hours of sleep per night. It might just be the change that shifts your sleep data for the better! 

References. 

  1. Zuraikat et al. “Sleep and Diet: Mounting Evidence of a Cyclical Relationship.” Annual review of nutrition vol. 41 (2021): 309-332.  
  2. Ward, Zachary J et al. “Projected U.S. State-Level Prevalence of Adult Obesity and Severe Obesity.” The New England journal of medicine vol. 381,25 (2019) 
  3. Chen Y, Tan F, Wei L, Li X, Lyu Z, Feng X, et al. Sleep duration and the risk of cancer: a systematic review and meta-analysis including dose-response relationship. BMC Canc 2018;18(1):1149. 
  4. Cappuccio FP, Cooper D, D'Elia L, Strazzullo P, Miller MA. Sleep duration predicts cardiovascular outcomes: a systematic review and meta-analysis of prospective studies. Eur Heart J 2011;32(12):1484e92. 
  5. Cappuccio FP, D'Elia L, Strazzullo P, Miller MA. Quantity and quality of sleep and incidence of type 2 diabetes: a systematic review and meta-analysis. Diabetes Care 2010;33(2):414e20. 
  6. Pace-Schott EF, Spencer RM. Sleep-dependent memory consolidation in healthy aging and mild cognitive impairment. Curr Top Behav Neurosci 2015;25:307e30. 
  7. Bai, Chen et al. “Sleep duration, vegetable consumption and all-cause mortality among older adults in China: a 6-year prospective study.” BMC geriatrics vol. 21,1 373. 21 Jun. 2021 
  8. Chaput JP. Sleep patterns, diet quality and energy balance. Physiol Behav 2014;134:86e91. 
  9. Markus et al. 2000. The bovine protein alpha-lactalbumin increases the plasma ratio of tryptophan to the other large neutral amino acids, and in vulnerable subjects raises brain serotonin activity, reduces cortisol concentration, and improves mood under stress. Am. J. Clin. Nutr 71:1536–44  
  10. Godos, Justyna et al. “Association between diet and sleep quality: A systematic review.” Sleep medicine reviews vol. 57 (2021): 101430. 
  11. Godos J, Ferri R, Caraci F, Cosentino FII, Castellano S, Shivappa N, et al. Dietary inflammatory index and sleep quality in southern Italian adults. Nutrients 2019;11(6). 
  12. Palego L, Betti L, Rossi A, Giannaccini G. 2016. Tryptophan biochemistry: structural, nutritional, metabolic, and medical aspects in humans. J. Amino Acids 2016:8952520. 
  13. Irwin MR, Olmstead R, Carroll JE. Sleep disturbance, sleep duration, and inflammation: a systematic review and meta-analysis of cohort studies and experimental sleep deprivation. Biol Psychiatr 2016;80(1):40e52. 
  14. Wastyk, Hannah C et al. “Gut-microbiota-targeted diets modulate human immune status.” Cell vol. 184,16 (2021): 4137-4153 
  15. Pengpid, Supa, and Karl Peltzer. “Fruit and Vegetable Consumption is Protective from Short Sleep and Poor Sleep Quality Among University Students from 28 Countries.” Nature and science of sleep vol. 12 627-633. 26 Aug. 2020,