Do Foods Affect Sleep?

A few decades ago, sleep was often considered a waste of time.  Many people saw no reason not to “burn the candle at both ends” of the day, even going so far as saying, “I’ll sleep when I’m dead!”.  Ironically, going along with that phrase is likely to make death come sooner than it might have because, as we are now discovering, sleep is essential for long-term health.

Getting enough high-quality sleep is not only important for how you feel when you’re awake and rested.   It is significant for much more than that.

 

What are the Effects of Poor-Quality Sleep or Lack of Sleep?

• Lack of effective sleep raises the risks of many disorders such as heart disease, stroke, dementia and obesity. (1)
• Sleep deficiency, even for a single night, can impair cognitive functions, responsiveness and overall daily performance. (2)
• A good sleep helps to prepare your brain for another day of learning, remembering and creating. Conversely, not getting enough sleep can lead to difficulties in focusing on tasks and thinking clearly.  Surprising recent research has discovered that our brains change their function while we sleep.  During non-rapid eye movement deep sleep, regular waves of electrical impulses are sent through the brain neurons to activate the glymphatic system.  This generates successive floods of fresh cerebrospinal fluid throughout the brain which mixes with the waste-filled fluid surrounding brain cells and flushes it out into the lymphatic system and then the bloodstream for removal from the body.  Studies have shown that proteins linked with Alzheimer’s disease are cleared from the brain twice as quickly during sleep compared to during wakefulness. (3,1,4)
• Sleep deprivation negatively affects mood and has been linked to anxiety, depression and impulsive behaviour. (5)
• Many parts of the body use sleep as a time for repair. If you’re not getting enough sleep, cell renovation will be compromised.  (1)
• During sleep, the cardiovascular system enjoys a rest as blood pressure and heart rate are lowered. (4)
• Some parts of our immune system are only active during sleep. This is likely why lack of sleep is linked to higher incidences of colds and other infections. (4)
• Inferior sleep leads to activation of the reward centers in the brain and increases the consumption of food, especially high-fat, high-sugar and high-salt foods. (4)
• Levels of the hunger causing hormones, leptin and ghrelin, increase when not getting enough sleep. On the other hand, the production of hormones such as testosterone, estrogen and progesterone are severely impaired if sleep is of low quality or lacking.  (4)
• Poor sleep is associated with decreased physical activity, metabolic syndrome and weight gain. (4)   Note: Metabolic syndrome is a state that can include high blood pressure, high blood sugar, excess body fat around the waist and high blood levels of cholesterol or triglycerides.
• Poor sleep reduces the ability of the body to respond to insulin. (4)
• New research from 2023 found that getting fewer than 6 hours of sleep a night, more than 10 hours of sleep a night, or poor-quality sleep in general increases the risk for type-2 diabetes. (6)
• Both sleeping too few hours or too many hours are significant predictors of early death in prospective population studies. (5)

 

Can Foods Affect Sleep?

A study from June 2023 showed that plant-based diets may help optimize sleep quality. The research included 2,424 participants from China 45 years of age or older.   Their diets were categorized into three dietary patterns:  the overall plant-based diet index, the healthful plant-based diet index or the unhealthful plant-based diet index. A healthful plant-based diet emphasizes vegetables, legumes, fruits, whole grains and nuts. Results demonstrated that the participants choosing most of their foods from the healthful plant-based diet index had 55% higher chance of achieving better sleep quality.  Those choosing most of their foods from the unhealthful plant-based diet index had twice the odds of poor sleep. (7)

In 2020, an investigation followed the diets of more than 400 women from the US.  Results illustrated that higher intakes of nutrient-dense fruits and vegetables, legumes, unsaturated fat and plant-based proteins were related to better future sleep quality.  Legumes in particular were associated with enhanced sleep overall with the more servings of legumes consumed, the more significant the improvement in sleep efficiency observed.  (8)

Note:  Sleep efficiency is the ratio of the number of hours slept to the number of hours spent in bed.

The authors note that plant-based foods are rich sources of fiber which is connected by various mechanisms to a healthy gut microbiome.  For instance, signals from the gut microbiome help to regulate many body processes including the sleep-wake cycle.

Additionally, fruits and vegetables are excellent sources of beneficial antioxidant compounds called polyphenols.  Polyphenols have been found to promote relaxation and better sleep quality.

Plant-sourced foods like legumes, leafy greens, soy and seeds are also high in tryptophan, an amino acid that is needed for the production of the sleep hormone melatonin.  Though animal-sourced foods like turkey and dairy also contain tryptophan, the form found in animal-sourced foods does not get used as efficiently by the brain.  This may be due to the B vitamins and carbohydrates that are needed to process tryptophan, both of which come along with the tryptophan when eating plants.  (8)

Foods low in fiber and high in saturated fat, sugar and refined carbohydrates can damage sleep quality.  Studies have found that participants take longer to fall asleep and spend less time in deep, restorative sleep when they eat these types of foods.  (9)

 

Take-Home Messages

Plant-sourced foods are revealing their health advantages in many different aspects of life including the quality and quantity of sleep.  We have likely all experienced a sleepless night or two, the frustration of hours spent in bed but not sleeping and the added insult of coping with the challenges of the next day in a fatigued state.  Knowing that our food choices can help avert sleeping problems may encourage higher consumption of foods derived from plants.

Remember that there are other bonuses here too.  Eating more plant-based foods will increase the amount of fiber in the diet.  We now know that those eating the highest quantities of fiber have a 15 to 30% decrease in mortality from all causes including cardiovascular disease.  In addition, consuming fiber-rich foods reduces the incidence of coronary heart disease, stroke, type-2 diabetes and colorectal cancer by 16 to 24%.  People worldwide consume less than 20 grams of fiber a day.  Research has suggested an adequate amount of 25 to 29 grams daily but recent data points out the need for even higher intakes for best health. Fiber comes only from plants. (10)  Furthermore, plant-based foods are much richer in phytonutrients and antioxidants than are animal-sourced foods.  These plant components have extensive benefits for health and are associated with a reduced risk for cardiovascular and other diseases. (11)

And so, reasons for eating mostly plants continue to mount and we’ve moved long past the time when eating plant-based needed to be justified.  If you haven’t already made the transition, isn’t it time you did?

  

SOURCES:

1  https://newsinhealth.nih.gov/2021/04/good-sleep-good-health

2 https://scitechdaily.com/harvard-researchers-help-unravel-the-mystery-of-sleep/

3  Fultz, N.E., Bonmassar, G., Setsompop, K., Stickgold, R.A., et al.  Coupled electrophysiological, hemodynamic, and cerebrospinal fluid oscillations in human sleep.   Science. Nov 2019; 366(6465): 628-631.  Doi: 10.1126/science.aax5440.

4  https://www.nhlbi.nih.gov/health/sleep/why-sleep-important

5  Cappuccio ,FP.,. D’Elia, L., Strazzullo, P., Miller, M.A. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep. 2010 May; 33(5): 585-592. Doi: 10.1093/sleep/33.5.585. PMID: 20469800; PMCID: PMC2864873.

6  https://www.endocrine.org/news-and-advocacy/news-room/2023/endo-2023-press-kim

7  Tang, S., Zhou, J., Liu, C., et al. Association of plant-based diet index with sleep quality in middle-aged and older adults: The Healthy Dance Study. Sleep Health. 2023: S2352-7218(23)00081-5. Doi:10.1016/j.sleh.2023.04.003.

8  Zuraikat, F.M., Makarem, N., St-Onge, M.P., Xi, H., Akkapeddi, A., Aggarwal, B. A Mediterranean Dietary Pattern Predicts Better Sleep Quality in US Women from the American Heart Association Go Red for Women Strategically Focused Research Network. Nutrients. 2020 Sep 16; 12(9): 2830. Doi: 10.3390/nu12092830. PMID: 32947817; PMCID: PMC7551612.

9  St-Onge, M.P., Roberts, A., Shechter, A., Choudhury, A.R. Fiber and Saturated Fat Are Associated with Sleep Arousals and Slow Wave Sleep. J Clin Sleep Med. 2016 Jan; 12(1): 19-24. Doi: 10.5664/jcsm.5384. PMID: 26156950; PMCID: PMC4702189.

10  Reynolds, A., Mann, J., Cummings, J., Winter, N., Mete, E., Te Morenga, L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019 Feb 2; 393(10170): 434-445. Doi: 10.1016/S0140-6736(18)31809-9. Epub 2019 Jan 10. Erratum in: Lancet. 2019 Feb 2;393(10170):406. PMID: 30638909.

11  Leitzmann, C. Characteristics and Health Benefits of Phytochemicals. Forsch Komplementmed. 2016;23(2): 69-74. Doi: 10.1159/000444063. Epub 2016 Feb 4. PMID: 27160996.