January/February 2023

Eating for Better Sleep
By Michele Deppe
Today’s Geriatric Medicine
Vol. 16 No. 1 P. 14

The Mediterranean Diet Helps Older Adults Sleep

A study published in the American Journal of Medicine in 2006 indicated that approximately 50% of older people reported experiencing insomnia, which is defined as insufficient or nonrestorative sleep.1 According to the National Institute on Aging, one of the greatest myths about growing older is that people come to need less sleep than the recommended seven to nine hours each night. This is a harmful misconception, the National Institute on Aging says, since older adults need the same amount of sleep as other adults, and inadequate sleep can lead to more falls and feelings of decreased mental well-being.2 Good news for older adults is that what they eat can make all the difference.

Widely touted for being healthful, the Mediterranean diet, according to new research, may also have sleep-enhancing qualities.3

A 2018 study in Greece with 1,639 participants older than 65 concluded that the Mediterranean diet positively influenced sleep quality. Conversely, sleep duration didn’t seem to improve in that study.4 A variety of components in the popular diet appear to contribute to a more restful night’s sleep.

Omega-3s
The Mediterranean diet is rich in omega-3 fatty acids, which seems to be one reason that the Mediterranean diet helps people sleep. “There are two main types of omega-3s: EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), which come from fish. Another is ALA (alpha-linolenic acid), which is derived from plants,” explains Katie Dodd, MS, RDN, CSG, LD, FAND, a geriatric dietitian and author of The Geriatric Dietitian blog.

Dodd, referring to an article from the Harvard TH Chan School of Public Health, says, “Omega-3 fatty acids are a key family of polyunsaturated fats and are a starting point for making hormones; they are in the cell membranes and affect cell receptors.”5 Our bodies can make other fats, but that is not the case for omega-3. “These are essential fats, and we must get them from food,” Dodd says, noting that—unlike the Mediterranean diet—the typical American diet is far higher in omega-6 fats, which could potentially lead to some health problems. Although the exact mechanism isn’t known, she says, omega-3s’ known benefits of hormone production and health promotion seem to encourage sound sleep.

“Omega-3 fatty acids are found in fatty fish like salmon, walnuts, flax seed, and chia seed,” Dodd says. “Omega-3s are beneficial for heart health and may be beneficial for mental health as well. In my experience, most people, older adults included, do not get enough Omega-3s.” Eating fish twice weekly, she says, is an excellent way to get more omega-3s in the diet. If your geriatric patient isn’t a fan of seafood, the other options can be sufficient sources. “If someone doesn’t like fish due to taste or if they follow a vegetarian or vegan diet, they can get omega-3s through walnuts, flax, or chia seeds,” Dodd says. Strategies for working these into the diet include snacking on a small handful of walnuts during the day or adding them to oatmeal or chicken salads and green salads. Ground flax seeds or chia seeds can be added to cereals, parfaits, and smoothies.

But sound sleep isn’t the only goal of a good night’s rest. Proper duration of sleep is also important. In 2022, The American Journal of Clinical Nutrition reported evidence linking dietary fat levels to support of good sleep after researchers evaluated data from more than 20,000 people, spanning 12 studies conducted in five countries. The paper was described by the director of the Institute for the Advancement of Food and Nutrition Sciences as “one of the largest papers published on links between sleep and dietary fats and opens up new lines of inquiry to benefit public health.” A main finding of the research is that people who had consumed long-chain omega-3s found in fish and some marine plants had lowered risk of “long sleep duration,” which is another health benefit.6 According to the Sleep Foundation, “long sleepers”—those who sleep more than nine hours a night—may have elevated risks for heart disease, stroke, and diabetes. However, it’s important to note that some experts say 2% of people are “natural long sleepers” and perhaps just need more sleep than others and/or have a genetic component that makes them long sleepers.7

“One way omega-3 fatty acids may influence sleep is through hormonal regulation,” says Lauri Wright, PhD, RDN, LD/N, FADA, an associate professor and director of the Doctorate in Clinical Nutrition program at the University of North Florida. “Specifically, omega-3 fatty acids are needed to make melatonin, the sleep hormone. Research has shown a diet rich in omega-3s increases melatonin levels and, consequently, may increase the amount of sleep.”

A small study of obese adults with sleep apnea showed that diets higher in DHA lessened the risk for apnea and promoted better sleep.8 Another study in coastal Ecuador evaluating 677 adults found that oily fish intake was associated with better sleep quality.9 Published in Nutrients, an American Heart Association 2020 study of more than 400 women aged 20 through 76 years found that the “alternate Mediterranean diet” (aMed) provided women better sleep quality, higher sleep efficiency, and fewer sleep disturbances. The aMed diet was described as including “nutrient-dense fruits and vegetables and foods high in plant-based protein and unsaturated fats, which are often rich in sleep-promoting nutrients and compounds.” The aMed diet may include fewer servings of meat and less alcohol and may not include dairy. Researchers’ conclusions were that following the diet would improve sleep in American women, as it was shown to do for older European populations.10

Other Healthful Components
According to a recent report published in Nutrients, the traditional Mediterranean diet is characterized by an abundance of olive oil for both preparation and seasoning, more than two servings of both vegetables and fruit at each meal, nuts used in meals or as snacks, and cereals and legumes. It features two to four servings weekly of fish, poultry, eggs, alcohol, and dairy, along with sprinklings of fresh herbs, but there are few servings of red meat, processed meats, and foods loaded with sugar and saturated fat.3

Various foods included as part of the Mediterranean diet seem to promote sleep, although the evidence isn’t conclusive. Fish may help sleep because its vitamin D and omega-3 fatty acid content help the body’s regulation of serotonin.11 Fatty fish, eggs, and nuts that contain tryptophan can also encourage good sleep.12 Walnuts, cashews, and pistachios may be helpful for sleep. A study found that melatonin, magnesium, and zinc—present in nuts to varying degrees—helped older adults overcome insomnia.13 Research shows that foods in the Mediterranean diet—such as leafy greens—that are rich in nitrates are converted to nitric oxide and are likely to help by contributing to better circulation and heart function, ushering the body into a deeper sleep.14 Tart cherries and their juice have been linked to concentrations of melatonin that help sleep.15 Some types of red grapes have been found to have high levels of melatonin, but grapes seem to be inconsistent in their levels.16 Kiwi fruit, which is rich in vitamins and minerals, including potassium and folate, appears to improve sleep, although researchers have not pinpointed the reason. People who ate two kiwi fruits one hour before bed fell asleep faster and had better sleep quality and duration.17

The Microbiome Affects Sleep
Studies have shown some sleep disturbance in people with lower gut microbiota diversity.3 One concluded that when participants who regularly ate a Western diet consumed the Mediterranean diet for two weeks, there was a “remarkable change in the metabolic activity of gut microbiota” and a higher level of butyrate-producing bacteria. Butyrate is a short-term fatty acid produced when beneficial bacteria break down in the colon.

“The Mediterranean diet has been shown to beneficially affect the abundance, composition, and metabolic activity of the gut microflora,” Wright says. “This is mostly because of the variety of fibers from vegetables, fruits, whole grains, and legumes. Research hasn’t identified just one component impacting the gut-brain connection, so I think what is important to know is that a variety and adequate intake of fiber aids in sleep.”

Conclusion
“I think there are many factors that affect sleep,” Dodd says. “From medications to stress management to exercise to diet. It’s often difficult to pinpoint one cause contributing to poor sleep quality. But we do know that good overall health can maximize sleep quality. This includes eating a well-balanced diet complete with omega-3s.”

“The Mediterranean diet is associated with healthier body weight. Obesity has been shown to negatively impact sleep quality,” Wright says. “And inflammation is associated with altered circadian rhythms and to poor sleep quality and quantity, as well.” The Mediterranean diet is rich in antioxidants, she explains, which helps to quell inflammation. “The bottom line,” she says, “is that the Mediterranean diet has so many health benefits, including better sleep!”

— Michele Deppe is a freelance writer based in South Carolina.

References
1. Kamel NS, Gammack JK. Insomnia in the elderly: cause, approach, and treatment. Am J Med. 2006;119(6):463-469.

2. 10 myths about aging. National Institute on Aging website. https://www.nia.nih.gov/health/10-myths-about-aging. Accessed October 7, 2022.

3. Scoditti E, Tumolo MR, Garbarino S. Mediterranean diet on sleep: a health alliance. Nutrients. 2022;14(14):2998.

4. Mamalaki E, Anastasiou CA, Ntanasi E, et al. Associations between the Mediterranean diet and sleep in older adults: results from the Hellenic Longitudinal Investigation of Aging and Diet study. Geriatr Gerontol Int. 2018;18(11):1543-1548.

5. Omega-3 fatty acids: an essential contribution. Harvard T.H. Chan School of Public Health website. https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/types-of-fat/omega-3-fats/. Accessed October 7, 2022.

6. Murphy RA, Tintle N, Harris WS, et al. PUFA ω-3 and ω-6 biomarkers and sleep: a pooled analysis of cohort studies on behalf of the Fatty Acids and Outcomes Research Consortium (FORCE). Am J Clin Nutr. 2022;115(3):864-876.

7. Long sleepers. Sleep Foundation website.
https://www.sleepfoundation.org/how-sleep-works/long-sleeper. Updated March 30, 2022. Accessed October 7, 2022.

8. Papandreou C. Independent associations between fatty acids and sleep quality among obese patients with obstructive sleep apnoea syndrome. J Sleep Res. 2013;22(5):569-572.

9. Del Brutto OH, Mera RM, Ha JE, Gillman J, Zambrano M, Castillo PR. Dietary fish intake and sleep quality: a population-based study. Sleep Med. 2016;17:126-128.

10. Zuraikat FM, Makarem N, St-Onge MP, 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;12(9):2830.

11. St-Onge MP, Mikic A, Pietrolungo CE. Effects of diet on sleep quality. Adv Nutr. 2016;7(5):938-949.

12. Whitbread D. Top 10 foods highest in tryptophan. My Food Data website. https://www.myfooddata.com/articles/high-tryptophan-foods.php. Updated September 26, 2022. Accessed October 7, 2022.

13. Rondanelli M, Opizzi A, Monteferrario F, Antoniello N, Manni R, Klersy C. The effect of melatonin, magnesium, and zinc on primary insomnia in long-term care facility residents in Italy: a double-blind, placebo-controlled clinical trial. J Am Geriatr Soc. 2011;59(1):82-90.

14. Kohansieh M, Makaryus AN. Sleep deficiency and deprivation leading to cardiovascular disease. Int J Hypertens. 2015;2015:615681.

15. Zeng Y, Yang J, Du J, et al. Strategies of functional foods promote sleep in human being. Curr Signal Transduct Ther. 2014;9(3):148-155.

16. Hitti M. Grapes may help with sleep. WebMD website. https://www.webmd.com/sleep-disorders/news/20060619/grapes-help-sleep. Published June 19, 2006. Accessed October 7, 2022.

17. Lin HH, Tsai PS, Fang SC, Liu JF. Effect of kiwifruit consumption on sleep quality in adults with sleep problems. Asia Pac J Clin Nutr. 2011;20(2):169-174.