Sleep, Nutrition, and Repair: Why good sleep is important to the cancer survivor
Annette Goldberg MS, RD, LDN, dipACLM
Senior Clinical Nutritionist – Cancer Care Specialist
Dana Farber Cancer Institute
Over the past ten years, sleep research has continued to grow. We are realizing the importance of sleep to our physical and mental well-being. Organizations like the Sleep Research Society, the Centers for Disease Control and Prevention, the Mayo Clinic and the National Institutes of Health have discussed the importance of sleep. It is now known as the “third pillar” of good health.1
The National Sleep Foundation recommends seven to nine hours of sleep per night for adults between 18 and 64 years old. Adults over 65 may need seven to eight hours. More than one-third of adults in the National Sleep Foundation’s 2020 Sleep in America Poll aren’t getting the recommended sleep.2 If you experience continued sleep deprivation, you will develop a condition called sleep deficiency. This is a state where you can’t make up for the lost hours of sleep. Sleep deficiency increases the risk of obesity, diabetes, cardiovascular disease, depression, dementia and even early death.3
Is there a connection between sleep and cancer? Long-term sleep disruptions may raise the risk of some cancers. Disruptions of the body’s “biological clock,” which controls sleep and thousands of other functions, may raise the odds of cancers of the breast, colon, ovaries and prostate. It is challenging to get a good night’s sleep after a diagnosis and during treatment, when anxiety, depression, deep fatigue, digestive problems, breathing problems, hot flashes, night sweats and pain can all affect falling asleep and staying asleep. It can also be a lifelong challenge for survivors.4
There are four stages of sleep
- N1 – During stage 1, you are just relaxing and preparing for sleep. The brain activity starts to slow, your surroundings are a bit hazy, and you may experience “twitching” of the muscles. This phase lasts one to five minutes.
- N2 – During stage 2, you enter a more relaxed phase, where the body temperature drops, the muscles relax, and breathing and heart rate slow down. This stage lasts 10–25 minutes and almost half of our sleep time is spent in this phase.
- N3 – During stage 3, you enter a deep sleep. As the body relaxes further, your breathing, pulse and muscle tone relax even further. Your brain enters a distinct pattern known as delta waves. Experts believe that this stage is critical to restorative sleep, allowing for bodily recovery and growth. N3 may also bolster the immune system and other key bodily processes. This stage lasts 20–40 minutes.
- N4 – N4 is known as Rapid Eye Movement or REM sleep. During this stage, brain activity picks up almost to the level where you are awake. This stage is essential to cognitive functions such as memory, learning and creativity. This is also the stage where we have the most vivid dreams. This stage may last 10–60 minutes.5
On average, a cycle of these stages lasts 90 minutes, although the time within each stage may vary and change throughout the night.5 Sleep stages are important because they allow the brain and body to recuperate and develop. Failure to obtain both enough sleep and the phases of deep sleep and REM sleep may explain some of the challenges we have with our emotional and physical health.
Nutrition can affect your quality of sleep. The standard American diet of ultra-processed foods, high saturated fats and low fiber is strongly associated with poor sleep quality and duration.6 Deficiencies in vitamin B1, folate, phosphorus, magnesium, iron, zinc, and selenium have been associated with shorter sleep duration. Low selenium, calcium, vitamins D and C and lycopene were also connected to poor sleep. Increasing zinc-rich foods in particular has been shown to improve the ability to fall asleep and get better sleep. The amino acid glycine as well as magnesium, sodium, potassium and electrolytes in general are all well-known to lower cortisol, modulate the stress response and improve sleep quality.6 The best strategy to ensure you are receiving all the required vitamins and minerals in your diet is to eat a balanced plate where 50% of your plate at every meal consists of fruits and vegetables, 25% whole grains and 25% protein. The DASH diet and Mediterranean diet are good templates of healthy eating.
Here are nutrition and sleep hygiene tips to help you get the best sleep
- Set a sleep schedule and stick to it. Go to bed at night and awaken in the morning around the same times, even on weekends. This helps to regulate the body’s sleep cycles and circadian rhythms.
- Exercise at some point in the day but avoid vigorous activity (running, fast dancing, high-intensity interval training or HIIT) one hour before bedtime. Regular exercise of adequate intensity can promote muscle relaxation and deeper sleep later on.
- Avoid large meals, heavy snacking, spicy foods and alcohol three hours before bed.
- If you are sensitive to caffeine, avoid drinking caffeinated beverages four to six hours before bedtime.
- Stop using electronic devices an hour before bed, especially those emitting blue light such as smartphones, tablets and televisions.
- Schedule before-bed activities to signal that you are winding down, such as changing into pajamas and brushing teeth.
- Create a quiet, dark, relaxing environment in your bedroom. Dim the lights and turn off your cell phone’s sound and vibration modes if possible.
- Ensure a comfortable temperature, as feeling too hot or cold can disrupt sleep.
- Create calming bedtime rituals such as practicing deep breathing exercises, doing light yoga stretches or listening to soothing music. Many meditation podcasts, apps and YouTube videos offer these tools for free.
- If you awaken and can’t return to sleep, don’t stay in bed. Get up and do quiet relaxing activities, such as reading, until you feel tired enough to fall back asleep.
- Eat complex carbohydrates such as whole-wheat toast or a bowl of oatmeal before bed. These foods will trigger the release of the sleep hormone serotonin, and they don’t take long to digest.
- Other foods to try: milk (high tryptophan, calcium, and other essential minerals as well as being pre-balanced with protein, fat and carbohydrates), Kiwi (high antioxidant content, high vitamin C and E, and they are one of the few foods to contain high levels of serotonin), tart cherry juice (high melatonin concentration) and oyster (high zinc levels).6,3,7
If you are struggling to achieve good sleep patterns, talk to the members of your care team. Avoid using any sleep supplements until you have spoken with your care team. They can refer you to sleep specialists or clinics. The National Sleep Foundation (thensf.org) and The Sleep Foundation (sleepfoundation.org) are good references for educational information on sleep.
- Ryan Fiorenzi. SLEEP STATISTICS: UNDERSTANDING SLEEP AND SLEEP DISORDERS. Start Sleeping. Published February 20, 2022. Accessed October 2, 2022. https://startsleeping.org/statistics/
- Sleep by the Numbers. National Sleep Foundation. Published May 12, 2021. Accessed October 2, 2022. https://www.thensf.org/sleep-facts-and-statistics/
- Harvard T.H Chan School of Public Health. The Nutrition Source. Accessed October 2, 2022. https://www.hsph.harvard.edu/nutritionsource/sleep/
- Lack of Sleep and Cancer: Is There a Connection? Published January 3, 2022. Accessed October 2, 2022. https://www.hopkinsmedicine.org/health/wellness-and-prevention/lack-of-sleep-and-cancer-is-there-a-connection
- Stages of Sleep: What Happens in a Sleep Cycle. Sleep Foundation. Published December 2, 2021. Accessed October 2, 2022. https://www.sleepfoundation.org/stages-of-sleep
- Amanda Bourbonais. University of Texas at Austin, Nutrition Institute. How diet affects sleep: five tips for a better night’s sleep through nutrition. Published April 28, 2021. Accessed October 2, 2022. https://utnutritioninstitute.org/whats-fresh/how-diet-affects-sleep
- Rachel E Salas MD. John Hopkins Medicine. Health. Accessed October 2, 2022. https://www.hopkinsmedicine.org/health/wellness-and-prevention/better-sleep-3-simple-diet-tweaks