Nutrition and sleep

Thursday 03 May 2018

The importance of a good night’s sleep is often underrated but yet lack of sleep is a problem that seems to affect so many people.

Sleep problems and cancer
According to research, sleep problems and fatigue are 2 of the most common side effects of cancer treatment. Over the past decade there has been a steady growth of interest between a good night sleep and cancer development and recurrence. This has included the complex relationship between sleep and cancer symptoms, most notably pain and depression.

In my experience through the work I have done, good quality sleep is definitely a problem for so many people. It seems to particularly affect women.

There appear to be 3 main patterns of poor sleep.

  1. Having problems getting off to sleep.
  2. Getting off to sleep and then waking in the small hours wide awake, alert and mind racing
  3. Restless sleep.

Hormones and sleep

A good night’s sleep is very dependent on our hormone levels particularly Cortisol and Melatonin.

Cortisol is a hormone released by the adrenal glands usually during times of stress and exercise. Cortisol makes us feel alert and sharp which is part of the fight or flight syndrome. It has a natural rhythm, it should reach its peak first thing in the morning and slowly decline over the day and be at its lowest at midnight. This natural rhythm however can be easily disrupted due to stress, anxiety, pain, poor nutrition or medication. Any one or a combination of these can cause a disruption in the natural cycle which can cause it to peak mid afternoon/early evening and consequently we cannot get to sleep easily. Cortisol also helps to regulate the immune activity, including the release of natural killer cells which help the body to fight cancer. High cortisol levels suppress the function of the natural killer cells and immune system generally.

Interestingly, Professor Spiegel noted that shift workers who worked nights had higher rates of cancer, simply because their cortisol rhythm and sleep patterns were disrupted.

A similar study was carried out by Dr. LI Li who tested 412 postmenopausal breast cancer patients. They were tested for the oncotype DX which is one of the tools doctors use to predict whether the cancer will recur or not. They also surveyed their sleep patterns over a period of 2 years and they found a clear correlation between high scoring oncotype DX and poor sleep.

Poor blood sugar regulation can also affect our sleep. If we get off to sleep ok but wake with a start in the small hours this can be because the blood sugar has fallen too low and when this happens we release cortisol. This is because low blood sugar creates internal stress, and as we know that when we are stressed, for whatever reason, we produce cortisol and as I have explained this makes us feel alert. Consequently we wake and usually have a job getting back off to sleep.

Melatonin is a hormone produced by the pineal gland in the brain during the hours of darkness. It induces drowsiness and sleep. Melatonin also has an antioxidant property that helps prevent damage to cells that can lead to cancer. In order to produce melatonin we firstly need to have sufficient serotonin. This is a name most of you will be familiar with.

Serotonin is the happy neurotransmitter that helps us to relax and feel calm. The amount of serotonin that we produce is directly affected by what we eat. It is made from the amino acid (building blocks of protein) Tryptophan. It is also dependent on how much tryptophan crosses the blood brain barrier so that it can make serotonin. Simply put low tryptophan in the brain equals low serotonin levels which equal low melatonin levels which equals poor sleep.

What can we do to sleep better?

OK so now we know what can influence our sleep but what can we do about it? Nutritionally there is quite a lot that may help. Not just with sleep but with the anxiety, depression or poor blood sugar control which may be contributing to your poor sleep.

  • Try to include foods in your diet that are rich in magnesium and calcium as both of these minerals have been shown to have a calming sedative effect on the nervous system. These foods include, bananas, avocados, dried apricots, almonds, cashew nuts, seeds and dark green leafy vegetables. These foods have a natural balance of magnesium and calcium.
  • Include foods that are naturally rich in the neurotransmitter serotonin as we know that from serotonin we make melatonin. These foods are; turkey, chicken, walnuts, eggs, cottage cheese and omega 3 from oily types of fish. Interestingly omega 3 is needed in the brain for the efficient transmission of messages across the synapses from one neuron to another.
  • Try to have a snack before bedtime that contains both protein and carbohydrate. It gets a little complicated here but basically protein foods contain the amino acid Tryptophan which is the precursor to serotonin. Protein also contains other amino acids which normally all compete for absorption through the blood brain barrier. When this happens tryptophan is stifled. However carbohydrates induce the release of insulin. Insulin requires all the other amino acids except tryptophan to help carry the sugar from the blood into the muscles. This leaves tryptophan un opposed to enter the blood brain barrier to make serotonin. (As a point of interest when people overeat on carbohydrates it is not always lack of willpower but the body craving the sedative effect of the tryptophan. People often report that after a lot of carbohydrates they feel calm and sleepy)
  • Some ideal snacks would be some oatcakes spread with almond nut butter or hummus; a bowl of whole wheat sugar free cereal with almond milk; a chicken or turkey sandwich made with whole meal bread; some live natural yogurt over a chopped banana sprinkled with some seeds.
  • Research has shown that the more active people are during the day that they have a better night’s sleep. So a good walk may help.
  • Avoid all stimulants like coffee and alcohol in the evening.
  • Avoid sweet foods because both high and low blood sugar stimulates the release of cortisol and as we know cortisol keeps us awake and if too much is released on a regular basis will suppress immune function.
  • Morello cherries which you can buy as a juice are naturally rich in melatonin. You can buy a product called cherry active which is sold for its sedative properties (amongst others).

There are of course many other therapies that will help that are not nutritional. Like yoga, tai chi and meditation. It may also help to talk about your worries or concerns.  See our pages about exercise and cancer.

Drop into any of our Centres to find out how Maggie’s can help.  

It is the most natural thing in the world to be stressed by the cancer and its treatment but if you can think about including some of the ideas in this blog they may help reduce some of the stress and worry and help you to have a good nights sleep.

Original blog written by Caroline, April 2013 - links updated 2021

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