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Can nutrition affect sleep?

By Jennifer Williams
Tuesday, January 15, 2019

Did you sleep well last night? How much sleep did you get? 6, 7, 8 hours? less or more? If you are getting less than 8 hours a night you are likely to be one of the millions who are chronically sleep-deprived. Maybe you already know this and would love a good night's sleep or maybe you believe that you do only need 5-6 hours sleep.

There seems to be some misplaced pride by people regarding the little amount of sleep that they need each night. Many famous names have proudly got by on 4-5 hours of sleep. World leaders Margaret Thatcher, Ronald Reagan, George HW Bush, Winston CHurchill all had less than 5 hours of sleep a night.

Before Edison invented the light bulb sleep was pretty much driven by natural daylight. Work was done whilst there was light and in the dark winter nights sleep could be 9-10 hours. Now we have the means to continue to work into the wee small hours and many people do just this. Interestingly Edison himself got by on only 3-4 hours of sleep.

Is sleep important? The answer is an emphatic yes.

It is now known that routinely getting less than 6-7 hours of sleep a night

  • Disrupts immune function, increasing the risk of illnesses, including cancer
  • Disturbs blood sugar levels, increasing risk of diabetes
  • Increases the risk of Alzheimers, cardiovascular disease, stroke, depression and anxiety.
  • It also affects appetite and weight gain as ghrelin, the appetite stimulating hormone, increases. This can make it very difficult to lose weight.

Margaret Thatcher and Ronald Reagan both had Alzheimer's, Winston Churchill had heart disease and suffered from strokes before he died. George HW Bush had Parkinson's disease and Edison himself died as a result of complications of type 2 diabetes.

Sleeping PersonSleep hormones

Sleep is controlled by serotonin, melatonin and cortisol.

We know serotonin as the "feel good" hormone because it helps to regulate our mood and low levels of it can lead to depression. However, it is also the precursor to melatonin which is secreted from the pineal gland, in response to a signal sent from the hypothalamus. Melatonin is not a sedative hormone, it does not directly initiate sleep, it is triggered by changing light levels signalling the body to prepare for sleep. Melatonin also has a role as an anti-oxidant, meaning that it can help maintain healthy immune function. Melatonin levels will then decrease overnight allowing us to wake up with the early morning light; think of how easy it is to get up in the light summer months compared to the winter. As melotonin decreases cortisol levels start to increase, cortisol helps to keep us alert and wakeful but it is also increased as a response to stress. People in a highly stressed state are likely to be producing higher levels of cortisol that do not lower naturally towards the end of the day and also causes melatonin production to fall. The end result will be poor sleep.

Good Sleep hygiene

  • Regulate your sleep/wake cycle
  • Get daytime exposure to light, spend some time away from artificial lights
  • Have time before bed with dimmed lights, use lamps or dimmer switches rather than bright overhead lights.
  • Avoid screen use for 1-2 hours before bed, or use an app on devices to block the blue light.
  • Sleep in darkness and quiet.
  • Avoid having mobile phones in the bedroom
  • Have a set bedtime routine and a set time for bed.
  • Wake up at the same time each day - if you need to have an alarm clock then you are not getting enough sleep.

How can nutrition help

Making sure that you are eating well may aid sleep by balancing blood sugar levels and providing the correct nutrients for the production of the necessary hormones and neurotransmitters.

  • Having balanced blood sugars through the day can prevent cortisol levels from rising, this means cutting back on sugars and refined carbohydrates.
  • Avoid alcohol before bed and cut down on caffeine intake from coffee and energy drinks.
  • Tryptophan is an essential amino acid (meaning that we cannot make it in our bodies we have to consume it from food) that is the starting point for serotonin production.

Sources include: turkey, milk, cottage cheese, chicken, eggs, soybeans, tofu and nuts (especially almonds), cauliflower and dark green leafy vegetables. However, research has shown that eating high protein meals actually reduces the amount of serotonin reaching the brain as the tryptophan is in competition with the other amino acids. Having a meal high in plant based foods is a better option.

If you need further persuasion that a full night's sleep is essential and not a luxury then listen to this talk by Prof. Matthew Walker. It's a lengthy video but well worth watching.

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