Sleep problems are common among the general population but particularly so among those suffering from 'environmental', or 'invisible', illnesses such as chronic fatigue syndrome (ME/CFS), fibromyalgia (FMS) and multiple chemical sensitivity (MCS). Everyone will be familiar with common causes of insomnia and poor sleep quality such as consumption of stimulants like caffeine (coffee, tea, soda/fizzy drinks) and psychological factors such as work or relationship stresses. For those suffering from environmental illnesses there may be other less obvious contributors to sleep problems, however.
Hypoglycaemia, or low blood sugar, is frequantly experienced by those suffering from environmental illnesses and is exacerbated by a diet that contains significant amounts of foods containing sugar or refined carbohydrates e.g. candy/sweets, chocolate, white bread, white pasta, white rice, baked goods, fast food. When levels of blood sugar (glucose) drop too low or too rapidly it is the brain that is affected first since it relies (almost) exclusively on glucose for energy. The most common symptoms of hypoglycaemia include nervousness, irritability, anxiety, tremors and cold sweats - so knowing this it's not surprising that it can afect our sleep. The problem will be exacerbated if you eat the foods mentioned above in the evening or shortly before going to bed as this may result in a hypoglycaemic episode during the night, likely waking you up. Tip: Eat a balanced whole foods diet that contains low glycaemic index (GI) and low glycaemic load (GL) foods. See more on hypoglycaemia here.
Disturbed Circadian Rhythm
The body is naturally programmed by environmental factors, particuarly sunlight, to produce and secrete a multitude of hormones and other chemicals in varying amounts depending on the time of day. For example, the adrenal glands should secrete the highest amounts of the steroid hormone cortisol in the morning when the sun comes up, with blood levels then slowly tailing off throughtout the day until they reach their lowest concentrations at night. Cortisol is often referred to as a 'stress' hormone but it is essential for health under normal circumstances too. It gives us the energy and motivation to get us going in the morning and helps us handle daily stresses all day long. Unfortunately in environmental illnesses dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis which regulates cortisol means that the normal rhythm of cortisol secretion can get out of synch. Often too little is produced during the morning making it hard for us to wake up and get out of bad, while too much is released into the blood at night. The upshot of the latter is that the excessive cortisol at night means that when we should be going to bed and sleeping we feel awake, perhaps even 'wired', making it very difficult to get off to sleep until cortisol levels begin to drop again...which may not be until 3 or 4am!. Another important hormone affected by an out of synch circadian rhythm is melatonin - the so-called 'sleep hormone'. When the sun goes down the neurotransmitter serotonin is usually converted to melatonin, which induces sleep. If your circadian rhythm is out of whack then you may not be producing sufficienct melatonin at night. In seasonal affective disorder (SAD), which is itself a condition resulting from disrupted circadian rhythm, it is thought that insufficient secretion of melatonin at night but excessive secretion during the day leads to typical symptoms of depression and daytime lethargy.
More on melatonin here.
More on adrenal hormones here and adrenal hormone testing here.
Gut dysbiosis is defined as an imbalance in the normal, healthy composition of microbes that inhabit our intestines. Studies have shown that small intestinal bacterial overgrowth (SIBO) is common in people diagnosed with ME/CFS, fibromyalgia irritable bowel syndrome (IBS) - and it may be an issue in other environmental illnesses. In SIBO there is excessive growth of bacteria in the small intestine and the important point to note is that the small intestine is where we digest and absorb nutrients from the food we eat. If there are large colonies of bacteria in he small intestine as in SIBO then these bacteria are fed by the food we eat and produce toxic waste products including hydrogen sulphide (H2S) and ammonia. Because the bacteria are living in the small intestine these waste products are readily absorbed into our bodies. These chemicals and others produced by the bacteria are neurotoxic and can interfere with brain function...and as a result, sleep.
Respiratory Allergies (Hayfever)
Respiratory allergies like hayfever and dust mite allergy could be a significant cause of your problems with sleep. Not only as a result of the typical irritating symptoms of itchy, watery eyes, sneezing and stuffy nose, but also due to histamine's action on the brain. During an allergic reaction IgE antibodies produced by the immune system bind to their target (a harmless substance e.g. pollen) to form an 'immune complex', which then binds to a type of cell called a mast cell, which in turn releases histamine. It is histamine (and other inflammatory) chemicals that are responsible for the symptoms of allergy. Histamine however, is also an excitatory neurotransmitter, which means that it stimulates brain activity - acting like a stimulant and keeping you awake if you are particularly sensitive to its effects.
Multiple food sensitivities are a common feature of environmental illnesses and are reported to cause a wide range of symptoms, including sleep disturbances. Although controversial it is thought that in addition to the classical IgE-mediated allergies that cause immediate symptoms (throat tightening etc), foods can trigger the production of IgG antibodies which trigger more subtle and prolonged symptoms. It is important to recognise that the immune system and nervous system are in constant two-way communication and use the same chemicals to send messages. IgG antibodies produced after consuming foods to which you are sensitive could therefore influence brain function and interfere with sleep.
If you suffer from MCS, or have hidden/masked chemical sensitivities (see TILT Theory), your reactions to chemicals (particularly in your bedroom) could be keeping you awake at night or disturbing your sleep. Leading theories about the pathophysiology of MCS indicate that the brain becomes hypersensitive to various chemicals and even small amounts trigger a reaction in the limbic system (emotional centre of the brain) known as 'kindling', which is akin to that seen in epilepsy and seizures. It obviously follows that this would be likely to disrupt sleep!
Institute for Functional Medicine (2005) Textbook of Functional Medicine Institute for Functional Medicine
Nichols TW and Faass N (eds) (1999) Optimal Digestion: New Strategies for Achieving Digestive Health Quill
Pert CB (1997) Molecules of Emotion: Why You Feel The Way You Feel Pocket Books
About: Matthew Hogg ("Maff")
Diagnosed with M.E./chronic fatigue syndrome aged only 11 years old and subsequently associated illnesses including irritable bowel syndrome (IBS) and multiple chemical sensitivity (MCS). Despite his own struggles he has constantly sought to educate and support others suffering from such "invisible illnesses" through his website, The Environmental Illness Resource. He fully recovered from MCS using his own approach and holds a Bachelor of Science Degree in Nutritional Health.