Irritable bowel syndrome, serotonin levels and the role of diet

Irritable bowel syndrome (IBS) is becoming an increasingly common gut disorder in which the sufferer typically experiences: abdominal pain, cramping, bloating, excess wind, diarrhoea, and/or constipation, or an alternating combination of the two. Whilst the severities of these symptoms vary considerably between individuals, IBS has a profound effect on the sufferer’s quality of life. Many of the day to day activities that the majority of us take for granted can pose much more of challenge when you have IBS. You no longer simple take your body for granted, with careful forward planning essential in order to cope with the unpleasant, and often, embarrassing symptoms. Understanding IBS and what triggers the variety of symptoms is paramount to developing coping strategies.

It is thought that people with IBS have an abnormal gastrocolic response. This is the physiological reflex that controls the movements of the gastrointestinal tract (GI tract). Simply put, this mechanism controls the movement (peristalsis) that pushes food through and out of the gut. In IBS, simply eating or drinking can cause an over reaction of this process resulting in painful cramps, often resulting in diarrhoea.

Whilst the action of eating causes an increase in gut mobility, eating large meals seems to cause excessive cramping and bouts of diarrhoea, so a key tip is to try to eat small amounts and to try to eat regularly. Many people with IBS also find there are specific dietary triggers that can result in discomfort and bowel dysfunction. Knowing what foods to include, and what foods to avoid, can make a dramatic impact on regulating or avoiding specific symptoms.

Several gut peptides (types of protein), and neuropeptides are involved in the control of the gastrocolic reflex, of which serotonin is one such example. Serotonin, a neurotransmitter peptide, is generally known for its role in the regulation of mood, appetite, sleep, and some cognitive functions including memory and learning. However approximately 80% of the serotonin is actually produced in the body by the enterochromaffin cells found in the gut lining. The function of serotonin within the gut is to control muscle contractions, thereby functioning to maintain the movement of the intestines. Importantly however, many IBS sufferers can directly link stress to the onset of symptoms and it appears that there may, in some cases, be a link between serotonin, stress and IBS.

During a stressful experience there is a complex set of interactions between the hypothalamus (a part of the brain), the pituitary gland (also part of the brain) and the adrenal glands (at the top of each kidney). Several types of neurotransmitters are involved in this system, collectively known as the HPA-axis, which is thought to be dysfunctional in individuals with several conditions including fibromyalgia, chronic fatigue syndrome and depression to which IBS is often linked. Sufferers of these conditions can have numerous abnormalities in their hormonal, metabolic and brain-chemical activity including levels of serotonin. Dysregulation of the serotonin system has been found in individuals with IBS, with low levels associated with constipation, and high levels with diarrhoea (Sikander et al, 2009).

The link between stress, diet and IBS means that suffers can help reduce symptoms not only by modifying their diet, but also from reducing tension and stress through simple relaxation techniques such as: meditation, yoga and the Alexander Technique. Certainly living with IBS is far from pleasant, but with the right diet and learning how to manage stress, there is no reason why IBS should not be controllable. Let you control your IBS and not your IBS control you!

FOODS TO INCREASE FOODS TO AVOID
Carbohydrates
Complex carbohydrates, also known as starchy foods, are broken down slowly in the body to produce energy and are much kinder to the GI tract. This includes foods such as rice, oats and barley as well cooked vegetables.
Carbohydrates
Avoid foods high in fast releasing sugars such as unrefined grains, confectionary, cakes and biscuits. Avoid raw vegetables, salads and raw fruit.
Fats
Increasing omega-3 from oily fish (mackerel, sardines, pilchards, salmon) or through supplements can help alleviate inflammation and calm the guts. Try including evening primrose oil as a source of GLA, an anti-inflammatory omega-6 fatty acid
Fats
Avoid saturated fats from red meat and dairy food and fried food as these are classic triggers that exacerbate the symptoms of IBS
Protein
Lean chicken, pork, turkey and fish can supply good animal protein.
Protein
Avoid protein from red meat.
Fibre
Soluble fibre absorbs excess fluids forming a gel which bulks out faeces and can therefore help to reduce diarrhoea. By bulking out faeces, soluble fibre keeps the muscles of the GI tract gently stretched thus giving them something to grip on during a peristaltic motion and helps to avoid painful spasms. This in turn can help relieve constipation by softening and pushing through any impacted faecal matter.
Fibre
Insoluble fibre (bran, raw fibrous vegetables, salad greens, unpeeled fruits) can trigger painful gastrointestinal spasms
Fluids
Drink plenty of fluid to avoid constipation. The following teas can help eliminate gas and bloating but also can relax the intestine smooth muscle: peppermint, fennel, ginger and chamomile.
Fluids
Coffee, tea (even decaffeinated) and alcohol are powerful GI tract irritants, and can have the same effects as fats and insoluble fibres. Also avoid sugary carbonated drinks or drinks containing the sweeteners sorbitol or xylitol.
Probiotics
Available as dietary supplements and foods such as yogurt, with most products containing one of two types of bacteria – Lactobacillus or Bifidobacterium. Probiotics are often combined with prebiotics to form synbiotics. Prebiotics are simply non-digestible food ingredients that selectively stimulate the growth and activity of beneficial microorganisms already in the colon.

Sikander A, Rana SV, Prasad KK. (2009) Role of serotonin in gastrointestinal motility and irritable bowel syndrome. Clin Chim Acta. 403:47-55.

Low-carbohydrate diet – The Atkins diet

The Atkins diet has caused quite a debate with regards to its use and safety ever since Dr. Atkins launched his ‘Diet Revolution’ in 1972. So what’s wrong with it exactly? For starters, the diet totally excludes all carbohydrates, which are actually an absolutely vital component of our diet. By excluding them, the body must rely on protein and fat, not only as a source of energy, but also for vital nutrients and macronutrients. Therefore, by completely depleting the body of carbohydrate we also decrease our intake of many essential vitamins and minerals as well as fibre and another important type of carbohydrate called ‘non-starch polysaccharide’ which is absolutely essential for normal gut function.

In addition, high intake of fat, especially saturated fat derived from animal products, can increase both lipid and cholesterol levels, both of which are know to increase the risk of developing heart disease. By combining a high fat diet with one that is low in fibre results in a diet that carries an even stronger risk of developing heart disease. Furthermore, consuming too much protein is known to put strain on the kidneys, which can result in possible renal injury. Because the body cannot store protein, once the body’s needs are met, any excess must then be removed. This excess protein is converted by the liver into compounds, like urea, which are finally eliminated through the kidneys as part of urine. High protein intake also causes loss of calcium from the bones into the blood with corresponding implications on bone health.
High protein diet.gifGenerally, whilst the immediate positive benefit attributed to the Atkins diet is quick and relatively easy weight loss, the long-term consequences on cardiac, renal, bone and liver health must be all be taken into consideration. However, the ‘new’ version of the Atkins diet differs from its older counterpart in that rather than excluding carbohydrate completely, after a certain amount of weeks (depending on weight loss targets), carbohydrate is slowly reintroduced. The diet then continues, but as a ‘low-carbohydrate’ diet.

On the whole, this would appear to be a better option to restricting carbohydrate completely. However, it’s still a diet that is very low in fruit, vegetables and fibre, so in terms of digestive health, it’s not in keeping with fibre and ‘complex’ carbohydrate recommendations. Complex carbohydrates are important because they are broken down into glucose slowly, therefore providing a gradual steady stream of energy throughout the day. Eating a diet that has plenty of complex carbohydrate can help reduce the chances of developing type II diabetes for example.

The simple truth is that anyone carrying too much weight has most likely consumed more calories than they should have for some period of time. Whilst you can lose weight on anything that helps you to eat less, it does not mean it’s good for you. If you want to lose weight you need to look the amount of energy you put into your body and compare it to the amount of energy you burn. Men need approximately 2500 Kcal daily and women 2000 Kcal daily. So what do we need these calories for? Our daily calorie intake can be divided into the 3 following areas: firstly, basal metabolic rate (BMR) is the minimum amount of energy needed for our bodies to function on a daily basis and includes things like our heart beating and our breathing. Secondly is something called diet induced thermogenesis (DIT) which is the energy used when we digest our food. Finally, we need energy for physical activity, to move and to exercise and the more active a person is, the more energy they use.

Consuming more calories than we need will simply make the body store them as fat for ‘later use’. With our chaotic modern lifestyles, many of us exercise much less than we should, driving places rather than walking, with many of us having office jobs that require little, if no physical activity. The down side of all this is that sedentary individuals are much more likely to be overweight than active ones. All in all, it’s pretty easy in today’s world to pile on the pounds. Fad diets simply target vulnerable individuals who want a quick fix, and whilst the Atkins may deliver in regards to weight loss, the long-term consequences for our health may outweigh the short-term benefits. If you are really keen to shed those pounds, think about easy changes you can make to you life style and try being more active as well as adjusting what you eat to your level of activity. You simply don’t need as much energy to sit on the sofa watching television as you would playing sport for example. Being active also has numerous other benefits for our stress levels, not to mention its release of ‘happy hormones’.