Feeding the Sensitive Gut – Dr Nick Read

Dr Nick Read, Chair and Medical Adviser of the IBS Network, explains how a sensitive gut can rule your life – and how best to manage it.

It is a curious fact that at a time when we are better nourished that ever before, as many as a third of us are intolerant of, or allergic to the food we eat.  Free-from foods are big business these days, but only about 1% of the adult population have a specific food allergy.  Most are intolerant of a range of foods.  

In one unpublished study, we carried out
in 1995, we found that people with unexplained abdominal pain, bloating and bowel upset, were sensitive to between 5 and 22 different foods.  Other studies have reported similar results (1).  Moreover, their food intolerance could tend to come and go, often
according to what was happening in their lives.  This suggested that it was not so the food that was the problem as their sensitive gut. 

The gut has sensory nerve endings just
like the skin; only these respond to distension and the chemical composition and texture of food causing diffuse abdominal sensations of pain, fullness or bloating,  and stimulating  gut reactions, like nausea, vomiting, diarrhoea or constipation and even affecting breathing, alertness, posture and bladder function (2).   So depending on you and what you have eaten, your sensitive gut can cause a whole range of symptoms.

Most people with a sensitive gut do not have a specific disease, although some may be sensitised by a previous attack of gastroenteritis (3).   But the greatest cause of gut sensitivity is stress (4). Many people develop a sensitive gut after a particular life event that shocks or wrenches their gut out kilter. Frights, deadlines, grief, trauma can so often go to the gut. Just think how often we use gut metaphors to describe the effect of emotion:  ‘Gutted’, ‘It makes me sick’,  ‘I can’t stomach it.’ ‘It gives me the runs’.   What happened may fade from the mind but the memory can linger on in the sensitive brain/gut.  
       
If the gut is sensitive, anything that stimulates it can trigger symptoms. But for the most part, this is  stress and diet (mood and food).  Anxiety, panic, shock, deadlines, frustration, obligations, over-commitments,  anger, rage, torment, grief, despair; these can stimulate the sympathetic nerves causing spasm, pain, bloating, nausea and bowel upset and making people more sensitive to the foods they eat.    

But there are some food ingredients that are particularly implicated.  Fats, chilli or coffee may cause spasm and diarrhoea (5,6).  Coarse wheat bran can be a direct irritant (7,8).   Certain fruits and fruit juices may retain fluid in the gut by osmotic action and cause diarrhoea and some vegetables and fruits, wheat and milk may be fermented to gas and cause abdominal pain, bloating or bowel upset.  The latter are collectively known as FODMAPs (9-12) ,  an acronym which stands for fermentable oligosaccharides, disaccharides, mononsaccharides and polyols, a range of short chain, poorly absorbed complex sugars that are either fermented in the colon  or retain excess fluid in the bowel.   Foods that contain these ingredients include:

• Foods that are high in fat, such as red meat, butter, cheese, chocolates, high fat milk.  
• Chilli, black pepper. 
• Coffee.  
• Fruit including apples, pears, peaches, mango, sugar snap peas, watermelon, tinned fruit in natural juice, dried fruit, fruit juice, apricots, cherries, lychee, nectarine, plums, prunes and Sharon fruit.
• Milk from cows, goats and sheep; ice-cream, yogurt, soft, fresh cheese such as ricotta and cottage cheese
• Vegetables including artichokes, asparagus, beetroot, Brussels sprout, cabbage, fennel, garlic, leeks, okra, onions, peas, shallots, avocado, cauliflower, mushrooms, peas.
• Cereals including wheat and rye when eaten in large amounts for example in bread, pasta, couscous, crackers and biscuits.
• Legumes including chickpeas, lentils, red kidney beans and baked beans.
• Honey and sweet foods containing honey, fructose and high fructose corn syrup.
  

Although this list is a useful guide to the sorts of foods that may usually tend to cause symptoms in people with a sensitive gut, it is not prescriptive.  People are individual, their guts work in different ways; the physiology of digestion and the rate of transit through the small intestine will influence the amount and rate different foods are delivered to the sensitive colon (13); variation in bacterial populations may profoundly influence rates of fermentation, and some people may have had such a bad experience in the context of a specific meal, that just the thought of those foods brings on the symptoms all over again.

So what can you eat without suffering the torment of gut upset or needing to put yourself on a diet that is bland and boring?  And how can you make sure you are getting all your essential nutrients?   You can’t rely on restaurants or ready meals unless you really study the ingredients.  Most chefs use lots of butter and cream, are generous with onion and garlic, and may use high fructose corn syrups. So to be sure, you are better off cooking  for yourself.

Luckily, there is a whole range of healthy ingredients, that will not upset your sensitive gut and can be purchased at low cost at your local supermarket, and can be used to create delicious recipes (see Dr Joan Ransley’s recipes in Freefrom Recipes Matter and her blog, Cooking for the Sensitive Gut), but there are some tips to bear in mind.

• Although garlic contains about 20% of fructans,  the oil is so pungent that you may only need add a gram or two to any dish to add flavour.
• Use the green parts of spring onions, chives and leeks, which contain much less fructans and still provide the flavour of onions. 
• Most fresh herbs are well tolerated by people with a sensitive gut and make a meal taste special.   
• Sweetening fruits with glucose will facilitate fructose absorption and allow more to be ingested without the risk of bloating. 
• Wheat flour only contains about 1% of fructans, so modest amounts can be tolerated as long as you do not have coeliac disease.   Certain varieties of wheat, such as spelt or buckwheat  have a low fructan content and can be tolerated in larger amounts.  The same applies to sourdough where the fructans are already partly fermented before baking.  
• Nuts contain fats in a form that is slowly digested so more can be tolerated.  
• Unripe fruits may contain more fructans while the riper the fruit, the greater the content of fructose and polyols.  
• Bananas should be eaten ripe and yellow.  Unripe bananas are poorly tolerated while overripe bananas may contain significant amounts of polyols. 

So get to know your gut.  Understand the way it works.  Know what upsets it and why.  Be in control.  Give yourself time to relax while you eat your meal.  That will relieve the abdominal tension and give you confidence.  Select the diet that suits you. And even if you are sensitive to some foods, they do not necessarily need to be excluded from your diet. 

Everybody can tolerate modest amounts of all the foods on the list and adjustments can be made as a result of your own experience.   And remember, the sensitive gut will not tolerate too much food.  Eat to comfort and if this means that you can’t eat a lot at each meal, eat less but more often. 

References

• Locke, G. R., Zinsmeister, A. R., Talley, N. J., Fett, S. L., & Melton, L. J. (2000). Risk factors for irritable bowel syndrome: role of analgesics and food sensitivities. The American journal of gastroenterology, 95(1), 157-165.
• Delvaux, M. (2002), Role of visceral sensitivity in the pathophysiology of irritable bowel syndrome. Gut 51 i67-i71.
• Bergin, A. J., Donnelly, T. C., McKendrick, M. W., & Read, N. W. (1993). Changes in anorectal function in persistent bowel disturbance following salmonella gastroenteritis. European journal of gastroenterology & hepatology,5(8), 617-620.
• Murray, C. D., Flynn, J., Ratcliffe, L., Jacyna, M. R., Kamm, M. A., & Emmanuel, A. V. (2004). Effect of acute physical and psychological stress on gut autonomic innervation in irritable bowel syndrome. Gastroenterology, 127(6), 1695-1703.
• Simrén, M., Månsson, A., Langkilde, A. M., Svedlund, J., Abrahamsson, H., Bengtsson, U., & Björnsson, E. S. (2001). Food-related gastrointestinal symptoms in the irritable bowel syndrome. Digestion, 63(2), 108-115.  
• Gonlachanvit, S., Mahayosnond, A., & Kullavanijaya, P. (2009). Effects of chili on postprandial gastrointestinal symptoms in diarrhoea predominant irritable bowel syndrome: evidence for capsaicin-sensitive visceral nociception hypersensitivity. Neurogastroenterology & Motility, 21(1), 23-32.
• Francis CY and Whorwell PJ (1994) Bran and Irritable Bowel Syndrome.  Time for reappraisal. Lancet. 344, 39-40.
• Cann PA, Read NW, Holdsworth CD (1984). What is the benefit of coarse wheat bran in patients with irritable bowel syndrome? Gut. 25:168–173.
• Gibson PR and Shepherd (2012) Food Choice as a management strategy for Irritable Bowel Syndrome.  Am J . Gastroenterology, 2012.  107.  655-666.
• Shepherd SJ , Parker FC , Muir JG et al. Dietary triggers of abdominal symptoms in patients with irritable bowel syndrome: randomized placebo-controlled evidence . Clin Gastroenterol Hepatol 2008 ; 6 : 765 – 71 .
• Staudacher, H. Whelan K, Irving PM, Lomer MC. (2011) Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome..  J Hum Nutr Diet. 24:487-95. 
• De Roest, RH, Dobbs, BR, Chapman BA et al (2013). The low FODMAP diet improves gastrointestinal symptoms in patients with IBS: A prospective study.  Int. J. Clin. Practice 67. 895-903. 
• Cann PA, Read NW, Brown C, Hobson N, Holdsworth CD (1983). Irritable bowel syndrome: relationship of disorders in the transit of a single solid meal to symptom patterns. Gut. 1983 24(5):405–411. 

July 2014

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