Peter Cartwright MSc MA Human Microbiota Specialist, Probiotics International Ltd
Lactose Intolerance The term ‘lactose intolerance' refers to the inability of some adults to digest the sugar lactose, which is present in milk. Lactose is digested by the enzyme lactase, and if too little lactase is produced then the undigested lactose causes intestinal difficulties. Most of the world's adult population are lactose intolerant, although they may be able to digest small amounts of milk (up to 25 grams a day) without difficulty. Greater amounts than this cause symptoms of excess gas, bloating, diarrhea, cramps, abdominal rumblings and flatulence. In severe cases, there may be nausea and vomiting. The excess gas is probably caused by the resident gut microflora fermenting the lactose. The diarrhea may be caused by an osmotic response to the lactose, leading to the maintenance of high water content in the feces. Numerous studies have shown better lactose digestion and less flatulence in lactose-intolerant people who have consumed live yoghurt rather than milk. Symptoms have been reduced by about two-thirds. The reason why yoghurt is helpful is because the two bacteria that turn milk into yoghurt, Lactobacillus bulgaricus and Streptococcus thermophilus, produce significant quantities of the lactase enzyme. They are able to digest lactose in live yoghurt product, but also to continue such digestion in the small intestine once the yoghurt has been eaten. Furthermore, yoghurt moves more slowly along the intestine compared with milk, therefore allowing more time for intestinal lactase to digest lactose. Freeze-dried probiotic products that contain strains known to produce the lactase enzyme may also help to reduce lactose intolerance. Constipation Constipation is the infrequent and difficult passing of hardened stool. Based on surveys in developed countries, the proportion of the population suffering from constipation at any one time is about 15%. The proportion among women is greater. Not only does constipation give a general feeling of abdominal discomfort, but straining to pass stool may put pressure on the anal area with the potential for negative consequences, such as hemorrhoids (piles). A major cause of constipation is the shortage of fiber in diet. Other factors may be lack of exercise, or the consumption of certain drugs, such as antidepressants. The main approach in relieving constipation is to increase the amount of fiber in diet, by eating more vegetables and fruit, plus wholemeal bread and whole grain breakfast cereals. The only disadvantage with a high fiber diet is that sometimes it leads to uncomfortable bloating and flatulence, which is excessive gas in the intestines produced by some of the microfloral bacteria. In a small proportion of people, a high fiber diet does not fully resolve the constipation problem. In such cases, there are various medicines that have a laxative effect, but laxatives should not be used for long periods as they may encourage a weakening of natural gut muscle contractions. Relief of abdominal pain that occasionally arises from constipation is something of a problem, because the main painkiller drugs, the non-steroidal anti-inflammatory drugs (NSAIDs), have a constipating effect. There are several studies, which show probiotics relieving constipation. The improvements were in the range of a 20-50% increase in the number of bowel movements a week. Antibiotic Associated Diarrhea Despite the huge benefits that antibiotics have provided since World War II in the treatment of bacterial infection, saving countless lives, they can produce a number of side effects. One is the tendency to promote the rise of resistant strains of bacteria and so reduce the effectiveness of antibiotic. Another side effect is the tendency of antibiotics to disturb the gut microflora, making the person vulnerable to subsequent pathogenic infection. Such an infection of the intestine usually leads to diarrhea and, as such, it is described as ‘antibiotic associated diarrhea' (AAD). The proportion of people developing AAD after taking a course of antibiotics is about 20%. Many of such infections are quite mild, but others can be severe. In about one-fifth of cases of AAD, the microbial pathogen involved is Clostridium difficile. This can be a difficult pathogen to eradicate because it can form spores, which remain dormant and then grow again at a later date. C. difficile infection may also cause a serious condition known as pseudomembranous colitis. There have been a number of studies in which probiotics have prevented AAD, although not all studies have shown probiotics to be effective. In the successful studies, probiotics were mostly taken at the same time as the antibiotic and usually continued for at least one week after completion of the course of antibiotics. In those studies, people taking probiotics reduced the risk of developing AAD by about two-thirds. References 1. Floch MH & Montrose DC. 2005. Use of Probiotics in Humans: An Analysis of Literature. Gastroenterology Clinics of North America 34: 547-570. 2. Allen SJ, Okoko B, Martinez E, Gregorio G, Dans LF. 2003. Probiotics for treating acute infectious diarrhea. Cochrane Database of Systematic Reviews 4: CD003048.pub 2. 3. Lemberg DA, Ooi CE & Day AS. 2007. Probiotics in paediatric gastrointestinal diseases. Journal of Paediatrics and Child Health 43: 331-336. 4. AlFaleh KM & Bassler D. 2008. Probiotics for prevention of necrotizing enterocolitis in preterm infants. Cochrane Database of Systematic Reviews, Issue 1, Art. No.: CD005496. 5. de Vrese M, Stegelmann A, Richter B, Fenselaw S, Laue C, Schrezenmeir J. 2001. Probiotics – compensation for lactase insufficiency. American J. Clinical Nutr 73: 421S-429S. 6. Johnston BC, Supina AL, Ospina M, Vohra S. 2007 Probiotics for the prevention of pediatric antibiotic-associated diarrhea (Review) Cochrane Database of Systematic Reviews 2: CD004827.pub2. 7. Rioux KP & Fedorak RN. 2006. Probiotics in the Treatment of Inflammatory Bowel Disease. Journal of Clinical Gastroenterology 40: 260-263. 8. Spiller R. 2008. Review article: probiotics and prebiotics in irritable bowel syndrome. Alimentary Pharmacology & Therapeutics 28: 385-396. 9. Lesbros-Pantoflickova D, Corthesy-Theulaz I & Blum AL. 2007 Helicobacter pylori.
