12 yo M with Fructose Malabsorption

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    • #10658
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      I have recently seen a 12 year old boy w-46kg, H-1.48m. He was diagnosed with fructose intolerance in Feb this year by consultant following breath test.


      He was born naturally full term, breast-fed until age 1. Mum advises that age 1 he began getting tonsillitis and ear infections, these were recurring and as such he was placed on antibiotics every 2 weeks until age 4 years old when tonsils and adenoids removed. Since this he has been well.

      Digestive symptoms began in September last year, some stress due to due football academy intensive training and starting secondary school. Symptoms were bloating, pain and loose stools. These were severe he was given Buscopan and taking large doses of Calpol and Ibuprofen and diagnosed as IBS by GP.

      Parents paid for private consultant who did endoscopy, colonoscopy and various blood tests (I am waiting the report to find out exact details) am aware lactose and coeliac testing was undertaken both negative, eventually fructose intolerance was diagnosed and he saw a dietician who has advised low fructose and sugar free diet. Client has improved but his diet is very restrictive and pasta and grain heavy. They have tried low FODMAPs diet but feel that fructose and sugar are issues, very difficult to get them to look at anything other than what dietician has advised. He recently was given 2 courses of antibiotics as tested positive for SIBO, these have improved symptoms and at the moment he is well with no pain or loose stools. Has been symptom free for almost 4 weeks.

      The boy is taking VS3 Probiotics as advised by Consultant but no other meds or supplements. I would like suggestions for supplements to give a good base(Multi) whilst I work on improving diet. They are happy to stay on the probiotic but I am also considering whether to add in some glutamine or other gut support. I would also like advice on whether to add in a Omega or cod liver oil, not sure which would be best. All advice gratefully received.

      Posted by Christine Bailey

    • #10660
      Christine Bailey

      Dear Maria,

      Many thanks for your question. It is encouraging that the underlying triggers have been investigated and have been addressed. I have seen young children with fructose intolerance and it is important they do stick with a low fructose diet.

      It may be useful to provide some background information on fructose intolerance.

      Typical symptoms of fructose intolerance include loose stools or diarrhea after consumption of fruits / vegetables/ foods high in fructose

      Fructose intolerance is usually caused by impaired absorption of fructose. However, there are rare cases in which intolerance of fructose is due to a deficiency in one of the enzymes responsible for the digestion of fructose

      Fructose is consumed in three forms:
      As the pure monosaccharide, fructose;
      In the disaccharide, sucrose, which is made up of fructose and glucose in a 1:1 ratio;
      In carbohydrates such as oligosaccharides and polysaccharides. They include inulins, fructans, and fructo-oligosaccharides. These are considered to be dietary fibre and are not readily broken down by human digestive enzymes. They are often used as prebiotics or non-digestible food ingredients that stimulate the activity and growth of micro-organisms in the colon that are beneficial to the body’s health.

      An inability to digest and absorb fructose polymers (chains of fructose molecules) is not an intolerance in the food sensitivity sense because all humans lack the enzymes needed to split the bonds between the fructose molecules in the chain. Molecules of fructose are therefore not free to be transported through the gut wall and instead remain within the gut. This is often why people improve generally on a low FODMAPs diet.

      Intestinal fructose absorption depends on the low-affinity transporter molecule GLUT2, which will carry the monosaccharides glucose, fructose, and galactose across the small intestine epithelium (through the gut wall).

      GLUT2 transports the sugars down a concentration gradient which is facilitated by glucose, which permits lower concentrations of glucose to be taken up by the cell by an active process.

      The process is not entirely understood, but because glucose is more easily absorbed, excess fructose may not get absorbed. This unabsorbed fructose will move into the large bowel, where it causes an increase in osmotic pressure and a net influx or reduced outflow of water, resulting in loose stools or diarrhoea. It also acts as a substrate for microbial fermentation with production of gas (especially hydrogen) and organic acids. These activities are responsible for the symptoms of fructose intolerance.

      Sucrose contains both glucose and fructose in a 1:1 ratio. Consumption of sucrose does not result in malabsorption of fructose, because when sucrose is split into its constituent monosaccharide sugars by sucrase, the fructose level does not exceed that of the glucose. However, some sucrose-containing fruits contain a higher fructose-to-glucose ratio than most other fruits.

      Diarrhoea after eating apples, pears, watermelon, blackcurrant, cherries, or juices from these fruits, and honey and high fructose corn syrup, when no other cause for the loose stool is evident, is a sign that fructose malabsorption may be the problem.

      Only a limited amount of ‘free’ fructose can be absorbed in the small intestine, with up to one-half of the population unable to completely absorb a dose of 25g of fructose. Average daily intake of fructose is estimated to vary from 11g to 54g around the world, depending on the dietary habits of the population sampled.

      Although many people, especially children, develop loose stools and diarrhoea after consuming a high dose of fructose, there are inherited conditions in which metabolism of fructose is impaired and that require more careful avoidance of all sources of fructose. This may include avoidance of sucrose, sorbitol, and the polymerized forms of fructose.

      Management of fructose intolerance involves reducing the intake of foods that contain fructose. A fructose-restricted diet inevitably means limiting the consumption of fruit, especially those with a high fructose-to-glucose ratio. It is usually only necessary to avoid the fruits and foods that contain considerably more fructose than glucose. The worst culprits are:

      High fructose corn syrup
      Agave syrup
      Grapes and raisins

      A 2010 review suggests the following should be avoided:

      Foods and beverages containing greater than 0.5g fructose in excess of glucose per 100g

      Greater than 3g fructose in an average serving quantity regardless of glucose intake

      Greater than 0.2g of fructans per serving

      Fruit juices are more of a problem than the whole fruit, because the sugar tends to be concentrated in the juice, which will then have a higher level of fructose than the whole fruit.

      Hereditary fructose intolerance in Brazilian patients Mol Genet Metab Rep. 2015 Sep; 4: 35–38. http://tinyurl.com/hca9fcx

      Asberg C et al. Fructose 1,6-bisphosphatase deficiency: enzyme and mutation analysis performed on calcitriol-stimulated monocytes with a note on long-term prognosis. J Inherit Metab Dis. 2010.http://tinyurl.com/jesy7lh

      Mayatepek E et al. Inborn errors of carbohydrate metabolism. Best Pract Res Clin Gastroenterol. 2010;24(5):607-618.http://tinyurl.com/hj7dear

      There are several reasons why fructose intolerance can occur. The first is a genetic disease that is hereditary and does not allow the body to deal with fructose, which is very rare. In other cases GLUT5 and GLUT2 transporters could be deficient. GLUT5 and GLUT2 transporters are little escorts that guide the fructose across the intestinal wall and into the blood. If they are not around to escort the fructose, it cannot be absorbed. However, in many cases it is linked to bacterial dysbiosis. Often SIBO can be a contributing factor for fructose malabsorption and therefore once addressed you may find slightly higher levels of fructose can be tolerated in the diet. However, during the healing process you need to remove them and replace the nutrients needed to heal the gut and improve digestive function.

      Restoring the gut flora and supporting digestive function is an important strategy to help your client. VSL #3 is an very useful probiotic to continue with but in addition I would consider gentle gut healing with vitamin D and A, collagen powder and essential fats. Colostrum can be helpful and there are products that are low in lactose if that is a concern. If you suspect general malabsorption then do consider adding some free amino acids and a liquid multi vitamin and mineral supplement. I would not use glutamine as this can exacerbate bloating and yeast overgrowth if dysbiosis has not been resolved.

      There is a food supplement containing the enzyme Xylose Isomerase, which is able to change the fructose into glucose, which can be ingested easily. You may be able to ask the consultant about this. This is not an excuse, however, to eat lots of high fructose foods of course. It is also important to ensure with repeat testing that bacterial overgrowth has now been resolved.

      Oral xylose isomerase decreases breath hydrogen excretion and improves gastrointestinal symptoms in fructose malabsorption – a double-blind, placebo-controlled study. Aliment Pharmacol Ther. 2012 Nov;36(10):980-7. doi: 10.1111/apt.12057. Epub 2012 Sep 24. http://tinyurl.com/hm5zco9


      The following supplements are suggested for you to consider in light of your relevant expertise and intimate understanding of the needs of your client or patient. They may be used in isolation or as part of a multi supplement strategy, but at all times the consideration of their use should be tied into the specific needs of the individual you are responsible for.

      Digestive function / enzyme support

      Full Spectrum Digest (ARG) – take 1 with each meal

      To address nutrient absorption

      Amino Sport (BRC) – take 2 capsulestwice daily – http://tinyurl.com/gler36k
      Aqueous Multi Plus (liquid) (BRC) – take 2tspndaily – http://tinyurl.com/z8jgbob

      Gut Healing

      Arthred Collagen powder (ARG) – take 1 scoop three times a day – http://tinyurl.com/jf92sv3
      Immuno-gG (BRC) – take 3 capsules in the evening
      Arctic Cod Liver Oil with Vitamin D Lemon (Nordic Naturals) – 1-2tspn daily

      I hope this helps with your client

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