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Fructose is found in:

Fructose is a natural sugar found in fruit, vegetables, and honey.23 Although all fruit (especially fruit juices) contains fructose, the varying amounts of fructose, glucose and sorbitol in different juices may affect absorptive capacities (as demonstrated above with apple, pear and grape juice).8 Because the concentration of the sugars (glucose, fructose and sucrose) in fruit juice is influenced by storage and the particular types of fruit (for example, type of apple) used, each juice will differ in concentration of the different sugars.4 cutoranges2.JPG - 3407 Bytes

Also, fruit juice manufacturers around the world may use different methods in processing; they may use different concentrations of fruit juice; adding or not adding, for example, deflavoured apple juice, which may be imported or produced locally. Thus, the concentrations of sugars in fruit juices may differ extensively from country to country.

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It must be borne in mind that relatively low doses of processed (commercial) fruit juice may cause as much malabsorption as eating excessive amounts of fresh fruit. pears3.JPG - 2845 Bytes

Fructose is widely used as a food additive, as it gives many useful attributes to food and beverages, including sweetness, flavour enhancement, humectancy, colour and flavour development, freezing-point depression, and osmotic stability.24

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Fructose, sucrose and sorbitol in foods

(adapted from Shaw V, Lawson M. Clinical Paediatric Dietetics. Blackwell Science Ltd, UK, 1994.)

  • Apart from the whole food sources, fructose, sucrose and sorbitol is used in many manufactured foods. So much so that very few manufactured foods are allowed in the diet. Sugar is used in obvious products such as sweets, desserts and soft drinks, but also in many other less obvious products such as canned food, bottled sauces, savoury biscuits, etc.
  • Flavourings is another potential trace source of these sugars as they are sometimes used as carriers for flavouring compounds.
  • Only vegetables that contain predominantly starch are allowed in the diet. Cooked vegetables have a lower fructose content and are recommended in preference to raw as the cooking process causes a loss of free sugars.
  • New potatoes have a higher fructose content than old potatoes.
  • Wholemeal flour contains more fructose than white flour because the germ and bran contains sucrose. Similarly other wholegrain foods (e.g. brown rice and wholemeal pasta) contain more sucrose than the refined products.
  • Sorbitol is used as an artificial sweetener, especially in diabetic foods and drinks. These foods should therefore be avoided. Isomalt and lycasin, alternative sweeteners that are predominantly used in confectionary, also contain sorbitol. Glucose can be used as an alternative sweetener and as a source of energy.
  • Sucrose and sorbitol are used in medications as bulking agents or to improve the taste.

Hereditary fructose intolerance (HFI):
HFI is a rare autosomal recessive disorder of fructose metabolism, due to a deficiency of fructose-1-phosphate aldolase activity. This condition initiates severe toxic symptoms following ingestion of fructose. Glycogen breakdown and glucose synthesis can be inhibited, causing severe hypoglycemia, which manifests as tremors, disorientation, vomiting and, in the worst cases, severe convulsions and coma. Chronic ingestion of fructose during infancy may also result in clinical findings such as failure to thrive, hepatomegaly, and jaundice, which ultimately leads to hepatic and/or renal failure and death. 5,25,26

Fructose-1,6-diphosphate deficiency is another form of fructose intolerance, which usually presents as neonatal hypoglycemia. With fructose-1-phosphate aldolase deficiency, hypoglycemia is experienced after fructose ingestion, whereas in fructose-1,6-diphosphate deficiency, acidosis and hypoglycemia are experienced during caloric deprivation, in fasting or during intercurrent illness.27

In general fruit juice…
(adapted from the American Academy of Pediatrics' paper "The Use and Misuse of Fruit Juice in Pediatrics")

  • has no nutritional benefit for infants younger than 6 months. 
  • has no nutritional benefit over fresh fruit for children older than 6 months. In fact, fruit juice contains less fibre than whole fruit; kilocalorie for kilocalorie, fruit juice can be consumed more quickly than whole fruit; and the reliance on fruit juice instead of whole fruit to provide the recommended daily intake of fruits does not promote the healthy eating behaviours associated with consumption of whole fruits.
  • is not appropriate in the treatment of dehydration or management of diarrhoea. Malabsorption may cause diarrhoea to worsen. Additionally, fruit juice is low in electrolytes (with sodium concentrations of 1 - 3 mEq/L) compared to oral electrolyte solutions (which contain 40 - 45 mEq/L). As a replacement for fluid losses, juice may predispose infants to development of hyponatremia.
  • is more than adequate in intakes of 120-180ml per day (if well tolerated). Infants can be encouraged to consume whole fruits that are mashed or pureed.
  • should be given only to infants who can drink from a cup. Teeth begin to erupt at approximately 6 months of age, and prolonged exposure of the teeth to the sugars in fruit juice has been associated with the development of dental caries.15

Other health concerns related to fruit juice consumption:
Fruit juice has been shown to account for 50% of all fruit servings consumed by children aged 2 through 18 years, and 1/3 of all fruits and vegetables consumed by preschoolers. With the increase in fruit juice consumption, there has been an overall decline in milk intake, which is a cause for concern, as milk is the major source of calcium in the diet. It was found that 11% of healthy preschoolers consumed > or = 375ml/day of fruit juice, which is considered excessive. Excess fruit juice consumption has been reported as a contributing factor to nonorganic failure to thrive and to decreased stature. In other children, excessive fruit juice consumption has been associated with an increased caloric intake and obesity.9

                                                                                    compiled by Karen du Plessis B.Sc. Diet.
Food & Allergy Consulting & Testing Services (FACTS)

PO Box 565

E. Comments by our editors

Chronic diarrhoea is a common complaint in children. Often no cause is found despite extensive medical investigations. In very young children soy and milk allergy may be suspected or alternatively, lactose intolerance. I see a number of adults and children, where a restriction of dairy and soy products has not led to a resolution of diarrhoea. Usually a careful history reveals an overconsumption of hyperosmolar fluids, diet sweets, sweets, fruit leathers or fruit. In some cases food intolerances (histamine, salicylates) may play a role. In fructose intolerance the first stools of the day are usually formed and night-time diarrhoea is uncommon. When re-introducing fructose into the diet, it is always an idea to challenge in the pure form to establish a tolerance threshold. Should there be no response to a low fructose diet, it can be assumed that other food intolerances need to be investigated. – Sabine Spiesser

This case report demonstrates clearly that one should pay careful attention to a patient’s history, and illustrates how modifying an allergic child’s diet may have adverse consequences, even if an ostensibly “healthy” food is the replacement. - Dr. Harris Steinman

Prof Janice Joneja Ph. D.
Sabine Spiesser B.Sc. Dip. Ther. Diet.
Dr. Harris Steinman M.B.Ch.B.

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F. References 
1. David TJ. Food and Food additive intolerance in childhood. Blackwell Scientific Publications, Oxford, 1993.
2. Gotze H, Mahdi A. Fructose malabsorption and dysfunctional gastrointestinal manifestations. Monatsschr Kinderheilkd 1993;141(4):276.
3. Talal AH, Murray JA. Acute and chronic diarrhea. How to keep laboratory testing to a minimum. Postgrad Med 1994;96(3):30-2.
4. Hyams JS, Leichtner AM. Apple juice. An unappreciated cause of chronic diarrhea. Am J Dis Child 1985;139(5):503-5.
5. Mahan LK, Escott-Stump S. Krause's Food, Nutrition and Diet Therapy 10th edition. W.B. Saunders Company, Philadelphia Pennsylvania USA, 2000.
6. M Gracey, N Kretchmer, R Ettore. Nestle Nutrition Workshop Series Vol 25. Sugars in Nutrition. Raven Press, New York, 1991.
7. Lifshitz F, Ament ME, Kleinman RE, et al. Role of juice carbohydrate malabsorption in chronic nonspecific diarrhea in children. J Pediatr 1992;120(5):825-9.
8. Smith MM, Davis M, Chasalow FI, Lifshitz F. Carbohydrate absorption from fruit juice in young children. Pediatrics 1995;95(3):340-4.
9. Dennison BA. Fruit juice consumption by infants and children: a review. J Am Coll Nutr 1996;15(5 Suppl):4S-11S.
10. Hoekstra JH, van den Aker JH, Ghoos YF, et al. Fluid intake and industrial processing in apple juice induced chronic non-specific diarrhoea. Arch Dis Child 1995;73(2):126-30.
11. Hyams JS, Etienne NL, Leichtner AM, Theuer RC. Carbohydrate malabsorption following fruit juice ingestion in young children. Pediatrics 1988;82(1):64-8.
12. Unrecognized Fructose Intolerance Often Underlies Unexplained GI Symptoms. 66th Annual Scientific Meeting of the American College of Gastroenterology.
13. Walker WA, et al. Pediatric Gastrointestinal Disease 2nd Edition, Vol 1. Mosby, Inc, USA, 1996. 14. American Academy of Pediatrics. The Use and Misuse of Fruit Juice in Pediatrics. Pediatrics 2001;107(5):1210-1213.
15. Ledochowski M, Widner B, Bair H, Probst T, Fuchs D. Fructose- and sorbitol-reduced diet improves mood and gastrointestinal disturbances in fructose malabsorbers. Scand J Gastroenterol 2000;35(10):1048-52.
16. Duro D, Rising R, Cedillo M, Lifshitz F. Association between infantile colic and carbohydrate malabsorption from fruit juices in infancy. Pediatrics 2002;109(5):797-805.
17. Behrman RE, Kliegman RM, Jenson HB. Nelson Textbook of Pediatrics 16th edition. W.B. Saunders Company, Philadelphia Pennsylvania USA, 2000.
18. Cohen SA, Hendricks KM, Eastham EJ. Chronic Nonspecific Diarrhea, A Complication of Dietary Fat Restriction. Am J Dis Child 1979;133:490-2.
19. Hoekstra JH, van den Aker JH, Hartemink R, Kneepkens CM. Fruit juice malabsorption: not only fructose. Acta Paediatr 1995;84(11):1241-4.
20. Hoekstra JH, van Kempen AA, Kneepkens CM. Apple juice malabsorption: fructose or sorbitol? J Pediatr Gastroenterol Nutr 1993;16(1):39-42.
21. Kneepkens CM, Jakobs C, Douwes AC. Apple juice, fructose, and chronic nonspecific diarrhoea. Eur J Pediatr 1989;148(6):571-3.
22. Hoekstra JH, van Kempen AA, Bijl SB, Kneepkens CM. Fructose breath hydrogen tests. Arch Dis Child 1993;68(1):136-8.
23. Park YK, Yetley EA. Intakes and food sources of fructose in the United States. Am J Clin Nutr 1993;58(suppl):737S-47S.
24. Hanover LM, White JS. Manufacturing, composition, and applications of fructose. Am J Clin Nutr 1993;58(5 Suppl):724S-732S.
25. Rudolph AM. Pediatrics, 17th Edition. Appleton-Century-Crofts, Norwalk, Connecticut, 1982.
26. HFI Laboratory at Boston University. 

27. CH Kempe, HK Silver, D O'Brien. Current Pediatric diagnosis and treatment, 7th Edition. Lange Medical Publications, Los Altos, California. 1982.

G. CPD Questions (for South African dietitians only)

Returns for this CPD session are now closed.

Pleas contact karen@allergyadvisor.com for further information.


1. True or false: Fructose intolerance does not occur frequently in normal, healthy children and adults. (a.) True
(b.) False

2. The proposed mechanism for fructose absorption is as follows:
(a.) Against a chemical gradient
(b.) Against a concentration gradient
(c.) Facilitated transport via a carrier
(d.) Passive diffusion

3. Which statement is correct regarding fructose absorption?
(a.) Malabsorption is more apparent when the source is sucrose.
(b.) Absorption is more complete when the fructose concentration exceeds that of glucose.
(c.) Absorption is more complete when fructose and glucose are present in equal concentrations.
(d.) Absorption is more complete when fructose is ingested alone.

4. True or false: Unprocessed apple juice does not promote diarrhoea, compared to enzymatically processed apple juice.
(a.) True
(b.) False 5.

Which of the following has not been associated with fructose intolerance?
(a.) Increased incidence of dental caries
(b.) Abdominal pain, bloating and flatulence
(c.) Aversion to sweet-tasting foods, including fruit
(d.) Early signs of mental depression

6. Which of the following does not contribute to the persistence of chronic non-specific diarrhoea?
(a.) Excessive fluid intake
(b.) Excessive fat intake
(c.) Excessive intake of carbonated fluids
(d.) Food poisoning

7. True or false: Fructose intolerance is generally not associated with failure to thrive, but hereditary fructose intolerance is.
(a.) True
(b.) False

8. Choose the correct statement regarding fruit juice:
(a.) It is recommended to infants younger than 6 months of age.
(b.) It has no nutritional benefit over fresh fruit in children older than 6 months.
(c.) It is an appropriate treatment of dehydration.
(d.) An intake of 120-180ml per day is not adequate for infants.


1. a [  ]  b [ x ]          2. a [  ]  b [  ]  c [ x ]  d [  ]               3. a [  ]  b [  ] c [ x ]  d [  ]
4. a [ x ]  b [  ]   5. a [ x ]  b [  ]  c [  ]  d [ ]   6. a [  ]  b [ x ]  c [  ]  d [  ]
7. a [ x ]  b [  ]   8. a [  ]  b [ x ]  c [  ]  d [  ]    

1. b. False
2. c. Facilitated transport via a carrier
3. c. Absorption is more complete when fructose and glucose are present in equal
4. a. True
5. a. Increased incidence of dental caries
6. b. Excessive fat intake
7. a. True
8. b. It has no nutritional benefit over fresh fruit in children older than 6 months.

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