Following the fructose-restricted diet developed by dietitians at the University
of Iowa Hospitals and Clinics (UIHC) has relieved symptoms for 80% of patients
diagnosed with dietary fructose intolerance. A study by Frederick Johlin,
Mary Panther, and Nancy Kraft, revealed those who followed the diet 100% had
symptom improvement by 75 - 100%[i]. Improvement was in direct correlation
to the degree the diet was followed. Results in another study at the UIHC
by Choi YK, Johlin FC, Summers RW, Jackson M, and Rao S documented that fructose
intolerance is an under-recognized problem[ii].
Relief from the symptoms of Dietary Fructose Intolerance (DFI) are limited to:
1) avoiding foods containing High Fructose Corn syrup (HFCS), fructose, most
fruits, some vegetables, commercially baked goods, and sorbitol; and 2) incorporating
dextrose into the diet. Dextrose bonds to the free fructose in the GI tract
where it can be absorbed as sucrose (common table sugar)[iii] to relieve symptoms. The
future holds hope for an enzyme to break down fructose to an absorbable state.
Dextrose is a simple sugar not normally available in U.S. grocery stores. It
may be found in some health food stores and at wine making supply shops. It
has been found in some Asian, African or European markets in the U.S. Pharmacy
grade dextrose is expensive and this quality is not necessary.
Sorbitol, a sugar alcohol food additive used as a sweetener in commercially prepared
low sugar foods and gum, creates havoc in the GI tract similar to fructose. The
combination of fructose and sorbitol increases symptoms and should be avoided[iv].
Restricting fructose eliminates fruits and most vegetables from the diet, and
therefore the nutrients from fruits and vegetables. It is important to
replace those nutrients with a daily vitamin/mineral supplement. Additional
250 mg Vitamin C tablets once or twice daily, plus a daily 200 400 mg IU natural
Vitamin E complex are recommended as well.
Read the ingredient list on labels for all vitamin/mineral supplements and over-the-counter
medications. If reading the label is confusing, consult the pharmacist. It
is common for fructose and/or sorbitol to be used as filler in vitamin/mineral
supplements or medications.
The fructose-restricted diet recommendations serve as a guideline only. Everyone
experiences different levels of tolerance. The University physicians encourage
following the diet strictly for four to six weeks before slowly testing tolerance
of individual foods not part of the basic diet. When exploring personal
tolerance, eat a questionable food no more frequently than every four days. Fructose
takes three days to pass through the GI tract for most individuals[v]. Symptoms
commonly continue until the offending food is eliminated. A food tolerated
on day one may not be tolerated on day two or three because it remains in the
colon. Foods containing fructose are often dose-dependent (small amounts
may be tolerated while larger amounts are not). For best tolerance always
consume a small amount of a questionable food with a recommended food.
As a young college age patient recently said and is paraphrased, I am grateful
for the fructose restrictions. I have abandoned the soda, greasy hamburgers
and fries of my peers. My diet is healthy and varied. I feel great. I
enjoy cooking and want to learn to cook more.
Another patient proclaimed the diet is limited only by a lack of imagination.
In a nutshell, include the maximum tolerated amount of vegetables and grains,
go easy on the allowed fruit, and avoid commercially prepared drinks and sweets. Take
your vitamins. Go forth and enjoy life!
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[i] Johlin FC, Panther M, Kraft N. A fructose restricted diet and dietary
counseling in patients with dietary fructose intolerance demonstrates significant
reduction in symptoms and improvement in quality of life proportionate to the
amount of fructose eliminated. Gastroenterology. 2000;20(5):A-265.
[ii] Choi YK, Johlin FC, Summers RW, Jackson M, Rao S. Fructose intolerance:
an under-recognized problem. American Journal of Gastroenterology. 2003;(6):1348-53.
[iii] Rumessen JJ. Fructose and related food carbohydrates: sources, intake
absorption and clinical implications. Scandinavian Journal of Gastroenterology.
1992;27:819-828
[iv] Fernex-Bas F, Esteve-Pardo M, Leon R, Humbert P, Cabr, Llovet JM, Gassull
MA. Sugar malabsorption in functional bowel disease: clinical implications. American
Journal of Gastroenterology. 88(12):2044-2064.
[v] Brostoff J, Gamlin L. Food Allergies and Food Intolerance. Healing
Arts Press. Rochester, VT.
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