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Part 2 - Dietary Fructose Intolerance
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[Ref. #3]
Scand J Gastroenterol. 2000 Oct;35(10):1048-52
Full text in PDF format (paste this address together):
http://www.waldenu.edu/residency/summer03/handouts/Role%20of%20Nutrition-
Hunter.pdf
Fructose- and sorbitol-reduced diet improves mood and gastrointestinal
disturbances in fructose malabsorbers.
Ledochowski M, Widner B, Bair H, Probst T, Fuchs D.
Dept. of Clinical Nutrition, Institute of Medical Chemistry and
Biochemistry, University of Innsbruck, Austria.
BACKGROUND: Fructose malabsorption is characterized by the inability to
absorb fructose efficiently. As a consequence fructose reaches the colon
where it is broken down by bacteria to short fatty acids, CO2 and H2.
Bloating, cramps, osmotic diarrhea and other symptoms of irritable bowel
syndrome are the consequences and can be seen in about 50% of fructose
malabsorbers. We have previously shown that fructose malabsorption is
associated with early signs of mental depression and low serum tryptophan
concentrations. It was therefore of interest whether a fructose-reduced
diet could not only improve gastrointestinal complaints but also depressive
signs seen in fructose malabsorbers. METHODS: Fifty-three adults (12 males,
41 females), who were identified as fructose malabsorbers according to
their breath-H2 concentrations, filled out a Beck's depression inventory-
questionnaire, and a questionnaire with arbitrary scales for measurement of
meteorism, stool frequency and quality of life for a 4-week period before
dietary intervention and 4 weeks after dietary change as for fructose- and
sorbitol-reduced diet. RESULTS: Depression scores were reduced by 65.2%
after 4 weeks of diet (P < 0.0001), and there was a significant reduction
of meteorism (P < 0.0001) and stool frequency (P < 0.01). Improvement of
signs of depression and of meteorism was more pronounced in females than in
males. CONCLUSION: Fructose- and sorbitol-reduced diet in subjects with
fructose malabsorption does not only reduce gastrointestinal symptoms but
also improves mood and early signs of depression.
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[Ref. #4]
J Clin Invest. 1996 Nov 15;98(10):2398-402
Full text HTML format:
http://www.jci.org/cgi/content/full/98/10/2398
Full text PDF format
http://www.jci.org/cgi/reprint/98/10/2398.pdf
Molecular analysis of the fructose transporter gene (GLUT5) in isolated
fructose malabsorption.
Wasserman D, Hoekstra JH, Tolia V, Taylor CJ, Kirschner BS, Takeda J, Bell
GI, Taub R, Rand EB.
Children's Hospital of Philadelphia, Division of Gastroenterology &
Nutrition, Pennsylvania 19104, USA.
Fructose, a naturally occurring monosaccharide, is increasingly used as an
added sweetener in processed foods in the form of high fructose corn syrup.
Increased fructose intake combined with the identification of children with
clinical evidence of isolated fructose malabsorption (IFM) has stimulated
interest in possible disorders of fructose absorption. The intestinal
absorption of fructose is carried out by the facilitative hexose
transporter, which has been designated as GLUT5. Functional properties and
tissue distribution of GLUT5 suggest that IFM might be due to mutations in
the GLUT5 gene. To test this hypothesis, we screened the GLUT5 gene for
mutations in a group of eight patients with IFM and in one subject with
global malabsorption, as compared with 15 healthy parents of subjects and
up to 6 unrelated controls. No mutations were found in the protein coding
region of this gene in any of the subjects. A single G to A substitution in
the 5' untranslated region of exon 1 was identified in the subject with
global malabsorption. This subject and her healthy mother were heterozygous
for the variant sequence, suggesting that it was unlikely to be clinically
significant. In addition, sequence analysis of each of the 12 GLUT5 exons
was performed in the index case and confirmed the negative single-strand
conformation polymorphism findings. These studies demonstrate that IFM does
not result from the expression of mutant GLUT5 protein.
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[Ref. #5]
Cochrane Database Syst Rev. 2002;(1):CD003198
Tryptophan and 5-hydroxytryptophan for depression.
Shaw K, Turner J, Del Mar C.
School of Population Health, University of Queensland, Public Health
Building, Herston Rd, Herston, Queensland, Australia, 4006.
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BACKGROUND: 5 Hydroxytryptophan (5-HTP) and tryptophan are so-called
natural alternatives to traditional antidepressants, used to treat unipolar
depression and dysthymia. OBJECTIVES: To determine whether 5-HTP and
tryptophan are more effective than placebo, and whether they are safe to
use to treat depressive disorders in adults. SEARCH STRATEGY: Trials were
searched in computerized general (Medline, Psychlit, and Embase) and
specialized databases (Cochrane Controlled Clinical Trials Register,
Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trial
Register); by checking reference lists of relevant articles; by
handsearching relevant specialist journals; and by contacting relevant
authors where appropriate. Publications in all languages were sought.
SELECTION CRITERIA: Trials were included if they were randomized, included
patients with unipolar depression or dysthymia, compared preparations of 5-
HTP or tryptophan with placebo, and included clinical outcomes assessed by
scales assessing depressive symptoms. DATA COLLECTION AND ANALYSIS: Data
was extracted independently by the three reviewers, onto data collection
forms. Inclusion criteria were applied to all potential studies
independently and a coefficient of agreement (Kappa) was calculated for
them. Disagreement was resolved by reaching consensus. Trial quality was
scored according to risk of bias. Analysis for 5-HTP and tryptophan were
combined due to the small number of included trials. MAIN RESULTS: 108
trials were located using the specified search strategy. Of these, only two
trials, involving a total of 64 patients, were of sufficient quality to
meet inclusion criteria. The available evidence suggests these substances
were better than placebo at alleviating depression (Peto Odds Ratio 4.10;
95% confidence interval 1.28-13.15; RD 0.36; NNT 2.78). However, the
evidence was of insufficient quality to be conclusive. REVIEWER'S
CONCLUSIONS: A large number of studies appear to address the research
questions, but few are of sufficient quality to be reliable. Available
evidence does suggest these substances are better than placebo at
alleviating depression. Further studies are needed to evaluate the efficacy
and safety of 5-HTP and tryptophan before their widespread use can be
recommended. The possible association between these substances and the
potentially fatal Eosinophilia-Myalgia Syndrome has not been elucidated.
Because alternative antidepressants exist which have been proven to be
effective and safe the clinical usefulness of 5-HTP and tryptophan is
limited at present.
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[Ref. #6]
Adv Exp Med Biol. 1999;467:461-8
Eosinophilia-myalgia syndrome case-associated contaminants in commercially
available 5-hydroxytryptophan.
Klarskov K, Johnson KL, Benson LM, Gleich GJ, Naylor S.
Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester,
MN 55905, USA.
Recently, 5-hydroxy-L-tryptophan (5-OHTrp) has been promoted as an
alternative to banned L-tryptophan as a dietary supplement. It has been
claimed to help alleviate obesity, insomnia, depression, and headaches.
However, eosinophilia-myalgia syndrome (EMS)-like symptoms have also been
associated with ingestion or exposure to 5-OHTrp. HPLC-UV analysis of EMS-
implicated 5-OHTrp revealed the presence of peak X, described as case-
implicated. We show that peak X is actually a family of contaminants with
the same molecular weight (234 Da) and similar HPLC retention times. We
also demonstrate that all eight samples of commercially available 5-OHTrp
analyzed by HPLC-MS contained three or more contaminants of the peak X
family. The significance of these findings is discussed.
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