fructose/glycation: don't worry about it.
Posted by: arugula ()
Date: March 17, 2007 11:42PM
I had previously stirred up some concern with fructose and glycation, I had also suggested that this might be a problem only with pure fructose, and there were protective substances in fruits that might cancel the negative effects. Here are a few studies to confirm. In case you wanted to know more about rutin, it's found in many fruits and vegetables.
see the bottom of the page here for rutin sources:
basically all the flavonoids or bioflavonoids will be protective, just eat your fruits and veggies and not processed garbage.
Eur J Nutr. 2007 Mar 13; [Epub ahead of print]
Flavonoids inhibit the formation of the cross-linking AGE pentosidine in
collagen incubated with glucose, according to their structure.
Urios P, Grigorova-Borsos AM, Sternberg M.
Equipe de recherche "Proteines modifiees, proteases et physiopathologie de
l'endothelium vasculaire", Dept. de Biochimie, Faculte de Medecine & Laboratoire
de Pharmacologie, Faculte de Pharmacie, Universite Rene Descartes, Paris,
BACKGROUND: Glycoxidation of collagens contributes to development of vascular
complications in diabetes. AIM OF THE STUDY: Since flavonoids are potent
antioxidants present in vegetal foods, it was interesting to examine their
effect on the formation of a cross-linking advanced glycation endproduct,
pentosidine, in collagens. METHODS: Collagen was incubated with glucose (250
mM), in the presence of different flavonoids. Pentosidine was measured by HPLC,
hydroxyproline colorimetrically. RESULTS: Monomeric flavonoids (25 and 250
microM) markedly reduced pentosidine/hydroxyproline values in a concentration-
and structure-dependent manner. In decreasing order of their specific inhibitory
activity, they rank as follows: myricetin >/= quercetin > rutin > (+)catechin >
kaempferol. Thus 3'-OH or 4-oxo + Delta(2-3) increase the inhibitory activity;
conjugation by Rha-Glc on 3-OH decreases it. Procyanidin oligomers from grape
seed were more active than pine bark procyanidin oligomers: this may be related
to the galloyl residues present in grape seed oligomers only. Procyanidin
oligomers are known to be cleaved into monomers in the gastric milieu and
monomeric flavonoids to be absorbed and recovered at micromolar concentrations
(with a long plasmatic half-life) in extracellular fluids, in contact with
collagens. CONCLUSION: Flavonoids are very potent inhibitors of pentosidine
formation in collagens. They are active at micromolar concentrations; these
might be achieved in plasma of diabetic patients after oral intake of natural
PMID: 17356796 [PubMed - as supplied by publisher]
J Nutr Biochem. 2006 Aug;17(8):531-40. Epub 2005 Oct 28.
Inhibition of advanced glycation end product formation on collagen by rutin and
Cervantes-Laurean D, Schramm DD, Jacobson EL, Halaweish I, Bruckner GG,
Department of Pharmacology and Toxicology, College of Pharmacy, Arizona Cancer
Center, University of Arizona, Tucson, AZ 85724, USA.
Several lines of evidence suggest that rutin, flavonoid in fruits and
vegetables, or one of its metabolites may effectively modulate advanced
glycation end product (AGE) formation. Following ingestion, rutin forms
metabolites that include 3,4-dihydroxyphenylacetic acid (3,4-DHPAA),
3,4-dihydroxytoluene (3,4-DHT), m-hydroxyphenylacetic acid (m-HPAA),
3-methoxy-4-hydroxyphenylacetic acid (homovanillic acid, HVA) and
3,5,7,3',5'-pentahydroxyflavonol (quercetin). We studied the effects of rutin
and its metabolites on the formation of AGE biomarkers such as pentosidine,
collagen-linked fluorescence, N(epsilon)-carboxymethyllysine (CML) adducts,
glucose autoxidation and collagen glycation, using an in vitro model where
collagen I was incubated with glucose. Rutin metabolites containing vicinyl
dihydroxyl groups, i.e., 3,4-DHT, 3,4-DHPAA and quercetin, inhibited the
formation of pentosidine and fluorescent adducts, glucose autoxidation and
glycation of collagen I in a dose-dependent manner, whereas non-vicinyl
dihydroxyl group-containing metabolites, i.e., HVA and m-HPAA, were much less
effective. All five metabolites of rutin effectively inhibited CML formation. In
contrast, during the initial stages of glycation and fluorescent AGE product
accumulation, only vicinyl hydroxyl group-containing rutin metabolites were
effective. These studies demonstrate that rutin and circulating metabolites of
rutin can inhibit early glycation product formation, including both fluorescent
and nonfluorescent AGEs induced by glucose glycation of collagen I in vitro.
These effects likely contribute to the beneficial health effects associated with
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
PMID: 16443355 [PubMed - indexed for MEDLINE]
J Agric Food Chem. 2005 Apr 20;53(8):3167-73.
Inhibitory effect of naturally occurring flavonoids on the formation of advanced
Wu CH, Yen GC.
Department of Food Science, National Chung Hsing University, 250 Kuokuang Road,
Taichung 40227, Taiwan.
The objective of this study was to investigate the inhibitory effect of
naturally occurring flavonoids on individual stage of protein glycation in vitro
using the model systems of delta-Gluconolactone assay (early stage),
BSA-methylglyoxal assay (middle stage), BSA-glucose assay, and G.K.
peptide-ribose assay (last stage). In the early stage of protein glycation,
luteolin, qucertin, and rutin exhibited significant inhibitory activity on HbA1C
formation (p < 0.01), which were more effective than that of aminoguanidine (AG,
10 mM), a well-known inhibitor for advanced glycation endproducts (AGEs). For
the middle stage, luteolin and rutin developed more significant inhibitory
effect on methylglyoxal-medicated protein modification, and the IC50's were 66.1
and 71.8 microM, respectively. In the last stage of glycation, luteolin was
found to be potent inhibitors of both the AGEs formation and the subsequent
cross-linking of proteins. In addition, phenyl-tert-butyl-nitron served as a
spin-trapping agent, and electron spin resonance (ESR) was used to explore the
possible mechanism of the inhibitory effect of flavonoids on glycation. The
results indicated that protein glycation was accompanied by oxidative reactions,
as the ESR spectra showed a clear-cut radical signal. Statistical analysis
showed that inhibitory capability of flavonoids against protein glycation was
remarkably related to the scavenging free radicals derived from glycoxidation
process (r = 0.79, p < 0.01). Consequently, the inhibitory mechanism of
flavonoids against glycation was, at least partly, due to their antioxidant
Research Support, Non-U.S. Gov't
PMID: 15826074 [PubMed - indexed for MEDLINE]
Biosci Biotechnol Biochem. 2004 Jan;68(1):200-5.
Tomato paste fraction inhibiting the formation of advanced glycation
Kiho T, Usui S, Hirano K, Aizawa K, Inakuma T.
Gifu Prefectural Institute of Health and Environmental Sciences, Gifu, Japan.
A water-soluble and low-molecular-weight fraction (S was obtained from tomato
paste. The effects of SB on the formation of advanced glycation end-products
(AGE) in protein glycation were studied by the methods of specific fluorescence,
ELISA and a Western blot analysis, using the anti-AGE antibody after incubating
protein with sugar. The results suggest that SB had strong inhibitory activity,
in comparison with aminoguanidine as a positive control, and that the inhibitory
mechanism of SB differed from that of aminoguanidine to involve trapping of
reactive dicarbonyl intermediates in the early stage of glycation. SB contained
an antioxidant, rutin, which showed potent inhibitory activity. The results also
suggest that rutin chiefly contributed to inhibiting the formation of AGE, and
that other compounds in SB may also have been related to the activity.
PMID: 14745184 [PubMed - indexed for MEDLINE]
Mol Cell Biochem. 2003 Oct;252(1-2):141-7.
Dietary G-rutin suppresses glycation in tissue proteins of
streptozotocin-induced diabetic rats.
Nagasawa T, Tabata N, Ito Y, Aiba Y, Nishizawa N, Kitts DD.
Food and Health Science, Faculty of Agriculture, Iwate University, Morioka,
Iwate, Tokyo, Japan.
The present study focused on examining the efficacy of feeding a rutin-glucose
derivative (G-rutin) to inhibit glycation reactions that can occur in muscle,
kidney and plasma proteins of diabetic rats. Both thiobarbituric acid-reactive
substance levels and protein carbonyl contents in muscle and kidney were
significantly (p < 0.05) reduced in streptozotocin-induced diabetic rats fed
G-rutin supplemented diet, compared to diabetic rats fed control diet. The
N(epsilon)-fructoselysine content in muscle and kidney, a biomarker of early
glycation reaction, was markedly (p < 0.05) increased by diabetes, but
significantly (p < 0.05) reduced in diabetic rats fed G-rutin. Advanced
glycation end-products (AGEs) in serum and kidney protein were measured by
immunoblot using anti-AGE antibody, and were also reduced in diabetic rats fed
dietary G-rutin. Feeding G-rutin also slightly inhibited aldose reductase
activity in these animals. These results demonstrate for the first time that
dietary G-rutin consumption can provide potential health benefits that are
related to the inhibition of tissue glycation reactions common to diabetes.
PMID: 14577587 [PubMed - indexed for MEDLINE]
Re: fructose/glycation: don't worry about it.
Posted by: la_veronique ()
Date: March 18, 2007 12:51AM
<<just eat your fruits and veggies and not processed garbage>>
that's what i say
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