Vegetables and glycation

As if you needed another reason to eat your broccoli and kale, vegetables apparently have glycation inhibiting properties. These are attributed to isothiocyanate and other flavonoid substances.

Advanced Glycation and Lipoxidation End Products–Amplifiers of Inflammation: The Role of Food
"Glutathione (-glutamyl-cysteinyl glycine [GSH]) is regarded as an important factor for optimal cellular function and defense against oxidative stress. Dietary supply of GSH has been shown to reduce glycation and prevents diabetic complications such as diabetic nephropathy and neuropathy.¹³⁶ Rich supply of vitamins A, C, E, and particularly B₆, B₁₂, and folic acid (Figure 2) is often emphasized in the literature.¹³⁷ Vitamin D should most likely also be supplemented, especially at higher latitudes.⁴⁹ Several thousands of plant-derived chemopreventive agents, polyphenols, and many others, most often yet unexplored, have the potential to reduce the speed of aging and prevent degenerative malfunctions of organs, among them, isothiocyanates in cruciferous vegetables, anthocyanins and hydroxycinnamic acids in cherries, epigallocatechin-3-gallate (EGCG) in green tea, chlorogenic acid and caffeic acid in coffee beans and also tobacco leaves, capsaicin in hot chili peppers, chalcones in apples, eugenol in cloves, gallic acid in rhubarb, hisperitin in citrus fruits, naringenin in citrus fruits, kaempferol in white cabbage, myricetin in berries, rutin and quercetin in apples and onions, resveratrol and other procyanidin dimers in red wine and virgin peanuts, various curcumenoids, the main yellow pigments in turmeric curry foods,¹³⁸ and daidzein and genistein from the soybean. These compounds have all slightly different functions and seem to complement each other well. Several, most likely the majority, of these substances have a great capacity to inhibit the second phase of the glycation process, eg, the conversion of the Amadori products to AGEs. A significant number of animal studies support health benefits of these antioxidants and AGE/ALE scavengers.^139,140 Again, human studies are largely lacking."

Protective Effects of Broccoli (Brassica oleracea) against Oxidative Damage in Vitro and in Vivo
"The antioxidative effect and protective potential against diabetes of the broccoli flower were investigated both in vitro and in a diabetic rat model. Among fractions of MeOH, CH₂Cl₂, BuOH, and H₂O, the BuOH fraction exerted the strongest inhibitory activities on 1,1-diphenyl-2-picrylhydrazyl radical, radical-induced protein oxidation, and nitric oxide generation by sodium nitroprusside. The in vitro results suggest that the BuOH fraction from the broccoli flower has a protective potential against oxidative stress. The rat model with diabetes induced by streptozotocin was employed to evaluate the protective effect of the BuOH fraction in vivo. Diabetic rats showed reduced body weight gain and heavier kidney and liver weights than normal rats, while oral administration of the BuOH fraction at an oral dose of 100 or 200 mg/kg body weight/d for 20 d attenuated the physiological changes induced by diabetes. In addition, oral administration of the BuOH fraction to diabetic rats led to significant decreases in serum glucose and glycosylated protein, while it resulted in the increase of serum albumin, implying that the BuOH fraction improves the abnormal metabolism of glucose and protein that leads to oxidative stress. Moreover, it significantly reduced thiobarbituric acid-reactive substance levels in serum, hepatic and renal mitochondria. This suggests that the BuOH fraction would alleviate the oxidative stress associated with diabetes through the inhibition of lipid peroxidation. The present study demonstrates that the BuOH fraction has an antioxidative effect in vitro and it protects against oxidative stress induced by diabetes in an in vivo model."

Flavonoids inhibit the formation of the cross-linking AGE pentosidine in collagen incubated with glucose, according to their structure
"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 µM) 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. <a name="ASec5">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 flavonoids."

Quercetin has a high prevelence in broccoli and other leafy green vegetables.

Plant-derived health: the effects of turmeric and curcuminoids
"Plants contain numerous polyphenols, which have been shown to reduce inflammation and hereby to increase resistance to disease. Examples of such polyphenols are isothiocyanates in cabbage and broccoli, epigallocatechin in green tee, capsaicin in chili peppers, chalones, rutin and naringenin in apples, resveratrol in red wine and fresh peanuts and curcumin/curcuminoids in turmeric. Most diseases are maintained by a sustained discreet but obvious increased systemic inflammation. Many studies suggest that the effect of treatment can be improved by a combination of restriction in intake of proinflammatory molecules such as advanced glycation end products (AGE), advanced lipoperoxidation end products (ALE), and rich supply of antiinflammatory molecules such as plant polyphenols. To the polyphenols with a bulk of experimental documentation belong the curcuminoid family and especially its main ingredient, curcumin. This review summarizes the present knowledge about these turmericderived ingredients, which have proven to be strong antioxidants and inhibitors of cyclooxigenase-2 (COX-2), lipoxygenase (LOX) and nuclear factor kappa B (NF-kappaB) but also AGE. A plethora of clinical effects are reported in various experimental diseases, but clinical studies in humans are few. It is suggested that supply of polyphenols and particularly curcuminoids might be value as complement to pharmaceutical treatment, but also prebiotic treatment, in conditions proven to be rather therapy-resistant such as Crohn's, long-stayed patients in intensive care units, but also in conditions such as cancer, liver cirrhosis, chronic renal disease, chronic obstructive lung disease, diabetes and Alzheimer's disease."

Indeed, didn't I already say this on several other posts? I wonder if those vegetarians in the study showing higher circulating plasma AGEs levels were eating enough green vegetables.

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chlorogenic acid and caffeic acid in coffee beans and also tobacco leaves

Woohoo! Health food!

Indeed, didn't I already say this on several other posts?

No, unlike Skotkonung, you were making unsubstantiated claims.

Interesting read! Thanks for the info.

Indeed, didn't I already say this on several other posts? I wonder if those vegetarians in the study showing higher circulating plasma AGEs levels were eating enough green vegetables.

Yeah, I think a vegetable based diet can be perfectly healthy, but it is not as "fool-proof" as an omnivorous diet. Based on what I have seen, it seems like a raw vegan diet may have the following issues:

- Low amino acid taurine and related glycation
- Low B12 can drive up homocysteine
- Hazards from food poisoning from certain foods such as buckwheat greens and beans, etc
- Low meat derived glycation inhibitors such as carnosine, carnitine, alpha liopic acid
- High fructose and related glycation (if bulk of diet comes from fruits / juices)
- High PUFAs and related glycation (if bulk of diet comes from nuts / seeds)

Based on those observations, it would be poignant for anyone attempting raw veganism to supplement at least the above compounds and adjust dietary composition to retrieve the majority of calories from stable MUFAs or MCTs.

I think a well organized raw diet might offer a panacea of benefits (although this is not reflected in the published literature), if you could of course adhere to it for any length of time. I personally know I can't do such a diet nor can I do CR, so I choose to eat mostly raw fruits / vegetables/ berries / nuts with lightly cooked meat.

If you're an omnivore who is worried about AGE consumption, alternating meat meals with raw (or lightly cooked) sprouted tofu may help alleviate some concern.

Edited by Skotkonung, 04 December 2009 - 07:40 PM.

Indeed, didn't I already say this on several other posts?

No, unlike Skotkonung, you were making unsubstantiated claims.

No, they weren't unsubstantiated. I said word for word that isoflavones and flavanoids in vegetables and legumes have anti-glycation properties. And I said it long before anyone else, with the possible exception of two other users here. I knew this because I studied the literature over a year ago.

Indeed, didn't I already say this on several other posts?

No, unlike Skotkonung, you were making unsubstantiated claims.

No, they weren't unsubstantiated. I said word for word that isoflavones and flavanoids in vegetables and legumes have anti-glycation properties. And I said it long before anyone else, with the possible exception of two other users here. I knew this because I studied the literature over a year ago.

Did you cite any research? You could link to the post in question.

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Indeed, didn't I already say this on several other posts?

<br />No, unlike Skotkonung, you were making unsubstantiated claims.<br />

<br />No, they weren't unsubstantiated. I said word for word that isoflavones and flavanoids in vegetables and legumes have anti-glycation properties. And I said it long before anyone else, with the possible exception of two other users here. I knew this because I studied the literature over a year ago.<br />

<br />Did you cite any research? You could link to the post in question.<br />

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I didn't need to cite research, I learned it in school. It's no worse off than linking someone to a paleo blog for an ideological dieters opinion, which is something you, Duke and many others have done.

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Indeed, didn't I already say this on several other posts?

<br />No, unlike Skotkonung, you were making unsubstantiated claims.<br />

<br />No, they weren't unsubstantiated. I said word for word that isoflavones and flavanoids in vegetables and legumes have anti-glycation properties. And I said it long before anyone else, with the possible exception of two other users here. I knew this because I studied the literature over a year ago.<br />

<br />Did you cite any research? You could link to the post in question.<br />

<br /><br /><br />
I didn't need to cite research, I learned it in school.

I really don't think that's going to carry a lot of weight around here. We all learned all kinds of stuff in school, some right, some wrong, and some mis-remembered. What's with all the <br/>'s?

Your diet sounds ideal to me.

I think a well organized raw diet might offer a panacea of benefits (although this is not reflected in the published literature), if you could of course adhere to it for any length of time. I personally know I can't do such a diet nor can I do CR, so I choose to eat mostly raw fruits / vegetables/ berries / nuts with lightly cooked meat.

If you're an omnivore who is worried about AGE consumption, alternating meat meals with raw (or lightly cooked) sprouted tofu may help alleviate some concern.

- High PUFAs and related glycation (if bulk of diet comes from nuts / seeds)

Do you have a link for this? It's a little worrisome.