8 replies to this topic

[Pablo M]

Okay, I thought if anyone could shed some light on this it would be you guys. I've read (mostly on raw food sites, so this could be false information) that any cooking of food is enough to produce AGEs. Now, according to Inflammation and The Perricone Prescription, it is a matter of how you cook foods-- obviously charring meat is a lot worse than boiling it in stew.

So is the formation of AGEs in food inevitable?

[John Schloendorn]

Indeed, during cooking some of the "same" reactions occur as during AGE formation in humans. This led Steve Austad to his famous reply to what is aging: "We rust and we cook", referring to oxidative DNA lesions and AGE formation respectively.

But no worries, AGE is not synonymous with poison, you can eat them without trouble. You get trouble only when your own body proteins get modified in this way, which changes there mechanical properties, e.g. friction in skin, which is thought to cause wrinkles or the heart also tends to run less smoothly. When you eat glycated proteins, on the other hand, your stomach chops them up into individual amino acids like every protein, and then usually your cells degrade them to make energy, so you don't get any of these mechanical problems at all.

(I'm not saying that charred meat is healthy. It is rumored that other bad things may happen there, although I have not seen any really convincing reports of this.)

[LifeMirage]

Okay, I thought if anyone could shed some light on this it would be you guys. I've read (mostly on raw food sites, so this could be false information) that any cooking of food is enough to produce AGEs.

That is true.

Click on table 2 at the bottom of the webpage: Heat + Food = AGEs

Now, according to Inflammation and The Perricone Prescription, it is a matter of how you cook foods-- obviously charring meat is a lot worse than boiling it in stew.

Correct.

So is the formation of AGEs in food inevitable?

No, raw or fermented food is the only way to get about zero AGEs.

As far as cooking goes: Steaming, boiling, poaching and stir fry produces the lowest amounts.

Microwaving, frying, baking, and grilling the highest.

For more info: http://www.lef.org/m...03_awsi_01.html

[LifeMirage]

Indeed, during cooking some of the "same" reactions occur as during AGE formation in humans. This led Steve Austad to his famous reply to what is aging: "We rust and we cook", referring to oxidative DNA lesions and AGE formation respectively.

But no worries, AGE is not synonymous with poison, you can eat them without trouble. You get trouble only when your own body proteins get modified in this way, which changes there mechanical properties, e.g. friction in skin, which is thought to cause wrinkles or the heart also tends to run less smoothly. When you eat glycated proteins, on the other hand, your stomach chops them up into individual amino acids like every protein, and then usually your cells degrade them to make energy, so you don't get any of these mechanical problems at all.

(I'm not saying that charred meat is healthy. It is rumored that other bad things may happen there, although I have not seen any really convincing reports of this.)

Prepare to be convinced.


Medline Review: Dietary AGEs are Bad News


Med Hypotheses. 2005;64(2):394-8.
The low-AGE content of low-fat vegan diets could benefit diabetics - though concurrent taurine supplementation may be needed to minimize endogenous AGE production.

McCarty MF. NutriGuard Research, 1051 Hermes Avenue, Encinitas, CA 92024, USA. mccarty@pantox.com

Increased endogenous generation of advanced glycation endproducts (AGEs) contributes importantly to the vascular complications of diabetes, in part owing to activation of the pro-inflammatory RAGE receptor. However, AGE-altered oligopeptides with RAGE-activating potential can also be absorbed from the diet, and indeed make a significant contribution to the plasma and tissue pool of AGEs; this contribution is especially prominent when compromised renal function impairs renal clearance of AGEs. Perhaps surprisingly, foods rich in both protein and fat, and cooked at high heat, tend to be the richest dietary sources of AGEs, whereas low-fat carbohydrate-rich foods tend to be relatively low in AGEs. Conceivably, this reflects the fact that the so-called "AGEs" in the diet are generated primarily, not by glycation reactions, but by interactions between oxidized lipids and protein; such reactions are known to give rise to certain prominent AGEs, such as epsilonN-carboxymethyl-lysine and methylglyoxal. Although roasted nuts and fried or broiled tofu are relatively high in AGEs, low-fat plant-derived foods, including boiled or baked beans, typically are low in AGEs. Thus, a low-AGE content may contribute to the many benefits conferred to diabetics by a genuinely low-fat vegan diet. Nonetheless, the plasma AGE content of healthy vegetarians has been reported to be higher than that of omnivores - suggesting that something about vegetarian diets may promote endogenous AGE production. Some researchers have proposed that the relatively high-fructose content of vegetarian diets may explain this phenomenon, but there so far is no clinical evidence that normal intakes of fructose have an important impact on AGE production. An alternative or additional possibility is that the relatively poor taurine status of vegetarians up-regulates the physiological role of myeloperoxidase-derived oxidants in the generation of AGEs - in which case, taurine supplementation might be expected to suppress elevated AGE production in vegetarians. Thus, a taurine supplemented low-fat vegan diet may be recommended as a strategy for minimizing AGE-mediated complications in diabetics and in patients with renal failure.

Biochem Soc Trans. 2003 Dec;31(Pt 6):1383-5.Glycation in food and metabolic transit of dietary AGEs (advanced glycation end-products): studies on the urinary excretion of pyrraline.

Foerster A, Henle T. Institute of Food Chemistry, Technical University of Dresden, D-01062 Dresden, Germany.

Pyrraline [epsilon-(2'-formyl-5'-hydroxymethyl-pyrrolyl)-L-norleucin] belongs to the group of AGEs (advanced glycation end-products) formed in the final stage of the Maillard reaction in foods and in vivo. As it is generally accepted that AGEs are pathophysiologically relevant in aging and in diseases such as diabetes and uraemia, physiological consequences resulting from the ingestion of dietary AGEs are discussed, but balance studies for well defined AGEs are still lacking. The aim of our study was to investigate the influence of nutrition on the urinary excretion of pyrraline. After the first day without dietary restrictions, seven healthy volunteers were asked, starting on the morning of day 2, to ingest a diet virtually free of Maillard compounds (i.e. no cooked or roasted foods, no bakery products, no coffee, etc.). Dietary control was stopped on the morning of day 5. We collected 24 h urine samples for these 5 days, which were analysed for free pyrraline by reverse-phase HPLC with UV detection at 297 nm. We found that urinary excretion of free pyrraline was directly affected by the composition of the diet, decreasing from 4.8+/-1.1 mg/day on day 1 to levels of 1.6, 0.4 and 0.3 mg/day on days 2, 3 and 4 respectively, followed by a significant increase to 3.2+/-1.4 mg/day on the 5th day. The results of this work prove, for the first time, that urinary excretion of pyrraline is strongly dependent on its dietary intake. Thus the influence of nutrition should be taken into consideration in studies directed to the physiological role of glycation compounds.


Am J Kidney Dis. 2003 Sep;42(3):532-8.
Dietary glycotoxins correlate with circulating advanced glycation end product levels in renal failure patients.

Uribarri J, Peppa M, Cai W, Goldberg T, Lu M, Baliga S, Vassalotti JA, Vlassara H. Department of Medicine, Division of Nephrology, Mount Sinai School of Medicine, New York, NY 10029, USA. jaime.uribarri@mssm.edu

BACKGROUND: Levels of advanced glycation end products (AGEs), well-known proinflammatory compounds, are markedly elevated in patients with renal failure, raising the speculation that they have a role as cardiovascular risk factors in this population. Although elevated AGE levels in patients with renal failure have been attributed to impaired renal clearance and increased endogenous AGE formation, recent data suggest an important role for diet as a source of AGEs. METHODS: To determine the relationship between dietary AGE content and serum AGE levels, a cross-sectional study was performed in our long-term dialysis patients. Dietary AGE intake was estimated by means of dietary records and questionnaires, and sera were obtained for measurement of 2 well-characterized AGEs, carboxymethyl-lysine (CML) and methylglyoxal (MG) derivatives. RESULTS: The study population included 189 patients; 139 hemodialysis and 50 peritoneal dialysis patients. Serum CML level correlated significantly with dietary AGE intake, based on either 3-day food records (r = 0.5; P = 0.003) or dietary questionnaires (r = 0.22; P = 0.03). Although no correlation was observed with nutrient intake (protein, fat, saturated fat, or carbohydrate), both serum CML and MG levels correlated with blood urea nitrogen (r = 0.2; P = 0.03 and r = 0.2; P = 0.02, respectively) and serum albumin levels (r = 0.16; P = 0.04 and r = 0.18; P = 0.02, respectively). CONCLUSION: Data indicate that dietary AGE content, independently of other diet constituents, is an important contributor to excess serum AGE levels in patients with renal failure. Moreover, the lack of correlation between serum AGE levels and dietary protein, fat, and carbohydrate intake indicates that a reduction in dietary AGE content can be obtained safely without compromising the content of obligatory nutrients

Proc Natl Acad Sci U S A. 2002 Nov 26;99(24):15596-601. Epub 2002 Nov 12.
Inflammatory mediators are induced by dietary glycotoxins, a major risk factor for diabetic angiopathy.

Vlassara H, Cai W, Crandall J, Goldberg T, Oberstein R, Dardaine V, Peppa M, Rayfield EJ. Division of Experimental Diabetes and Aging, Department of Geriatrics, Mount Sinai School of Medicine, New York, NY 10029, USA. helen.vlassara@mssm.edu

Diet is a major environmental source of proinflammatory AGEs (heat-generated advanced glycation end products); its impact in humans remains unclear. We explored the effects of two equivalent diets, one regular (high AGE, H-AGE) and the other with 5-fold lower AGE (L-AGE) content on inflammatory mediators of 24 diabetic subjects: 11 in a 2-week crossover and 13 in a 6-week study. After 2 weeks on H-AGE, serum AGEs increased by 64.5% (P = 0.02) and on L-AGE decreased by 30% (P = 0.02). The mononuclear cell tumor necrosis factor-alphabeta-actin mRNA ratio was 1.4 +/- 0.5 on H-AGE and 0.9 +/- 0.5 on L-AGE (P = 0.05), whereas serum vascular adhesion molecule-1 was 1,108 +/- 429 and 698 +/- 347 ngml (P = 0.01) on L- and H-AGE, respectively. After 6 weeks, peripheral blood mononuclear cell tumor necrosis factor-alpha rose by 86.3% (P = 0.006) and declined by 20% (P, not significant) on H- or L-AGE diet, respectively; C-reactive protein increased by 35% on H-AGE and decreased by 20% on L-AGE (P = 0.014), and vascular adhesion molecule-1 declined by 20% on L-AGE (P < 0.01) and increased by 4% on H-AGE. Serum AGEs were increased by 28.2% on H-AGE (P = 0.06) and reduced by 40% on L-AGE (P = 0.02), whereas AGE low density lipoprotein was increased by 32% on H-AGE and reduced by 33% on L-AGE diet (P < 0.05). Thus in diabetes, environmental (dietary) AGEs promote inflammatory mediators, leading to tissue injury. Restriction of dietary AGEs suppresses these effects.


Also: Full Dietary AGEs Study

[Pablo M]

Prepare to be convinced.

I saw that study too, Mirage. So, eat a diet low in AGEs (which it seems likely that vegetarian diets are) and your body ramps up endogenous AGE production. Or perhaps there's another reason. Many of the vegetarians I know consume large amounts of sugar and refined flour products, which could definitely explain the increased AGEs found among vegetarians in this study.

[John Schloendorn]

Prepare to be convinced.

OK, if you have diabetes or renal failure I hope you are aware that you do have special dietary requirements. Please don't take anything I'm saying as medical advice for a particular condition. My advice was of course for healthy persons. (Yes, I know that scientifically speaking my mechanistic explanation was simplified, thanks for expanding.) Aside, even with foods chosen for age content, it is not clear that the effect is due to AGE content and not some correlate therof such as ROS, but I admit given the other studies it is not unlikely. Only the last study found some indications that in a disease background this may activate pathogenic signals and even that was in some points not significant, in others only just significant.

In sum, sorry, it takes more than one study from a disease-state, which is at most equivalent to phase 1, to convince me that there is a non-disease state effect.

I'm not saying it hurts to eat steamed food only, and I'm not saying it hurts to believe that you eat healthly. I think that either can be quite beneficial.

[LifeMirage]

OK, if you have diabetes or renal failure I hope you are aware that you do have special dietary requirements. Please don't take anything I'm saying as medical advice for a particular condition. My advice was of course for healthy persons. (Yes, I know that scientifically speaking my mechanistic explanation was simplified, thanks for expanding.) Aside, even with foods chosen for age content, it is not clear that the effect is due to AGE content and not some correlate therof such as ROS, but I admit given the other studies it is not unlikely. Only the last study found some indications that in a disease background this may activate pathogenic signals and even that was in some points not significant, in others only just significant.

In sum, sorry, it takes more than one study from a disease-state, which is at most equivalent to phase 1, to convince me that there is a non-disease state effect.

I'm not saying it hurts to eat steamed food only, and I'm not saying it hurts to believe that you eat healthly. I think that either can be quite beneficial.

AGEs are well accepted as a factor in aging and disease, I see no difference in either the body producing them or your dietary intake of them. Can you cite a study showing otherwise? Aside from your Phase 1, 2, 3 theory?

Also why even take the chance?

[John Schloendorn]

The pathogenesis of extracellular matrix (ECM) derived AGEs due changes of its mechanical properties is discussed e.g. here. As I already explained, dietary AGEs are unlikely to contribute to this type of pathogenesis (i.e. integrate in the existing ECM), because the turnover of the respective ECM proteins is very low (which is precisely the problem).
Thus we are facing (at least) two distinct types of pathogenesis mechanisms. One through inflammatory signalling (both dietary and non-dietary) and one through structural modification of the existing ECM (non-dietary). Which type is more important is for future research to decide. I have already pointed out the preliminary character of the existing studies as far as healthy people are concerned.

I do not recommend any intervention, or indeed any particular behavior on the basis of such preliminary studies, but I do not expect you to comply by any means. Can we live with that?

Also why even take the chance?

Why even take the chance to cross a road, given the chance to be hit by a truck. I'm saying, we're facing a continuum of risks and chances in life. In the end, everyone has to draw their own lines with the limited information we have.

[LifeMirage]

The pathogenesis of extracellular matrix (ECM) derived AGEs due changes of its mechanical properties is discussed e.g. here. As I already explained, dietary AGEs are unlikely to contribute to this type of pathogenesis (i.e. integrate in the existing ECM), because the turnover of the respective ECM proteins is very low (which is precisely the problem).
Thus we are facing (at least) two distinct types of pathogenesis mechanisms. One through inflammatory signalling (both dietary and non-dietary) and one through structural modification of the existing ECM (non-dietary). Which type is more important is for future research to decide. I have already pointed out the preliminary character of the existing studies as far as healthy people are concerned.

Nothing on your posted link suggest AGEs from food are safe, the weight of the facts so far in my opinion show they are not and should be avoid. Unless you considered fried food healthy unless proven 100% otherwise in phase 3 studies. Common sense plays a large role in medicine. I understand your difficulty understanding and making sense of this complication process, as most people don't know how to interpret studies or understand biochemistry. You have to draw a lot of data out of studies. Example, even though the studies were not done on healthy humans it showed that dietary AGEs are definitely absorbed into the bloodstream of human beings. If you are interested in antiaging you would use the information available (in my opinion) instead of slowing dying waiting for 100% conclusive studies, especially if you go by the FDA’s reasoning. They still think fish oil has no proven benefits. Now that said I do respect your right to your opinion of the evidence at hand. I encourage anyone to defend their viewpoint, as I defend mine, without openly stating the other person is wrong but that our understanding and viewpoint differs.

I do not recommend any intervention, or indeed any particular behavior on the basis of such preliminary studies, but I do not expect you to comply by any means. Can we live with that?

QUOTE 
Also why even take the chance? 

Why even take the chance to cross a road, given the chance to be hit by a truck. I'm saying, we're facing a continuum of risks and chances in life. In the end, everyone has to draw their own lines with the limited information we have.

If I know there is a possibly of increased risk (though not conclusive) of getting hit by a truck by crossing a certain road….I’ll avoid that road. I agree with you everyone needs to make up their own opinion based on the facts and defend it unless something or someone convinces them otherwise.

Thank you for the discussion John. I would like to see studies done on healthy people someday.

Yours In Health