Guest guest Posted November 14, 2004 Report Share Posted November 14, 2004 I think I dislike the tone of this article -- I'd be interested in tracking down their granting agencies to see if there's a 'party line'... I would point out, the suggestion that toxins the have been in our food chain for thousands of years may not be significant for us, even if they are significant for other species (rodents -- same kind of reason why we don't turn to rats for vitamin C studies). by virtue of their own reasons in their note that fruit and vegetable consumption is associated with lower cancer rates in human, should we not look to population studies for cancer rates associated with manmade pesticides. I may be grossly mistaken, but I believe such studies point to the same thing we all hold as common knowledge... Someone correct me if I'm wrong (and besides, while I'd like to avoid aflatoxins, I do love the caffeine...). Cheers, > -----Original Message----- > From: Dowling [mailto:christopher.a.dowling@...] > Sent: Sunday, November 14, 2004 2:38 AM > > Subject: Re: [ ] Chromium Supplementation > > > > More on this topic: > > NATURE'S PESTICIDES: MUTAGENICITY AND CARCINOGENICITY > > " Plants are not just food for animals. . . The world is not green. It > is colored lectin, tannin, cyanide, caffeine, aflatoxin, and > canavanine " > [Janzen (16)]. > > Dietary Pesticides are 99.99% All Natural. Nature's pesticides are one > important subset of natural chemicals. Plants produce toxins to > protect themselves against fungi, insects, and animal predators > (5,16-23). Tens of thousands of these natural pesticides have been > discovered, and every species of plant analyzed contains its own set > of perhaps a few dozen toxins. When plants are stressed or damaged, > such as during a pest attack, they may greatly increase their natural > pesticide levels, occasionally to levels that can be acutely toxic to > humans. We estimate that Americans eat about 1.5 g of natural > pesticides per person per day, which is about 10,000 times more than > they eat of manmade pesticide residues (see below). As referenced in > this paper (see 16-21 and Legends to Table 1, 2) there is a very large > literature on natural toxins in plants and their role in plant > defenses. The human intake of these toxins varies markedly with diet > and would be higher in vegetarians. Our estimate of 1.5 g of natural > pesticides per person per day is based on the content of toxins in the > major plant foods (e.g. 13 g roasted coffee per person per day > contains about 765 mg of chlorogenic acid, neochlorogenic acid, > caffeic acid, and caffeine; see (22,23) and Table 2). Phenolics from > other plants are estimated to contribute another several hundred mg of > toxins. Flavonoids and glucosinolates account for several hundred mg; > potato and tomato toxins may contribute another hundred, and saponins > from legumes another hundred. Grains such as white flour and white > rice contribute very little, but whole wheat, brown rice, corn (maize) > may contribute several hundred mg more. The percentage of a plant's > weight that is toxin varies, but a few percent of dry weight is a > reasonable estimate: e.g. 1.5% of alfalfa sprouts is canavanine and 4% > of coffee beans is phenolics. However, the percentage in some plant > cultivars is lower, e.g. potatoes and tomatoes. > > Concentrations of natural pesticides in plants are usually measured in > parts per thousand or million (16-23) rather than parts per billion > (ppb), the usual concentration of synthetic pesticide residues or of > water pollutants (1,24). We estimate that humans ingest roughly 5,000 > to 10,000 different natural pesticides and their breakdown products > (16-23). For example, Table 1 shows 49 natural pesticides (and > metabolites) that are ingested when eating cabbage and indicates how > few have been tested for carcinogenicity or clastogenicity. Lima beans > contain a completely different array of 23 natural toxins that, in > stressed plants, range in concentration from 0.2 to 33 parts per > thousand fresh weight; none appears to have been tested yet for > carcinogenicity or teratogenicity (19). Many Leguminosae contain > canavanine, a toxic arginine analog that, after being eaten by > animals, is incorporated into protein in place of arginine. Feeding > alfalfa sprouts (1.5 % canavanine dry weight) or canavanine to monkeys > causes a lupus erythematosus-like syndrome (44). Lupus in man is > characterized by a defect in the immune system that is associated with > autoimmunity, antinuclear antibodies, chromosome breaks, and various > types of pathology. The toxicity of non-food plants is well known: > plants are among the most commonly ingested poisonous substances for > children under five. > > Surprisingly few plant toxins have been tested for carcinogenicity > (10-13,45). Among 1052 chemicals tested in at least one species in > chronic cancer tests, only 52 are naturally occurring plant pesticides > (10-13). Among these, about half (27/52) are carcinogenic. Even though > only a tiny proportion of plant toxins in our diet has been tested so > far, the 27 natural pesticides that are rodent carcinogens are present > in the following foods: anise, apple, apricot, banana, basil, > broccoli, Brussels sprouts, cabbage, cantaloupe, caraway, carrot, > cauliflower, celery, cherries, cinnamon, cloves, cocoa, coffee, > collard greens, comfrey herb tea, currants, dill, eggplant, endive, > fennel, grapefruit juice, grapes, guava, honey, honeydew melon, > horseradish, kale, lentils, lettuce, mango, mushrooms, mustard, > nutmeg, orange juice, parsley, parsnip, peach, pear, peas, black > pepper, pineapple, plum, potato, radish, raspberries, rosemary, sesame > seeds, tarragon, tea, tomato, and turnip. Thus, it is probable that > almost every fruit and vegetable in the supermarket contains natural > plant pesticides that are rodent carcinogens. The levels of these 27 > rodent carcinogens in the above plants are commonly thousands of times > higher than the levels of manmade pesticides. Table 2 shows a variety > of natural pesticides that are rodent carcinogens occurring in the ppm > range in plant foods. > > The catechol-type phenolics such as tannins, and caffeic acid and its > esters (chlorogenic and neochlorogenic acids), are more widespread in > plant species than other natural pesticides (e.g., Table 1 and 2). It > may be that these phenolics have an antimicrobial role analogous to > the respiratory burst of oxygen radicals from mammalian phagocytic > cells. The phenolics oxidize when a plant is wounded, yielding a burst > of mutagenic oxygen radicals, e.g. the browning when an apple is cut. > > Caution is necessary in interpreting the implications of the > occurrence in the diet of natural pesticides that are rodent > carcinogens. It is not argued here that these dietary exposures are > necessarily of much relevance to human cancer. Indeed, a diet rich in > fruit and vegetables is associated with lower cancer rates (86,87). > This may be because anticarcinogenic vitamins and antioxidants come > from plants (86,87). What is important in our analysis is that > exposures to natural rodent carcinogens may cast doubt on the > relevance of far lower levels of exposures to synthetic rodent > carcinogens. > > Residues of Manmade Pesticides. A National Research Council report has > discussed the regulation of synthetic pesticides that are rodent > carcinogens, but ignored natural pesticides (88). The U.S. Food and > Drug Administration (FDA) has assayed food for 200 chemicals including > the manmade pesticide residues thought to be of greatest importance > and the residues of some industrial chemicals such as polychlorinated > biphenyls (PCBs) (24). FDA found residues for 105 of these chemicals: > the U.S. intake of the sum of these 105 chemicals averages about 0.09 > mg per person per day, which we compare to 1.5 g of natural pesticides > (i.e. 99.99% natural). Other analyses of synthetic pesticide residues > are similar (90). About half (0.04 mg) of this daily intake of > synthetic pesticides is composed of 4 chemicals (24) that were not > carcinogenic in rodent tests: ethylhexyl diphenyl phosphate, > chlorpropham, malathion, and dicloran (10,89). Thus, the intake of > rodent carcinogens from synthetic residues is only about 0.05 mg a day > (averaging about 0.06 ppm in plant food) even if one assumes that all > the other residues are carcinogenic in rodents (which is unlikely). > > Cooking food. The cooking of food is also a major dietary source of > potential rodent carcinogens. Cooking produces about 2 g per person > per day of mostly untested burnt material that contains many rodent > carcinogens, e.g. polycyclic hydrocarbons (81,91) heterocyclic amines > (92,93), furfural (22,23), nitrosamines and nitroaromatics (1,94), as > well as a plethora of mutagens (91-95). Thus, the number and amounts > of carcinogenic (or total) manmade pesticide residues appear to be > minimal compared to the background of naturally-occurring chemicals in > the diet. Roasted coffee, for example, is known to contain 826 > volatile chemicals (22); 21 have been tested chronically and 16 are > rodent carcinogens (10-13); caffeic acid, a non-volatile rodent > carcinogen, is also present (Table 2). A typical cup of coffee > contains at least 10 mg (40 ppm) of rodent carcinogens (mostly caffeic > acid, catechol, furfural, hydroquinone, and hydrogen peroxide)(Table > 2). The evidence on coffee and human health has been recently > reviewed, and the evidence to date is not sufficient to show that > coffee is a risk factor for cancer in humans (81,86). The same caution > about the implications for humans of rodent carcinogens in the diet > that were discussed above for nature's pesticides apply to coffee and > the products of cooked food. > > Clastogenicity and Mutagenicity Studies. Results from in vitro studies > also indicate that the natural world should not be ignored and that > positive results are commonly observed in high-dose protocols. For > example, Ishidate et al. (26) reviewed experiments on the > clastogenicity (ability to break chromosomes) of 951 chemicals in > mammalian cell cultures. Of these 951 chemicals, we identified 72 as > natural plant pesticides: 35 (48%) were positive for clastogenicity in > at least one test. This is similar to the results for the remaining > chemicals, of which 467/879 (53%) were positive in at least one test. > > Of particular interest are the levels at which some of the > carcinogenic plant toxins in Table 2 were clastogenic (26) a) Allyl > isothiocyanate was clastogenic at a concentration of 0.0005 ppm, which > is about 200,000 times less than the concentration of sinigrin, its > glucosinolate, in cabbage. Allyl isothiocyanate was among the most > potent chemicals in the compendium (26), and is also effective at > unusually low levels in transforming (96) and mutating animal cells > (30). (See also the discussion of cancer tests in Table 1.) Safrole > was clastogenic at a concentration of about 100 ppm, which is 30 times > less than the concentration in nutmeg, and roughly equal to the > concentration in black pepper. The rodent carcinogens safrole and > estragole, and a number of other related dietary natural pesticides > that have not been tested in animal cancer tests, have been shown to > produce DNA adducts in mice (97). c) Caffeic acid was clastogenic at a > concentration of 260 and 500 ppm, which is less than its concentration > in roasted coffee beans and close to its concentration in apples, > lettuce, endive, and potato skin. Chlorogenic acid, a precursor of > caffeic acid, was clastogenic at a concentration of 150 ppm, which is > 100 times less than its concentration in roasted coffee beans and > similar to its concentration in apples, pears, plums, peaches, > cherries and apricots. Chlorogenic acid and its metabolite caffeic > acid are also mutagens (Table 1). The genotoxic activity of coffee to > mammalian cells has been demonstrated (98). > > The carcinogenicity and mutagenicity of many plant pesticides have > been recently reviewed (45): 5- and 8-methoxypsoralen are light > activated mutagens (17); benzyl acetate and ethyl acrylate mutate > mouse lymphoma cells (30). Plant phenolics such as caffeic acid, > chlorogenic acid, and tannins (esters of gallic acid) have been > reviewed for their mutagenicity and anti-mutagenicity, clastogenicity, > and carcinogenicity (99). > > ACKNOWLEDGMENT > > We are indebted to R. Peto, N. B. Manley, T. H. Slone, C. Wehr, R. > Beier, L. W. Wattenberg, R. Hall, T. Jukes, G. R. Fenwick, J. > Caldwell, J. Duke, C. VanEtten, D. Freedman, R. Prokopy, and N. Ito. > This work was supported by National Cancer Institute Outstanding > Investigator Grant CA39910, by National Institute of Environmental > Health Sciences Center Grant ES01896; Contract No. DE-AC03-76SF00098: > Director, Office of Energy Research, Office of Health and > Environmental Research, Division of the U.S. Department of Energy. We > dedicate this paper to the memory of Havender. > > Original Source: NIEHS Center for Environmental Health Sciences at the > University of California, Bereley > http://ist-socrates.berkeley.edu/mutagen/ames.PNASII.html > > > > > On Sun, 14 Nov 2004 04:23:31 -0500, Dowling > <christopher.a.dowling@...> wrote: > > Have to note this is a press release by a company selling chromium > > supplements, though. So taken with the proverbial grain of salt? > > > > > > > > > > On Sun, 14 Nov 2004 04:20:44 -0000, Rodney > <perspect1111@...> wrote: > > > > > > > > > Hi folks: > > > > > > More stuff suggesting chromium supplementation does seem to be a good > > > idea. I take 200 mcg once a week in the form of picolinate. fwiw. > > > > > > http://www.prnewswire.com/cgi-bin/stories.pl? > > > ACCT=109 & STORY=/www/story/11-11-2004/0002404122 & EDATE > > > > > > http://snipurl.com/amjg > > > > > > Rodney. > > > > > > > > > > > > Quote Link to comment Share on other sites More sharing options...
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