Ervaringen van kankerpatienten met complementaire aanpak kunt u lezen onder uw verhaal - patienten ervaringen. Ervaringen van kankerpatienten met complementaire aanpak op video kunt u bekijken als u hier klikt of op videoknop linksbovenaan deze pagina. Voorlichtigingsfilmpjes over verschillende vormen van complementaire aanpak kunt u ook bekijken op de website van het SNFK = Stichting Nationaal Fonds tegen Kanker.
Broccoli verliest beschermende werking (sulfarofaan verdwijnt nagenoeg) tegen kanker als het gekookt wordt gegeten. Dit tonen Nederlandse onderzoekers van TNO aan in een studie. Als broccoli wordt gekookt dan neemt de persoon die de broccoli eet nog maar 3,4% op tegen 37 % als broccoli rauw wordt gegeten. Wij menen dat wanneer je broccoli beetgaar stoomt en bv. van het stoomvocht een sausje maakt de vitamines enz. beter worden bewaard en ingenomen maar of dat ook voor dit sulforane geldt durf ik niet te zeggen, al lijkt de kookduur wel degelijk van invloed. Hier respectievelijk een artikel over deze studie en daaronder het abstract van de Nederlandse studie en daaronder een ander studie die aantoont hoe korter broccoli en andere groenten worden gekookt hoe meer de persoon die deze groenten eet opneemt aan vitamines en ook sulfarofaan.
Raw broccoli best for anti-cancer potential: study
By Stephen Daniells, 28-Oct-2008
Consuming cooked or processed broccoli may result in less of the potential anti-cancer compounds being available for absorption, suggests a new study from TNO Quality of Life.
Consumption of the cooked vegetable led to lower levels of a compound called sulforaphane being measured in the blood and urine, compared to consuming raw broccoli, according to findings published in the Journal of Agricultural and Food Chemistry.
The bioavailability of sulforaphane was calculated to be 37 per cent from the raw vegetable, and only 3.4 per cent from cooked broccoli, reported Martijn Vermeulen and co-workers from TNO Quality of Life.
The study extends out understanding of the potential anti-cancer benefits of broccoli, and may offer important information to companies involved in the production of broccoli extracts for the functional food and dietary supplements industry.
Sulforaphane is the main isothiocyanate from broccoli. The tissue of cruciferous vegetables, like broccoli, cauliflower, cabbage and Brussels sprouts, contain high levels of the active plant chemicals glucosinolates. These are metabolised by the body into isothiocyanates, which are known to be powerful anti-carcinogens.
Glucoraphanin, also known as sulforaphane glucosinolate (SGS), is the precursor of sulforaphane.
The Netherlands-based researchers recruited eight men to participate in the study. The men consumed 200 grams of crushed raw or cooked broccoli with a warm meal. The randomised, free-living, open cross-over trial used blood and urine levels of sulforaphane to elucidate the bioavailability of the proposed anti-carcinogen.
Vermeulen and co-workers report that the glucoraphanin content of the cooked broccoli was 61.4 micromoles, while glucoiberin and glucobrassicins were also detected. On the other hand, raw broccoli contained 9.92 micromoles of sulforaphane, and no other isothiocyanates.
“The sulforaphane content of raw broccoli was lower than the glucoraphanin content of cooked broccoli, 9.92 and 61.4 micromoles, respectively. It seems that the conversion from glucosinolate to isothiocyanate was incomplete or that another reaction occurred,” they wrote.
In addition to less sulforaphane being measured in the blood and urine when cooked broccoli was consumed, compared to raw broccoli, the absorption of the compound was delayed when the broccoli was cooked: the optimal levels were observed after six hours for the cooked broccoli, compared to only 1.6 hours after consumption of raw broccoli.
“Consumption of raw broccoli resulted in faster absorption, higher bioavailability, and higher peak plasma amounts of sulforaphane, compared to cooked broccoli,” wrote the researchers.
“In future research, care should be taken that glucoraphanin is not hydrolyzed into other metabolites when broccoli is crushed,” they concluded.
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, ASAP Article, doi: 10.1021/jf801989e
“Bioavailability and Kinetics of Sulforaphane in Humans after Consumption of Cooked versus Raw Broccoli”
Authors: M. Vermeulen, I.W.A.A. Klopping-Ketelaars, R. van den Berg, W.H.J. Vaes
1: J Agric Food Chem. 2008 Oct 25. [Epub ahead of print]
Bioavailability and Kinetics of Sulforaphane in Humans after Consumption of Cooked versus Raw Broccoli.
Martijn.Vermeulen@TNO.NL.
The aim of this study was to determine the bioavailability and kinetics of the supposed anticarcinogen sulforaphane, the hydrolysis product of glucoraphanin, from raw and cooked broccoli. Eight men consumed 200 g of crushed broccoli, raw or cooked, with a warm meal in a randomized, free-living, open cross-over trial. Higher amounts of sulforaphane were found in the blood and urine when broccoli was eaten raw (bioavailability of 37%) versus cooked (3.4%, p = 0.002). Absorption of sulforaphane was delayed when cooked broccoli was consumed (peak plasma time = 6 h) versus raw broccoli (1.6 h, p = 0.001). Excretion half-lives were comparable, 2.6 and 2.4 h on average, for raw and cooked broccoli, respectively ( p = 0.5). This study gives complete kinetic data and shows that consumption of raw broccoli results in faster absorption, higher bioavailability, and higher peak plasma amounts of sulforaphane, compared to cooked broccoli.
PMID: 18950181 [PubMed - as supplied by publisher]
1: Br J Nutr. 2007 Apr;97(4):644-52.
Effect of meal composition and cooking duration on the fate of sulforaphane following consumption of broccoli by healthy human subjects.
School of Life Sciences, The Robert Gordon University, St Andrew Street, Aberdeen, AB25 1HG, UK. v.rungapamestry@macaulay.ac.uk
The isothiocyanate, sulforaphane, has been implicated in the cancer-protective effects of brassica vegetables. When broccoli is consumed, sulforaphane is released from hydrolysis of glucoraphanin by plant myrosinase and/or colonic microbiota. The influence of meal composition and broccoli-cooking duration on isothiocyanate uptake was investigated in a designed experiment. Volunteers (n 12) were each offered a meal, with or without beef, together with 150 g lightly cooked broccoli (microwaved 2.0 min) or fully cooked broccoli (microwaved 5.5 min), or a broccoli seed extract. They received 3 g mustard containing pre-formed allyl isothiocyanate (AITC) with each meal. Urinary output of allyl (AMA) and sulforaphane (SFMA) mercapturic acids, the biomarkers of production of AITC and sulforaphane respectively, were measured for 24 h after meal consumption. The estimated yield of sulforaphane in vivo was about 3-fold higher after consumption of lightly cooked broccoli than fully cooked broccoli. Absorption of AITC from mustard was about 1.3-fold higher following consumption of the meat-containing meal compared with the non meat-containing alternative. The meal matrix did not significantly influence the hydrolysis of glucoraphanin and its excretion as SFMA from broccoli. Isothiocyanates may interact with the meal matrix to a greater extent if they are ingested pre-formed rather than after their production from hydrolysis of glucosinolates in vivo. The main influence on the production of isothiocyanates in vivo is the way in which brassica vegetables are cooked, rather than the effect of the meal matrix.
PMID: 17349076 [PubMed - indexed for MEDLINE]
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