Home / Nieuws / ...

 

Vette voeding doet de werking van antioxidanten verminderen.*

Uit Engels onderzoek blijkt dat vet in de voeding de werking van antioxidanten in de maag doet verminderen. De gevolgen zijn dat daardoor de kans op kanker in de maag sterk doet verhogen. In ons speeksel kunnen nitraten uit de voeding omgezet worden in nitrieten. Als die nitrieten in de maag komen worden, onder invloed van het maagzuur, deze omgezet in nitroverbindingen die kunnen leiden tot carcinogene N-nitroverbindingen. Antioxidanten in de voeding zoals vitamine C voorkomen dat deze laatste omzettingen kunnen plaats vinden door de nitroverbindingen om te zetten in stikstofoxide (NO). Vetten doen echter een reactie teweeg brengen tussen het NO en zuurstof waardoor weer nitroverbindingen ontstaan en dus het werk van de antioxidant teniet gedaan wordt.

Fat In Stomach Overrides Effects Of Vitamin C

Fats in our stomach may reduce the protective effects of antioxidants such as vitamin C. Scientists at the University of Glasgow found that in the presence of lipid the ability of antioxidants, such as ascorbic acid (the active component of vitamin C), to protect against the generation of potential cancer-forming compounds in the stomach is less than when no lipids are present. "Our results illustrate how diet can influence gastric biochemistry", says Emilie Combet, the post-doctoral researcher working on the project, who presented her results at the Society of Experimental Biology's Annual Main Meeting.
The incidence of cancer of the proximal stomach has been increasing over the last 20 years for which environmental factors, such as diet, certainly play a part. Nitrite, which is present in our saliva and is derived from nitrate in our diet, is thought to be a pre-carcinogen for gastric cancer. When it is swallowed and enters the acidic environment of the stomach, nitrite spontaneously forms nitrosating species able to convert a range of targets, such as secondary amines and bile acids, into carcinogenic N-nitrosocompounds. Antioxidants such as ascorbic acid protect against the formation of these nitrosocompounds by converting the nitrosating species back into nitric oxide (NO). However, NO diffuses rapidly to lipids, where it reacts with oxygen to reform nitrosating species. The presence of lipids therefore overrides the protective effect of vitamin C against the formation of harmful compounds.
###
The research, funded by the World Cancer Research Fund, will investigate further the impact of dietary lipids on gastric biochemistry and the fate of nitrite, in relation to malignancies of the upper stomach.
(Mei 2007)

 

 

 

    Printen