6 april 2014 kl 12:18
T Springsson - Natriumet du får i dig om du äter rödbetor omvandlas också till nitrit, du får dock skilja på nitrit och nitrosaminer. Jag tror du har blandat ihop begreppen lite?
Så som du beskriver det så är alla vegetarianer i riskzonen eftersom majoriteten av nitrat intas via gröna bladväxter och rotfrukter.
Kopplingen nitrat-cancer uppstod 1976 från ett forkarteam lett av en man vid namn Spiegelhalder då man såg kopplingar vid väldigt höga intag av nitrit hos djur och cancerutveckling. Mängderna vad dock extrema och resultaten har aldrig kunnat påvisas hos människor. Låt mig citera lite från de ledande organisationerna:
"Concern for dietary nitrate arose in 1976,when Spiegelhalder et al. [116] and Tannenbaum et al. [115], both independently suggested that conversion to nitrite in the enterosalivary circulation, could result in the formation of N-nitrosoamines. Whilst N-nitroso compounds have repeatedly been shown to be carcinogenic in animals [200, 204],reviews such as the 2003 Joint FAO/WHO Expert Committee on Food Additives (JEFCA) of the epidemiological and toxicological studies in humans have failed to establish a definite link between nitrate intake and risk of developing cancer [205–207].
"TheWorld Cancer Research Fund/American Institute of Cancer Research, Second Report 2007, did not show any increased risk of cancers, such as stomach or ovarian, with green leafy vegetables, and even showed trends towards beneficial effects [209]. Indeed, the recommendation from the report was to eat at least five portions/servings (at least 400 g) of a variety of non-starchy vegetables and fruits every day, specifically including green, leafy vegetables. Some epidemiological studies have shown that fruit and vegetables have protective effects against certain cancers [210]."
Koppling finns men bara på epidemiologiskt plan, inga samband har visats vara kausala men å andra sidan så har det inte forskats tillräckligt mycket än enligt mitt tycke.
"The National Institutes of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study prospectively studied large cohorts and have recently identified some potential associations between high nitrate intake, assessed using a 124-item food frequency questionnaire, and epithelial ovarian cancer [220] and thyroid cancer (nitrate competitively inhibits iodide uptake) [221]. However, no associations have been demonstrated between total nitrate or nitrite intake (processed meat) and pancreatic cancer [222], adenocarcinoma of the stomach and oesophagus [223], non-Hodgkin lymphoma risk overall [224], renal cell carcinoma [225] or bladder cancer.However, most of the associations are small, do not prove causality and should be interpreted with extreme caution. The limitations of extrapolating from epidemiological studies has been recently reviewed by Milkowski et al. [32]. Thus, the lack of data concerning the long term effects of dietary nitrate is a limitation,and this will need to be addressed in future trials."
Rödbetor verkar snarare vara positivt.
"Beetrootmay represent a particularly safe source of dietary nitrate, with the potential to reduce, rather than increase cancer risk.Indeed,beetroot juice has even achieved a considerable degree of acceptance as an alternative medicine for cancer patients [231, 232]. However, the mechanisms require further clarification."
