Molecula Silver Explained
a.
The Three Main Grades of Processed Silver
b.
The Silver Problem
c.
Molecula Silver is high in nitrates, why?
Molecula Silver Explained
a.
The Three Main Grades of Processed Silver
b.
The Silver Problem
c.
Molecula Silver is high in nitrates, why?
Molecula Silver is high in nitrates, why?
Health Stream Literature summary - Issue 15 September 1999
Dietary nitrate in man: friend or foe?
McKnight GM, Duncan CW, Leifert C, Golden MH. Br J Nutrit. (1999) 81(5) p349 -358.
A number of adverse human health effects have been attributed to nitrate, including infantile methemoglobinaemia, carcinogenesis and possibly teratogenesis. Government and public concern has led to increasingly strict regulations over nitrate concentrations in food and water, which may soon threaten crop production in some areas of northern Europe.
However, recent studies have suggested that nitrate may in fact have a beneficial effect on the physiology of the intestinal tract and have a protective effect against food and waterborne pathogens. Nitrate may also be protective against ischaemic heart disease, and the evidence for supposed harmful effects has not been substantiated by recent epidemiological studies.
Understanding the metabolism of dietary nitrate is important when evaluating its harmful or beneficial effects. Ingested nitrate is absorbed into the bloodstream from the stomach and small intestine, then concentrated by the salivary glands and secreted in saliva at 10 times the plasma concentration. About 25% of dietary nitrate is recirculated in this way. Specialised bacteria on the tongue rapidly reduce nitrate to nitrite, which is then swallowed and reduced to nitric oxide and other oxides of nitrogen by the stomach acid. The existence of an active recycling system for nitrate suggests that some overall evolutionary benefit must be conferred by this mechanism.
Concerns over the role of nitrate in drinking water in methemoglobinaemia have been reduced by recent findings that the effect is associated with the presence nitrate reducing bacteria which produce nitrite. It also appears that young infants do not carry the oral bacteria necessary for conversion of nitrate to nitrite, although it is not known at what age the plasma/saliva recirculation of nitrate begins.
Cancer risks from nitrate have been postulated on the basis that carginogenic nitrosamines may be formed in the stomach, however epidemiological studies have given inconsistent results. On the other hand, it is well established that intake of high amounts of salads and vegetables (which are rich in nitrates) is associated with an overall reduction in cancer risks. Vegetarian people have lower mortality from stomach cancer than omnivores, but have an average nitrate intake three times higher. Recent research has also shown that physiological conditions in the stomach and digestive tract are unlikely to permit nitrosamine formation at dietary nitrate levels.
Animal studies have suggested teratogenic effects with high doses of nitrite, but not nitrate. Human epidemiological studies have given conflicting results on correlations between rates of congenital defects and nitrate in drinking water, and there has been one report of a decrease in spontaneous abortion rate associated with nitrate. While studies in this area are scanty, they do not support an association of nitrate with teratogenesis.
Possible mechanisms for favorable effects of dietary nitrate are discussed. Consumption of a meal high in nitrate produces nitrite which in combination with stomach acid, has an antimicrobial affect on many gastrointestinal pathogens such as Salmonella. Preliminary evidence of the role of nitrates in cardiovascular protection has been suggested by a small study showing a reduction in platelet aggregation, and the authors suggest this may partially explain the benefits of high vegetable intake. When a high-nitrate diet is eaten, nitrate may also have a gastroprotective effect by causing enhanced emptying and rapid recovery of gastric acidity and modulating of microcirculation.
The authors propose that the salivary recirculation of dietary nitrate may be an important non-immunological host defense mechanism, and that nitrate may also provide substantial benefits for intestinal and cardiovascular function. Recognition of these benefits may result in new modes of treatment for illness of the mouth, stomach, intestine and cardiovascular system in both human medicine and animal husbandry.
Comment: The two above articles draw together many strands of evidence and argue that the labeling of nitrate as a "harmful contaminant" of drinking water is unwarranted. The evidence presented appears to remove many of the health concerns previously held about nitrate. In fact, if McKnight et al. are correct in their conclusions, nitrate may well acquire a place in future as an important therapeutic agent.