Some nitrogenous compounds, such as nitrate, since long have been and still are considered potential human health hazards; especially when given to infants, nitrates in bacterially contaminated well water could be reduced to nitrite and cause the condition known as methemoglobinemia [20]. However, the exposure studies on children and adults have not confirmed that nitrate intake is associated with methemoglobinemia [36] and [37], and alternative explanations for methemoglobinemia in infants has been suggested such as gastroenteritis and associated iNOS-mediated production of nitric oxide induced by bacteria contaminated water [38]. The data supporting the toxicity of nitrates and nitrites for healthy adolescent and adult populations is questionable, as is the scientific basis for exposure regulations for nitrate and nitrite [20], [21] and [39]. Another issue, especially in Japan, is that ingested nitrites may react with secondary amines or N-alkylamides to generate carcinogenic N-nitroso compounds (NOCs) [40] and the prevalence of gastric cancer in the Japanese population is very high. Although shown in animal models [41], the proof in humans has not been substantiated. Furthermore, the nitrites in foods may be “neutralized” if accompanied by vitamin C, an antioxidant that inhibits the nitrosation effect of nitrites on secondary amines [42]. Clearly, more research is needed to address whether nitrate and nitrite intake is associated with increased cancer risk.