Nitrate INFORMER Water Study

Nitrate is a controversial component of vegetables, meat, and drinking water. The now well-established benefits of nitrate, through the enterosalivary nitrate-nitrite-nitric oxide (NO) pathway, on cardiovascular risk factors and long-term cardiovascular disease risk are tarnished by a continuing concern about a link between nitrate ingestion and cancer. This can result in misguided advice to avoid consumption of high-nitrate leafy green vegetables by both the media and the scientific literature. A recent media headline stated, "Cancer alert over rocket: trendy salad leaves exceed safe levels of carcinogenic nitrates in one in every ten samples". One scientific review stated, "the presence of nitrate in vegetables, as in water and generally in other foods, is a serious threat to man's health". Controversy in the literature, and gaps in the knowledge are leading to confusing messages around vegetables that may play a critical role in cardiovascular health.The major dietary sources of nitrate are vegetables, meat, and drinking water. Source of nitrate could be a crucial factor determining whether the consumption of nitrate is linked with beneficial (such as improving cardiovascular health) versus harmful (N-nitrosamine formation) effects. For example, unlike meat and water-derived nitrate, vegetables contain high levels of vitamin C and/or polyphenols that may inhibit the production of N-nitrosamines. So far, no study has investigated the formation of N-nitrosamines after consumption of these different sources in humans. This study will compare N-nitrosamine formation after intake of water with and without added nitrate.

Inclusion Criteria:The recruitment will be as inclusive as possible so that the results are relevant to much of the general population. Twenty-five men and women will be recruited from the Perth general population according to the following criteria:aged between 18 to 70 years oldhealthy, ambulant, community-dwellingwith no history of major chronic diseaseExclusion Criteria:Individuals volunteering to participate in the study will be excluded according to the following criteria:current or recent (<12 months) smokingbody mass index (BMI) <18 or > 35 kg/m2systolic blood pressure > 160 mmHgdiastolic blood pressure > 100 mmHgany major illness such as cancer, psychiatric illness, diagnosed diabetesuse of any of the following medications: statins, antihypertensives, nitric oxide donors, antithrombotic medication, anti-coagulant medication, anti-arrhythmic drugs, beta-blockers, regular aspirin use, regular proton pump inhibitor usealcohol consumption > 30g/daywho are pregnant, lactating, or wishing to become pregnant during the studyuse of antibiotics within the previous 12 weeks of the studyregular use of mouthwash and not willing to cease mouthwash use for the duration of the study participation on other research studiesmajor gastrointestinal tract condition e.g. Crohns disease and inflammatory bowel disease and inability or unwillingness to follow the study protocol.