Nitrate INFORMER Vegetable Study

NCT05886023 | Completed

• 1 other identifier: 2023-04297-BONDONNO
• Study Type: interventional
• Target: 27
• Locations: 1 country
• Sites: 1

Brief Summary

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 vegetables with high nitrate content and vegetables with a low nitrate content.

Conditions

Health Risk Behaviors

Outcome Measures

Primary Outcomes (2)

• N-nitrosamines in urine post intervention (up to 24 hours)

  Participants will be provided with sterilized containers and instructions to collect all urine until 24 hours post intervention\> Urine aliquots will be frozen at -80°C until analysis. N-nitrosamines will be measured by gas chromatography mass spectrometry (GCMS).

  At each clinic visit, all urine from the start of intervention up till 24 hours will be collected

• N-nitrosamines in stool samples post intervention (up to 24 hours)

  Participants will be provided with instructions and a stool sample collection pack (collection bags, cable ties, large zip lock bags, freezer ice blocks and a designated cooler bag for transport). Collected stool samples will be weighed and frozen at -80°C until analysis. N-nitrosamines will be measured by gas chromatography mass spectrometry (GCMS).

  At each clinic visit, all stool samples from the start of intervention up till 24 hours will be collected

Study Arms (2)

Active Intervention

ACTIVE COMPARATOR

The intervention comprises vegetable burger containing high nitrate vegetables (100g of spinach, \~1000mg/kg FW nitrate) on white bread sandwich, provided at breakfast and lunch.

Dietary Supplement: High nitrate vegetables

Control Intervention

PLACEBO COMPARATOR

The intervention comprises vegetable burger containing low nitrate vegetables (200g of peas, sweet corn, \< 30 mg/kg FW nitrate) on white bread sandwich, provided at breakfast and lunch.

Dietary Supplement: Low nitrate vegetables

Interventions

High nitrate vegetables DIETARY_SUPPLEMENT

Vegetable burger containing high nitrate vegetables

Active Intervention

Low nitrate vegetables DIETARY_SUPPLEMENT

Vegetable burger containing to low nitrate vegetables

Control Intervention

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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 75 years old
• healthy, ambulant, community-dwelling
• with no history of major chronic disease

You may not qualify if:

• Individuals volunteering to participate in the study will be excluded according to the following criteria:
• current or recent (\<12 months) smoking
• body mass index (BMI) \<18 or \> 35 kg/m2
• systolic blood pressure \> 160 mmHg
• diastolic blood pressure \> 100 mmHg
• any major illness such as cancer, psychiatric illness, diagnosed diabetes
• use 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 use
• alcohol consumption \> 30g/day
• who are pregnant, lactating, or wishing to become pregnant during the study
• use of antibiotics within the previous 12 weeks of the study
• regular use of mouthwash and not willing to cease mouthwash use for the duration of the study participation on other research studies
• major gastrointestinal tract condition e.g. Crohns disease and inflammatory bowel disease and inability or unwillingness to follow the study protocol.

Sponsors & Collaborators

• Edith Cowan University: lead
• The University of Western Australia: collaborator
• Flinders University: collaborator

Study Sites (1)

Royal Perth Hospital Research Foundation

Perth, Western Australia, 6000, Australia

Location

Related Publications (5)

• Lundberg JO, Weitzberg E. NO-synthase independent NO generation in mammals. Biochem Biophys Res Commun. 2010 May 21;396(1):39-45. doi: 10.1016/j.bbrc.2010.02.136.

  PMID: 20494108 RESULT

• Blekkenhorst LC, Bondonno NP, Liu AH, Ward NC, Prince RL, Lewis JR, Devine A, Croft KD, Hodgson JM, Bondonno CP. Nitrate, the oral microbiome, and cardiovascular health: a systematic literature review of human and animal studies. Am J Clin Nutr. 2018 Apr 1;107(4):504-522. doi: 10.1093/ajcn/nqx046.

  PMID: 29635489 RESULT

• Spiegelhalder B, Eisenbrand G, Preussmann R. Influence of dietary nitrate on nitrite content of human saliva: possible relevance to in vivo formation of N-nitroso compounds. Food Cosmet Toxicol. 1976 Dec;14(6):545-8. doi: 10.1016/s0015-6264(76)80005-3. No abstract available.

  PMID: 1017769 RESULT

• Gangolli SD, van den Brandt PA, Feron VJ, Janzowsky C, Koeman JH, Speijers GJ, Spiegelhalder B, Walker R, Wisnok JS. Nitrate, nitrite and N-nitroso compounds. Eur J Pharmacol. 1994 Nov 1;292(1):1-38. doi: 10.1016/0926-6917(94)90022-1.

  PMID: 7867685 RESULT

• Blekkenhorst LC, Prince RL, Ward NC, Croft KD, Lewis JR, Devine A, Shinde S, Woodman RJ, Hodgson JM, Bondonno CP. Development of a reference database for assessing dietary nitrate in vegetables. Mol Nutr Food Res. 2017 Aug;61(8). doi: 10.1002/mnfr.201600982. Epub 2017 May 3.

  PMID: 28105786 RESULT

MeSH Terms

Conditions

Health Risk Behaviors

Condition Hierarchy (Ancestors)

Health Behavior; Behavior

Study Officials

• Catherine Bondonno, PhD

  Edith Cowan University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Given the nature of the interventions, participants, and the investigators responsible for delivering the interventions will be unblinded throughout the trial. However, all researchers performing the laboratory analyses and data analyses will be blinded to the interventions that the participants received until after the data analysis has been performed.
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: prospective, mono-centre, randomised, controlled, crossover study

Study Record Dates

• First Submitted: May 23, 2023
• First Posted: June 2, 2023
• Study Start: June 26, 2023
• Primary Completion: October 31, 2023
• Study Completion: October 31, 2023
• Last Updated: April 16, 2024

Record last verified: 2024-04

Data Sharing

• IPD Sharing: Will not share

Locations

AU (1)