NCT05075720

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 meat with and without added nitrate.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
25

participants targeted

Target at below P25 for not_applicable

Timeline
Completed

Started Sep 2022

Shorter than P25 for not_applicable

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

August 30, 2021

Completed
1 month until next milestone

First Posted

Study publicly available on registry

October 13, 2021

Completed
12 months until next milestone

Study Start

First participant enrolled

September 27, 2022

Completed
3 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 13, 2022

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 13, 2022

Completed
Last Updated

February 1, 2023

Status Verified

January 1, 2023

Enrollment Period

3 months

First QC Date

August 30, 2021

Last Update Submit

January 30, 2023

Conditions

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 (3)

Dietary Supplement: Meat with added nitrate

EXPERIMENTAL

The intervention comprises 50 g salami and 35 g ham on white bread sandwich at breakfast and lunch. This intervention will allow us to determine both endogenous formation of N-nitrosamines as well as N-nitrosamines present in the commercially prepared meat.

Dietary Supplement: Meat without added nitrateDietary Supplement: Control

Dietary Supplement: Meat without added nitrate

EXPERIMENTAL

The intervention comprises 65 g Pork mince on white bread sandwich at breakfast and lunch. Nitrate is not an allowed additive in pork mince. This intervention will allow us to determine if there is endogenous formation of N-nitrosamines as well as N-nitrosamines present in the prepared meat due to the natural content of nitrate in meat.

Dietary Supplement: Meat with added nitrateDietary Supplement: Control

Dietary Supplement: Control

SHAM COMPARATOR

The control comprises low nitrate vegetable protein burger on white bread. Protein content matched to interventions 1 and 2.

Dietary Supplement: Meat with added nitrateDietary Supplement: Meat without added nitrate

Interventions

Meat with added nitrateDIETARY_SUPPLEMENT

The intervention comprises 50 g salami and 35 g ham on white bread sandwich at breakfast and lunch. This intervention will allow us to determine both endogenous formation of N-nitrosamines as well as N-nitrosamines present in the commercially prepared meat.

Dietary Supplement: ControlDietary Supplement: Meat without added nitrate
Meat without added nitrateDIETARY_SUPPLEMENT

The intervention comprises 65 g Pork mince on white bread sandwich at breakfast and lunch. Nitrate is not an allowed additive in pork mince. This intervention will allow us to determine if there is endogenous formation of N-nitrosamines as well as N-nitrosamines present in the prepared meat due to the natural content of nitrate in meat.

Dietary Supplement: ControlDietary Supplement: Meat with added nitrate
ControlDIETARY_SUPPLEMENT

The control comprises low nitrate vegetable protein burger on white bread. Protein content matched to interventions 1 and 2.

Dietary Supplement: Meat with added nitrateDietary Supplement: Meat without added nitrate

Eligibility Criteria

Age18 Years - 70 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (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 70 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.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Royal Perth Hospital Research Foundation

Perth, Western Australia, 6000, Australia

Location

Related Publications (18)

  • 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.

  • 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.

  • Bondonno CP, Blekkenhorst LC, Liu AH, Bondonno NP, Ward NC, Croft KD, Hodgson JM. Vegetable-derived bioactive nitrate and cardiovascular health. Mol Aspects Med. 2018 Jun;61:83-91. doi: 10.1016/j.mam.2017.08.001. Epub 2017 Sep 7.

  • 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.

  • Tannenbaum SR, Weisman M, Fett D. The effect of nitrate intake on nitrite formation in human saliva. Food Cosmet Toxicol. 1976 Dec;14(6):549-52. doi: 10.1016/s0015-6264(76)80006-5. No abstract available.

  • 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.

  • Mirvish SS. Role of N-nitroso compounds (NOC) and N-nitrosation in etiology of gastric, esophageal, nasopharyngeal and bladder cancer and contribution to cancer of known exposures to NOC. Cancer Lett. 1995 Jun 29;93(1):17-48. doi: 10.1016/0304-3835(95)03786-V.

  • IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. IARC monographs on the evaluation of carcinogenic risks to humans. Ingested nitrate and nitrite, and cyanobacterial peptide toxins. IARC Monogr Eval Carcinog Risks Hum. 2010;94:v-vii, 1-412. No abstract available.

  • Hord NG, Tang Y, Bryan NS. Food sources of nitrates and nitrites: the physiologic context for potential health benefits. Am J Clin Nutr. 2009 Jul;90(1):1-10. doi: 10.3945/ajcn.2008.27131. Epub 2009 May 13.

  • 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.

  • Bartsch H, Ohshima H, Pignatelli B. Inhibitors of endogenous nitrosation. Mechanisms and implications in human cancer prevention. Mutat Res. 1988 Dec;202(2):307-24. doi: 10.1016/0027-5107(88)90194-7.

  • Levallois P, Ayotte P, Van Maanen JM, Desrosiers T, Gingras S, Dallinga JW, Vermeer IT, Zee J, Poirier G. Excretion of volatile nitrosamines in a rural population in relation to food and drinking water consumption. Food Chem Toxicol. 2000 Nov;38(11):1013-9. doi: 10.1016/s0278-6915(00)00089-2.

  • Bartholomew B, Hill MJ. The pharmacology of dietary nitrate and the origin of urinary nitrate. Food Chem Toxicol. 1984 Oct;22(10):789-95. doi: 10.1016/0278-6915(84)90116-9.

  • Bondonno CP, Croft KD, Puddey IB, Considine MJ, Yang X, Ward NC, Hodgson JM. Nitrate causes a dose-dependent augmentation of nitric oxide status in healthy women. Food Funct. 2012 May;3(5):522-7. doi: 10.1039/c2fo10206d. Epub 2012 Feb 16.

  • Bondonno CP, Downey LA, Croft KD, Scholey A, Stough C, Yang X, Considine MJ, Ward NC, Puddey IB, Swinny E, Mubarak A, Hodgson JM. The acute effect of flavonoid-rich apples and nitrate-rich spinach on cognitive performance and mood in healthy men and women. Food Funct. 2014 May;5(5):849-58. doi: 10.1039/c3fo60590f.

  • Callahan BJ, McMurdie PJ, Rosen MJ, Han AW, Johnson AJ, Holmes SP. DADA2: High-resolution sample inference from Illumina amplicon data. Nat Methods. 2016 Jul;13(7):581-3. doi: 10.1038/nmeth.3869. Epub 2016 May 23.

  • Cole JR, Wang Q, Fish JA, Chai B, McGarrell DM, Sun Y, Brown CT, Porras-Alfaro A, Kuske CR, Tiedje JM. Ribosomal Database Project: data and tools for high throughput rRNA analysis. Nucleic Acids Res. 2014 Jan;42(Database issue):D633-42. doi: 10.1093/nar/gkt1244. Epub 2013 Nov 27.

  • Parks DH, Chuvochina M, Waite DW, Rinke C, Skarshewski A, Chaumeil PA, Hugenholtz P. A standardized bacterial taxonomy based on genome phylogeny substantially revises the tree of life. Nat Biotechnol. 2018 Nov;36(10):996-1004. doi: 10.1038/nbt.4229. Epub 2018 Aug 27.

MeSH Terms

Conditions

Health Risk Behaviors

Interventions

Meat

Condition Hierarchy (Ancestors)

Health BehaviorBehavior

Intervention Hierarchy (Ancestors)

FoodDiet, Food, and NutritionPhysiological PhenomenaFood and Beverages

Study Officials

  • Catherine P Bondonno, PhD, RNutr.

    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
Model Details: prospective, mono-centre, randomised, controlled, crossover study
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

August 30, 2021

First Posted

October 13, 2021

Study Start

September 27, 2022

Primary Completion

December 13, 2022

Study Completion

December 13, 2022

Last Updated

February 1, 2023

Record last verified: 2023-01

Data Sharing

IPD Sharing
Will not share

Locations