'Low-salt' Bread as a Means of Reducing Dietary Salt and Lowering Blood Pressure

NCT04003597 | Completed

• 1 other identifier: 06/rd/c/455
• Study Type: interventional
• Target: 97
• Locations: 1 country
• Sites: 1

Brief Summary

In the context of public health, reformulation of bread in terms of salt content remains an important measure to help achieve a reduction in salt intake in the population. Therefore, the aim of this study was to examine, using a 5-week cross-over design, food-based intervention trial, the potential for inclusion of 'low-salt' bread as part of a pragmatic reduced-salt diet on blood pressure (BP) in adults with slightly to moderately elevated BP. The study consisted of a randomized crossover trial of the effect of reduced-salt intake or usual-salt intake for 5 weeks on BP (as the primary outcome) in adults with slightly to moderately elevated BP (seated office systolic BP \>120 and \<160 mmHg or a diastolic BP \>80 and \<95 mmHg; identified by a pre-screening phase). Subjects were randomly assigned to the reduced-salt diet or their usual-salt diet (control) for 5 weeks, followed by crossover to the alternative dietary regimen for a further 5 weeks. Subjects randomized to start on the reduced-salt diet were asked to restrict their consumption of dietary salt using a combination of pragmatic dietary advice as well as the replacement of bread and a limited number of other foods with equivalent foods which had lower salt content; these were provided to the participants. At the beginning of the salt restriction period, a research nutritionist provided the subjects with a list of the common salt-containing food and were asked to limit the consumption of such, as feasible. The subjects received in-house prepared 'low-salt (\<0.3 g/100 g)' brown or white sliced pan bread as well as no-salt margarine/butter, and were given luncheon meats with no added salt, if desired (optional); these were supplied regularly by the research staff. Subjects commencing the trial on the control diet were allowed to follow their usual diet but were asked to consume an in-house produced brown or white sliced pan bread equivalent in composition to the low-salt version but with its more typical salt content (1.2 g/100 g). Participants met the research staff weekly to receive breads and no-salt margarine/butter as well as luncheon meats (where applicable), and at these meetings the staff promoted compliance with the intervention and encouraged completion of the study protocol. BP and other assessments were made at baseline and at the end of week 5 and week 10.

Conditions

Elevated Blood Pressure

Keywords

Low-salt bread; Dietary sodium restriction; Pre-hypertension; Hypertension stage 1

Outcome Measures

Primary Outcomes (1)

• Systolic blood pressure at end of intervention periods

  Measured as seated office systolic blood pressure at end of usual salt dietary period and at end of reduced-salt dietary period

  After 5 weeks of intervention

Secondary Outcomes (11)

• Diastolic blood pressure

  After 5 weeks of intervention

• Urinary Calcium

  After 5 weeks of intervention

• Urinary N-telopeptides of Type I collagen

  After 5 weeks of intervention

• Serum Parathyroid Hormone

  After 5 weeks of intervention

• Serum C-telopeptide of Type I collagen

  After 5 weeks of intervention

Study Arms (2)

Usual-salt diet

PLACEBO COMPARATOR

Usual-salt diet followed for 5 weeks

Other: Usual-salt diet

Reduced-salt diet

ACTIVE COMPARATOR

Reduced-salt diet followed for 5 weeks

Other: Reduced-salt diet

Interventions

Usual-salt diet OTHER

Subjects followed their usual-salt diet but were asked to consume an equivalent in-house produced brown or white sliced pan bread equivalent in composition to the low-salt version but with its more typical salt content (1.2 g/100 g).

Usual-salt diet

Reduced-salt diet OTHER

Subjects randomized to start on the reduced-salt diet were asked to restrict their consumption of dietary salt using a combination of pragmatic dietary advice as well as the replacement of bread and a limited number of other foods with equivalent foods which had lower salt content; these were provided to the participants. At the beginning of the salt restriction period, a research nutritionist provided the subjects with a list of the common salt-containing food (salted and naturally salty) and were asked to limit the consumption of such, as feasible. The subjects received in-house prepared 'low-salt (\<0.3 g/100 g)' brown or white sliced pan bread as well as no-salt margarine/butter, and were given luncheon meats with no added salt if desired (optional).

Reduced-salt diet

Eligibility Criteria

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

You may qualify if:

• consenting adult Caucasian men and women, aged ≤65 y;
• a seated office systolic BP \>120 and \<160 mmHg and/or a diastolic BP \>80 and \<95 mmHg (based on the mean BP across 3 screening visits as part of a pre-intervention phase of the trial)
• willing to consume study breads

You may not qualify if:

• taking anti-hypertensive medication;
• taking any medications known to interfere with blood pressure or calcium or bone metabolism;
• Severe medical illness;
• celiac disease;
• hypercalcemia;
• known intestinal malabsorption syndrome,
• excessive alcohol use (\>14 drinks/week);
• pregnancy

Sponsors & Collaborators

• University College Cork: lead

Study Sites (1)

School of Food and Nutritional Sciences, University College Cork

Cork, Ireland

Location

MeSH Terms

Conditions

Hypertension; Prehypertension

Interventions

Diet, Sodium-Restricted

Condition Hierarchy (Ancestors)

Vascular Diseases; Cardiovascular Diseases

Intervention Hierarchy (Ancestors)

Diet Therapy; Nutrition Therapy; Therapeutics; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Officials

• Kevin D Cashman, PhD

  University College Cork

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: The biochemical outcome measures were assessed by researchers masked to the phase of the cross-over intervention from which the samples were derived.
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor of Food and Health

Study Record Dates

• First Submitted: June 21, 2019
• First Posted: July 1, 2019
• Study Start: January 3, 2008
• Primary Completion: July 30, 2010
• Study Completion: July 30, 2010
• Last Updated: July 1, 2019

Record last verified: 2019-06

Data Sharing

• IPD Sharing: Will not share

Locations

IE (1)