Cardiovascular DiseasesPhase 2NCT00000511
Polyunsaturates and KCL to Control Mild Hypertension
A Phase 2 study testing mineral supplements, Trial 1: fatty acids, omega-3; Trial 2: Mineral supplements and dietary supplements in people with Cardiovascular Diseases and Heart Diseases, run by Brigham and Women's Hospital.
Trial summary
To test the efficacy of omega-3 fatty acids in untreated mild hypertensives and magnesium, calcium, and potassium supplementation supplementation in non-hypertensives. These clinical trials were conducted in sequence over a four year period. Read more about this study
- Who is it for?
- Ages 21 to 70 years
- Conditions the study is for
- Cardiovascular Diseases, Heart Diseases, Hypertension
- What is being tested?
- mineral supplements, Trial 1: fatty acids, omega-3; Trial 2: Mineral supplements and dietary supplements
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- Not given
- Where
- No sites listed yet
- Study dates
- Dec 1983to Nov 1994
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 21 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Mild hypertensives, ages 21 to 70, with no evidence of end-organ damage.. Untreated hypertensives.
About this study
To test the efficacy of omega-3 fatty acids in untreated mild hypertensives and magnesium, calcium, and potassium supplementation supplementation in non-hypertensives. These clinical trials were conducted in sequence over a four year period.
Read the detailed description
BACKGROUND:
The hypothesis that omega-3 fatty acids as well as magnesium and potassium in the diet lowered blood pressure in mild hypertensives needed further documentation, although preliminary and less well controlled studies had suggested such an effect was possible. In a previous study the investigators did not find a hypotensive effect of another polyunsaturated fatty acid, linoleic acid. In addition, findings of lower blood pressures in vegetarians and results obtained from a study in which vegetarian diets were fed to normotensives led to the conclusion that dietary factors other then linoleic acid were responsible for the possible hypotensive effect of vegetarian diets. The nutrients which were selected for further study, omega-3 fatty acids, magnesium and potassium, occur in higher amounts in vegetarian diets.
Dietary supplementation with fish oils had only been done in a few studies with inconclusive results. However, the relationship of omega-3 fatty acids to the synthesis of prostacyclins, which are locally active vasodilators and which decrease with the excretion of the vasoconstrictor thromboxane, provide a possible mechanism for an effect of these compounds on blood pressure.
The role of potassium in the control of blood pressure was first suggested from cross-cultural studies in which populations consuming high levels of potassium displayed lower rates of hypertension and a decrease in blood pressure with age. Cohort studies within this country have also shown a relationship between potassium intake or the ratio of potassium and sodium, as measured by urinary excretion and blood pressure. Most constantly it found that blood pressure differences between blacks and whites have been related to differences in potassium excretion.
The results from human experimental studies involving potassium supplementation in normotensives and hypertensives have indicated mixed effects but blood pressure lowering was most consistently observed in subgroups with a family history of hypertension or those with higher blood pressure.
DESIGN NARRATIVE:
Trial 1: Subjects were randomized to a fish oil treatment group of 6 or 12 grams/day of omega-3 fatty acids or to a placebo group. At the end of 12 and 24 weeks, participants in the three groups were crossed-over to one of the other two treatments for an additional 12 weeks. The primary outcome was clinic blood pressure on 3 days at the end of the treatment period.
Trial 2: Subjects were randomly assigned to one of four treatments and placebo: magnesium supplementation; potassium supplementation; calcium supplementation; all 3 supplements; matching placebos. The trial was double-blinded. Each of the treatments was administered for six months with measurements taken at baseline and at the end. The primary outcome was 24-hour ambulatory systolic BP.
The study completion date listed in this record was obtained from the Query/View/Report (QVR) System.
- Being tested
- mineral supplements, Trial 1: fatty acids, omega-3; Trial 2: Mineral supplements, dietary supplements
- Medical subject headings
- Cardiovascular Diseases, Heart Diseases, Hypertension, Vascular Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
mineral supplementsDietary supplement
Trial 1: fatty acids, omega-3; Trial 2: Mineral supplementsDietary supplement
dietary supplementsBehavioural
| Study group | Role | What they receive |
|---|---|---|
| Potassium, Magnesium, Calcium, The 3 together, Placebo | Placebo comparator | Parallel study design, 4 treatment groups Receives: Dietary Supplement: mineral supplements; Dietary Supplement: Trial 1: fatty acids, omega-3; Trial 2: Mineral supplements; Behavioral: dietary supplements |
What is being measured
The primary outcome is the main question the study is designed to answer.
Blood Pressure
14 hour ambulatory BP
Measured: End of study
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Oct 1999 (estimated)
- Study startDec 1983
- Primary completionNov 1994
- Study completionNov 1994
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Cardiovascular DiseasesStudies of the same condition, open and under way.
- More trials run by Brigham and Women's HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
Sponsor and investigators
- Lead sponsor
- Brigham and Women's Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Responsible party
- Principal investigator, Frank M. Sacks, Brigham and Women's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00000511
- Sponsor's protocol ID
- 30
- Other IDs
- R01HL034593, R01HL034593-05
- Status last verified
- Dec 2013
- First submitted
- 27 Oct 1999
- Last updated
- 13 Dec 2013
- Results posted
- No
Publications
Morris MC, Taylor JO, Stampfer MJ, Rosner B, Sacks FM. The effect of fish oil on blood pressure in mild hypertensive subjects: a randomized crossover trial. Am J Clin Nutr. 1993 Jan;57(1):59-64. doi: 10.1093/ajcn/57.1.59.
PubMed 8416666
Study at a glance
From the registry record, last updated by the sponsor on 13 Dec 2013. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Polyunsaturates and KCL to Control Mild Hypertension
- ClinicalTrials.gov ID
- NCT00000511
- Acronym / sponsor ID
- 30
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Lead sponsor
- Brigham and Women's HospitalUniversity, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Study start
- Dec 1983
- Primary completion
- Nov 1994 (actual)
- Study completion
- Nov 1994 (actual)
- First posted
- 28 Oct 1999 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
To test the efficacy of omega-3 fatty acids in untreated mild hypertensives and magnesium, calcium, and potassium supplementation supplementation in non-hypertensives. These clinical trials were conducted in sequence over a four year period.
Detailed description
BACKGROUND:
The hypothesis that omega-3 fatty acids as well as magnesium and potassium in the diet lowered blood pressure in mild hypertensives needed further documentation, although preliminary and less well controlled studies had suggested such an effect was possible. In a previous study the investigators did not find a hypotensive effect of another polyunsaturated fatty acid, linoleic acid. In addition, findings of lower blood pressures in vegetarians and results obtained from a study in which vegetarian diets were fed to normotensives led to the conclusion that dietary factors other then linoleic acid were responsible for the possible hypotensive effect of vegetarian diets. The nutrients which were selected for further study, omega-3 fatty acids, magnesium and potassium, occur in higher amounts in vegetarian diets.
Dietary supplementation with fish oils had only been done in a few studies with inconclusive results. However, the relationship of omega-3 fatty acids to the synthesis of prostacyclins, which are locally active vasodilators and which decrease with the excretion of the vasoconstrictor thromboxane, provide a possible mechanism for an effect of these compounds on blood pressure.
The role of potassium in the control of blood pressure was first suggested from cross-cultural studies in which populations consuming high levels of potassium displayed lower rates of hypertension and a decrease in blood pressure with age. Cohort studies within this country have also shown a relationship between potassium intake or the ratio of potassium and sodium, as measured by urinary excretion and blood pressure. Most constantly it found that blood pressure differences between blacks and whites have been related to differences in potassium excretion.
The results from human experimental studies involving potassium supplementation in normotensives and hypertensives have indicated mixed effects but blood pressure lowering was most consistently observed in subgroups with a family history of hypertension or those with higher blood pressure.
DESIGN NARRATIVE:
Trial 1: Subjects were randomized to a fish oil treatment group of 6 or 12 grams/day of omega-3 fatty acids or to a placebo group. At the end of 12 and 24 weeks, participants in the three groups were crossed-over to one of the other two treatments for an additional 12 weeks. The primary outcome was clinic blood pressure on 3 days at the end of the treatment period.
Trial 2: Subjects were randomly assigned to one of four treatments and placebo: magnesium supplementation; potassium supplementation; calcium supplementation; all 3 supplements; matching placebos. The trial was double-blinded. Each of the treatments was administered for six months with measurements taken at baseline and at the end. The primary outcome was 24-hour ambulatory systolic BP.
The study completion date listed in this record was obtained from the Query/View/Report (QVR) System.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Potassium, Magnesium, Calcium, The 3 together, Placebo | Placebo comparator | Dietary Supplement: mineral supplements, Dietary Supplement: Trial 1: fatty acids, omega-3; Trial 2: Mineral supplements, Behavioral: dietary supplementsParallel study design, 4 treatment groups |
Who may qualify
- Ages
- 21 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| mineral supplements | Dietary supplement | Potassium, Magnesium, Calcium, The 3 together, Placebo |
| Trial 1: fatty acids, omega-3; Trial 2: Mineral supplements | Dietary supplement | Potassium, Magnesium, Calcium, The 3 together, Placebo |
| dietary supplements | Behavioural | Potassium, Magnesium, Calcium, The 3 together, Placebo |
Primary outcome
Blood Pressure
Time frame: End of study
14 hour ambulatory BP
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Dec 2013.
- Background: PubMed 8416666Morris MC, Taylor JO, Stampfer MJ, Rosner B, Sacks FM. The effect of fish oil on blood pressure in mild hypertensive subjects: a randomized crossover trial. Am J Clin Nutr. 1993 Jan;57(1):59-64. doi: 10.1093/ajcn/57.1.59.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing mineral supplements, Trial 1: fatty acids, omega-3; Trial 2: Mineral supplements and dietary supplements in people with Cardiovascular Diseases and Heart Diseases, run by Brigham and Women's Hospital.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 13 Dec 2013. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Blood Pressure (time frame: End of study). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00000511, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Dec 2013.