None listed
Conditions
Brief summary
Cardiovascular disease is a major disease burden, accounting for over 45% of all deaths. Obesity, and its consequences, the metabolic syndrome and type 2 diabetes increase the risk of heart disease potentially leading to early death or disability. Reducing dietary salt is a neglected, valuable intervention with the potential to reduce cardiovascular events. The primary aim of the study is to determine, in a 12 week study the effect of a reduced salt diet (6g salt/day, 100mmol Na/day) compared to a usual salt diet (10g salt/day, 166mmolNa/day) on blood vessel function, as assessed by the ultrasound measurement of blood flow in overweight people with and without the metabolic syndrome who are at increased risk of heart disease. The expected outcomes are that a lower salt intake will have a beneficial effect on the way blood vessels work and reduce an individual’s risk for heart attack. The results will support moves to reduce salt in the food supply thereby reducing heart disease risk in the general community as well as in individuals at higher risk. Data from this study will provided a very strong incentive to reduce dietary salt.
Interventions
In a randomised cross-over fashion, participants will follow a reduced salt diet (6g salt/day, 100mmol Na/day) for 6 weeks and a usual salt diet (10g salt/day, 166 Na/day) for 6 weeks. The higher salt diet will be achieved by the addition of 6 tablets a day containing a small amount (10mmol sodium each) to the reduced salt diet. There will be no wash-out period between interventions. Participants will attend 2 half hour education sessions with the dietitian at Visit 1 & Visit 2 during the first
In a randomised cross-over fashion, participants will follow a reduced salt diet (6g salt/day, 100mmol Na/day) for 6 weeks and a usual salt diet (10g salt/day, 166 Na/day) for 6 weeks. The higher salt diet will be achieved by the addition of 6 tablets a day containing a small amount (10mmol sodium each) to the reduced salt diet. There will be no wash-out period between interventions. Participants will attend 2 half hour education sessions with the dietitian at Visit 1 & Visit 2 during the first week of the study and will attend another 2 half hour education sessions at Visit 3 & Visit 4 at week 6. Dietitian instruction will cover how to follow a reduced salt diet and participants will receive extensive education about the salt content of foods, label reading and example meal recipes to aid compliance with the diet. Compliance with diets will be measured by 24hour urinary sodium excretion at baseline, day 2, week 6, 2 days after week six and week 12. Trial managers will also collect tablets at the end of the normal salt diet periods as another measure of compliance.
Sponsors
CSIRO Human Nutrition
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
40 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
Weight stable individuals with systolic blood pressure between 120-139mmHg and diastolic blood pressure between 80-89mmHg. Those with and without the metabolic syndrome (defined as waist circumference >94cm for men and >80cm for women plus two of the following: fasting triglycerides (TG) = to or > 1.7mmol/L, high density lipoprotein (HDL) cholesterol<1.03 (men) or 1.29 (women), fasting glucose 5.6-6.9mmol/L) will be eligible to participate in the study.
Exclusion criteria
Previous cardiovascular disease, treated hypertension, significant weight loss (>5% body weight) in the previous 6months, use of non-steroidal anti-inflammatory drugs, known metabolic disease such as liver or kidney disease
Outcome results
None listed