Blood Pressure, Hypertension, Cardiovascular Disease, Nutrition, Vascular Health Nutritional, Metabolic, Endocrine
Conditions
Interventions
Group A: Receive nitrate supplementation via commercially available beetroot juice (BEET IT) that contains ~2000 mg of nitrate per liter. Participants drink 70 ml of concentrated beetroot juice per da
Sponsors
Newcastle University (UK)
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: 1. Non-smoking men and women 2. Healthy (no established diagnosis) 3. 55-70 years old 4. Body Mass Index (BMI) of 25-40 kg/m2
Exclusion criteria
Exclusion criteria: 1. Current participation in other clinical investigations 2. Physical disabilities, trauma or surgery that limit mobility and impede physical performance (i.e. not able to comply with the assessment of physical strength and influence on cardio-metabolic functions) 3. Vegetarianism (likely to have very high nitrate intake) 4. Aversion to beetroot consumption or inability to comply with the study diet (lack of compliance) 5. Weight change more than 3.0 kg in the last 3 months (important influence on systemic metabolism and vascular function) 6. Active cancer and any diagnosis of malignant cancer in the last 5 years (systemic effects on study outcomes) 7. Chronic and acute metabolic and inflammatory conditions interfering with the study outcome (systemic effects on study outcomes). For example, severe hypertension (SBP/DBP=>180 mmHg/>110), kidney stones, gallstones or rheumatoid arthritis 8. Previous diagnosis of type 1 or type 2 diabetes treated with insulin (modification of regulation of intermediate metabolism) 9. Weight loss medications (sibutramine, orlistat, rimonabant) and history of bariatric surgery (weight loss related changes in systemic metabolism) 10. Drugs: oral corticosteroids, sildenafil, diuretics, laxatives, anticoagulants, nitrate-derived agents, anti-cholinergic (all drugs have either an effect on NO production or insulin sensitivity via different mechanisms) 11. Subjects on hormonal therapies (oestrogens, thyroxine, progesterone, oral hypoglycaemic agents), anti-hypertensive (beta-blockers, calcium antagonists, ACE inhibitors and angiotensin receptor inhibitors), statins and any other anti-dyslipidaemic agent and psychiatric drugs (antidepressants, sedatives, antipsychotics) will be excluded if dose has been started/changed in the previous 3 months (make sure that these disorders are under strict control to avoid interference with the study outcomes) 12. Haematological disorders including severe anaemia (Hb 21 units/week for men and >14 units/week for women 15. Non-English speakers or volunteers requiring translators or interpreters (since these services are not available for this study)
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| 1. The effect of nitrate supplementation on resting, daily and 24-hr BP and the stability of these effects on BP once supplementation is removed Resting blood pressure: At baseline and at day 21 and 28 resting BP will be measured in triplicate using a manual BP monitor. Before the measurement participants will be invited to rest in a sitting position for at least 15 minutes. Subjects will be provided with an automated monitor for daily measurements of resting BP. Duplicate measurements will be conducted at home in a seated position after a 10-minute rest in the morning and in the evening before going to bed. Participants will be asked to write down the two measurements and the time of the measurement. Ambulatory 24-hr blood pressure monitoring: The BP monitor will be fitted to each participant at baseline and at day 21 and 28 and he/she will be asked to wear it for 24 hours. 2. The effect of nitrate supplementation on endothelial function 3. Questionnaires: Before and after the intervention participants will complete questionnaires on general health and lifestyle and physical activity. In addition, participants' diet will be assessed using a self-administered food frequency questionnaire for the assessment of overall dietary and nitrate intake. 4. Body composition: Measurements will be performed at baseline and at the end of the beetroot and carry-over phases. Body composition will be assessed using a leg-to-leg bioelectrical impedance device (TANITA 300 MA). Body weight, height and waist and upper-arm circumferences will be measured using standardised protocols. | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. The effect of nitrate supplementation on muscle strength. Hand-grip strength will be assessed in both arms at baseline and the end of each phase to measure the maximum isometric strength of the hand and forearm muscles. 2. The effect of nitrate supplementation on free-living physical activity. Daily physical activity (PA) will be measured at the beginning and end of the study in free-living conditions. Participants will be asked to wear a wrist-worn accelerometer for 7 days. 3. The effect of nitrate supplementation on pulmonary function. Vascular health: a non-invasive device (laser doppler) will be used to assess the post-reactive hyperaemic responses at baseline and at day 21 and 28. | — |
Countries
United Kingdom
Outcome results
None listed