Dataset Information

Nitrate-Rich Beetroot Juice Reduces Blood Pressure in Tanzanian Adults with Elevated Blood Pressure: A Double-Blind Randomized Controlled Feasibility Trial.

ABSTRACT:

Background

In Sub-Saharan Africa, current strategies are struggling to control the burgeoning hypertension epidemic. Dietary interventions such as inorganic nitrate or folic acid supplementation could represent promising strategies for reducing blood pressure (BP) in this setting.

Objectives

This feasibility study explores the effects of dietary inorganic nitrate supplementation, alone or in combination with folic acid, on BP in Tanzanian adults with elevated BP in Tanzania.

Methods

A placebo-controlled, double-blind, randomized controlled feasibility trial was conducted. Forty-seven middle-aged and older participants (age: 50-70 y, BMI: 26.3-29.1 kg/m2) were randomly assigned to 3 conditions for a period of 60 d: 1) high-nitrate beetroot juice (∼400 mg nitrate) and folic acid (∼5 mg folic acid) (N + F), 2) high-nitrate beetroot juice and placebo (N + P), or 3) nitrate-depleted beetroot juice and placebo (P + P). Clinic and 24-h ambulatory BP and measurements of compliance in plasma (nitrate and folate concentrations) and saliva (nitrate and nitrite) were obtained at baseline, 30 d, and 60 d.

Results

Baseline resting systolic and diastolic BP (mean ± SD) was 151.0 ± 19.4 mm Hg and 91.8 ± 11.7 mm Hg, respectively. Compliance to the interventions was high (>90%) in all groups which was confirmed by the significant increase in nitrate and folic acid concentrations in plasma and saliva samples in the treatment arms. After 60 d, 24-h systolic BP dropped by -10.8 ± 9.8 mm Hg (P < 0.001), -6.1 ± 13.2 mm Hg (P = 0.03), and -0.3 ± 9.7 mm Hg (P = 0.83) in the N + P, N + F, and P + P groups, respectively. There was a significant decrease in 24-h diastolic BP in the N + P group (-5.4 ± 5.0 mm Hg, P = 0.004), whereas changes were not significant in the N + F (-1.8 ± 8.1 mm Hg, P = 0.32) and P + P (1.6 ± 8.3 mm Hg, P = 0.43) groups.

Conclusions

Dietary inorganic nitrate represents a potential nutritional strategy to lessen the hypertension epidemic in Sub-Saharan Africa. These findings support the rationale for future long-term investigations exploring the efficacy of dietary nitrate for lowering BP and attenuating cardiovascular disease risk in this setting.This trial was registered at isrctn.com as ISRCTN67978523.

SUBMITTER: Siervo M

PROVIDER: S-EPMC7467850 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:There have been recent calls for strategies to improve oral health in athletes. High carbohydrate diets, exercise induced dehydration and transient perturbations to immune function combine to increase oral disease risk in this group. We tested whether a single dose of nitrate (NO3-) would offset the reduction in salivary pH following carbohydrate ingestion before and after an exercise bout designed to cause mild dehydration. Eleven trained male runners ([Formula: see text] 53 ± 9 ml∙kg-1∙min-1, age 30 ± 7 years) completed a randomised placebo-controlled study comprising four experimental trials. Participants ingested the following fluids one hour before each trial: (a) 140 ml of water (negative-control), (b) 140 ml of water (positive-control), (c) 140 ml of NO3- rich beetroot juice (~12.4 mmol NO3-) (NO3- trial) or (d) 140 ml NO3- depleted beetroot juice (placebo-trial). During the negative-control trial, participants ingested 795 ml of water in three equal aliquots: before, during, and after 90 min of submaximal running. In the other trials they received 795 ml of carbohydrate supplements in the same fashion. Venous blood was collected before and after the exercise bout and saliva was sampled before and repeatedly over the 20 min following carbohydrate or water ingestion. As expected, nitrite (NO2-) and NO3- were higher in plasma and saliva during the NO3- trial than all other trials (all P<0.001). Compared to the negative-control, salivary-pH was significantly reduced following the ingestion of carbohydrate in the positive-control and placebo trials (both P <0.05). Salivary-pH was similar between the negative-control and NO3- trials before and after exercise despite ingestion of carbohydrate in the NO3- trial (both P≥0.221). Ingesting NO3- attenuates the expected reduction in salivary-pH following carbohydrate supplements and exercise-induced dehydration. NO3- should be considered by athletes as a novel nutritional strategy to reduce the risk of developing acidity related oral health conditions.