Can consumption of a vitamin C rich fruit and vegetable derived supplement for 12 weeks, reduce blood pressure in normotensive overweight/obese individuals?
Authors: Tsiountsioura Melina , Sayegh Marietta , Ray Sumantra 
Published: November 2023

Background and Aim

Cardiovascular disease (CVD) is the number one cause of death globally. Measurement of brachial (peripheral) blood pressure (pBP) has become well established within clinical settings for evaluating CVD risk. However, recent research has shown that central blood pressure (cBP) might be a more accurate measure and able to predict CVD risk with greater precision compared to pBP. In addition to that few studies have focused on the effect of fruit and vegetable extracts on early markers of vascular function in overweight/obese individuals. One aim of this study was to assess any differences between cBP and pBP following ingestion of vitamin C rich fruit and vegetable extracts over 12 weeks, compared with placebo in overweight and obese individuals. In addition, differences in augmentation index adjusted for heart rate (AIx@HR75) before and after supplementation were examined.

Methods

This was a double‐blind, randomised, placebo‐controlled trial that included overweight and obese but otherwise healthy participants (Table 1). Participants were randomly allocated to one of two groups; active supplementation or placebo taken twice daily for 12 weeks while both groups were given the “5‐A‐Day” dietary advice. Seated pBP was measured using an automated blood pressure monitor (OMRON M7, OMRON Healthcare GmbH, Germany) and the average value of two readings was calculated. A third measurement was taken in case there was a disparity of more than 10mmHg between the first two readings. cBP and AIx@HR75 were derived from the right wrist (radial pulse) using the SphygmoCor Vx version 7.01 (AtCor Medical, Sydney, Australia). The SphygmoCor device provides a quality index (QI) which represents reproducibility of the waveform and any recordings with a QI < 80 were excluded.

Results

Data were normally distributed and independent t‐tests were used in order to compare systolic and diastolic cBP vs systolic and diastolic pBP between low (Group A) and high (Group B) vitamin C consumers. There were no statistically significant differences observed for any of the measured BP parameters in either intervention group. Data are presented as mean±SD along with p values (Table 2). Analysis also included exploratory comparisons of within group changes to Pulse Pressure.

Conclusion

From preliminary analyses of breaking results it would appear that there were no significant improvements to blood pressure and related parameters, following ingestion of vitamin C rich fruit and vegetable supplements in normotensive overweight/obese individuals. Further analyses are however required to arrive at firm conclusions.

Support or Funding Information

The above study was funded by NSA.

Participants’ demographic characteristics.

Values
Group AMean ± SD
Group BMean ± SD

Males (N)
12
18

Females (N)
27
22

Age (yrs)
46.6 ± 9.8
45.1 ± 8.8

BMI (kg/m2)
TV1
29.0 ± 2.7
29.6 ± 2.6

TV2
29.1 ± 2.6
29.7 ± 2.8

Vitamin C (μmol/litre)
TV1
66.6 ± 17.4
60.2 ± 18.8

TV2
64.6 ± 19.6
76.5 ± 16.4

Differences on blood pressure parameters between Group A and B pre‐ and post‐supplementation.

Group A(mean ± SD)
Group B(mean ± SD)
P values

Pre‐supplementation
Central
Systolic BP
115±12
111±13
0.203

Diastolic BP
80±8
78±9
0.358

Peripheral
Systolic BP
125±12
122±13
0.276

Diastolic BP
80±8
77±9
0.127

AIx@HR75
17.1±13.1
13.7± 12.3
0.242

Post‐supplementation
Central
Systolic BP
111±13
111±13
0.812

Diastolic BP
81±8
79±8
0.520

Peripheral
Systolic BP
122±12
123±13
0.667

Diastolic BP
80±7
78±8
0.293

AIx@HR75
15.8±11.7
11.6±9.7
0.171