Effects of a Commercial Fruit, Vegetable and Berry Juice Powder Concentrate on Metabolic Safety and Cardiovascular Health in Older Adults: 6-Month Results of a Randomized Controlled Trial.

Background/

Objectives

Fruit, vegetable and berry (FVB) juice powder concentrates are increasingly used to support cardiovascular health. Since they are usually consumed over long periods, this study assessed the metabolic safety of a commercial FVB supplement and its impact on selected biomarkers of systemic oxidative stress and cardiovascular health.

Methods

In this open-label, randomized controlled trial, generally healthy older adults were allocated to a control group (n = 16) or an FVB group (n = 18), ingesting six capsules/day. This work reports the pre-specified 6-month timepoint of a 1-year trial. The primary outcome, metabolic safety, was assessed by hepatic, renal, thyroid, lipid and glucose metabolism markers. Exploratory analysis assessed carbonyl proteins, malondialdehyde, and oxidized LDL as markers of systemic oxidative stress, together with homocysteine and blood pressure as markers of cardiovascular health, while plasma vitamin C served as a compliance marker.

Results

The FVB concentrate was well tolerated, and no safety-relevant deteriorations were observed in the FVB group. Carbonyl proteins decreased significantly in the FVB group (interaction p = 0.030). Homocysteine remained stable in the FVB group but increased significantly in the control group (interaction p = 0.002). Furthermore, systolic blood pressure decreased significantly (interaction p = 0.036), with a comparable interaction of diastolic blood pressure (p = 0.011), and plasma vitamin C increased significantly in the FVB group (interaction p = 0.004). After adjustment for baseline values, age and BMI, between-group differences persisted for homocysteine and diastolic blood pressure, whereas the differences in systolic blood pressure and carbonyl proteins were attenuated and no longer reached statistical significance.

Conclusions

Six months of supplementation with a commercial FVB concentrate was metabolically safe and well tolerated. Since these findings are based on a pre-specified timepoint and a limited number of participants, they are hypothesis-generating rather than confirmatory and require confirmation by the complete trial. Registered at ClinicalTrials.gov (NCT04763291; registered on 21 February 2021).