New research reveals that just one week of elderberry juice consumption significantly improves fat oxidation, glucose levels, and gut microbiota, making it a promising dietary addition for managing obesity in overweight adults.
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A study published in the journal Nutrients highlights the effectiveness of anthocyanin-rich elderberry juice in improving gut health and managing obesity among overweight or obese adults.
Background
Obesity is a multifactorial disease associated with a range of cardiometabolic complications. The prevalence of obesity has been estimated to be 42% in the United States, which is predicted to reach 48–55% by 2050.
Healthy dietary patterns, such as the Mediterranean-style diet, play an important role in mitigating cardiometabolic complications associated with obesity. This type of diet contains higher amounts of fruits and vegetables, which are rich sources of various bioactive compounds, including polyphenols and flavonoids.
Anthocyanins are a subclass of flavonoids with known health benefits against obesity-related morbidities, including diabetes, dyslipidemia, and cardiovascular disease. Evidence indicates that anthocyanins exert health benefits by preventing intestinal absorption of monosaccharides, increasing adipose and muscle cell metabolism, and modulating gut microbiota composition.
Elderberry juice contains significantly high amounts of cyanidin-based anthocyanins. The scientists of the current study have previously shown that rodents fed a 45% fat diet supplemented with 10% elderberry juice powder exhibit physical and metabolic improvements, partly mediated by elderberry juice-induced changes in the gut microbiota.
In a randomized, placebo-controlled crossover clinical trial, scientists investigated the effects of anthocyanin-rich elderberry juice on glucose tolerance, fat oxidation, and gut microbiota in healthy, overweight adults.
Study Design
The study was conducted on 18 overweight adults, who were randomly categorized into the intervention group and the control group. All participants underwent two one-week study intervention periods separated by a three-week washout period.
In the intervention group, participants were given 100% elderberry juice twice daily for one week. In the control group, participants were given a flavor-and-color-matched placebo beverage daily for one week.
In the second 1-week intervention period, which started after the washout period, the groups switched study interventions (elderberry juice and placebo beverage).
Each intervention period included four days of controlled feeding with a 40% fat diet to facilitate the comparison of study parameters between the two study groups. This crossover design allowed participants to serve as their own control, increasing the robustness of the findings.
Important Observations
A total of 18 participants completed the study protocol. The analysis of self-reported questionnaires revealed 100% adherence to the test beverage consumption. None of the participants reported experiencing gastrointestinal distress or inability to consume the prescribed food and test beverages.
Indirect colorimetry-based measurements of carbohydrate, fat, respiratory quotient (CO2 produced/O2 consumed), and energy expenditure revealed that elderberry juice consumption caused a significant reduction in respiratory quotient compared to placebo.
This corresponded to a significant induction in fat oxidation and reduction in carbohydrate oxidation in the elderberry juice group. Notably, while fat oxidation increased during the 30-minute treadmill walk, the difference was only marginally significant (p = 0.071), meaning further investigation is needed to confirm this finding. Regarding energy expenditure, no significant difference was observed between the groups.
Elderberry juice consumption also significantly reduced the respiratory quotient during moderate physical activity, indicating increased fat oxidation even outside of meal challenges.
Regarding glucose tolerance, the study found that the elderberry juice meal challenge is associated with a significant reduction in blood glucose levels and a moderate reduction in blood insulin levels.
Gut Microbiota Profiling
The study found that elderberry juice intake significantly increased the abundance of Firmicutes and Actinobacteria and reduced the abundance of Bacteroidetes at the phylum level.
At the genus level, elderberry juice intake increased Faecalibacterium, Ruminococcaceae, and Bifidobacterium and decreased Bacteroides and lactic acid-producing bacteria. These observations indicate a positive impact of elderberry juice on gut microbiota profiles. However, these changes were subtle and not indicative of profound shifts in the microbiota.
Study Significance
The study finds positive effects of elderberry juice on blood glucose tolerance, fat oxidation, and gut microbiota profile.
The study protocol includes 355 grams of elderberry juice daily, corresponding to more than 720 milligrams of cyanidin-based anthocyanins. With this regimen, the study finds a 24% reduction in the blood glucose response curve, a 9% reduction in the insulin response curve, and a 27% increase in fat oxidation.
Regarding gut microbiota profile, the study finds modest improvements in microbial communities with health benefits following elderberry juice consumption.
These observations collectively indicate that elderberry juice consumption for one week may effectively support obesity management in healthy adults with a body mass index (BMI) of more than 25 kg/m2.
However, the study has limitations. The one-week treatment period means it could not provide a long-term safety profile and health benefits associated with elderberry juice consumption.
Two challenge meals used in the study exhibit a 15-gram difference in total sugar content. Considering this limitation, scientists suggest that the observed improvement in glucose tolerance and insulin sensitivity is suggestive but must be confirmed with additional testing, where better control is placed on meal challenge design, including macronutrients and energy matching between meals.
The scientists also highlight the need for future studies to investigate the mechanisms of action of elderberry juice using longer-term clinical trials and preclinical and translational research models.
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