Enhanced Walking-Induced Fat Oxidation by New Zealand Blackcurrant Extract Is Body Composition-Dependent in Recreationally Active Adult Females

Preliminary study on the effects of boysenberry juice intake on brown adipose tissue activity in healthy adults

Brown adipose tissue (BAT) plays an important role in energy metabolism because it uses fatty acids for thermogenesis during cold exposure. Preclinical studies found that boysenberry anthocyanins (BoyACs) activate BAT. Therefore, the aim of this preliminary study was to evaluate how BoyAC intake affects BAT in humans. We performed an open-label single-arm nonrandomized study in healthy volunteers. Before and after 4 weeks of daily consumption of 100 ml boysenberry juice (BoyJ) containing 61 mg of BoyACs, participants were assessed at 24 °C and then after 1 h of mild cold exposure (18 °C). An infrared thermography camera was used to measure skin surface temperatures in the supraclavicular BAT region (Tscv) and the non-BAT region of the upper chest (Tch). Energy metabolism was measured by indirect calorimetry. For each endpoint, we calculated Δ as the difference between values before and after cold exposure and compared the values before and after BoyJ intake. 10 volunteers participated (age: 36.1 ± 4.1, body mass index (BMI): 20.9 ± 0.6). After BoyJ intake, ΔTscv-ch was significantly higher (p = 0.029), but Δ energy expenditure, Δ fat oxidation, and Δ carbohydrate oxidation were not significantly different. We found a significant positive correlation between BMI and Δfat oxidation with BoyJ intake. The results indicate that 4 weeks of BoyJ intake activates cold-induced thermogenesis in the scv-BAT but does not have a significant effect on energy metabolism. BoyJ intake may increase fat oxidation during cold exposure in individuals with higher BMI.Trial registry number: UMIN000043476, 05/03/2021.

A One-Week Elderberry Juice Intervention Augments the Fecal Microbiota and Suggests Improvement in Glucose Tolerance and Fat Oxidation in a Randomized Controlled Trial

Obesity is a costly and ongoing health complication in the United States and globally. Bioactive-rich foods, especially those providing polyphenols, represent an emerging and attractive strategy to address this issue. Berry-derived anthocyanins and their metabolites are of particular interest for their bioactive effects, including weight maintenance and protection from metabolic aberrations. Earlier findings from small clinical trials suggest modulation of substrate oxidation and glucose tolerance with mediation of prospective benefits attributable to the gut microbiota, but mixed results suggest appropriate anthocyanin dosing poses a challenge. The objective of this randomized, placebo-controlled study was to determine if anthocyanin-dense elderberry juice (EBJ) reproduces glucoregulatory and substrate oxidation effects observed with other berries and if this is mediated by the gut microbiota. Overweight or obese adults (BMI > 25 kg/m2) without chronic illnesses were randomized to a 5-week crossover study protocol with two 1-week periods of twice-daily EBJ or placebo (PL) separated by a washout period. Each treatment period included 4 days of controlled feeding with a 40% fat diet to allow for comparison of measurements in fecal microbiota, meal tolerance testing (MTT), and indirect calorimetry between test beverages. Eighteen study volunteers completed the study. At the phylum level, EBJ significantly increased Firmicutes and Actinobacteria, and decreased Bacteroidetes. At the genus level, EBJ increased Faecalibacterium, Ruminococcaceae, and Bifidobacterium and decreased Bacteroides and lactic acid-producing bacteria, indicating a positive response to EBJ. Supporting the changes to the microbiota, the EBJ treatment significantly reduced blood glucose following the MTT. Fat oxidation also increased significantly both during the MTT and 30 min of moderate physical activity with the EBJ treatment. Our findings confirm the bioactivity of EBJ-sourced anthocyanins on outcomes related to gut health and obesity. Follow-up investigation is needed to confirm our findings and to test for longer durations.

Effects of CurraNZ, a New Zealand Blackcurrant Extract during 1 Hour of Treadmill Running in Female and Male Marathon des Sables Athletes in Hot Conditions: Two Case Studies

Four weeks before competition in the 2023 Marathon des Sables, a 6-stage, ~250 km running event in the Sahara Desert, we examined the effects of a 7-day intake of New Zealand blackcurrant extract (210 mg anthocyanins per day) on 1 h treadmill running-induced physiological and metabolic responses in the heat (~34 °C, relative humidity: ~30%) in non-acclimatized amateur female and male athletes (age: 23, 38 yrs, BMI: 24.2, 28.4 kg·m-2, body fat%: 29.2, 18.8%, V˙O2max: 50.1, 52.1 mL·kg-1·min-1). During the 1 h run at 50%V˙O2max (speed female: 7.3, male: 7.5 km·h-1), indirect calorimetry was used, and heart rate was recorded at 15 min intervals with core temperature monitoring (0.05 Hz). The 1 h runs took place 3 h after a light breakfast and 2 h after intake of the final dose of New Zealand blackcurrant extract with water allowed ad libitum during the run. The New Zealand blackcurrant extract had no effects on the female athlete. The respiratory exchange ratio (RER) of the female athlete in the non-supplement control condition was 0.77 ± 0.01, indicating an existing ~77% contribution of fat oxidation to the energy requirements. In the male athlete, during 1 h of running, fat oxidation was higher by 21% (p < 0.01), carbohydrate oxidation was 31% lower (p = 0.05), RER was 0.03 units lower (p = 0.04), and core temperature was 0.4 °C lower (p < 0.01) with no differences for heart rate, minute ventilation, oxygen uptake, and carbon dioxide production for the New Zealand blackcurrant condition compared to the non-supplement control condition. Seven-day intake of New Zealand blackcurrant extract (210 mg anthocyanins per day) provided beneficial physiological and metabolic responses during exertional heat stress by 1 h of indoor (~34 °C) treadmill running in a male Marathon des Sables athlete 4 weeks before competition. Future work is required to address whether New Zealand blackcurrant provides a nutritional ergogenic effect for Marathon des Sables athletes during long-duration running in the heat combined with personalized nutrition.

Running-Induced Metabolic and Physiological Responses Using New Zealand Blackcurrant Extract in a Male Ultra-Endurance Runner: A Case Study

Physical training for ultra-endurance running provides physiological adaptations for exercise-induced substrate oxidation. We examined the effects of New Zealand blackcurrant (NZBC) extract on running-induced metabolic and physiological responses in a male amateur ultra-endurance runner (age: 40 years, body mass: 65.9 kg, BMI: 23.1 kg·m−2, body fat: 14.7%, V˙O2max: 55.3 mL·kg−1·min−1, resting heart rate: 45 beats·min−1, running history: 6 years, marathons: 20, ultra-marathons: 28, weekly training distance: ~80 km, weekly running time: ~9 h). Indirect calorimetry was used and heart rate recorded at 15 min intervals during 120 min of treadmill running (speed: 10.5 km·h−1, 58% V˙O2max) in an environmental chamber (temperature: ~26 °C, relative humidity: ~70%) at baseline and following 7 days intake of NZBC extract (210 mg of anthocyanins·day−1) with constant monitoring of core temperature. The male runner had unlimited access to water and consumed a 100-kcal energy gel at 40- and 80 min during the 120 min run. There were no differences (mean of 8, 15 min measurements) for minute ventilation, oxygen uptake, carbon dioxide production and core temperature. With NZBC extract, the respiratory exchange ratio was 0.02 units lower, carbohydrate oxidation was 11% lower and fat oxidation was 23% higher (control: 0.39 ± 0.08, NZBC extract: 0.48 ± 0.12 g·min−1, p < 0.01). Intake of the energy gel did not abolish the enhanced fat oxidation by NZBC extract. Seven days’ intake of New Zealand blackcurrant extract altered exercise-induced substrate oxidation in a male amateur ultra-endurance runner covering a half-marathon distance in 2 h. More studies are required to address whether intake of New Zealand blackcurrant extract provides a nutritional ergogenic effect for ultra-endurance athletes to enhance exercise performance.

Effects of New Zealand Blackcurrant Extract on Sequential Performance Testing in Male Rugby Union Players

Previous studies on performance effects by New Zealand blackcurrant (NZBC) extract used mainly a single exercise task. We examined the effects of NZBC extract in a battery of rugby union–specific tests including speed, agility and strength testing. University male rugby union players (n = 13, age: 21 ± 2 years, height: 182 ± 6 cm, body mass: 87 ± 13 kg) completed two full familiarisations and two experimental visits in an indoor facility. The study had a double blind, placebo-controlled, randomised, crossover design. For the experimental visits, participants consumed NZBC extract (210 mg/day of anthocyanins for 7 days) or placebo with a 7-day wash-out. Testing order was the running-based anaerobic sprint test, the Illinois agility test, seated medicine ball (3 kg) throw, and handgrip strength. With NZBC extract, there may have been an effect for average sprint time to be faster by 1.7% (placebo: 5.947 ± 0.538 s, NZBC extract: 5.846 ± 0.571 s, d = −0.18 (trivial), p = 0.06). However, with NZBC extract there may have been reduced slowing of sprint 2 (d = −0.59 (moderate), p = 0.06) and reduced slowing for sprint 6 (d = −0.56 (moderate), p = 0.03). In the Illinois agility test, there may have also been an effect for the mean time to be faster by 1.6% (placebo: 18.46 ± 1.44 s, NZBC extract: 18.15 ± 1.22 s, d = −0.24 (small), p = 0.07). The correlation between the %change in average sprint time and %change in mean agility time was not significant (Pearson R² = 0.0698, p = 0.383). There were no differences for the seated medicine ball throw distance (p = 0.106) and handgrip strength (p = 0.709). Intake of NZBC extract in rugby union players seems to improve tasks that require maximal speed and agility but not muscle strength. NZBC blackcurrant extract may be able to enhance exercise performance in team sports that require repeated movements with high intensity and horizontal change of body position without affecting muscle strength.