Journal Articles

Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915

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Author: search.filters.author.Wong MSubject: search.filters.subject.Adult

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    The Effect of a 14-Day gymnema sylvestre Intervention to Reduce Sugar Cravings in Adults
    (MDPI (Basel, Switzerland), 2022-12-12) Turner S; Diako C; Kruger R; Wong M; Wood W; Rutherfurd-Markwick K; Stice E; Ali A
    Gymnemic-acids (GA) block lingual sweet taste receptors, thereby reducing pleasantness and intake of sweet food. Objective: To examine whether a 14-day gymnema-based intervention can reduce sweet foods and discretionary sugar intake in free-living adults. Healthy adults (n = 58) were randomly allocated to either the intervention group (INT) or control group (CON). The intervention comprised of consuming 4 mg of Gymnema sylvestre containing 75% gymnema acids, a fibre and vitamin supplement, and an associated healthy-eating guide for 14 days; participants in the CON group followed the same protocol, replacing the GA with a placebo mint. Amount of chocolate bars eaten and sensory testing were conducted before and after the 14-day intervention (post-GA or placebo dosing on days zero and 15, respectively). Food frequency questionnaires were conducted on days zero, 15 and after a 28-day maintenance period to examine any changes in intake of sweet foods. A range of statistical procedures were used to analyse the data including Chi square, t-test and two-way analysis of variance. Post dosing, INT consumed fewer chocolates (2.65 ± 0.21 bars) at day zero than CON (3.15 ± 0.24 bars; p = 0.02); there were no differences between groups at day 15 (INT = 2.77 ± 0.22 bars; CON = 2.78 ± 0.22 bars; p = 0.81). At both visits, a small substantive effect (r < 0.3) was observed in the change in pleasantness and desire ratings, with INT showing a slight increase while CON showed a small decrease over the 14-day period. No differences were found in the intake of 9 food categories between groups at any timepoint. There were no differences in consumption of low sugar healthy foods between visits, or by group. The 14-day behavioural intervention reduced pleasantness and intake of chocolate in a laboratory setting. There was no habituation to the mint over the 14-day period. This study is the first to investigate the effect of longer-term gymnema acid consumption on sweet food consumption outside of a laboratory setting; further research is needed to assess how long the effect of the 14-day intervention persists.
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    Pharmacokinetics of Nitrate and Nitrite Following Beetroot Juice Drink Consumption
    (MDPI (Basel, Switzerland), 2021-01-20) Jakubcik EM; Rutherfurd-Markwick K; Chabert M; Wong M; Ali A
    BACKGROUND: Nitrate (NO3 -)-rich beetroot (BR) juice supplementation has been shown to improve cardiovascular function via reduction to nitrite (NO2 -) and then to the bioactive molecule nitric oxide (NO). However, limited research exists for the role of inorganic NO2 - that is contained naturally within BR. OBJECTIVE: As BR juice can naturally contain both NO3 - and NO2 - the objective of this study was to evaluate the individual effects of NO3 - and NO2 - consumed from BR on plasma [NO3 -]/[NO2 -] and their subsequent effects on various cardiovascular measures. DESIGN: In four separate treatments, 11 healthy adults consumed 250 mL of BR containing one of the following: (i) high NO3 -, low NO2 - (HL; 572 mg NO3 -, 32 mg NO2 -); (ii) medium NO3 -, medium NO2 - (MM; 280 mg NO3 -, 237 mg NO2 -); (iii) low NO3 -, medium NO2 - (LM; 43 mg NO3 -, 262 mg NO2 -); (iv) placebo (PL; low NO3 -, low NO2 -: 8 mg NO3 -, 5.8 mg NO2 -). Plasma [NO3 -]/[NO2 -], blood pressure, heart rate, mean arterial pressure (MAP), cardiac output and stroke volume were measured at baseline and every hour or second hour for 6 h post-BR consumption. OUTCOMES: Ingestion of the HL and MM BR increased plasma [NO2 -] and [NO3 -] after 2 h, with both remaining elevated after 6 h (p < 0.05). LM increased plasma [NO3 -] (p < 0.05) but did not increase plasma [NO2 -] compared to PL (p = 0.177). MAP was lower following the consumption of HL at 4 h and LM at 6 h (p < 0.05). CONCLUSION: Inorganic NO3 - consumption is the critical factor in elevating plasma [NO3 -] and [NO2 -]; however, both NO2 - and NO3 - show potential to reduce MAP. The known reduction of systolic blood pressure (SBP)/diastolic blood pressure (DBP) following NO3 - supplementation was not observed, making it unclear if NO2 - contributes to a reduction in SBP/DBP alongside NO3 -.