Science shorts: Latest research on feijoa fruit, rice endosperm protein, and beetroot juice

Beetroot juice intake found to improve muscle recovery among female athletes after high-pressure training – Iran RCT​  ​

Beetroot juice supplementation among female volleyball players was found to improve muscle endurance and pain reduction after high-pressure training, says researchers.

The beetroot juice group saw significant decreases in perceived muscle soreness after 12, 24 and 48 hours of exercise-induced muscle damage (EIMD) as compared to the placebo group.

The results were based on a crossover, randomised, and double-blinded study design conducted during two phases with a 30-day interval. It involved 12 young female semi-professional volleyball players with almost five years of volleyball experience.

Health and trade potential: NZ’s backyard fruit Feijoa studied for its ability to prevent diabetes​  ​

New Zealand researchers are beginning a six-month study in Auckland exploring feijoa powder’s ability in preventing diabetes. Obtaining a health claim would also support the country’s export ambitions in Asia for the backyard staple.

Dr Jennifer Miles-Chan told NutraIngredients-Asia​ that it would be a double-blind randomised controlled trial involving 160 participants who are prediabetic and obese or overweight.

The feijoa fruit is high in polyphenols, such as tannic acid, that are commonly found in green tea and colourful fruits and vegetables. These active compounds are largely found in the skin of the fruit which tends to be discarded.

Diet diversity: Higher migraine frequency linked to less diverse diets – study​  

Dietary intake from diverse food groups could have a positive impact on the frequency of migraine and serum levels of nitric oxide, say researchers.

This is according to a study involving 262 Iranians aged between 20 and 50.

Findings showed that the higher the dietary diversity score, the lower the headache frequency and serum levels of nitric oxide. This shows that the quality of diet in people suffering from migraine is low, said the researchers.

Similar efficacy found between daily and intermittent supplementation of vitamin D – meta-analysis​  

There is “no significant difference” between the efficacy of daily and intermittent vitamin D supplementation under equivalent dosage and duration conditions, say Chinese researchers.

This is based on their review of 116 studies involving 11,376 participants.

Findings showed that there were no statistically significant differences in serum vitamin D concentration in the group taking vitamin D daily and the group taking vitamin D intermittently.

Single intake of rice endosperm protein (REP) may improve anxiety, nervousness – Japan RCT​  

The single intake of REP (rice endosperm protein) hydrolysate reduced anxiety and nervousness, but repeated intake over four weeks had limited effects on the mood state of participants, says Japanese researchers.

Significant results were observed in the subjective, for example tension–anxiety subscale, and objective measurements, such as salivary chromogranin A Concentrations for the intervention group after a single intake of REP hydrolysate.

However, limited effects were seen after repeated intake for four weeks, which the researchers said might be insufficient and might require a longer intervention period.