β-Carotene, the most abundant provitamin A carotenoid in the diet, is converted to retinal by β-carotene 15,15'-monoxygenase (BCMO1). However, β-caro

A number of epidemiological studies have suggested that diets rich in whole grains are linked to lower cardiovascular disease (CVD) risk and mortality. Quinoa, a pseudo-cereal, is included in the “whole grain” category but the effects of quinoa consumption in humans is not widely studied. Our aim was to undertake a dietary intervention study to investigate the effects of daily consumption of quinoa-enriched bread (providing 20 g quinoa flour) on CVD risk markers compared with a 100% refined wheat bread control. Thirty-seven healthy overweight men (35–70 years, body mass index >25 kg/m²) completed a 4-week cross-over intervention, separated by a 4-week washout period. Fasting blood samples were collected at the beginning and end of each intervention period. Continuous glucose monitoring was undertaken at the end of each intervention period. After 4 weeks of intervention, blood glucose and low density lipoprotein (LDL) cholesterol were significantly lower than baseline in both groups but there was no difference between quinoa and control. Anthropometric measures and other blood metabolites were not different between the two treatments. The cumulative area under the blood glucose curve for the last 4 days of the quinoa intervention tended to be lower than the first 4 days of wash-out (p = 0.054), and was significantly lower than the corresponding period of the wheat treatment (p = 0.039). In conclusion, daily consumption of quinoa in this short-term intervention appears to modify glucose response, but has minimal effects on other CVD risk biomarkers.

Quinoa, a gluten‐free pseudocereal, has a nutrient and phytochemical profile which may benefit health. Our aim was to investigate the variability in the phenolic and apparent antioxidant content of different quinoa varieties to identify a variety with a high phytochemical content to use in a quinoa‐enriched bread. The results showed that free phenolics contributed most (50–83%) to total phenolic content compared with conjugated or bound forms. Apparent antioxidant activities measured by FRAP, ABTS+• and DPPH of free, conjugated and bound extracts were broadly similar, except for free antioxidants when determined by FRAP, which were higher. Phenolic content was positively correlated with FRAP and ABTS+• apparent antioxidant activity. Quinoa samples had a high protein content (13.5 g/100 g dry weight), with a well‐balanced amino acid profile. Incorporation of quinoa into baked products such as bread is proposed as a way to deliver this healthy whole‐grain cereal into the diet.