Citrus fruit contains many polyphenolic compounds including anthocyanins, which may have an anti-obesity effect. Moro orange is a cultivar of red-orange, particularly rich in active compounds such as anthocyanins, hydroxycinnamic acids, flavone glycosides, and ascorbic acid, which displays anti-obesity effects in many studies.

 

    A double-blind, randomized clinical study that assessed the effectiveness of a "Moro" orange standardized extract over a 6-month supplementation period on weight loss was conducted in Brisbane, Australia. Overweight (25 < BMI <35 kg/m2) yet otherwise healthy female and male volunteers aged 20 to 65 years were recruited. The treatment supplement was in capsule form, each capsule containing 400 mg of standardized extract, taken with water after breakfast.

 

    The final composition of the standardized extract was as follows: cyanidin 3-O-glucoside (0.635% w/w), cyanidin 3-O-glucoside and derivatives (>0.699% w/w), hesperidin (2.13% w/w), narirutin (0.07%w/w), ferulic acid (1% w/w) and ascorbic acid (4.5% w/w). The placebo was maltodextrin in a matching capsule and administered using the same procedure.

 

    All participants received the same standard advice regarding physical activity. Specifically, participants were asked to undertake 30 minutes of walking 3 times per week and record all physical activity in their diaries. The study participants were also asked to follow a calorie-controlled diet, with the daily calories to be consumed by each participant calculated using the basal metabolic rate score from the individual body scans. Participants recorded their daily food intake and submit a 24-hour food recall every two months during the study. Participants then attended the study site after their baseline for a repeat of body measures every month.

 

    Compared to baseline, both groups had a significant reduction in body weight after the study (6-months). Participants on "Moro" orange standardized extract had a mean overall weight loss of 4.2% of starting body weight by month 6, and the placebo group had a mean overall weight loss of 2.2% of starting body weight. The change in body weight between groups was significantly different (p = 0.015). Additionally, 36% of the participants in the treatment group had a weight loss of more than 5% vs. 22.5% of the participants in the placebo group. The weight loss (kg) at the end of the study in both groups was statistically significant from baseline values, and there was a significant difference between groups at months 4 and 6.

 

    Both the treatment and placebo groups had a significant reduction in the waist (3.9 cm vs. 1.7 cm, respectively) and hip (3.4 cm vs. 2.0 cm, respectively) circumference from baseline following 6-month of supplementation. The treatment group had a significant reduction in both hip and waist circumference at 6-months compared to the placebo group (p = 0.017 and 0.049, respectively).

 

    Both the treatment and placebo groups had a significant reduction in fat mass after 3 and 6-months of supplementation (p < 0.05). However, at both 3 and 6-months, the treatment group had a significant reduction in fat mass compared with the placebo group (p = 0.01 and 0.012). This was supported by the lean muscle mass data that remained constant in both groups over the 6 months of the study. The treatment group also showed a significant reduction in the amount of abdominal fat at months 3 and 6 compared to placebo (p = 0.01 and 0.018). Additionally, visceral, and subcutaneous fat were reduced significantly at month 6 compared to placebo (p = 0.018 and 0.006, respectively).

 

    The Moro oranges had the highest levels of anthocyanins among the three common bloody orange varies (Moro, Tarocco, and Sanguinello). Of 281 Moro orange samples, the levels of anthocyanins were 16.8 ± 3.2 mg/100 g (mean ± standard deviation SD), with a range (P 5–95%) of 13.0–22.9 mg/100 g. The Tarocco oranges of 586 samples had a mean value of 6.2 mg/100 g of anthocyanins, while the SD = 0.3 and the range = 5.7–6.8 mg/100 g. The Sanguinello oranges comprised 77 samples. The anthocyanins in these samples were at 4.7 mg/100 g with an SD of 2.0 and a range (P 5–95%) of 1.4–8.0 mg/100 g, for composite samples (2).

 

    The vitamin C level in the Moro oranges among 87 samples had a mean value of 50.6 mg/100 g and a range (P 5–95%) of 46.4–54.8 mg/100 g. The ascorbic acid distribution in the Tarocco oranges was based on 545 samples. The mean value was 61.2 mg/100 g and the range (P 5–95%) was 59.5–62.9 mg/100 g. The ascorbic acid data in the Sanguinello oranges were based on 41 samples. The mean value was 52.0 mg/100 g and the range (P 5–95%) was 48.4–55.7 mg/100 g (2).

 

    The analytical results of the 400-mg study capsule from the study (1) showed that cyanidin 3-O-glucoside (0.635% w/w), cyanidin 3-O-glucoside and derivatives (>0.699% w/w), hesperidin (2.13% w/w), narirutin (0.07%w/w), ferulic acid (1% w/w) and ascorbic acid (4.5% w/w), which included ~ 5.3 mg anthocyanins and 4 mg ferulic acid.

 

    The mean levels reported for Moro oranges were: anthocyanins 16.8 ± 3.2 mg/100 g and ferulic 4.3 ± 0.5 mg/100 g (2). Perhaps eating 100 g per day of Moro blood oranges would provide more than enough of the bio-actives that were contained in the 400 mg capsule in the weight loss study (1). Even the less bloody variety Sanguinello oranges contained 4.7 ± 2.0 mg/100 g anthocyanins and 4.2 ± 0.3 mg/100 g ferulic acid, close to the bio-active levels contained in the study capsule.

 

    As shown in the study (1), the average starting body weights were 88.4 ± 11.2 kg for the treatment group and 90.8 ± 13.8 kg for the placebo group, respectively. There was a 4.2% body weight loss over 6 months for the treatment group and the average weight was 84.7 ± 11.7 kg (~4 kg weight loss) by the end of the study. The average body weight for the placebo group at 6 months was 88.8 ± 14.5 kg (~2 kg weight loss), which was a 2.2% weight loss from the baseline.

 

    Compared to the 2.2% body weight loss in the placebo group, the treatment group who were taking bloody orange supplements doubled the weight loss (4.2%) over the 6 months. The good part is that the weight loss was primarily the fat loss since the lean muscle mass stayed constant. Based on this study's findings, if you want to lose weight, eating one bloody orange per day may help you to double your weight/fat loss.

 

References:

1. Briskey, D., Malfa, G. A., Rao, A. (2022). Effectiveness of "Moro" Blood Orange Citrus sinensis Osbeck (Rutaceae) Standardized Extract on Weight Loss in Overweight but Otherwise Healthy Men and Women-A Randomized Double-Blind Placebo-Controlled Study. Nutrients. 18;14(3):427. doi: 10.3390/nu14030427.

2. Fallico, B., Ballistreri, G., Arena, E., Brighina, S., & Rapisarda, P. (2017). Bioactive compounds in blood oranges (Citrus sinensis (L.) Osbeck): Level and intake. Food Chemistry, 215, 67–75. doi:10.1016/j.foodchem.2016.07.142