Cranberry Extract and Diabetes: Can They Help Regulate Blood Sugar?

Cranberry extract as a functional food is gaining importance due to its phytochemical profile. Cranberries contain catechins, triterpenoids, flavonols, hydroxycinnamic acid, anthocyanins, and proanthocyanidins¹. Cranberries contain 13.6-400 mg of anthocyanins per 100g. Cranberries are reported to contain glycosylated flavonols (myricetin and quercetin). Quercetin forms about 75% of the total cranberry flavonol content. One of the remarkable attributes of cranberries is their high proanthocyanidin content (1471-6563 mg/100 g), which makes cranberry extract an expensive supplement². There are numerous health benefits of cranberries. It is reported to possess antiviral, antibacterial, antioxidant, anti-inflammatory, anticancer and antidiabetic properties².

Elevated α-glucosidase activity is associated with hyperglycemia. In a study, it was observed that cranberry extract significantly inhibited glucosidase activity in a dose-dependent manner³. There are various clinical studies on the antidiabetic effect of cranberry extract. The hypoglycaemic effect of cranberry extract was studied in a randomized, cross-over clinical study involving 25 individuals. Cranberry supplementation significantly reduced serum glucose at 2 and 4 hours compared to control. Additionally, inflammatory markers (IL-18 and MDA) were reduced in the intervention group⁴. In a similar study, T2DM patients were advised to drink cranberry juice for 12 weeks and it was observed that cranberry supplementation significantly reduced serum glucose and apoB. Additionally, a significant increase in apo A1 and paraoxonase-1 activity was observed in the intervention group compared to placebo⁵. In another clinical study, participants were divided into two groups; one group received oral hypoglycemic drugs (metformin and sulfonylurea), while another group received cranberry extract in addition to oral hypoglycemic drugs⁶. It was observed that cranberry extract enhanced the efficacy of oral hypoglycemic drugs.

It can be concluded that cranberry extract module blood glucose levels and exerts its hypoglycemic effects by stimulating insulin secretion and inhibiting α-glucosidase activity.

References

1. Neto, C. C. Cranberry and Its Phytochemicals: A Review of In Vitro Anticancer Studies 1-3; 2007; Vol. 137.
2. Khalil, R. R.; Mohammed, E. T.; Mustafa, Y. F. Various Promising Biological Effects of Cranberry Extract: A Review. Clinical Schizophrenia and Related Psychoses. Walsh Medical Media, LLC 2021. https://doi.org/10.3371/CSRP.KRET.113021.
3. Pinto, M. da S.; Ghaedian, R.; Shinde, R.; Shetty, K. Potential of Cranberry Powder for Management of Hyperglycemia Using In Vitro Models. J Med Food 2010, 13 (5), 1036–1044. https://doi.org/10.1089/jmf.2009.0225.
4. Schell, J.; Betts, N. M.; Foster, M.; Scofield, R. H.; Basu, A. Cranberries Improve Postprandial Glucose Excursions in Type 2 Diabetes. Food Funct 2017, 8 (9), 3083–3090. https://doi.org/10.1039/c7fo00900c.
5. Shidfar, F.; Heydari, I.; Hajimiresmaiel, S. J.; Hosseini, S.; Shidfar, S.; Amiri, F. The Effects of Cranberry Juice on Serum Glucose, ApoB, ApoA-I, Lp(a), and Paraoxonase-1 Activity in Type 2 Diabetic Male Patients; 2012; Vol. 355.
6. Majid, A.; Al-Juhaishi, R.; Al-Khafaji, T.; Mustafa, R.; Alshehristani, M.; Hussien Mousa, T.; Al-Shehristani, M. Effect of Cranberry in Enhancing Oral Hypoglycemic Agents in Uncontrolled Type-II Diabetic Patients; 2019. https://www.researchgate.net/publication/330144785.