Reviewed: Tajaddini A, Roshanravan N, Mobasseri M, et al. Saffron improves life and sleep quality, glycaemic status, lipid profile and liver function in diabetic patients: A double-blind, placebo-controlled, randomised clinical trial. Int J Clin Pract. August 2021;75(8):e14334. doi: 10.1111/ijcp.14334.
Abnormal blood glucose levels associated with type 2 diabetes mellitus (T2DM) increase the risk of heart disease, nerve damage, kidney disease, eye and skin disorders, sleep apnea, and possibly dementia. They can also cause sleep disorders and sexual dysfunction, diminish quality of life, and increase the risk of depression. The use of oral medications to manage the disease can sometimes result in severe adverse events. Studies have reported that saffron (Crocus sativus, Iridaceae), which has antioxidant and anti-inflammatory effects, may be an effective adjunctive therapy for T2DM. Studies also indicate that saffron may help treat depression and impaired sexual function. In this randomized, double-blind, placebo-controlled clinical trial, the authors investigated the effects of saffron supplementation on glycemic status, lipid profiles, liver function, mood, sexual function, sleep, and quality of life in people with T2DM.
The study was conducted from December 2017 to June 2018 and included 70 participants who were 30-60 years old, were overweight or obese, and had been diagnosed with T2DM for at least six months before the study. They were patients at the Endocrine and Metabolism Clinic of Tabriz University of Medical Sciences in Tabriz, Iran. Those who had been treated with insulin, hormone replacement therapy, or dietary or antioxidant supplements during the previous two months were excluded. The authors also excluded women who were pregnant or lactating and patients who had a history of surgery, serious illness, smoking, or alcohol intake.
For eight weeks, the 35 participants in the intervention group and 35 participants in the placebo group took one capsule daily before a meal. The capsules contained either 100 mg of saffron stigma powder or 100 mg of maltodextrin starch (placebo). Participants continued their usual dietary intake and physical activity and were monitored weekly by phone for the occurrence of any adverse events.
Anthropometric and dietary intake assessments were conducted at baseline and at the end of the study. These tools were used to assess the study outcomes: the Beck Depression Inventory-II (BDI-II), the Hurlbert Index of Sexual Desire (HISD), the Pittsburgh Sleep Quality Index (PSQI), the Diabetes Quality-of-Life-Brief Clinical Inventory (DQOL-BCI), and biochemical assays.
Baseline characteristics were similar between the two groups. No adverse events were reported during the study. Participants were 51.2 ± 10.3 years old, and their disease duration was 5.5 ± 4.5 years. Five participants in each group did not complete the study. In the saffron group, three withdrew because they lived far from the clinic, and two dropped out because of pregnancy. In the placebo group, three were dissatisfied with the treatment, and two withdrew because of personal reasons.
In the saffron group, significant reductions were observed in fasting plasma glucose (FPG), insulin, triglycerides, homeostatic model assessment of insulin resistance (HOMA-IR), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) compared with baseline (P < 0.001 for all). In the placebo group, low-density lipoprotein cholesterol (LDL-C; P = 0.03) and AST (P= 0.003) levels increased, and ALT levels decreased (P < 0.001) compared with baseline. Between-group comparisons revealed greater improvements in the saffron group compared with the placebo group for FPG (P = 0.04), insulin (P = 0.03), HOMA-IR (P = 0.01), triglyceride levels (P = 0.004), total cholesterol (P = 0.001), LDL-C (P = 0.008), AST (P = 0.002), and ALT (P = 0.01).
Scores on the BDI-II and DQOL-BCI significantly improved in the saffron group compared with baseline and compared with the placebo group (P < 0.001 for all). HISD scores did not change significantly in either group. On the PSQI, sleep quality (P = 0.01), duration (P = 0.02), efficiency (P = 0.04), and daytime functioning (P < 0.001) significantly improved in the saffron group compared with the placebo group. Both groups showed an improvement in the global PSQI score; however, the improvement was greater in the saffron group (P < 0.001).
Limitations of this study include its short duration and the fixed-dose design, which prevented the investigation of dose-dependent effects of the saffron intervention. (According to a peer reviewer of this article, significantly lower doses of saffron have been shown to have beneficial effects on sleep quality, for example, in clinical trials.1,2) Some dietary factors, which could have been confounders, were not evaluated.
The authors concluded that “saffron appears to have anti-diabetic effects” as it reduced hyperglycemia and levels of triglycerides and liver enzymes in people with T2DM, who also experienced improvements in depression, sleep quality, and overall quality of life.
- Lopresti AL, Smith SJ, Drummond PD. An investigation into an evening intake of a saffron extract (affron®) on sleep quality, cortisol, and melatonin concentrations in adults with poor sleep: A randomised, double-blind, placebo-controlled, multi-dose study. Sleep Medicine. 2021;86:7-18.
- Lopresti AL, Smith SJ, Metse AP, Drummond PD. Effects of saffron on sleep quality in healthy adults with self-reported poor sleep: A randomized, double-blind, placebo-controlled trial. Journal of Clinical Sleep Medicine. 2020;16(6):937-947.