Previous studies have reported that zinc and curcumin may individually offer glycemic benefits, no study to date has examined the potential of the combination, according to the researchers.
Data published in Phytotherapy Research indicated that the combined supplement led to a range of improvements in glycemic measures, including for fasting glucose, insulin, insulin sensitivity and resistance, and HbA1c (glycated hemoglobin), a marker of long-term presence of excess glucose in the blood, compared to placebo.
The researchers, led by Maryam Azhdari from the Ahvaz Jundishapur University of Medical Sciences, called the improvements “remarkable” and “the most important findings of this trial”.
Significantly greater improvements in BMI were also report, even though all of the participants were told to consumer a hypocaloric diet and exercise. However, the researchers noted that exercise levels did not change during the trial, which took place last year when Iran, like many countries, imposed lockdowns that limited time out of the home.
Dr Azhdari and her co-workers recruited 84 overweight or obese pre-diabetic people to participate in their randomized, placebo‐controlled trial. The volunteers were randomly assigned to one of four groups: Zinc only (30 mg per day), curcumin only (500 mg of BCM95), zinc plus curcumin, or placebo for three months.
Results from the 82 people who completed the study showed that there were no significant differences between the groups for dietary micronutrient intakes, exercise, and body weight, but the zinc and zinc plus curcumin groups experienced decreases in BMI, compared to placebo.
The researchers note that no zinc deficiency was observed for the groups, but the zinc supplement groups both displayed significant increases in serum zinc levels. Both zinc groups also displayed significant reductions in BMI, which were greater than those seen in the placebo and curcumin-only groups.
For the glycemic measures, all three supplement groups displayed improvements, with great statistical significance in the combination group.
Commenting on the potential mechanisms of action, Dr Azhdari and her co-workers noted that curcumin’s effects may be linked to its ability to impact body weight, while zinc may work via multiple pathways, from direct effects on insulin production and secretion in the pancreas to anti-inflammatory and antioxidant effects or an impact on the formation of fat cells or other mechanisms.
“Further RCTs are suggested with longer duration, different doses, diversity in the form of the supplements (i.e., syrup, nano‐capsule, nano‐tablet, or nano oral solution), and multiple centers,” wrote the researchers.
“… this study is unique due to the use of zinc and curcumin supplements in prediabetic subjects,” they added.
Source: Phytotherapy Research
Published online ahead of print, doi: 10.1002/ptr.7136
“The effect of curcumin and zinc co‐supplementation on glycemic parameters in overweight or obese prediabetic subjects: A phase 2 randomized, placebo‐controlled trial with a multi‐arm, parallel‐group design”
Authors: M. Karandish, et al.