NAFLD and liver fibrosis are common in people diabetes and can lead to more serious liver conditions (1). This study was important because it looked at the role of ginger in supporting the liver in diabetic patients. They had a rigorous selection procedure to ensure that patients with similar levels of disease were selected.

The study showed that 2g ginger a day in capsules for 3 months improved systolic and diastolic blood pressure, showed a tendency to improve weight and anthropometric measures although was not significant, and had no effect on blood biochemistry compared to a placebo. There were no changes to the fat of fibrotic nature of the liver.

There is a host of clinical research on the effects of ginger in diabetes and metabolic syndrome. For example one study saw improvements in blood glucose and lipids following 2g daily ingestion of ginger powder (2). It could be that the present study was perhaps underpowered (patient numbers were too low) or there was too much variation between the patient groups.

In the abstract of the paper they state that for the ginger group there were improvements in insulin resistance and HDL-cholesterol over time, although the data was not shown within the paper. There were equal proportions of men and women in the ginger group and proportionally far more females in the placebo group, and whether this would have affected the results is not clear.

Although the dietary intakes were recorded they were not reported, and it is not clear how detailed these were. As we know, a host of other herbs and spices like fenugreek and cinnamon (3) that influence metabolic function, so it is also possible that dietary intake may have influenced the results.

It is interesting to note that the ginger group tended to reduce their physical activity and increase calorific intake during the study, and the opposite was seen in the placebo group. Both physical activity or food intake should have been more tightly controlled, and certainly, future studies could look at the combination of ginger along with lifestyle improvements to improve metabolic health.

Ginger has anti-inflammatory properties but in this study did not alter systemic inflammatory markers like TNF alpha or produce any noticeable visible changes to the liver anatomy. Fibrosis is a slow progressing condition so it is likely that any improvement may not occur rapidly. Other studies have shown that ginger can significantly alter systemic inflammation, and a meta-analysis that pooled the results of 20 randomised-controlled trials found that CRP, TNF-alpha and IL-6 were all altered, with the doses of ginger ranging between 0.5 and 3 g per day for up to 3 months.

It was interesting to see in this paper that does of 1-2g of ginger for 2-3 months seemed to be an optimal duration, and results were more pronounced in older patients over 40 years of age compared to younger age groups. One might speculate that general inflammation is more pronounced in the older groups (4). 

The final point of variation could be around the quality and composition of ginger. For this study fresh ginger was purchased at a local market in Iran and authenticated, showing 36.7% zingiberene and other volatile compounds. The drying and storage conditions can greatly alter the chemical composition of a herb (5). In the present study it did not state the drying temperature, but this may have altered the potency of the final preparation.