Patrick Holford is promoting a new supplement, Cinnachrome, to support his GL Diet. He claims that it is “specifically designed to support natural blood sugar balance”. Cinnachrome sounds delightful, like something that could be used to spice an apple pie but there is little to indicate that it might be that useful. Holford writes:
Cinnachrome contains a combination of chromium and cinnamon, nutrients which have shown to be useful for anyone needing to pay particular attention to their blood sugar levels. Chromium polynicotinate is a natural form of chromium that provides two major ingredients of the glucose tolerance factor – chromium and niacin (nicotinic acid). Cinnulin PF is a concentrate extract of Cinnamon. The combination of chromium with cinnamon makes this powerful, natural formula ideally suited to all those following a low GL diet.
As a matter of interest, a Google search on the term “blood sugar balance” returned mostly supplement information, varying from cinnamon, bitter melon, fenugreek or chlorella to sources of fibre: reference 32 was to the abstract of a paper; there were possibly another half dozen general articles in the top 100 hits. So, it seems as if there are lots of pill distributors with more or less plausible stories as to why their supplements should contribute to “blood sugar balance”.
Is the clinical evidence for cinnamon or chromium any better than the claims made for bitter melon, fenugreek etc.? It seems not but at least there are some trials (albeit of variable quality) on which to base that assessment. A number researchers have investigated whether chromium supplementation has a beneficial effect for glucose or lipid metabolism: most of these studies or trials have involved people with Type 2 diabetes. A systematic review of the relevant randomised controlled chromium supplementation trials by Balk et al. concludes that:
[n]o significant effect of chromium on lipid or glucose metabolism was found in people without diabetes.
The authors do add that:
[t]he evidence was limited by poor study quality, heterogeneity in methodology and results, and a lack of consensus on assessment of chromium status.
However, at present, a review of the clinical evidence does not support the use of chromium to modify glucose metabolism in people without diabetes. It is worthwhile mentioning that these trials involve different forms of chromium which may have a different bio-availability than the chromium polynicotinate in this supplement and which has been the subject of comparatively little research (we comment futher on the quality of research on chromium elsewhere).
There have been some interesting studies on cinnamon but few on continuous rather than experimental use and even fewer involving healthy people rather than those with Type 2 diabetes. E.g., Effect of cinnamon on postprandial blood glucose, gastric emptying, and satiety in healthy subjects: cinammon supplementation delayed gastric emptying but did not affect satiety.
When discussing the evidence for cinnamon as your blood sugar’s best friend Holford relies upon animal studies and studies in people with Type 2 diabetes however, these may be of limited relevance to people who are not diabetic. In a recent study of people with diabetes, cinnamon supplementation did not improve diabetic control in a western population. Interestingly, the authors commented that there were significant baseline differences between their study population and that in a previous trial that had reported benefits. Participants in the previous study had much higher fasting glucose and triglyceride levels, and they were using different anti-diabetic medications and combinations of them. The participants in the US trial seem to have much better control of biomarkers such as glucose and triglyceride levels. Such a difference might suggest that there is even less evidence to support the use of cinnamon in people who do not have dysregulated glucose metabolism.
There is no substantial evidence to support chromium supplementation for the people with Type 2 diabetes, far less the general population. Cinnamon may have its uses as a spice but it is premature at best to recommend it for use by either the general population or people with Type 2 diabetes. It is difficult to understand why Cinnachrome might “support natural blood sugar balance” whether or not somebody is on a low GL diet.
Update October 17: There was some interesting correspondence that followed-up the Balk chromium review mentioned above. Kleefstra et al commented on the inclusion of a study that involved a large number of people in China that skewed the results substantially because of the relatively large number of people in the trial. when compared to other trials that were included. There is some discussion of the apparent consistency in various studies that argues for looking at outcomes for different groups rather than all diabetics:
Western and non-Western patients, as it seems that the beneficial effects on A1C are for the most part found in studies in non-Western countries.
The letter authors argued that
chromium has no (relevant) effect on A1C, especially not in Western patients with type 2 diabetes.
Consequently, they expressed the belief that future trials should concentrate on assessing the impact of chromium supplementation on those who are known to be chromium deficient rather than all diabetics. They acknowledged the lack of consensus for a test to establish chromium deficiency.
In their Authors’ Response, Balk et al did not make a good case for their inclusion of the disputed study. They restate their position that, “available trials on chromium supplementation are of poor quality and have heterogeneous results” which is not a good reason for including them. They go on to acknowledge again that:
[t]he overall poor quality of the evidence clearly limits any conclusions that are drawn about the effect of chromium supplementation.
They concluded by agreeing that there is a need for a consistent and reliable test to establish a individual’s chromium status and that:
well-conducted trials in clearly defined populations (preferably with an indicator of chromium status) are needed before definitive conclusions can be made about the value of chromium supplementation.
Update 2 Jan 2008: (courtesy of commenter). Baker et al have performed an analysis of the 5 prospective RCTs: Effect of cinnamon on glucose control and lipid parameters. In summary, a meta-analysis of several trials shows that cinnamon does not have a beneficial effect on the blood glucose or cholesterol levels of people with Diabetes Type I or II; this result holds true even for sub-groups.
None of the trials reported significant changes in the usual critical biomarkers for diabetics such as Ac1 (the test that gives a longer-term, better insight into blood sugar control than the snapshot of the fasting blood glucose test); the fasting blood glucose levels (FBG); or the breakdown of cholesterol levels. The results held true for both diabetes Type I and Type II; they were also true for all of the sub-groups analyses that looked to identify any group of people for whom there might be some benefit.