Diabetes Mellitus Prevention with Cavsor
BENEFITS OF TAKING CAVSOR FOR PATIENTS WITH DIABETES AND FOR THE PREVENTION OF DIABETES
Cavsor contains three n-3 (also called omega-3) polyunsaturated fatty acids (PUFAs), two n-6 (omega-6) and one n-9 (omega-9) PUFAs. Whereas both n-3 and n-6 PUFAs are thought to be beneficial for patients with diabetes, in particular by improving lipid profiles, much more is known about the effects of n-3 than those of n-6 PUFAs [1]. Cavsor contains one short-chain n-3 PUFA (α-linolenic acid) and two long-chain ones (eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA).
Since fish is a good source of n-3 PUFAs, many studies have assessed the effects of n-3 PUFA intake and/or fish consumption (as a measure n-3 PUFA intake) in diabetic patients or the potential role of n-3PUFAs in the prevention of diabetes.
Effects of n-3 PUFAs in patients with diabetes
A study conducted at Harvard University examined a potential association between fish consumption or n-3 PUFA intake and the risk of coronary heart disease and total mortality in women diagnosed with type 2 diabetes The study enrolled 5,103 female diabetic patients who were initially free of cardiovascular disease or cancer. The authors found that an increase in the frequency of fish consumption resulted in a significant reduction in the risk of coronary heart disease and mortality. A similar tendency was observed for n-3 PUFA consumption [2].
A study conducted in Denmark enrolled 1,014 diabetic patients who previously had a myocardial infarction [3]. Each patient received one of three combinations of n-3 PUFAs or a placebo. The authors found that patients who received a combination of α-linolenic acid, EPA, and DHA (i.e., n-3 PUFAs included in Cavsor) had fewer ventricular arrhythmia–related events and fatal myocardial infarctions in comparison with the placebo group [3].
A forthcoming study conducted in Norway assessed the effects of supplementation with n-3 long-chain PUFAs on the risk of acute myocardial infarction in patients with coronary artery disease and concomitant diabetes (95% type 2 and 5% type 1), pre-diabetes, and those without diabetes (2,378 patients in total, 80% of them men) [4]. The authors found that high n-3 long-chain PUFA consumption was associated with a lower risk of acute myocardial infarction in patients with diabetes but with an increased risk of fatal acute myocardial infarction in those without diabetes. However, potential confounding factors in this study may have been patients’ age, because patients with diabetes were statistically significantly older; they also had a higher body mass index and more often had hypertension [4]. Nevertheless, this study suggests that patients who have coronary artery disease and diabetes at the same time would benefit from taking n-3 PUFA–containing supplements, whereas these supplements should be used with caution in patients with coronary artery disease only.
Although n-3 PUFAs do have beneficial effects in diabetic patients, it should be noted that they do not affect fasting glucose or insulin levels, as revealed by a meta-analysis of 23 clinical trials [5].
The role of n-3 PUFAs in the prevention of diabetes
A number of studies have found that consumption of large amounts of n-3 PUFAs is associated with a reduced prevalence of impaired glucose tolerance (which is a risk factor for the development of diabetes [6]) and type 2 diabetes (reviewed by Nettleton and Katz [7]). For example, Adler and coworkers [8] found that consumption of seal oil and salmon, which have a high content of n-3 PUFAs, reduces the risk of glucose intolerance. However, a recent meta-analysis of the data from nine clinical studies (438,214 participants in total) on the effect of fish or n-3 PUFA consumption on the incidence of diabetes did not find any overall effect, although the authors found an inverse association between fish consumption and the risk of diabetes in three studies conducted in Asia (Japan and China) [9]. The authors suggested that a possible reason for the difference between Eastern and Western populations may be explained by a difference in the prevalent ways of cooking fish: whereas in Asia fish is mainly consumed raw, boiled, or steamed, in Western countries it is often fried, which may reduce the content of n-3 long-chain PUFAs and increase the content of trans-fatty acids and lipid oxidation products, which are known to increase the risk of diabetes [9]. Another possible explanation could be that fish consumption in Eastern countries is higher than in Western countries, resulting in a higher n-3 long-chain PUFA intake [9]. If the latter explanation is correct, then n-3 long-chain PUFA intake via food supplements such as Cavsor could be expected to reduce the risk of development of diabetes in Western populations as well.
The beneficial effect of n-3 PUFA intake (as assessed from fish consumption) on the prevention of type 2 diabetes in Asian but not Western populations has also been revealed by an independent meta-analysis, which included 24 studies that enrolled 545,275 participants, including 24,509 patients with type 2 diabetes [10]. The authors also found that tissue levels of n-3 PUFAs in patients with diabetes were significantly lower than those in healthy participants in Asian populations but not in Western populations, and suggested that genetic differences and gene–diet interaction may play a role. However, despite the several possible explanations suggested, reasons for this difference between Asians and Westerners remain to be established.
The meta-analyses by Xun et al. [9] and Zheng et al. [10] reflect the general tendency mentioned above: many studies have assessed fish consumption as a proxy for the consumption of n-3 PUFAs. In addition to possible uncertainties because of differences in fish species consumed or different ways of cooking fish, another confounding factor in such studies may be the presence of pollutants in fish, for example mercury, which is a well-known toxin [11]. To address the uncertainties about the effect of n-3 PUFAs on the risk of type 2 diabetes, a study conducted in Finland, which lasted for almost two decades and was published in 2014 [11], directly measured the actual serum levels of n-3 PUFAs in addition to assessing their intake, and also controlled for the presence of mercury in hair. This study enrolled 2,212 middle-aged and older Finnish men, of whom 422 developed type 2 diabetes over the observation period (19.3 years). The authors found that the combined content of EPA, DHA, and docosapentaenoic acid was statistically significantly associated with a lower long-term risk of type 2 diabetes, whereas mercury had no effect [11]. Therefore, unlike studies using fish consumption as a measure of n-3 PUFA intake, this study has established a link between n-3 PUFA levels and reduced risk of type 2 diabetes also in a Western population, which warrants the use of n-3 PUFA–containing supplements (such as Cavsor) by Westerners, regardless of the level of fish consumption.
Whereas most studies have assessed the effect of n-3 PUFA on the most prevalent type 2 diabetes or combined the data for type 1 and type 2 diabetes, a recent study has reported that type 1 diabetes reduces availability of n-3 PUFA, in particular n-3 long-chain PUFA, at least in children with concomitant celiac disease [12]. Whereas the cause–effect relationship between type 1 diabetes and the content of n-3 PUFAs remains to be elucidated, this finding suggests that n-3 PUFA supplementation might benefit type 1 diabetes patients or be useful for the prevention of this form of diabetes as well.
As mentioned above, fish is a good source of n-3 PUFAs; however it also contains pollutants from seawater, such as mercury, which makes the health benefits of regularly consuming large amounts of fish questionable. In particular, mercury exposure, at least in young adults, is known to increase the risk of diabetes later in life [13]. Therefore, n-3 PUFA–containing supplements such as Cavsor are a good alternative to fish as a source of these essential fatty acids.
References
- Jeppesen, C., Schiller, K. & Schulze, M.B. Omega-3 and omega-6 fatty acids and type 2 diabetes. Curr Diab Rep 13, 279-288 (2013).
- Hu, F.B., Cho, E., Rexrode, K.M., Albert, C.M. & Manson, J.E. Fish and long-chain omega-3 fatty acid intake and risk of coronary heart disease and total mortality in diabetic women. Circulation 107, 1852-1857 (2003).
- Kromhout, D. et al. n-3 fatty acids, ventricular arrhythmia-related events, and fatal myocardial infarction in postmyocardial infarction patients with diabetes. Diabetes Care 34, 2515-2520 (2011).
- Strand, E. et al. Dietary intake of n-3 long-chain polyunsaturated fatty acids and risk of myocardial infarction in coronary artery disease patients with or without diabetes mellitus: a prospective cohort study. BMC Med 11, 216 (2013).
- Hartweg, J. et al. Omega-3 polyunsaturated fatty acids (PUFA) for type 2 diabetes mellitus. Cochrane Database Syst Rev, CD003205 (2008).
- http://www.diabetes.co.uk/impaired-glucose-tolerance.html.
- Nettleton, J.A. & Katz, R. n-3 long-chain polyunsaturated fatty acids in type 2 diabetes: a review. J Am Diet Assoc 105, 428-440 (2005).
- Adler, A.I., Boyko, E.J., Schraer, C.D. & Murphy, N.J. Lower prevalence of impaired glucose tolerance and diabetes associated with daily seal oil or salmon consumption among Alaska Natives. Diabetes Care 17, 1498-1501 (1994).
- Xun, P. & He, K. Fish Consumption and Incidence of Diabetes: meta-analysis of data from 438,000 individuals in 12 independent prospective cohorts with an average 11-year follow-up. Diabetes Care35, 930-938 (2012).
- Zheng, J.S., Huang, T., Yang, J., Fu, Y.Q. & Li, D. Marine N-3 polyunsaturated fatty acids are inversely associated with risk of type 2 diabetes in Asians: a systematic review and meta-analysis. PLoS One 7, e44525 (2012).
- Virtanen, J.K., Mursu, J., Voutilainen, S., Uusitupa, M. & Tuomainen, T.P. Serum omega-3 polyunsaturated fatty acids and risk of incident type 2 diabetes in men: the Kuopio Ischemic Heart Disease Risk Factor study. Diabetes Care 37, 189-196 (2014).
- Tarnok, A., Marosvolgyi, T., Szabo, E., Gyorei, E. & Decsi, T. Low n-3 long-chain polyunsaturated fatty acids in newly diagnosed celiac disease in children with preexisting type 1 diabetes mellitus. J Pediatr Gastroenterol Nutr 60, 255-258 (2015).
- He, K. et al. Mercury exposure in young adulthood and incidence of diabetes later in life: the CARDIA Trace Element Study. Diabetes Care 36, 1584-1589 (2013).