Omega-3s, allies of cardiovascular health, could protect against the risks of diabetes. A new study helps to understand when and in what doses to take them, and what benefits to expect.
Is it worth taking Omega-3s to protect the heart and arteries from the risks inherent in diabetes? Years of research have shown the importance of these fats for heart health; a new study helps to understand when and in what doses they should be taken and what benefits can be expected from this supplementation.
Published in the New England Journal of Medicine and conducted at the University of Oxford in the United Kingdom, the study in question involved more than 15 thousand patients with diabetes, monitoring their health for an average of as much as 7.4 years. About half of the patients were asked to take an Omega-3 capsule every day; the other half, however, were made to take olive oil.
From published data it would seem that in the absence of cardiovascular problems for those living with diabetes, taking Omega-3 or olive oil would not make a difference. However, a closer analysis reveals benefits in terms of reducing deaths from vascular causes. Moreover, the benefits of Omega-3 intake may be more pronounced with adequate doses of these essential fatty acids.
Diabetes and cardiovascular risk
Cardiovascular disease is one of the leading causes of death for people living with type 1 diabetes, and in this respect the heart of those who develop type 2 diabetes cannot be considered peaceful either. This form of diabetes is also associated with an increased incidence of cardiovascular problems and mortality from heart and artery disease.
Most of the studies on the subject have been conducted precisely on patients with type 2 diabetes and have led to estimates of an increase in coronary artery disease and ischemic stroke ranging between 2 and 4 times; the increase in mortality, on the other hand, is estimated to vary between 1.5 and 3.6 times. Added to this is the fact that type 2 diabetes is a major risk factor for heart failure, peripheral arterial insufficiency, and microvascular complications-all issues that adversely affect both quality and life expectancy, so much so that in the presence of diabetes the latter is reduced by 4 to 8 years.
Underlying this increased cardiovascular risk are well-known problems:
- Hypertension, which is associated with insulin resistance. It is not uncommon for diabetes to be associated precisely with hypertension, and this combination doubles cardiovascular risk.
- Increased triglycerides and LDL ("bad cholesterol") and HDL ("good cholesterol") levels below desirable standards. This set of factors is characteristic of atherogenic dyslipidemia, which in the presence of diabetes is called diabetic dyslipidemia.
Omega-3 and cardiovascular risk
Omega-3s have attracted the interest of researchers precisely because of their link to cardiovascular health. The first studies date back nearly 50 years, when it was observed that in Greenland Eskimo populations, heavy consumers of fish rich in these fatty acids, the incidence of atherosclerosis was significantly reduced.
The European Food Safety Authority(EFSA) concluded that Omega-3s are legitimate to attribute several health properties, including:
- Contribute to normal heart function and maintenance of normal blood pressure and triglycerides (EPA and DHA).
- Contribute to the maintenance of cholesterol values in the normal range (ALA).
Omega-3 and diabetes: the study
The one conducted by the Oxford researchers is not the first study to test the hypothesis that Omega-3 intake may help combat cardiovascular risk associated with diabetes. In patients with type 2 diabetes, for example, taking EPA compared with a placebo was associated with a significant reduction in triglycerides and non-HDL cholesterol.
This new study shows a lower incidence of death from vascular causes among participants who took Omega-3 compared to those who took olive oil (196 cases compared to 240). However, the authors suggest that greater benefits could be achieved with higher dosages, 2 to 4 g per day of EPA+DHA, than the 840 mg used in the study.
In addition, the EPA/DHA ratio appears to influence the results: the study used a ratio of 1.2, but previous analyses indicate more pronounced benefits when that ratio is at least 1.5. This suggests that higher doses and a higher EPA/DHA ratio may be associated with significant cardiovascular benefits.
The importance of patients' nutritional status
Another crucial factor was the nutritional status of the participants. Experts reported that subjects who took Omega-3 had an already high Omega-3 Index, close to the level considered protective. In other words, many participants may have had no real need for supplementation.
In addition, the high intake of food-derived Omega-6-common in Western diets-can compromise cardiovascular health, making it important to maintain a balanced ratio of Omega-3 to Omega-6, which was not analyzed in this study.
Omega-3s against diabetes: a viable way forward
Available evidence suggests that Omega-3 supplementation can provide real benefits to people living with diabetes, provided the right conditions are met: dose, EPA/DHA ratio and patient's health status. According to EFSA, to maintain:
- Triglycerides in normal range: 2 g EPA+DHA daily
- Blood pressure in normal range: 3 g EPA+DHA daily
- Cardiac function: 250 mg EPA+DHA daily
- Cholesterol in normal range: 2 g ALA daily
Sources
- American Heart Association. Cardiovascular Disease and Diabetes.
- ASCEND Study Collaborative Group. Effects of n-3 Fatty Acid Supplements in Diabetes Mellitus. N Engl J Med, 2018
- Casaccia Bertoluci M, Zorzanelli Rocha V. Cardiovascular risk assessment in patients with diabetes. Diabetol Metab Syndr, 2017
- Chen C et al. Effects of Omega-3 Fatty Acid Supplementation on Glucose Control and Lipid Levels in Type 2 Diabetes. PLoS One, 2015
- Dyerberg J, Bang HO. Haemostatic function and platelet polyunsaturated fatty acids in Eskimos. Lancet, 1979
- European Commission. EU Register of nutrition and health claims made on foods.
- Lee SI et al. Cardiovascular disease and type 1 diabetes. Ther Adv Chronic Dis, 2015
- Schultz H. Omega-3s fail to prevent heart events in trial on diabetics. NutraIngredients-USA, 2018.
- Tajuddin N et al. Prescription omega-3 fatty acid products: considerations for patients with diabetes mellitus. Diabetes Metab Syndr Obes, 2016
- Tenenbaum A, Fisman EZ. Omega-3 polyunsaturated fatty acids supplementation in patients with diabetes and cardiovascular disease risk. Cardiovasc Diabetol, 2018
