Age-related macular degeneration: Omega-3s make the heart stronger in the elderly affected

Omega-3 supplements may act positively on the cardiac health of patients with macular degeneration, an eye disease that occurs with advancing age. However, this effect is evident in those who have not previously had cardiovascular disease or suffered from hypertension.

This is according to a study conducted as part of a trial, "The Age-Related Eye Disease Study 2" (AREDS2), which involved several scientific centers with the aim of studying the effects of different supplements on macular degeneration. The research was published in the journal JAMA Internal Medicine.

Omega-3 and cardiovascular risk

Numerous studies over the past 30 years have shown that Omega-3s have a protective effect on the heart, reducing the likelihood of heart dysfunction and protecting against sudden cardiac death. They act in several ways, most notably lowering the levels of triglycerides and circulating cholesterol, which are important cardiovascular risk factors. Omega-3s also reduce the ability of platelets to aggregate with each other, stimulate vasodilation, and thus limit the likelihood of the formation of plaques responsible for atherosclerosis.

The details of the study

There were 4,203 participants in the study with an average age of 74 years. A predominantly white, married and highly educated sample. All subjects had intermediate to advanced macular degeneration of the eye, a syndrome that affects the retina and can cause total loss of vision. The volunteers were divided into four groups. One group received a daily Omega-3 supplement consisting of 650 mg of EPA (eicohexapentaenoic acid) and 350 mg of DHA (docosahexaenoic acid); the second received a supplement of 10 mg of lutein and 2 mg of zeaxanthin, two substances belonging to the carotenoid group known for their ability to preserve eye health. A third group received both types of supplements, and finally a fourth group, the control group, took a placebo. The treatments were in addition to daily treatments consisting of vitamins and minerals formulated for patients with maculopathy.

Cardiovascular protection in non-hypertensive subjects

The results showed no statistically significant reduction in cardiovascular risk, i.e., 25 percent, among the groups that had taken the supplements compared with the control group However, by dividing the subjects into subgroups, the results differed. Among those who had received Omega-3s, only those who had never had heart disease showed benefit. In subjects who had suffered from heart disease in the past, however, the supplements did not seem to act. In addition, a 34 percent reduction in cardiovascular risk occurred in the subgroup of patients who had never suffered from hypertension. A 19% reduction in cardiovascular risk was observable in patients who had not previously had cardiovascular disease.

The limitations of the study

One of the major limitations of the research is that it took into account both healthy subjects and those with cardiovascular disease and therefore subjected to drug treatments that may have side effects. The study then was designed to reveal a reduction in the risk of heart disease in patients with macular degeneration. AREDS2, on the other hand, was designed to detect changes in retinal pathology. The final results took into account the combination of all cardiac and circulatory issues, making it difficult to compare and analyze the effects, as opposed to other studies that looked at the reduction of only one factor, such as sudden cardiac death. 

Some meta-analyses that considered both healthy and heart disease subjects showed that EPA and DHA reduced the risk of cardiac death by 9 percent. To obtain such a value, the research in question would have had to analyze 36,000 patients, whereas it considered about 4,000. Clearly, the study was underpowered and the 25% significance threshold was overestimated. As suggested by researchers Evangelos Rizos and Evangelina Tzani, a 10-15% threshold would have been more realistic for this type of research. A 10-15% reduction in cardiovascular risk due to Omega-3s, without any kind of side effect, can have an important impact when reported to the general population The two researchers also pointed out other weaknesses, such as the fact that in the study both participants and researchers were aware of the treatment being followed. 

And that there was no information on basal triglyceride levels and their trend during treatment. The action of Omega-3s could vary in subjects with high triglyceride levels compared to those with lower values. Among the patients, then, some had a reduced cardiovascular risk, but for others, as many as 20%, heart disease had already been established.

EPA and DHA help keep the heart healthy 

This study unveiled that Omega-3 supplementation may help protect heart health in individuals without a history of hypertension, and to a lesser extent in those without cardiovascular disease. In recent years, a great deal of knowledge has accumulated on the effects of Omega-3 in relation to various diseases, but the use of supplements is not yet part of daily clinical practice It will therefore be necessary to wait for more studies to fill the lack of knowledge, so that Omega-3 supplements will not be considered only for their ability to lower blood triglyceride levels. 

It is therefore a good idea to suggest to patients the regular consumption of fish as a source of Omega-3, on which there are numerous epidemiological data available to testify its efficacy. 

Source: Writing Group for the AREDS2 Research Group "Effect of Long-Chain ω-3 Fatty Acids and Lutein + Zeaxanthin Supplements on Cardiovascular OutcomesResults of the Age-Related Eye Disease Study 2 (AREDS2) Randomized Clinical Trial. "JAMA Intern Med. Published online March 17, 2014. doi:10.1001/jamainternmed.2014.328