Age-Related Macular Degeneration: Omega-3 Make the Heart Stronger in Affected Elderly

Supplements containing Omega-3 may positively affect the heart health of patients with macular degeneration, an age-related eye disease. However, this effect is evident only in those who have never had cardiovascular disease nor suffered from hypertension before.

This emerges from a study conducted as part of the "Age-Related Eye Disease Study 2" (AREDS2), which involved several scientific centers aiming to investigate the effects of various 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-3 fatty acids exert a protective effect on the heart, reducing the likelihood of cardiac dysfunction and protecting against sudden cardiac death. They act in various ways, particularly by lowering circulating triglycerides and cholesterol levels, which are important cardiovascular risk factors. Omega-3 also reduce platelet aggregation, stimulate vasodilation, and thereby limit the formation of plaques responsible for atherosclerosis.

Study Details

The study involved 4,203 participants with an average age of 74 years. The sample mainly consisted of white, married, and highly educated individuals. All subjects had intermediate or advanced macular degeneration, a syndrome affecting the retina that can lead to total vision loss. Volunteers were divided into four groups: one received a daily Omega-3 supplement containing 650 mg of EPA (eicosapentaenoic acid) and 350 mg of DHA (docosahexaenoic acid); another received a supplement with 10 mg lutein and 2 mg zeaxanthin, carotenoids known for preserving eye health; a third group received both supplements; and a control group received a placebo. Treatments were in addition to daily vitamins and minerals formulated for maculopathy patients.

Cardiovascular Protection in Non-Hypertensive Subjects

Results did not show a statistically significant 25% reduction in cardiovascular risk between supplement groups and control. However, subgroup analysis revealed different outcomes: only participants who had never experienced heart disease benefited from Omega-3 supplementation. Those with previous cardiac conditions did not show benefits. Additionally, a 34% risk reduction was observed in patients without a history of hypertension, and a 19% reduction was seen in those without prior cardiovascular diseases.

Study Limitations

A major limitation of the research is that it included both healthy individuals and those with cardiovascular diseases, who were undergoing treatments that might have side effects. The study was initially designed to detect a reduction in heart disease risk in macular degeneration patients, while AREDS2 aimed to observe changes in retinal pathology. Final results combined all cardiovascular and circulatory issues, complicating comparisons and effect analysis, unlike other studies focused on a single factor such as sudden cardiac death.

Some meta-analyses involving both healthy and cardiac patients showed that EPA and DHA reduce the risk of cardiac death by 9%. To detect a similar effect, this study would have needed to analyze 36,000 patients, but only about 4,000 were included. It is clear the study was underpowered and the 25% significance threshold was overestimated. Researchers Evangelos Rizos and Evangelina Tzani suggested a more realistic threshold would be 10-15%. A 10-15% reduction in cardiovascular risk from Omega-3, without side effects, could have a significant impact at the population level. They also pointed out weaknesses such as both participants and researchers being aware of the treatment assignments and lack of information on baseline triglyceride levels and their changes during treatment.

Omega-3 effects may vary between subjects with high triglyceride levels and those with lower levels. Among participants, some had low cardiovascular risk, while about 20% had established heart disease.

EPA and DHA Help Maintain Heart Health

This study revealed that Omega-3 supplementation may help protect heart health in subjects without a history of hypertension, and to a lesser extent in those without cardiovascular disease. While many insights about Omega-3 effects on various diseases have accumulated in recent years, supplement use is not yet routine in clinical practice. More research is needed to fill knowledge gaps so that Omega-3 supplements are not considered solely for their triglyceride-lowering effects.

Therefore, patients should be encouraged to regularly consume fish as a source of Omega-3, supported by abundant epidemiological data demonstrating its efficacy.

Source: Writing Group for the AREDS2 Research Group “Effect of Long-Chain ω-3 Fatty Acids and Lutein+Zeaxanthin Supplements on Cardiovascular Outcomes — Results 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