(RxWiki News) Many people take omega-3 fatty acids to reduce their risk of heart disease. Some elderly patients may not be getting the benefit they hoped for.
Omega-3 fatty acids, which can be found in fatty fish, also come as supplements and have been shown to reduce fats in the blood and decrease the risk of dying, especially from heart disease. Two other compounds, lutein and zeaxanthin, also called xanthophylls, are found in green leafy vegetables and may also affect heart and vessel disease.
Researchers used a study on the use of these supplements in elderly patients with an eye disease called macular degeneration to see if the supplements also reduced heart disease.
The researchers did not find that the supplements reduced heart disease in these patients.
"Ask your doctor before taking any dietary supplements or vitamins."
The original research was conducted by the Writing Group for the Age-Related Eye Disease Study 2 (AREDS2). The lead authors of that research team were Denise E. Bonds, MD, MPH, from the Division of Cardiovascular Sciences at the National Institutes of Health in Bethesda, MD, and Traci E. Clemons, PhD, from EMMES Corporation in Rockville, MD.
A commentary on the study was written by Evangelos C. Rizos, MD, PhD, from the University Hospital of Ioannia, and Evangelia E. Ntzani, MD, PhD, from the University of Ioannina School of Medicine in Ioannina, Greece.
Macular degeneration is a disease that can occur in older people that causes loss of vision and blindness.
The AREDS2 study involved 4,203 patients aged 50 to 84 with macular degeneration. Some patients had cardiovascular disease (CVD), as well. These patients had different types of CVD that included heart attack, congestive heart failure and stroke, among others.
The patients were divided into four groups. One group took omega-3 supplements containing 350 mg of docosahexanoic acid and 650 mg of eicosapentanoic acid. Another group took xanthophyll supplements containing 10 mg of lutein and 2 mg of zeaxanthin. A third group took both, and a fourth group took a placebo (fake supplements).
The patients went to a clinic every year for evaluation and had a phone call from the researchers every six months. These evaluations and calls provided the researchers with information about any health updates, especially concerning CVD. Additional information was obtained from the patients’ medical records.
The average length of follow-up was nearly five years. Some patients did not continue to take the supplements and were not included in the study. This number ranged from 68 to 81 between the four groups. Another 30 to 42 patients could not be located by the researchers and were also excluded from the study.
Results of this study showed similar numbers of heart and blood vessel problems among the elderly patients with macular degeneration. A total of 82 patients in the omega-3 group and 65 patients in the groups not taking omega-3 had CVD events. CVD events occurred in 70 patients taking xanthophyll supplements, compared with 77 of those not taken such supplements.
A 33 percent decrease in risk of CVD was seen in patients taking omega-3 supplements who had a history of high blood pressure, compared to those not taking omega -3.
The AREDS2 authors noted that few patients in the study saw a significant change in the CVD events. These authors also noted that their study was limited by the fact that they did not control for the timing of when the supplements were taken and that patients in this study were older and some already had CVD.
These authors concluded that neither omega-3 or xanthophyll supplements benefited older patients in their study.
Drawing a conclusion from 22 clinical studies, Drs. Rizos and Ntzani stated, “What is evident so far is that omega-3 supplementation with daily doses close to 1 g in patients with or without established CVD shows no clear, considerable benefit.”
They recommended, “Patients raising the question of taking omega-3 supplements should be informed of the uncertainty surrounding their choice, and regular dietary consumption of (whole) fish should be preferentially encouraged as a source of omega-3 (not supplements) based on the wealth of the available epidemiological evidence.”
"Omega-3 supplements have been touted heavily in recent years as being 'heart-healthy.' There is now a growing body of research which cautions whether taking doses of these supplements (up to one gram/day) are truly beneficial in preventing cardiovascular disease. Although a few patients show improvement in CVD risk factors when taking these fatty acids, most patients who took omega-3 supplements from this most recent study did not show the necessary benefit to reduce their overall risk of heart attack, congestive heart failure, or stroke," said E. Lee Carter, RPh, Clinical Pharmacy Specialist at the Department of Veterans Affairs in Prestonsburg, Kentucky.
"What can patients take away from this latest study? The best source of Omega-3 fatty acids continues to come from natural sources (especially found in whole fish, but also available from green leafy vegetables, walnuts, and soybeans) rather than exogenous (dietary) supplements. Eating several servings of foods each week rich in omega-3s remains the best choice for patients wishing to pursue a heart-healthy lifestyle. Patient already taking fish oil prescribed to them should continue to do until they talk with their healthcare provider. In some cases, patients may be maintained on higher doses of fish oil (up to 4-6 grams/day) for other medical conditions," Carter said.
"Additionally, lutein and zeaxanthin, carotenoids found in the human diet and in numerous dietary supplements, especially in products for eye health, may have the ability to augment the antioxidant capacity of our own skin. Oral supplementation with lutein and zeaxanthin appears to diminish the effects of UVB (sunlight) radiation exposure," Carter told dailyRx News.
"The AREDS2 study (released last year) demonstrated positive endpoints related to eye health for many individuals not already getting enough dietary lutein and zeaxanthin. By the addition of these supplements, the study found a decrease of advanced age-related macular degeneration progression, a reduction in risk for severe cataracts, and a reduction of progression to cataract surgery. These two supplements do appear to be very beneficial for skin and eye health," he said.
These research papers were published in March in JAMA Internal Medicine.
The authors on the original study disclosed the following conflicts of interest: Dr. Jennifer Robinson has received research funding from Amarin, Amgen, Daiichi-Sankyo, Esperion, Genentech, Glaxo-Smith Kline and Merck; Dr. Hsia disclosed a relationship with AstraZeneca and Dr. Worral serves as an editor for the journal Neurology.
Dr. Rizos disclosed receiving consulting fees and funding from organizations not affiliated with the manufacture or market of the supplements used in the study.
Funding for the ARED2 study was provided by the National Institutes of Health.