Dear Julie,
In this week’s wellness spotlight, a very important new meta-analysis on the efficacy of omega-3 fatty acid supplementation for the treatment of dry eye disease will be highlighted. This meta-analysis was published in the journal Cornea in 2019.
The authors looked at 17 randomized clinical trials involving 3,363 patients. Compared with placebo, omega-3 FA supplementation decreased dry eye symptoms [standardized difference in mean values (SDM) = 0.968; 95% confidence interval (CI) 0.554–1.383; P , 0.001] and corneal fluorescein staining (SDM = 0.517; 95% CI, 0.043–0.991; P = 0.032), whereas it increased the BUT (SDM = 0.905; 95% CI, 0.564– 1.246; P , 0.001) and Schirmer test values (SDM = 0.905; 95% CI, 0.564–1.246; P , 0.001). The conclusion of the authors was that this meta-analysis provides evidence that omega-3 FA supplementation significantly improves dry eye symptoms and signs in patients with dry eye disease and that omega-3 FA supplementation may be an effective treatment for dry eye disease.
Please see Dr. Stuart Richer’s commentary below:
Richer SP. Efficacy of Omega-3 Fatty Acid Supplementation for Treatment of Dry Eye Disease: A Meta-Analysis of Randomized Clinical Trials. PracticeUpdate website. Available at: https://www.
“There is robust controversy concerning the prescription of omega-3 fatty acids for cardiovascular disease (CVD), age-related macular degeneration (AMD), and now dry eye disease (DED). Giuseppe Giannaccare et al have done a yeoman’s job teasing out the effects of omega-3 supplementation from multiple DED studies based on the publications’ use of questionnaires, fluorescein staining, break-up time, and the Schirmer test. The team employed meta-analysis, a powerful statistical tool, but not without its own bias. The most compelling aspect of their paper is their assessment of the methodological quality of each DED study using the Cochrane Collaboration’s tool for assessing risk of bias. Two independent reviewers assigned a judgment of high, low, or unclear risk of bias for each of seven domains: 1) random sequence generation; 2) allocation concealment; 3) masking of participants; 4) masking of outcome assessment; 5) incomplete outcome data; 6) selective reporting; and 7) other bias. The ultimate selection of studies reflects a careful unbiased choice, which appears to recognize the major shortcomings of meta-analysis process.
The results of this meta-analysis are not surprising. From an environmental medicine perspective, the fats used worldwide have undergone three major changes over the last 100 years. First, we have changed from butter and lard to industrial seed oils. Second, we have tripled the content of proinflammatory omega-6 by consuming these isolated, inexpensive, and often adulterated oils. Third, we have decreased our intake of anti-inflammatory omega-3 some tenfold.
As important as dry eye disease is, the seminal public health issue of our time is inflammation of the human vasculature. Inferior-quality oils accelerate both endothelial dysfunction and plaque formation. While distracted by cholesterol phobia, we ignore the determination of the omega-3 index in CVD, AMD, DED, and clinical practice. The omega-3 index is one of eight predictive biomarkers collectively describing 92% of the epigenetic risk for disease. An inexpensive blood spot test can measure the percent of red blood cell membrane omega-3 fatty acids (EPA and DHA combined). It is a superior benchmark for studying DED, as well as chronic vascular disease and myriad associated degenerative diseases. Readers interested in more detail can visit: Health Studies Collegium and Ocular Wellness & Nutrition Society“