Omega-3 fatty acids reduce risk of dry eye syndrome; Omega-6 fatty acids increase risk.

In a study from Harvard Medical School in Boston, Massachusetts, and Brigham and Women's Hospital, women with a higher dietary intake of omega-3 fatty acids were at decreased risk of developing dry eye syndrome (DES).

According to lead author Biljana Miljanovic, MD, of the Division of Preventive Medicine and Aging at Brigham and Women's Hospital, "Dry eye syndrome impacts quality of life, productivity and safety for millions of people. Unfortunately, there is little advice clinicians can offer about its prevention. Our study set out to examine how changing dietary habits in America, primarily a shift in the balance of essential fatty acids we are consuming, may be associated with onset of this eye condition. We found that a high intake of omega 3 fatty acids, often referred to as a 'good' fat, commonly found in fish and walnuts, is associated with a protective effect. Conversely, a higher ratio of omega 6, a fat found in many vegetable cooking and salad oils and animal meats, compared to omega 3 in the diet, may increase the risk of dry eye syndrome."

Women who ate the most Omega-3 fatty acids lowered their chances of dry eye syndrome by as much as 68 percent. Conversely, those who ate a higher ratio of omega-6 fats versus omega-3 fats doubled their odds of dry eye syndrome.

Of 39,876 women participating in the Women's Health Study, 32,470 female health professionals aged between 45 and 84 years provided information on diet and DES. The highest versus the lowest dietary intake of omega-3 fatty acids was associated with decreased risk of Dry Eye Syndrome (Odds Ratio, 0.83; 95% CI, 0.70 - 0.98; P for trend = 0.04), after adjustments for age, other demographic factors, postmenopausal hormone therapy, and total fat intake.

Tuna fish consumption also had a protective effect against DES, and results were similar in other models after adjustments for diabetes, hypertension, and connective tissue diseases.

In this study, the researchers report the following specific findings:

• Women with the highest levels of omega 3 in their diets reduced their risk of dry eye syndrome by 20 percent compared to women with the lowest levels of this fat in their diet.
• A dietary ratio of omega 6 to omega 3 greater than 15:1 was associated with a 2.5-fold increased risk of dry eye syndrome in women. Currently, the average American diet consists of a 20:1 ratio of omega 6 to omega 3 fatty acids.
• Tuna consumption reduced the risk of dry eye syndrome. Women who reported eating at least five servings of tuna per week had a 68 percent reduced risk of dry eye syndrome compared to women who consumed one serving per week.
• Other fish types that have lower levels of omega 3 fatty acids did not appear to protect against dry eye syndrome.

"Although this is the first study that has evaluated this relationship, and confirmation from other studies is needed, the findings are consistent with clinical observations and postulated biological mechanisms," the authors write. "Thus, further research on the role of omega-3 fatty acids in the prevention and/or treatment of DES would be of interest."

Advanced Vision Research, Inc., supported this study and has financial arrangements with its authors.

Abstract

Background: Dry eye syndrome (DES) is a prevalent condition, but information on risk or protective factors is lacking.

Objective: We aimed to determine the association between the dietary intake and ratio of n–3 and n–6 fatty acids (FAs) and DES occurrence.

Design: Of the 39876 female health professionals in the Women’s Health Study (WHS), 32470 women aged 45–84 y who provided information on diet and DES were cross-sectionally studied. We assessed FA intakes by using a validated food-frequency questionnaire and assessed DES by using self-reports of clinically diagnosed cases. Of the sample, 1546 (4.7%) subjects reported DES. We used logistic regression models to estimate the odds ratios (ORs) and 95% CIs to describe the relation of FA intake with DES.

Results: After adjustment for demographic factors, hormone therapy, and total fat intake, the OR for the highest versus the lowest quintile of n–3 FAs was 0.83 (95% CI: 0.70, 0.98; P for trend = 0.05). A higher ratio of n–6 to n–3 FA consumption was associated with a significantly increased risk of DES (OR: 2.51; 95% CI: 1.13, 5.58) for >15:1 versus <4:1 (P for trend = 0.01). In addition, tuna consumption [1 serving was 113 g (4 oz)] was inversely associated with DES (OR: 0.81; 95% CI: 0.66, 0.99 for 2–4 servings/wk; OR: 0.32; 95% CI: 0.13, 0.79 for 5–6 servings/wk versus 1 serving/wk; P for trend = 0.005).

Conclusions: These results suggest that a higher dietary intake of n–3 FAs is associated with a decreased incidence of DES in women. These findings are consistent with anecdotal clinical observations and postulated biological mechanisms.

Source

ARVO 2003 Annual Meeting: abstract 2112, presented May 6, 2003.

Miljanovic et al. Relation between dietary n–3 and n–6 fatty acids and clinically diagnosed dry eye syndrome in women. Am J Clin Nutr.2005; 82: 887-893.

Key concepts: Omega-3 fish oil, DHA, Dry eye syndrome