Blueberries and their key component, anthocyanins, are gaining attention for their potential benefits in eye health. Despite their known health benefits, few long-term studies have explored the impact of blueberries and anthocyanins on cataracts and age-related macular degeneration (AMD). This article delves into a study investigating the association between blueberry consumption, anthocyanin intake, and the incidence of cataract and AMD among middle-aged and older women.
Study Objectives
The primary goal was to examine whether the intake of blueberries and anthocyanins is linked to a reduced risk of developing cataracts, total AMD, and significant AMD in women aged 45 and older.
Methods
The study analyzed data from the Women’s Health Study, which included 36,653 women free of AMD and 35,402 women free of cataracts at the start, all aged 45 or older. Participants provided detailed dietary information via food frequency questionnaires. Blueberry intake was categorized as none, 1–3 servings per month, 1 serving per week, or 2 or more servings per week, with an additional category for those consuming at least one serving per week. Anthocyanin intake was adjusted for energy and divided into quintiles. The study adjusted for self-reported risk factors of eye disease to calculate multivariable hazard ratios (HRs) with 95% confidence intervals (CIs) for confirmed cataract, AMD, and visually significant AMD over an average follow-up period of 11 years.
Results
Among the participants, 10.5% consumed at least one serving of blueberries per week, with an average anthocyanin intake of 11.2 mg per day. Compared to those who did not consume blueberries, women who ate 1–3 servings per month, 1 serving per week, and 2 or more servings per week had a reduced risk of total AMD, with HRs of 0.90 (95% CI: 0.73, 1.11), 0.71 (95% CI: 0.50, 1.00), and 0.36 (95% CI: 0.14, 0.93) respectively (Ptrend = 0.011). Those eating at least one serving per week had an HR of 0.68 (95% CI: 0.47, 0.98). Similar trends were observed for visually significant AMD (Ptrend = 0.012), but not for cataracts. There were no significant associations between anthocyanin quintiles and AMD, but a modest reduction in cataract risk was noted in the top two quintiles (Ptrend = 0.022).
Discussion
The findings suggest that higher blueberry intake significantly reduces the risk of total AMD, although not significantly for visually significant AMD or cataracts. However, the effect size for visually significant AMD was similar to that of total AMD. There was a modest but significant inverse relationship between anthocyanin intake and cataract risk, but not AMD.
Conclusions
Increasing blueberry consumption may significantly lower the risk of developing total AMD, with a similar trend for visually significant AMD, but not cataracts. The study also highlights a modest protective effect of anthocyanins against cataracts.
Health Implications
These findings support the idea that a diet rich in fruits and vegetables, particularly those high in anthocyanins like blueberries, can contribute to better eye health. This is consistent with broader dietary guidelines that emphasize high intake of nutrient-rich foods to reduce overall and specific mortality rates.
Why Blueberries?
Blueberries are an excellent source of fiber, vitamin C, and anthocyanins—a type of flavonoid responsible for their blue color. Anthocyanins have potent antioxidant properties, crucial for eye health as oxidative stress is a known factor in age-related eye diseases. Animal studies suggest that diets rich in blueberries can reduce oxidative stress and inflammation in ocular tissues. Short-term human studies also show potential improvements in retinal response to light and faster visual recovery after exposure to bright light.
The Women's Health Study
The Women’s Health Study (WHS) is a landmark randomized, double-blind, placebo-controlled trial initially designed to explore the effects of low-dose aspirin and vitamin E on cardiovascular disease and cancer prevention. It included 39,876 female health professionals in the United States aged 45 and older. Participants provided detailed dietary and health information, making it an ideal cohort for examining the long-term effects of blueberry and anthocyanin intake on eye health.
Final Thoughts
As research continues to unfold, blueberries and their anthocyanins show promise as a simple, natural way to support eye health, particularly in reducing the risk of AMD. This adds to the growing body of evidence supporting the health benefits of a diet rich in diverse, nutrient-dense fruits and vegetables.
Source: PubMed
