In the news:Eating Blueberries Cuts AMD Risk; Plant-Based Diet For QOL in Prostate Cancer

Blueberries Linked to Reduced AMD Risk

In terms of diet and ocular health outcomes, including age related macular degeneration (AMD) and cataract, most research has focused on roles of dietary patterns, carotenoids, and phytochemicals.

One dietary component of interest that has been underexamined for its relationship to age related eye diseases is the blueberry, which most notably contains vitamin C and the bioactive anthocyanins.

Anthocyanins, flavonoids which give blueberries their characteristic blue color, have potent antioxidant properties. Animal studies have shown that a diet supplemented with blueberries results in intact anthocyanins in ocular tissues, and that they inhibit retinal oxidative stress and inflammation.

To investigate the prospective long-term relationship of blueberries and anthocyanins with cataract and AMD in women, Harvard researchers used data from the Women’s Health Study. The study assessed blueberry and anthocyanin intake and provided medical record-confirmed cataract and AMD in a large cohort of middle-aged and older women with more than a decade of follow-up(1).

The study included 37,653 and 35,402 women initially free of AMD and cataract, respectively. Blueberry intake was categorized as none,1-3 servings monthly, 1 serving per week, or 2 or more servings weekly. Total anthocyanin intake was energy-adjusted and categorized into quintiles.

Compared to no blueberry intake, women consuming 1-3 servings per month had a 10% risk reduction in AMD. Those eating 1 serving weekly showed a 29% risk reduction, while consuming more than 1 weekly serving resulted in a 32% reduction in AMD risk. Women consuming 2 or more servings per week exhibited a 64% reduction in risk (all p, trend 0.011). Similar risk reductions in visually significant AMD were also seen.

Blueberries were not associated with cataract, and anthocyanins did not appear to mediate the association between blueberries and AMD. On the other hand, greater intake of anthocyanins and selected subgroups of anthocyanins, particularly in the upper 2 quintiles of intake, were modestly and significantly associated with lower risk of developing cataracts but not AMD.

This is the first epidemiologic study to specifically examine both blueberry and anthocyanin intake in the primary prevention of eye disease. The findings, according to the authors, warrant investigation.

Plant-Based Diet & Quality of Life in Prostate Cancer Patients

For the first time, research has revealed an association between eating a plant-based diet and improved quality of life among men treated for (non-metastatic) prostate cancer. These findings lend credence to previous research showing that a plant-based eating pattern reduces the risk of prostate cancer recurring and improves survivorship in these patients.

The prospective study(2) included over 3,500 participants in the Health Professionals Follow-up Study with non-metastatic prostate cancer. Patients were categorized into quintiles (5 groups) based on the proportion of plant versus animal foods they reported ate, Quality-of-live scores were calculated using Expanded Prostate Cancer Index Composite.

The median time from diagnosis/treatment to the first quality-of-life questionnaire was 7 years. A higher plant-based diet index was associated with modestly better scores for sexual function, urinary irritation/ obstruction, urinary incontinence, and hormonal health (which assesses symptoms like low energy, depression and hot flashes).

The researchers conclude that a diet limiting meat and dairy but is rich in fruits, vegetables, grains, and nuts may improve quality-of-life issues that often arise after treatment for prostate cancer.

References

1. Sesso HD, et al. Intake of Blueberries, anthocyanins, and risk of eye disease in women. J Nutr. Epub Mar. 1, 2024.
2. Loeb S, et al. Plant-based diet associated with better quality of life in prostate cancer survivors. Cancer. Epub Feb. 13, 2024