In the news: If You Have AMD, Does What You Eat Matter? Flavonoids May Lower Alzheimer’s Risk

If you’re been thinking more about eating healthfully, several new studies might inspire you to transition to the Mediterranean (Med) diet. New research links the diet to ocular benefits. And if the fruits & veggies in the diet are packed with flavonoids, brain benefits too.

Following Med Diet May Slow Late-AMD Risk

If you’re being treated for age-related macular degeneration (AMD) and taking an AREDS2 supple-ment too, does what you eat make any difference to how the disease develops? The results of two new studies suggest that sticking to the Med diet matters.

In the first study (1), researchers looked at participants in the AREDS and AREDS2 clinical trials to see whether more closely following the Med diet affects the risk of the disease progressing to late stage AMD, either geographic atrophy (dry AMD) or neo-vascular disease (wet AMD).

Comparing the highest adherence to Med diet vs. the least showed a 22% reduction in relative risk for late AMD, a 29% reduction for dry AMD, and a 16% reduction for wet AMD. Consuming more fish
contributed to the diet’s protective effect, and the benefits were more pronounced in people who carried certain AMD-protective genes.

The second study (2) asked whether genetics and sticking with the Med diet could affect the growth and size of drusen in AREDS participants. Drusen are the yellow deposits found under the retina that increase the risk of developing AMD and, as the drusen grow larger, the risk of progressing to later stages of AMD.

The study found that inherited susceptibility to AMD was linked with drusen growth. But it also revealed that sticking more closely to a Med-style diet (fruits, veggies, legumes and fish), may lower the risk of drusen enlarging. While we can’t change the genetic hand we’re dealt, we can aim for a healthy diet.

Apples, Berries, & Tea May Curb Alzheimer’s

An observational study from Tufts University helps affirm a protective link between flavonoids and Alzheimer’s Disease plus other related dementias (3).

Most studies looking at links between foods and dementias have been short term. But dementias and Alzheimer’s don’t happen overnight – they develop over time. Microscopic changes in the brain begin long before the first signs of memory loss in Alzheimer’s, and blood vessel damage starts long before the problems of vascular dementia surface.

The new research looked at dementia risk and flavonoid intake over a 20-year period. Flavonoids are thought to help protect nerve cells and combat neuro-inflammation.

The study followed 2800 people in their 50s and free from dementias, updating their flavonoid intake about every five years. After adjusting for factors that affect the risk for dementia, the researchers found that low vs. high intake of 3 types of flavonoids was linked to higher dementia risk as follows:

• about 2x the risk for low vs. high intake of flavonols (apples, pears, tea);
• roughly 2x the risk for low vs. high intake of flavonoid polymers (pears, apples, tea);
• about 4 x the risk for low vs. high intake of anthocyanins (blueberries, strawberries, red wine);

The results were similar for Alzheimer’s. Examples of “high” intakes in the study were 8 apples and pears monthly (flavonols); for anthocyanins, 71/2 cups per month of blueberries or strawberries; and about 19 cups of tea monthly (flavonoid polymers).

References

1. Keenan TD, et al. Adherence to the Mediterranean diet and progression to late age-related macular degeneration in the Age-Related Eye Disease Studies 1 and 2. Ophthalmol. Epub ahead of print April 26, 2020
2. Merle BMJ, et al. Genetic susceptibility, diet quality, and two-step progression in drusen size. Invest Ophthalmol Vis Sci, 61:17, 2020. 
3. Shishtar E, et al. Long-term dietary flavonoid intake and risk of Alzheimer disease and related dementias in the Framingham Offspring Cohort. Am J Clin Nutr. 00:1–11, 2020. Open Access.