New research shows that 28g of goji berries daily may help prevent age-related macular degeneration.
Recently, a UC Davis research team published the results of a small clinical study in the nutritional journal Nutrients [1], where researchers found that 28g of goji berries taken daily five days a week for three months was more effective in replenishing carotenoids than supplements.
Carotenoid levels are closely related to age-related retinal macular degeneration (AMD), which means that a daily dose of goji berries may help prevent or slow down the progression of AMD.
Age-related macular degeneration is the leading cause of blindness, second only to uncorrected refractive errors and cataracts. Pigments in the macula, such as lutein (L) and zeaxanthin (Z), filter harmful blue light to act as antioxidants.
The relative concentration of lutein-like carotenoids in the retina, also known as macular pigment optical density (MPOD), is a marker of age-related macular degeneration, and low MPOD levels are more likely to develop age-related macular degeneration.
The researchers recruited a group of volunteers for the clinical study, and after screening for conditions, 31 healthy adults with an average age of 56 years were finally eligible. The test group took 28g of goji berries (grown in Ningxia) daily five days a week, while the control group ate supplements purchased from the market, each containing 6mg of lutein and 4mg of zeaxanthin.
Goji berries are very nutritious, 28g of goji berries contain 28.8mg of zeaxanthin, which is much higher than the control group. Lutein was not measured, and based on other data, the researchers estimated that there should be 0.15mg of lutein in 28g of goji berries.
On days 45 and 90 of the trial, the researchers tested the participants’ macular pigment optical density and skin carotenoid scores.
The effect of eating Goji berries was evident, with significant increases in MPOD observed on both day 45 and day 90. In contrast, the control group was lonely eating the supplements and the effect was not significant.
Similarly, skin carotenoid scores increased significantly over time in volunteers who ate goji berries, while there was no significant change in the control group.
Xiang Li, the first author of this study, who grew up in northern China, mentioned that “lutein and zeaxanthin are like sunscreen for the eyes” and that “the more lutein and zeaxanthin in the retina, the more protection it has.
Based on the results of this study, even adults with very healthy eyes can still protect their eyes by eating a small handful of goji berries every day.