California January 15 ANI A new study has found that regular consuming a small serving of dried goji berries may prevent or delay the development of age-related macular degeneration, or AMD, in healthy middle-aged people.
AMD is the leading cause of vision loss in older people, and is estimated to affect more than 11 million in the United States and 170 million globally.
Glenn Yiu, a co-author of the study and associate professor in the Department of Ophthalmology and Vision Sciences, said AMD affects your central field of vision and affects your ability to read or recognize faces.
The researchers found that 13 healthy participants aged 45 to 65 who consumed 28 grams of one ounce, or a handful of goji berries five times a week for 90 days increased the density of protective pigments in their eyes. 14 of the study participants who consumed a commercial supplement for eye health did not show an increase.
Pigments that increased in the group that ate goji berries, lutein and zeaxanthin filtered out harmful blue light and provided antioxidant protection. Both help to protect the eyes during ageing.
Xiang Li, a doctoral candidate in nutritional biology, held a small serving of dried goji berries.
Lead author Xiang Li, a doctoral candidate in the Nutritional Biology Program, said that lutein and zeaxanthin are like sunscreen for your eyes.
The higher the lutein and zeaxanthin in your retina, the more protection you have. Our study found that even in normal healthy eyes, these optical pigments can be increased with a small daily serving of goji berries, according to Li.
Goji berries are the fruit of Lycium chinense and Lycium barbarum, two species of shrubby bushes found in northwest China. Dried berries are a common ingredient in Chinese soups and are popular as herbal tea. They are similar to raisins and eaten as a snack.
Goji berries are said to have eye brightening qualities in Chinese medicine. Li grew up in northern China and became curious if there were any physiological properties to eye brightening. There are many types of eye diseases, so it is not clear what disease 'eye brightening' is targeting, said Li.
She researched the bioactive compounds in goji berries and found they contain high amounts of lutein and zeaxanthin, which are known to reduce the risk of eye diseases related to AMD. According to Li, the form of zeaxanthin in goji berries is a highly bioavailable form, meaning it is readily absorbed in the digestive system, so the body can use it.
The treatment for intermediate stages of AMD uses special dietary supplements called AREDS, which contain vitamins C, E, zinc, copper and lutein, and zeaxanthin. No known therapy has yet to be shown to impact the early stages of AMD.
According to Yiu, AMD is complex and multifactorial and involves a mixture of genetic risks, age-associated changes, and environmental factors like smoking, diet, and sun exposure. Early stages of AMD don't have symptoms, but doctors can detect AMD and other eye problems during a regular eye exam.
Yiu said that goji berries, which are a natural food source, can improve macular pigments of healthy participants beyond taking high-dose nutritional supplements.
Yiu said that the next step for our research will be to examine goji berries in patients with early-stage AMD.
The results are promising, but the researchers noted that the study size was small and more research will be needed.