Dried Goji Berries: Potential Protector Against Age-Related Vision Loss

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Age-related macular degeneration (AMD) is an eye condition that blurs your central vision and can affect your ability to read or recognize faces. AMD is the primary cause of blindness among older adults in developed countries and the third worldwide, affecting more than 11 million people in the United States and 170 million globally. 

According to PubMed, there’s no treatment for dry macular degeneration as of now, but many clinical trials are being done in search of possible treatments for the said condition. 

One of the research initiatives which shed light on this problem was conducted by researchers from the University of California, Davis. The 2021 study examined whether the daily intake of 28 g of goji berries or a commercially available supplement providing 6 mg of Lutein (L) and 4 mg of zeaxanthin (Z) for 90 days can improve the macular pigment optical density (MPOD) and skin carotenoid levels among healthy middle-aged adults aged 45 to 65 years old, with no signs of drusen or early AMD. 

Lutein and Zeaxanthin: The Eyes’ Sunscreen

Macular pigments such as Lutein, zeaxanthin, and isomer meso-zeaxanthin filter harmful blue light and offer oxidative defense in the macula, slowing the onset and progression of AMD. Egg yolks, some green leafy vegetables, and various fruits and vegetables with red, yellow, or orange coloring are common sources of dietary Lutein and zeaxanthin.

According to the study’s lead author – Xiang Li, Lutein and zeaxanthin serve as sunscreen for your eyes.

Higher amounts of Lutein and zeaxanthin in your retina equate to more protection for your eyes, and these optical pigments can be increased through a small daily serving of goji berries.

Goji Berries for Eye Health

Goji berry, which has been used in traditional Chinese medicine for more than 2000 years, contains the highest amount of zeaxanthin among all known dietary sources and is mainly present in a dipalmitate form. Dried berries are a common ingredient in Chinese soups and are popular as herbal tea. They are similar to raisins and are eaten as a snack. 

It is said in Chinese medicine that goji berries have eye-brightening qualities, which made Li curious about whether there were any physiological properties to “eye brightening.”

By researching the bioactive compounds of goji berries, Li found that they contain high amounts of Lutein and zeaxanthin, which are known to mitigate the risk of eye diseases related to AMD.

It is also found that zeaxanthin form in goji berries is readily absorbed in the digestive system so the body can use it.

Crucial Findings of the Study

The research initially involved 88 volunteers aged 45 to 65 years old in greater Sacramento, California, reduced to 27 people after the screening process and review of inclusion criteria. The participants consumed 28 g of goji berries or a commercially available supplement of L and Z five days per week for 90 days.

At the end of the trial, 28 g of goji berry intake significantly risen the Macular pigment optical density (MPOD) in healthy adults at 0.25 and 1.75 REs compared to those who took a supplement with 6 milligrams L and 4 millIgrams Z. Significant increases in skin carotenoids were also noted among goji berry group on the 45th and 90th days.

The results demonstrate that even healthy people with no signs of early AMD can benefit from the consumption of goji berries. Apart from the L and Z, other goji berry compounds, including taurine, vitamin C, zinc, and L. barbarum polysaccharides (LBP), can also help protect against AMD through oxidant stress and improve eye health.

The researchers also suggested that a higher intake of Z relative to L may help minimize the risk of AMD.

Key Takeaway

The study demonstrates that MPOD increases in healthy, middle-aged adults after 90 days of goji berry ingestion. Other bioactive substances found in Goji berries, besides L and Z, might contribute to the rise in MPOD. More so, the benefits of goji berries can be strengthened through further study of them as a dietary strategy to lessen the risk of AMD and as part of an integrative approach to reduce the consequences of this disorder.

Journal Reference

Li, X., Holt, R. R., Keen, C. L., Morse, L. S., Yiu, G., & Hackman, R. M. (2021). Goji Berry intake increases macular pigment optical density in healthy adults: A randomized pilot trial. Nutrients, 13(12), 4409. https://doi.org/10.3390/nu13124409 

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