Goji Berries Keep Eyes Healthy
Following thousands of years of traditional use and other research leading to this conclusion, two recent studies have found that goji berries can benefit the eyes, and even prevent macular degeneration and diabetic retinopathy.
In a Swiss study, 150 elderly persons aged between 65 and 75 years old were fed goji berries or placebo for 90 days. The subjects were given eye examinations and blood tests to measure antioxidant levels before and at the end of the 90 days. The placebo group had reduced eye pigmentation and a build up of drusen – microproteins that gradually destroy the optic disc (macula) – causing what is called macular degeneration.
Meanwhile, these symptoms were not evident in the goji berry group. Their eye health remained stable through the study period. The gojiberry group also had increased antioxidant capacity (by 57%), and increased plasma zeaxanthin levels (by 26%). Zeaxanthin is a prime antioxidant that helps protect the cells of the eyes.
In a recent laboratory study, this one from Australia’s University of Sydney, researchers found that goji berry extract prevented the progression of diabetic retinopathy. One mechanism found was the availability of taurine in Goji berries. Taurine has been shown in other studies to help protect the eyes from retinopathy.
Additional mechanisms were found at the genetic level. The goji extract stimulated PPAR-γ luciferase activity among retinal cells, which has been found to be at the root of diabetic retinopathy. The goji extract produced mediators and integrated the goji’s taurine and PPAR to bind with inflammatory factors to halt the progression of damage to the retinal cells.
Both of these studies highlight previous investigations that have led researchers to conclude that gojiberries – along with carotenoid-zeaxanthin foods such as chard, broccoli, spinach and romaine lettuce – are particularly healthy for the eyes.
The gojiberry, also common name wolfberry or scientific name Lycium barbarum, originates from southern China and has been used for centuries to stimulate health and reduce inflammatory diseases. It is chock full of nutrients, with 11 essential and 22 trace minerals; 18 amino acids; 6 vitamins; 8 polysaccharides; 6 monosaccharides; 5 unsaturated fatty acids, including the essential fatty acids linoleic acid and alpha-linolenic acid, beta-sitosterol and other phytosterols; 5 carotenoids including beta-carotene and zeaxanthin, lutein, lycopene and cryptoxanthin; and numerous phenolic pigments (phenols) associated with antioxidant properties.
One hundred grams of dried gojiberries contains approximately:
• 112 milligrams of calcium
• 1,130 milligrams of potassium
• 9 milligrams of iron
• 2 milligrams of zinc
• 50 micrograms of selenium
• 1.3 milligrams of riboflavin
• 30 to 150 milligrams of vitamin C
• 7 milligrams of beta-carotene
• 25 to 200 milligrams of zeaxanthin, up to 75% of total carotenoids. This upper range makes goji berries one of the best plant sources of this important nutrient.
Song MK, Salam NK, Roufogalis BD, Huang TH. Lycium barbarum (Goji Berry) extracts and its taurine component inhibit PPAR-γ-dependent gene transcription in human retinal pigment epithelial cells: Possible implications for diabetic retinopathy treatment. Biochem Pharmacol. 2011 Nov 1;82(9):1209-18.
Bucheli P, Vidal K, Shen L, Gu Z, Zhang C, Miller LE, Wang J. Goji berry effects on macular characteristics and plasma antioxidant levels. Optom Vis Sci. 2011 Feb;88(2):257-62.