Little red and orange wolfberries have been used in China for centuries to ensure longevity and treat age-related conditions of the liver and the eye. But those qualities and many more have only recently been confirmed due to researchers using modern high performance analytic methods.
College of Human Sciences assistant professor in nutritional sciences Daniel Lin and colleagues are among those researchers who are providing evidence of the little red berry’s effectiveness on delaying or preventing retinal degeneration.
Wolfberries, or Goji berries, are the fruits of two closely related perennial plants, Lycium barbarum and Lycium Chinense, which are native to Asia and southeast Europe. Commercial production mainly comes from plantations in Ningxia Hui and Xinjiang Uyghur regions in China.
The bioactive components in wolfberries include but are not limited to polysaccharides and carotenoids. The fruits contain large amounts of the carotenoids lutein and zeaxanthin which are believed to have significant importance in eye health. Lin and his colleagues sought to determine the nature of the preventative effects of dietary wolfberry on diabetic retinopathy.
During the study, mice were fed a diet that included 1% wolfberries. The control group’s diet did not include wolfberries. High-performance liquid chromatography indicated mice fed the wolfberry diet for eight weeks had increases of ~13.7% in overall zeaxanthin and lutein concentrations in the liver and retinal tissues.
Retinal damage caused by complications of diabetes is the leading cause of vision impairment and blindness in working age adults. Hyperglycemia is a major cause of the progression of the disease. No permanent cure is available at this time. In the early stages of diabetes the retina’s small blood vessels are still intact with no damage. As the hyperglycemia-induced oxidative stress progresses it alters cellular stability and mitochondrial health.
Mitochondria are often referred to as the powerhouse of the cell because they generate most of the cell’s supply of adenosine triphosphate which is the source of the cell’s energy. Mitochondrial dysfunction is the primary indicator of retinal degeneration in diabetes. Mitochondria damage in mice fed wolfberries for eight weeks was completely reversed. The study showed wolfberry improved dispersion of mitochondria and increased pigment granules in the retina’s epithelium cells.
The vascular system in the retina provides nutrients and oxygen to the inner retina, new blood vessels supply the outer retina. In diabetes, elevated blood glucose, hyperglycemia and blood flow decline result in hypoxia or oxygen shortages in the retina. Dietary wolfberries ameliorated hypoxia and slowed down vascular dysfunction in the retina of the mice.
“In the study, dietary wolfberry restored the thickness of the whole retina, in particular the inner nuclear layer and photoreceptor layer,” Lin said.
“To our knowledge, this is the first report that wolfberry bioactive constituents prevented or delayed the onset of the disease of diabetic retinopathy in an animal mode,” Lin said.
“We believe the inhibition of hypoxia may be beneficial to maintaining healthy vision for diabetic patients,” Lin said. “The bioactive components in wolfberry may very well delay the progression of retinal degeneration for people suffering from diabetes.”
Not satisfied with one aspect of wolfberries’ impact on health, Lin is also studying its effects on obese mice.
“High fat diets cause mitochondrial dysfunction and a study of obese mice indicates wolfberry dietary intervention can lead to the prevention of excessive amounts of triglycerides and other fats in liver cells,” Lin said.
With the burgeoning costs associated with pharmaceutical treatments, research-based evidence of the lasting effects of nutraceuticals such as wolfberries will have tremendous impact on the health and well-being of the world’s population.
Lin said the western world is taking notice of the tiny fruit’s potential as wolfberry production is being found in Arizona, California and Nevada.
“Shipping the fresh fruit is difficult so most of the fruit from China is dried,” he said. “The dried fruit is still highly effective, but as with all fruits, fresh wolfberry is best.”
It appears the ancient remedy will soon be the next new functional food to enhance and improve health.