Goji berries, contain numerous essential vitamins, minerals and phytochemicals that may support ocular health. Among them are nutrients sufficiently established as valuable to vision that they have been assessed in NIH-sponsored clinical trials and now are ingredients of commercial supplements essential vitamins A, C and E, the essential mineral zinc, and carotenoids, beta-carotene, lutein and zeaxanthin. (1, 5). A nutritional wonder of nature, the goji berry contains all of these eye health nutrients and more. In this essay, we’ll cover a dozen goji nutrients, where modern scientists are just beginning to verify what ancient Chinese shamans have practiced for centuries goji may be nature’s most complete eye health food.
Most of what we know about specific nutrients that affect eye health comes from clinical trials on patients with age-related eye diseases, given the acronym AREDs. This ongoing series of clinical trials is sponsored by the US National Eye Institute, a division of NIH, and conducted by ophthalmologists across the United States and Canada (1).
The main nutrients identified in the first AREDs reports were the antioxidant vitamins A, C and E combined with high doses of zinc and the carotenoid, beta-carotene (a pro-vitamin A compound converted to vitamin A upon digestion). Since then, further research not yet completed is considering food-derived carotenoid pigments found in the human retina zeaxanthin and lutein and other essential nutrients and antioxidant chemicals ingested via plant foods.
All the following nutrients are present in goji berries. Data sources are from two recently published books (3, 6).
- Antioxidant such as: A-C-E. Vitamin A, formed from precursors called retinol (from dairy products) or retinal (from plant carotenoids like beta-carotene present in goji), serves antioxidant, filtering and immune functions in the eye. Vitamins C and E are, respectively, water-soluble and lipid-soluble antioxidants that become resident in the eye with a variety of protective functions against oxidative and intense light stress. Goji- berries are an exceptionally good source of vitamin C (43 mg/100 g dried fruit).
- Zinc. As a cofactor for numerous enzymes, some of which play antioxidant roles, zinc can be viewed as a complementary element guarding eye health. Its precise role especially in age-related macular degeneration is not yet defined, but it is nonetheless included as one of the AREDs nutrients currently under clinical study. Zinc content per gram in goji berries (2 mg/100 g, 20% DRI) is high among edible plants (3).
- Beta-carotene and lycopene. Not only a precursor to vitamin A formation, beta-carotene also serves as a potent antioxidant source that seeks fat layers for storage. This has significance to eye protection, as the neural elements of the retina are lined with fatty sheaths where antioxidant protection is needed. Usually associated with tomatoes (a botanical relative of the goji berry), lycopene provides antioxidant functions. Beta-carotene and lycopene contents in goji berries are exceptional among edible plants (7.4 mg and 1.4 mg/100 g, respectively) (3,4,6).
- Magnesium and selenium. Although the research is preliminary at present, there is evidence that magnesium and selenium, essential minerals with rich contents in goji berries (109 mg and 50 mcg/100 g; 30% and 97% DRI, respectively), participate as cofactors in retinal antioxidant reactions (3).
- Riboflavin (vitamin B2). Like other B vitamins, riboflavin supports energy production by aiding the metabolism of carbohydrates, fats and proteins. It has not been conclusively proved that riboflavin serves a health function in the eye. Recent research has shown, however, that riboflavin is associated with nutrition of collagen fibrils affected by cataracts and keratoconus, a degenerative corneal disease. Goji berries have among the highest riboflavin content per gram in nature (1.3 mg/100 g or 100% DRI) (3).
- Phenolics. These chemicals from colorful plants are pigments with a great diversity of chemical structures and names. They are the main dietary antioxidants in foods Americans eat, and so likely contribute to eye health in ways not yet clear from modern research. In goji berries, phenolic concentration is particularly enriched (total phenolics of 1309 mg/100 g), with preliminary evidence that the phenolic well-known in red raspberries, ellagic acid is also localized in goji fruit (86 mg/100 g) (6).
Although it will take years for modern science to unravel the eye health nutrients in goji berries, we have enough evidence already by knowing that these dozen nutrients are involved in supporting vision and overall health (1,2,5).
Our choice is to involve plant foods containing these nutrients in our diets, whether by using goji berries or other colorful plants foods with similar nutrient characteristics (2,6).
1. Age-Related Eye Disease Study Research Group, A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss. Arch Ophthalmol. 2001 Oct;119(10):1417-36.
2. Bartlett H, Eperjesi F. An ideal ocular nutritional supplement? Ophthalmic Physiol Opt. 2004 Jul;24(4):339-49.
3. Gross PM, Zhang X, Zhang R, Wolfberry: Nature’s Bounty of Nutrition and Health, Booksurge Publishing, 2006.
4. Gross PM, Exploring exotic antioxidant superfruits. Nat Prod Insider Oct 16, 2006, p 92-4.
5. Naguib Y, Eye Health Update, Nutraceuticals World, May 2005, 46-55.
6. Young G, Lawrence R, Schreuder M, Discovery of the Ultimate Superfood, Essential Science Publishing, 2005
VII- Polysaccharides, are long-chain sugar molecules and are a distinguishing characteristic of goji berry. They are a primary source of dietary fiber in the intestinal system, and once they are metabolized polysaccharides:
^ support and maintain the health of the colonic mucosal lining*
^ lower pH and reduce colon disease risk*
^ enhance mineral uptake*
^ stabilize blood glucose levels*
^ stimulate the immune system*
^ offer antioxidant protection*
VIII- Zeaxanthin, an antioxidant in the carotenoid family—a group of naturally occurring, fat-soluble pigments found in plants that play a key role in our immune system support—are abundantly found in goji berry. Zeaxanthin is a powerful vision protector that accumulates in the macula, the prominent, bright yellow spot in the center of the retina that allows you to clearly distinguish fine detail. The concentration of zeaxanthin in the center of the macula is about 85 times greater than its concentration in the periphery. Consequently, many researchers believe zeaxanthin (and lutein, another carotenoid) may be a potent protectant against macular degeneration 1-6, and may retard aging of the lens in preventing cataracts from forming.7,8 So, vision support is another one of goji berry’s many health benefits. Goji berry effects on macular characteristics and plasma antioxidant levels. Optom Vis Sci. 2011 Feb;88(2):257-62.
IX- Beta-carotene, is a carotenoid pigment in orange-red foods like goji berry, pumpkins, carrots, and salmon. It is important for the synthesis of vitamin A (a fat-soluble nutrient and antioxidant that is essential for normal growth), vision, cell structure, bones and teeth, and healthy skin. Goji berry’s beta-carotene content is among the highest for edible plants.
Scientific research: Most of the research on goji berries over the past 30 years has come out of China, but international awareness about its health and therapeutic benefits is growing.
Goji berry, and cardiovascular health:
In the book Discovery of the Ultimate Superfood, the authors document the science behind goji berry and list 67 medical studies showing how goji berry supports healthy heart function.9 A Taiwanese study of the antioxidant activity of goji berry and two other Chinese herbs found goji berry to be the strongest inhibitor of lipid peroxidation (a major factor in cardiovascular disease) in animal models.10
Reduces blood glucose and lipids in animal models:
After three weeks of eating a diet supplemented with goji berry, laboratory animals with noninsulin dependent diabetes II showed a significant decrease in weight, cholesterol, triglycerides, and insulin levels, leading the researchers to conclude that goji berry may be helpful in improving insulin resistance.11
Another study found that goji berry contains potent antioxidants that reduced blood glucose levels, and total cholesterol and triglyceride concentrations in rabbits, while increasing highdensity lipoprotein cholesterol (HDL)—“good cholesterol” levels after 10 days of treatment.12
Goji berry, and immune system:
In a 1988 report published by the State Scientific and Technological Commission of China, researchers discovered that after eating 50 grams of goji berry, human volunteers showed an increase in white blood cell count and a 75 percent increase in the antibody immunoglobulin A (lgA). In a more recent animal study, goji berry polysaccharides stimulated production of interleukin-2, a hormone-like substance that stimulates the growth of blood cells important to the immune system, which protect against cancer cells and microbial invasion.13
Goji berry, and protection of DNA:
One of the most amazing things about this berry is that it has been shown to actually protect against DNA damage and reduce DNA damage that has already occurred in animals … which means it may very well counteract aging. Although studies haven’t been done yet on humans, the potential is tremendous. A recent study at the Fudan University in Shanghai, China, found that when goji berry polysaccharides were given to laboratory animals with DNA damage and non-insulin dependent diabetes, the animals showed a decrease in blood glucose levels and an increase in serum levels of superoxide dismutase (SOD)—an important antioxidant. Additionally, goji berry decreased DNA damage, possibly by decreasing oxidative stress levels, leading the researchers to theorize that goji berry extract supplementation may prevent the development of complications or even the tendency for diabetic animals to develop other health problems.14
Protects testicle cells in animal study:
Another animal study at the same university found that goji berry polysaccharides also protected against DNA damage in testicle cells that were pre-treated with goji berry and then exposed to hydrogen peroxide.15 This study could be of particular interest to men who have fertility issues.
Goji berry, and brain health:
Alzheimer’s disease is predicted to become an epidemic for Baby Boomers, and there are currently about 70,000 scientists working around the world to find a cure. In a recent study at the University of Hong Kong, researchers theorized that since goji berry extract has anti-aging effects, it probably also has neuroprotective effects against toxins in neurodegenerative diseases, namely Alzheimer’s disease. They were right. Goji berry extract protected the brain neurons of laboratory animals from the toxic effects of beta amyloid protein—a culprit in Alzheimer’s disease. The researchers concluded that studies on anti-aging herbal medicine like goji berry might open up a new therapeutic window for the prevention of Alzheimer’s disease.16
Goji berry, and cancer research:
Thousands of studies have been done using a variety of dietary supplements, with most of them on animals. A clinical trial done in China in 1994 on goji berry showed very promising results.
Seventy-nine advanced cancer patients were treated with LAK/IL-2 (a cancer drug) combined with goji berry. Initial results indicated that regression of the cancer was achieved in patients with malignant melanoma, renal cell carcinoma, colorectal carcinoma, lung cancer, nasopharyngeal carcinoma, and malignant hydrothorax. The response rate of patients treated with LAK/IL-2 plus goji berry was 40.9%, while that of the patients treated with just LAK/IL-2 was 16.1% (P<0.05). The remission period in the patients treated with LAK/IL-2 plus goji berry also lasted significantly longer. The results indicate that goji berry could be useful as an adjuvant (an agent added to another drug to enhance its medical effectiveness) in the treatment of cancer.17
In a more recent in vitro study, goji berry inhibited the growth of human leukemia cells.18
Goji berry is a potent hepatoprotective, or liver protector.
- One study discovered that goji berry helps counteract carbon tetrachloride toxicity in the iver.19
• A goji berry compound called cerebrosides—a combination of sugar and fat (glycolipids)—was shown to protect liver cells from a toxic dry-cleaning chemical better than the well-known liver protectant milk thistle. 20
• Pyrroles, another hepatoprotective compound in goji berry, are unusual molecules that have a nitrogen atom in their central ring and were found to outperform goji berry cerebrosides in protecting the liver. 21
It should be noted that in a study of herbal medicines on pharmaceutical drugs, goji berry was found to increase the anti-coagulation effect of warfarin (Coumadin®).22, 23 Therefore, persons on anticoagulant therapy should only use goji berry under medical supervision.
Amino acids- the precursors of the monoamine neurotransmitters are amino acids found in our foods. For the catecholamines dopamine and noradrenaline, the precursors are phenylalanine and tyrosine—in that order in the biosynthetic pathway. Tyrosine could be taken as a supplement—so why is phenylalanine preferred instead? Because tyrosine does not provide the same uplifting benefits as phenylalanine, which is required for the production of a metabolite, phenylethylamine, whose mood-elevating properties augment those of noradrenaline.
For serotonin, the precursor amino acid from foods is tryptophan. Tryptophan is one of the amino acids that is found in Goji berries. 5-HTP, is the immediate precursor of serotonin. 5-HTP is not found in our food, but it’s a safe and effective supplement.
The reaction sequences shown here involve two valuable nutritional supplements:
Phenylalanine and 5-HTP.
Amino acids in Goji berries: Alanine, Arginine, Aspartate, Glutamine, Glycine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine, Tryptophan, Tyrosine, Valine.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.