Goji also known as Wolfberry ORAC >30,000
[edit] Etymology
"Wolfberry" is the most commonly used English name for the plant, while gǒuqǐ (枸杞) is the Chinese name. In Chinese, the berries themselves are called gǒuqǐzi (枸杞子), with zi meaning "seed" or specifically "berry". Other common names are "the Duke of Argyll's Tea Tree",[1] and "matrimony vine."[2] Wolfberry is also known pharmacologically as Lycii Fructus (lycium fruit).
Lycium, the genus name, is believed to derive from the ancient Mid-Asian region of Lydia whereas barbarum, the species name, suggests that the plant was of foreign origin, perhaps originating outside China. Together, these names are used as specific botanical identifiers in the binomial (or binary) epithet. The end abbreviation, L., represents the nomenclature system devised by Carolus Linnaeus, the father of modern biological taxonomy. Lycium barbarum L. was apparently first named in the Linnaeus system in 1753.
In the English-speaking world, "goji berry" has been widely used in recent years as a synonym for wolfberry. While the origin of this spelling is unclear, it is probably a simplified contraction of gǒuqǐ.
In Japan the plant is known as kuko (クコ), in Korea the berries are known as gugija (hangul: 구기자; hanja: 枸杞子), and in Thailand the plant is called găo gèe (เก๋ากี่).
[edit] Medicinal use
Wolfberries and Lycium bark have long played important roles in traditional Chinese medicine (TCM), where they are believed to enhance immune system function, improve eyesight, protect the liver, boost sperm production, and improve circulation, among other effects. In TCM terms, wolfberries are sweet in taste and neutral in nature; they act on the liver, lung, and kidney channels and enrich yin. They can be eaten raw, consumed as juice or wine, brewed into a tea, or prepared as a tincture.
An early mention of wolfberry occurs in the 7th century Tang Dynasty treatise Yaoxing Lun. It is also discussed in the 16th century Ming Dynasty Compendium of Materia Medica of Li Shizhen.
There are also many published studies, mostly from China (see Pubmed), on the possible medicinal benefits of Lycium barbarum, including research on cancer, aging, immune functions and diabetes. Little of this research has been confirmed by western science, approved as clinical conclusions, or accepted by regulatory authorities to allow any health claims.
[edit] Culinary use
As a food, dried wolfberries are also eaten raw or cooked. Their taste is similar to that of raisins, though tarter and stronger. Dried wolfberry is an ingredient often used in Chinese soups. Young shoots and leaves are also grown commercially as a leaf vegetable. A wine containing wolfberries (called gǒuqǐ jiǔ; 枸杞酒) is also produced.[5]
[edit] Nutrient content
Wolfberries are nutritionally rich, containing the carotenoids - beta-carotene, zeaxanthin, lutein, β-cryptoxanthin and lycopene, at least 6 vitamins (examples, vitamins C, B1, B2), over 30 essential and trace minerals, polyphenolic antioxidants, and amino acids.
Companies marketing wolfberry products such as juice, powders and dried berries report contract laboratory assays showing uniformly high contents for 18 amino acids (examples, isoleucine, tryptophan, leucine and arginine), 11 essential minerals (examples, zinc, iron, copper, calcium, selenium, phosphorus), 22 trace minerals and vitamins (especially thiamin (B1), riboflavin (B2), niacin (B3) and vitamin C.[6][7] Of course, certain methods of preparation (e.g., the commonly available dried fruits) may have decreased the amount of water-soluble vitamins (vitamin C particularly, for which they are so highly reputed).
Two recent book publications[6][7] provide thorough nutrient assays by independent contract laboratories and discussions of these exceptional nutritional qualities in wolfberries, advancing a working thesis that wolfberry is one of nature's most nutrient-rich plant foods.
[edit] Macronutrients
Wolfberry contains significant percentages of a day's macronutrient needs – carbohydrates, protein, fat and dietary fiber. 68% of the mass of a wolfberry exists as carbohydrate, 12% as protein, and 10% each as fiber and fat, giving a total caloric value of 370 for a 100 gram serving.
Soybean, another ancient Chinese plant among the world's most complete foods, is comparable across macronutrients. Although wolfberries and soybeans are similar as regards their macronutrient content, wolfberries provide a significantly higher source of calories as energy from carbohydrates (soybeans = 173 calories). Blueberries, by contrast, do not have as much macronutrient or caloric value.
Seeds contain the wolfberry's polyunsaturated fats such as linoleic (omega-6) and linolenic (omega-3) acids.
[edit] Micronutrients
Wolfberry's diversity and high concentration of micronutrients brand it as an exceptional health food with quantitative examples below. The following data are presented for 100 grams of the most commonly eaten preparations, i.e., dried wolfberries,[7] fresh blueberries,[8] and boiled mature soybeans.[9] Although numerous other nutrients of wolfberries and soybeans or blueberries could be compared (as was done in [7]), the following nutrients represent examples of wolfberry's richness.
Calcium. The primary constituent of teeth and bones, calcium has a diverse role also in soft tissues where it is involved in cardiac, neuromuscular, enzymatic, hormonal, and transport mechanisms across cell membranes. Wolfberries and soybeans contain 112 mg and 102 mg per 100 gram serving, respectively, providing about 8-10% of the Reference Daily Intake (RDI).
Potassium. An essential electrolyte and enzyme cofactor, dietary potassium can lower high blood pressure. Giving about 24% of the RDI (1132 mg/100 gram), wolfberries are an excellent source, providing more than twice the amount of soybeans.
Iron. An oxygen carrier on hemoglobin, iron also is a cofactor for enzymes involved in numerous metabolic reactions. When intake is deficient, low iron levels cause iron deficiency anemia affecting millions of children worldwide. Wolfberry’s exceptional iron content, 100% DRI at 9 mg/100 grams, is twice that provided by soybeans, often regarded as the best plant source of iron.
Zinc. Essential for making proteins, DNA and functions of over 100 enzymes, zinc is involved in critical cell activities such as membrane transport, repair and growth, especially in infants. Zinc in wolfberries (2 mg/100 grams) has a high content (double the amount of soybeans), meeting 20% of RDI.
Selenium. Sometimes called the “antioxidant mineral”, selenium is often included in supplements. Selenium has unusually high concentration in wolfberries (50 micrograms/100 grams), nearly 100% of the RDI whereas blueberries and soybeans are not important sources (8 micrograms or less).
Riboflavin (vitamin B2). An essential vitamin supporting energy metabolism, riboflavin is needed for synthesizing other vitamins and enzymes. A daily wolfberry serving provides the complete RDI (1.3 mg) whereas soybeans and blueberries have relatively low levels of this important vitamin (< 0.3 mg/100 grams).
Vitamin C. A universal antioxidant vitamin protecting other antioxidant molecules from free radical damage, vitamin C content in dried wolfberries has a range (from different sources) of 29 mg/100 grams to as high as 148 mg/100 grams. Even the lower estimate is a multiple of equal weights of blueberries or soybeans, providing about 35% of the RDI. Reports on vitamin C content from other wolfberry preparations, such as juice concentrate or juice powder, have been significantly higher. The note below offers possible explanation for these discrepancies.
[Note on micronutrient contents: differences in the degree of berry maturation at the time of picking, soil conditions and geographic region where the berries were grown, post-harvest handling and processing, duration of storage, residual water content and assay preparation can significantly affect individual nutrient contents, especially those for vitamins and phytochemicals. These factors make data comparisons between different assays or sources difficult to reconcile].
[edit] Phytochemicals
Wolfberries contain dozens of phytochemicals whose properties are under scientific study. Five of these are of particular interest:[6][7]
Beta carotene. A carotenoid pigment in orange-red foods like wolfberries, pumpkins, carrots and salmon, beta-carotene is important for synthesis of vitamin A, a fat-soluble nutrient and antioxidant essential for normal growth, vision, cell structure, bones and teeth and healthy skin. Wolfberry's beta-carotene content per unit weight (7 mg/100 grams) is among the highest for edible plants.
Zeaxanthin. Wolfberries are an extraordinary source for this carotenoid important as a retinal antioxidant and pigment filter of ultraviolet light. Wolfberries contain 162 mg/100 grams.
Lycopene. Unknown previously as a constituent of berry fruit, lycopene in powder made from wolfberry juice concentrate has been measured at 1.4 mg/100 grams (contracted assay, UBE Analytical Labs) . As lycopene's antioxidant role as a possible cancer-inhibiting agent occurs at microgram blood levels in humans, this is a potentially important discovery inviting further research.
Polysaccharides. Long-chain sugar molecules characteristic of many herbal medicines like mushrooms and roots, polysaccharides are a signature constituent of wolfberries, making up 31% of pulp weight in premium quality wolfberries. Polysaccharides are a primary source of fermentable dietary fiber in the intestinal system. Upon colonic metabolism, fermentable or "soluble fibers" yield short-chain fatty acids which 1) are valuable for health of the colonic mucosal lining, 2) enhance mineral uptake, 3) stabilize blood glucose levels, 4) lower pH and reduce colon cancer risk and 5) stimulate the immune system. Polysaccharides also display antioxidant activity.
Phenolics. Also called phenols or polyphenols, this group of phytochemicals numbers in the thousands of individual chemicals existing across the plant kingdom, mainly as protective astringents or pigments that give bright colors to plants like the red, ripe wolfberry (photo top right). Phenolic pigments have the metabolic property of high antioxidant capability transferable to animals by eating the plant. New assays have demonstrated the presence in wolfberries of phenolics such as ellagic acid (86 mg/100 grams) and p-coumaric acid, with a total phenolics content of 1,309 mg/100 grams -- one of the highest values for any plant food yet tested.[6][10]
[edit] Oxygen Radical Absorbance Capacity
Wolfberry's richness in carotenoids, phenolics and vitamin C creates potential for an extraordinary synergy of antioxidant strength, a measure determined by test tube assays of oxygen radical absorbance capacity (ORAC).
In 2004, scientists with the U.S. Department of Agriculture published an extensive list of ORAC values for over 100 common foods (fruits, vegetables, nuts, seeds, spices, grains, etc.).[11] Values were reported as micromoles (μmol) of Trolox equivalents (TE, vitamin E derivative) per gram both for lipid-soluble ("lipophilic" as for carotenoids) and water-soluble ("hydrophilic" as for phenolics) antioxidant chemicals in foods, thus were a sum of lipophilic and hydrophilic values or total ORAC. The data of Wu et al. showed that all plants have variable amounts of both lipophilic and hydrophilic phytochemicals with antioxidant properties contributing to total ORAC.[11]
Spices (clove, cinnamon) showed the highest ORAC values (>250,000, converted to μmol TE per 100 grams) whereas, among commonly eaten foods, dark berries (known to be rich in phenolics), such as cranberry and lowbush blueberry, were highest (around 9,300 μmol TE per 100 grams) (note: wolfberries were not assessed in this study). By comparison, different species of apples had ORAC values of 4,275 μmol TE per 100 grams or less, white potato was under 1,100, peanut was 3,166 and tomato about 400.
In their 2005 book,[6] Young et al. report ORAC for dried wolfberries as 30,300 μmol TE per 100 grams, indicating exceptional antioxidant strength likely resulting from the synergy mentioned above for wolfberry's diversity of antioxidant phytochemicals. This exceptional ORAC has not been peer-reviewed or confirmed in publication by other research.
Among high-antioxidant berries and fruits whose ORAC values have been reported as marketing information (unconfirmed by scientific peer-review) are açaí at 34,000 (freeze dried powder, Sambazon) and pomegranate at 10,500 (References, Brunswick Laboratories).
[edit] Functional food and beverage applications
Cultivated for a variety of food and beverage applications within China, but increasingly today for export as dried berries, juice and powders of pulp or juice, wolfberries are prized for their versatility of color and nut-like taste in common meals, snacks, beverages and medicinal applications. A major effort is underway in Ningxia, China to process wolfberries for “functional” wine.
Despite no evidence from clinical research, myths of wolfberry’s traditional health benefits endure, including longevity, aphrodisia, analgesia, anti-cancer, anti-inflammatory, antiviral, and immune-stimulating properties, muscular strength, energy, and vision health.[12][7]
In laboratory animal models, in vitro methods and preliminary human research to date, whole wolfberry or its extracts have demonstrated potential benefits against cardiovascular and inflammatory diseases, some forms of cancer, diabetes, premature aging, memory deficits, vision degeneration (such as age-related macular degeneration and glaucoma), and lung disorders, among other diseases of oxidative stress (extensive references cited in [6][7]).
Particularly regarding its antioxidant strength, wolfberry's carotenoids (primarily beta-carotene and zeaxanthin) combined with polysaccharides and vitamin C may make this berry exceptional as an antioxidant food source, although this quality has not yet been adequately demonstrated in peer-reviewed research.
For retinal health specifically, wolfberry vitamin C, carotenoids and minerals like zinc would support prevention against age-related macular degeneration (the most common cause of blindness among the elderly). These nutrients are used together in commercial supplements for eye health during aging [7] and wolfberry has long been associated with this benefit in traditional Chinese medicine.
Although not yet confirmed in peer-reviewed literature, wolfberries may contain an abundance of phenolic acids (phenolics, phenols or polyphenols), the major class of water-soluble antioxidant pigments in blueberry, cranberry, black raspberry and açaí. At a reported 86 mg per 100 grams of fruit, the phenolic ellagic acid appears to be especially rich in wolfberries [6]. Should this phenolic capacity be confirmed and extended to include the likely presence of other phenolic chemicals, the combination of rich contents in wolfberries of lipid-soluble ("lipophilic") antioxidants (carotenoids) plus water-soluble ("hydrophilic") antioxidants (phenolics) would make wolfberries exceptional as an antioxidant food source.
Micronutrient density combined with diverse phytochemicals like carotenoids, phenolics and polysaccharides give wolfberries remarkable nutritional qualities, qualifying this berry as one of nature's most nutrient-rich plant foods