Wolfberry is the common name for the fruit of two very closely related species: Lycium barbarum and L. chinense two species of boxthorn in the family Solanaceae (which also includes the potato, tomato, eggplant, deadly nightshade, chili pepper, and tobacco). Although its original habitat is obscure (probably southeastern Europe to southwest Asia), wolfberry species currently grow in many world regions. Only in China, however, is there significant commercial cultivation.
According to the United States Department of Agriculture Germplasm Resources Information Network, it is also known as Chinese wolfberry, goji berry, barbary matrimony vine, bocksdorn, Duke of Argyll's tea tree, or matrimony vine. Unrelated to the plant's geographic origin, the names Tibetan goji and Himalayan goji are in common use in the health food market for products from this plant.
Since the early 21st century in the United States and other such developed countries, there has been rapidly growing recognition of wolfberries for their nutrient richness and antioxidant qualities, leading to a profusion of consumer products. Such rapid commercial development extends from wolfberry having a high ranking among superfruits expected to be part of a multi-billion dollar market by 2011.
Wolfberry species are deciduous woody perennial plants, growing 1-3 m high. L. chinense is grown in the south of China and tends to be somewhat shorter, while L. barbarum is grown in the north, primarily in the Ningxia Hui Autonomous Region, and tends to be somewhat taller.
The botanical division named to the upper right, Magnoliophyta, identifies plants that flower and the class Magnoliopsida represents flowering plants (Dicotyledons) with two embryonic seed leaves called cotyledons appearing at germination.
The order Solanales names a perennial plant with five-petaled flowers that are more or less united into a ring at the base; well-known members of the order include morning glory, bindweed, and sweet potato as well as the plants of the Solanaceae, mentioned below.
Lastly, Solanaceae is the nightshade family that includes hundreds of plant foods like potato, tomato, eggplant, wolfberry, peppers (paprika), crop commodities (tobacco), and flowers (petunia). Although the Solanales includes many plant foods, some members are poisonous (for example belladonna).
Wolfberry leaves form on the shoot either in an alternating arrangement or in bundles of up to three, each having a shape that is either lanceolate (shaped like a spearhead longer than it is wide) or ovate (egg-like). Leaf dimensions are 7 cm long by 3.5 cm wide with blunted or round tips.
One to three flowers (picture) occur on stems 1-2 cm in length. The calyx (eventually ruptured by the growing berry) is comprised of bell-shaped or tubular sepals forming short, triangular lobes. The corolla are lavender or light purple, 9-14 cm long with five or six lobes shorter than the tube. The stamens are structured with anthers that open lengthwise, shorter in length than the Filaments (picture).
In the northern hemisphere, flowering occurs from June through September and berry maturation from August to October, depending on latitude, altitude, and climate.
These species produce a bright orange-red, ellipsoid berry 1-2 cm long photo. The number of seeds in each berry varies widely based on cultivar and fruit size, containing anywhere between 10-60 tiny yellow seeds that are compressed with a curved embryo. The berries ripen from July to October in the Northern hemisphere.
Although origin of the common name "wolfberry" is undefined, it may have derived from the Greek word for wolf, "lycos" (λύκος), first applied to tomato (Solanum lycopersicum with derivation of 'lyco' as wolf, plus 'persicum' as peach, i.e., "wolf-peach") by Carolus Linnaeus in 1753 , the same year Lycium barbarum was entered into botanical nomenclature. Botanically related to tomato in family Solanaceae, wolfberry may have assumed its name from the more common, larger berry, tomato - the "wolf-peach". Why Linnaeus named tomato after the wolf remains unknown.
In the English-speaking world, "goji berry" has been widely used since the early 21st century as a synonym for "wolfberry". While the origin of the word "goji" is unclear, it is probably a simplified pronunciation of gǒuqǐ, the Mandarin name of the plant, developed by those marketing wolfberry products in the West.
Lycium, the genus name, is derived from the ancient southern Anatolian region of Lycia (Λυκία). Interpreters of botanical nomenclature believe barbarum, the species name, indicates that the wolfberry was of foreign origin, perhaps originating outside Anatolia or China, or was deemed a plant not native to the region where it was first discovered.
Together, these names are used as specific botanical identifiers in binomial nomenclature for which barbarum is the specific epithet. The end abbreviation, L., refers to Linnaeus, who described the species in 1753 in Species Plantarum. L. chinense was first described by the Scottish botanist Philip Miller in the eighth edition of his The Gardener's Dictionary, published in 1768.
In Japan the plant is known as kuko (クコ) and the fruits are called kuko no mi (クコの実) or kuko no kajitsu (クコの果実); in Korea the berries are known as gugija (hangul: 구기자; hanja: 枸杞子) ; in Vietnam the fruit is called "kỷ tử" (杞子), "cẩu kỷ" (枸杞), "cẩu kỷ tử"(枸杞子) but the plant and its leaves are known more popularly as "củ khởi"; and in Thailand the plant is called găo gèe (เก๋ากี่). In Tibetan the plant is called dretsherma with dre meaning "ghost" and tsherma meaning "thorn"; and the name of the fruit is dretshermǟ dräwu with dräwu meaning "fruit".
The majority of commercially produced wolfberries come from the Ningxia Hui Autonomous Region of north-central China and the Xinjiang Uyghur Autonomous Region of western China, where they are grown on plantations. In Zhongning County, Ningxia, wolfberry plantations typically range between 100 and 1000 acres (or 500-6000 mu) in area. As of 2005, over 10 million mu have been planted with wolfberries in Ningxia.
Cultivated along the fertile aggradational floodplains of the Yellow River for more than 600 years, Ningxia wolfberries have earned a reputation throughout Asia for premium quality sometimes described commercially as "red diamonds". Government releases of annual wolfberry production, premium fruit grades, and export are based on yields from Ningxia, the region recognized with:
In addition, commercial volumes of wolfberries grow in the Chinese regions of Inner Mongolia, Qinghai, Gansu, Shaanxi, Shanxi and Hebei. When ripe, the oblong, red berries are tender and must be picked carefully or shaken from the vine into trays to avoid spoiling. The fruits are preserved by drying them in full sun on open trays or by mechanical dehydration employing a progressively increasing series of heat exposure over 48 hours.
Wolfberries are celebrated each August in Ningxia with an annual festival coinciding with the berry harvest. Originally held in Ningxia's capital, Yinchuan, the festival has been based since 2000 in Zhongning County, an important center of wolfberry cultivation for the region. As Ningxia's borders merge with three deserts, wolfberries are also planted to control erosion and reclaim irrigable soils from desertification.
China, the main supplier of wolfberry products in the world, had total exports generating US$120 million in 2004. This production derived from 82,000 hectares farmed nationwide, yielding 95,000 tons of wolfberries.
Some Western resellers may state that their wolfberries are organically grown when in fact they are not. The Green Certificate claimed by some wolfberry marketers to be the equivalent of the United States Department of Agriculture's "USDA Organic" seal is in actuality simply an agricultural training program for China's rural poor. China's Green Food Standard, administered by the Chinese Ministry of Agriculture's China Green Food Development Center, does permit some amount of pesticide and herbicide use.
Despite some claims that wolfberries sold in Europe, the United States, and Canada meet organic standards, there is no public evidence for standardized organic certification of wolfberries from the Asian regions where they are commercially grown. Often, these berries are marketed as Tibetan or Himalayan Goji Berries that have been "wild crafted" or "wild harvested". On the contrary, however, Tibet's agriculture conventionally uses fertilizers and pesticides, and neither wolfberries ("goji") of Tibetan or Himalayan origin sold outside Tibet nor organic certification of such berries have been proved.
Although Lycium species do grow in some regions of Tibet, commercial export production of wolfberries in the Tibetan Himayalas must be a myth fabricated for a marketing advantage, as this mountain range bordering the Tibetan Plateau is a region inhospitable to commercial cultivation of plant foods of any kind. In the Himalayan foothills, bleak desolation is unrelieved by any vegetation beyond sparse, low bushes , whereas eastern valleys and plains of the Tibetan Plateau at lower altitude support growth of wild Lycium chinense
The Tibetan Plateau, comprising most of Tibet north and east of the Himalayas, lies at more than 3000 m (10,000 ft) in altitude, with poor soil and arid climate conditions unfavorable for fruit crops. Defined by the geography of Tibet, particularly in the western Himalayas, cold nighttime temperatures averaging -4°C year round with six months of continual frost would inhibit plant bud development and prevent fruit formation. Existing in Tibet are minimal subsistence agriculture and impoverished crop management and transportation facilities unsupportive of commercial berry production. Although limited fertile regions suitable for food crops exist in the valleys of Lhasa, Shigatse, Gyantse, and the Brahmaputra River, there are no objective economic, scientific, or government reports on the commercial production of Lycium berry species from these Tibetan regions
Although several wolfberry marketers state that their "Tibetan goji" is a specific species, given variously as Lycium eleganus, Lycium eleganus barbarum, or Lycium eleagnus, no such species exist. Elaeagnus (Silverberry or Oleaster) is a genus of about 50-70 species of flowering plants in the Elaeagnaceae family. The vast majority of Elaeagnus species are native to temperate and subtropical regions of Asia, including Elaeagnus umbellata, which grows near the Himalayas and bears an orange-red berry possibly confused with Lycium barbarum.
Some Internet authors claim Lycium eleagnus barbarum (another nonexistent species) is the original Lycium barbarum or an improved cultivar of it. However, Lycium and Elaeagnus are sufficiently disparate genera that successful cross-breeding is unlikely. Further, there is no evidence in the International Code of Nomenclature for Cultivated Plants of a Lycium species of Elaeagnus or vice versa.
The plant continues to grow wild in UK hedgerows. On 15 January 2003, the Department for Environment, Food and Rural Affairs (of the United Kingdom Government) launched a project to improve the regulations protecting traditional countryside hedgerows, and specifically mentioned Duke of Argyll's Tea Tree as one of the species to be found growing in hedges located in Suffolk Sandlings, Hadley, Bawdsey, near Ipswich, and Walberswick.
The wolfberry has been naturalized as an ornamental and edible plant in the UK for nearly 300 years. On June 18, 2007, the FSA (UK Food Standards Agency) stated that there was a significant history of the fruit being consumed in Europe before 1997, and has removed it from the Novel Foods list It is now legal to sell the goji berry in the UK as a food as reported by the British Food Standards Agency (also see discussion below, Marketing claims under scrutiny in Europe).
Wolfberries are almost never found in their fresh form outside of their production regions, and are usually sold in open boxes and small packages in dried form. The amount of desiccation varies in wolfberries: some are soft and somewhat tacky in the manner of raisins, while others may be very hard. Wolfberries with a vibrant orange-red color may have been treated with sulfites.
In the West, dried wolfberries are also eaten hand-to-mouth as a snack, in the manner of raisins, dried cranberries, or other dried fruit. Their taste has an accent of tomato and is similar to that of dates, dried cranberries or raisins, though drier, more tart, less sweet and with an herbal scent. Dried wolfberries are also used frequently in raw food diets.
In TCM terms, wolfberries are sweet in taste and neutral in nature. They act on the liver, lungs, and kidneys and enrich yin. They can be eaten raw, consumed as juice or wine, brewed into an herbal tea photo 1 photo 2 or prepared as a tincture. The berries are also used in traditional Korean medicine, traditional Japanese medicine and traditional Tibetan medicine.
Wolfberry leaves may be used to make tea and Lycium root bark (called dìgǔpí; 地骨皮 in Chinese) photo for TCM treatment of inflammatory and some types of skin diseases. A glucopyranoside and phenolic amides isolated from wolfberry root bark have inhibitory activity in vitro against human pathogenic bacteria and fungi.
From marketing literature for wolfberry products including several "goji juices", a reputation exists for wolfberry polysaccharides having extensive biological effects and health benefits, although none of these has been proved by peer-reviewed research. A May 2008 clinical study published by the peer-reviewed Journal of Alternative and Complementary Medicine indicated that parametric data, including body weight, did not show significant differences between subjects receiving Lycium barbarum berry juice and subjects receiving the placebo. The study concluded that subjective measures of health were improved and suggested further research in humans was necessary.
Wolfberry polysaccharides show antioxidant activity in vitro and might also have biological activities in vivo currently under research (20 publications on this topic since 1991; PubMed, February 2007). As a source of dietary fiber, however, polysaccharides would yield products from bacterial fermentation in the colon, such as several short-chain fatty acids, e.g., butyric acid, which may provide health benefits.
Wolfberry fruits also contain zeaxanthin, an important dietary carotenoid selectively absorbed into the retinal macula lutea where it is thought to provide antioxidant and protective light-filtering roles. A human supplementation trial showed that daily intake of wolfberries increased plasma levels of zeaxanthin.
Several published studies, mostly from China, have also reported possible medicinal benefits of Lycium barbarum, especially due to its antioxidant properties, including potential benefits against cardiovascular and inflammatory diseases, vision-related diseases (such as age-related macular degeneration and glaucoma), having neuroprotective properties or as an anticancer and immunomodulatory agent.
However, in the west, none of this research has been scientifically verified, confirmed in clinical studies, or accepted by regulatory authorities.
Atropine, a toxic alkaloid found in other members of the Solanacea family, occurs naturally in wolfberry fruit. The atropine concentrations of berries from China and Thailand are variable, with a maximum content of 19 ppb, below the likely toxic amount.
Select examples given below are for 100 grams of dried berries. Other nutrient data are presented in two reference texts
Wolfberries also contain numerous phytochemicals for which there are no established DRI values. Examples:
[Note on wolfberry polysaccharides: marketers of some wolfberry products report that polysaccharides have specific physiological roles mediated by specialized cell receptors, "master" control properties over other bioactive chemicals and cells, and characteristic spectral peaks defining one berry's geographic origin from another (Bibliography, Mindell, 2005). These unconfirmed theories are an important marketing message for wolfberry products branded as Tibetan Goji Berries or Himalayan Goji Juice Such statements, however, have no scientific evidence published under peer-review and are not compliant with regulatory guidelines for marketing natural food products (see below, Marketing claims under scrutiny in Europe, Canada and the United States)]
[Note on micronutrient and phytochemical 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].
As the Yellow River passes through Gansu downstream toward Ningxia, loess is wind-eroded into the river water where it is carried as silt in its downstream course. The Yellow River is renowned as the most silt-laden body of water in the world,from whence the river's name is derived.
Finer than sand, yellow Gansu loess was formed 2 million years ago after glaciation left behind dust rich in a host of minerals unlike anywhere else on Earth. Gansu erosion into the Yellow River is so dense that silt content in the Yellow River in Ningxia weighs 37 kg for every cubic meter of water -- the highest silt density measured.
Yellow River floods in Ningxia have occurred repeatedly over millennia, depositing the mineral-rich silt over the river's floodplains where wolfberry fields and other crops are renewed and fertilized by the deposited sediment. The dense mineral content of Gansu loess, therefore, may be the origin of the enriched soil which nourishes Ningxia wolfberries.
By unconfirmed reports, its most recognized nutritional attribute is an exceptional level of vitamin C, reputed to be among the highest in natural plants. However, demonstrated by independent assays on dried berries to actually be in a range of 29-148 mg per 100 grams of fruit, the level is actually comparable to many citrus fruits and strawberries Although considered nutritionally "excellent", wolfberry's vitamin C content is considerably lower than for numerous other fruits and berries, such as the Australian Kakadu "billy goat" plum (Terminalia ferdinandiana), blackcurrant, and sea-buckthorn.
Companies marketing the berries often also include the unsupported claim that a Chinese man named Li Qing Yuen, who was said to have consumed wolfberries daily, lived to the age of 252 years (1678-1930), another one of the numerous myths surrounding the health benefits of wolfberry.
Since 2005, wolfberry has been increasingly mentioned in reports on the emerging functional food industry as one of the "exotic superfruits". Superfruit is meant to imply nutrient richness with medical research results indicating potential health benefits, combined with uncommon but appealing taste, pigmentation, and antioxidant strength. During 2006-7, the market for wolfberries included 89 new product introductions in eight retail segments (not including the larger commercial area of network marketing) having an estimated sales total of $9 million, growing rapidly. An executive of one network marketing company was quoted as saying the juice market alone for wolfberries would be valued at more than $1 billion by 2013.
Other wolfberry consumer applications are as dried berries (picture above), berry pieces in granola bars, and skin soap made from seed oils.
Commercial suppliers have processed wolfberry as an additive for manufacturing, such as juice concentrate, whole fruit purée, powders from juice or juice concentrate made from spray drying, pulp powders, whole or ground seeds, seed oils (as done for grape seed oil), and essential oils derived from seeds.
In February 2007, the Food Standards Agency (FSA) of Great Britain, an advisor for food safety to the European Food Safety Authority of the European Union (EU), published an inquiry to retailers and health food stores requesting evidence of significant use of wolfberries in Europe before 1997. This period would document a safety history and evaluate how "novel" the berries are in the EU, affecting their authorization status for sale.
Proponents hoped this review would provide important safeguards for consumers by checking whether new foods are suitable for the whole population, including people with food allergies. Opponents on the other hand feared it would limit consumer choice and protect monopolistic interests rather than the public. Food safety in the EU relies importantly on a scientific basis for label information on foods like wolfberries that may be claimed to furnish health benefits.
In June 2007, the FSA announced its decision that wolfberries indeed had a history of use in Great Britain before 1997. Accordingly, wolfberries do not require registration as a novel food.
In a review of medical literature pertaining to each proposed claim of health benefits from Himalayan Goji Juice (Mindell and Handel, 2003), Gross et al. (2006, book chapter 6; see Article Bibliography) summarized that 22 of 23 claims had no evidence for providing a health benefit beyond that inferred from preliminary in vitro or laboratory animal research. For cancer specifically, four studies were reviewed in Chapter 4 of their book, but Gross et al. (2006) concluded the research was too preliminary to allow any conclusion about an anti-cancer effect of consuming wolfberries or wolfberry juice.
By one specific example in the CBC interview, Earl Mindell claimed the Memorial Sloan-Kettering Cancer Center in New York had completed clinical studies showing that use of wolfberry juice would prevent 75% of human breast cancer cases, a statement false in three ways:
Significant in nutrient and phytochemical composition, wolfberries are being developed as new products in the functional food industry under FDA regulatory review since December, 2006 for label and marketing claims as being conducted in 2007 by the European Union (above).
During 2006, the FDA placed two goji juice distributors on notice with warning letters about marketing claims. These statements were in violation of the United States Food, Drug and Cosmetic Act [21 USC/321 (g)(1)] because they "establish the product as a drug intended for use in the cure, mitigation, treatment, or prevention of disease" when wolfberries or juice have had no such scientific evaluation. Additionally stated by the FDA, the goji juice was "not generally recognized as safe and effective for the referenced conditions" and therefore must be treated as a "new drug" under Section 21(p) of the Act. New drugs may not be legally marketed in the United States without prior approval of the FDA, as stated in the letters below:
KANSAS-STATE STUDY USING CHINESE WOLFBERRIES AS DIETARY SUPPLEMENT TO IMPROVE VISION IMPERFECTIONS CAUSED BY TYPE-2 DIABETES
Mar 31, 2010; MANHATTAN, Kan., March 30 -- Kansas State University issued the following news release: A Kansas State University researcher is...
K-State Study Using Chinese Wolfberries as a Dietary Supplement to Improve Vision Imperfections Caused by Type-2 Diabetes.
Apr 16, 2010; A Kansas State University researcher is exploring the use of Chinese wolfberries to improve vision deficiencies that are common...
Dietary Supplementation with Lacto-Wolfberry Enhances the Immune Response and Reduces Pathogenesis to Influenza Infection in Mice1,2
Aug 01, 2012; Abstract Despite the availability of vaccines, influenza is a considerable public health problem, which emphasizes the need for...