2007-09-04 - By Dr. Paul Gross - Berrydoctor.com
Paul M. Gross, PhD

Global market interest in goji berries (Fig. 1 above, wolfberries, Lycium barbarum L., origin China) has intensified to where several dozen product launches have occurred within recent months (1). In the industry of functional foods and beverages, goji may have significant potential for staying power as a nutrient-rich, high-antioxidant natural food likely to attract western scientific validation and diverse product development.

Expansion of goji product development is likely for several reasons (1,2,3). The fruit

- remains mostly unknown to Western consumers who are demanding novel exotic tastes and nutritional sources
- has a broad range and significant density of nutrients
- is antioxidant rich among plant foods
- contains phytochemicals with potential health properties
- provides versatility in stable raw materials that can be shipped or stored as dried berries, pulp and juice powders, or juice concentrate
- can be used unprocessed as dried fruit (Fig. 2) or juice (Fig. 3) just as it is, unlike certain other fruits currently being developed as mainstream consumer products, such as açaí

Fig. 2. Sun-dried goji berries

Fig. 3. Goji juice concentrate

There is, however, much that is misunderstood about goji berry and its health properties. Its scientific literature, nutrients and health-related chemicals, name, origin of the current commercial supply of raw materials, and applications in consumer products are often questioned. Presented here is a 21-item FAQ sheet to help set the record straight about this fruit rapidly becoming popular among consumers in many industrialized countries.

What It Is

1. What is goji?

Goji is wolfberry (Lycium barbarum L.), a vine berry in the same plant family (Solanaceae) as tomato and eggplant. On the vine, the juicy, sweet berry looks like a miniature roma tomato (Fig. 1) and is harvested from July to September in its native China.

2. How is goji commonly used?

Close to where it's harvested, the freshly picked fruit (Fig. 4) is sold in local markets, but traditionally is sun-dried (to about 10% water content like a raisin), allowing storage over months for use in meals and drinks, such as tea or wine. In recent years, numerous goji juice products manufactured in the United States have been marketed worldwide as a health elixir.

Fig. 4. Freshly harvested goji berries being prepared for sun-drying, Ningxia, China, July 2007

3. What does goji smell and taste like?

Similar to other more common dried berries, dried goji berries have a sweet, fresh fragrance somewhat similar to roasted nuts. Their taste is unique, a combination of mild nut, tomato and cranberry. Pure goji juice has taste of a sweet, fruity tomato juice with nut and pleasant acidic tones.

4. Why should goji be of interest to Western consumers?

Aside from its reputation in Asia as a medicinal herb used over centuries (4-chapter 7, 5), contract laboratory analyses published in recent books (4,5) have demonstrated a wide nutrient profile including a richness of antioxidant phytochemicals.

As a member of the tomato family, goji has a high carotenoid content, including beta-carotene, beta-cryptoxanthin, lutein, zeaxanthin and lycopene which are rarely found in common berries.

5. Is goji popular?

In the United States, there are at least three major manufacturers of goji juice products and numerous others providing some 54 individual product introductions over the past year (1). As these are private firms, sales volumes are not released publicly, but are estimated at several hundred million dollars in annual revenues. One Australian distributor of an American manufacturer reported -- just for his own business -- more than double-digit annual growth and sales per month of Aus$4 million (6).

Goji has recently been evaluated by the British Food Standards Agency, declaring it with a history of consumption in the UK before May 1997 and therefore not subject to regulation as a novel food (7).

The berry has attracted such significant recent interest that more than 100 medical research studies have been completed over the past 20 years, with two books (4,5) published since 2005. By comparison, no science-based books exist for common berries, such as blueberry, cranberry or strawberry.

Origins

6. Where did the plant and name originate?

In China, the plant has been referenced in ancient textbooks dating to the earliest written records of the Han Dynasty around 200 AD, although it is believed by Chinese to have existed well before then (4). The Chinese government reported that wolfberry has been systematically cultivated in the Ningxia region since around 1400 (Fig. 5; 8).

Fig. 5. Location of the Ningxia Hui Autonomous Region in north-central China, the primary production region for goji berries

Botanically, the name Lycium barbarum was assigned in 1753 by the Swedish botanist, Carolus Linnaeus, who created the taxonomic nomenclature system used since his time until today to specify plant names, families and individual species (8).

There is no clear answer to the question of how the name goji was started, although it is most easily explained upon hearing the Mandarin name for wolfberry -- gouqi-- simplified in English pronunciation as goji.

“Goji” appears to have been publicly adopted as a simple marketing name in English-speaking countries in 2004 shown by Google Trends as the beginning of the goji era, http://google.com/trends?q=goji. This period coincides with appearance of several goji juice products on the United States market.

Not used in scientific literature, the name goji has become a popular slang substitute for wolfberry and will be used throughout this essay.

7. What about the name wolfberry?

In Mandarin, the berry is called gouqi or wolfberry, speculated by some Chinese to have been used first by ancient farmers who saw wolves seeking food and shelter among the dense vines.

In Linnaeus' taxonomic textbook, Species Plantarum (1753), description of tomato is made first with its name, Solanum lycopersicum, or by literal translation of lycopersicum, “wolf-peach”, followed a few pages later by the tomato cousin, Lycium barbarum, “wolfberry”. By inference, botanists following Linnaeus' system may have adopted the name wolfberry directly from its botanical relationship with the “wolf-peach”, tomato (8).

Wolfberry is the common name for plants of two closely related species: Lycium barbarum (Mandarin: ; Pinyin: Níngxià gouqi) and L. chinense (Mandarin; Pinyin: gouqi), each a specie of boxthorn in family Solanaceae.
In Tibetan, the plant is called dre-tsher-ma , with dre meaning "ghost" and tsher-ma meaning "thorn” (8).

What It's Not

8. What other names are connected to goji?

Lycium eleganus, Lycium eleganus barbarum, or Lycium eleagnus have appeared in internet discussions about goji. However, these names are a hoax, as no such plant species exist in botanical taxa (8,9).

According to the United States Department of Agriculture Germplasm Resources Information Network (9), goji is also known as Chinese wolfberry, barbary matrimony vine, bocksdorn, Duke of Argyll's tea tree, or matrimony vine. Unrelated to the plant's geographic origin (discussed below), the names “Tibetan goji” and “Himalayan goji” are in common use in the health food market for products from this plant.

9. What are the connections of the often associated relationship of goji to Tibet and the Himalayan Mountains?

Reports published in 2006-7 from sources working in Tibet have provided valuable perspectives on the growing regions of goji and, specifically, knowledge about goji's absence of history in Tibet. These two accounts are
r the Tibetan flag

The commercial legend of goji: Selling a Chinese crop under the Tibetan flag
http://www.tibetinfonet.net/content/update/73 (then type “goji berry” in the search box.)

A fruitless search for the Tibetan goji berry
http://wolfberry.org/documents/ParryFruitlessSearchforGoji12-06.pdf

Conclusions from the two articles are

• no history was found of written records or government knowledge of goji berries having ever been cultivated in significant quantities in Tibet
• no reference to goji was found in texts of traditional Tibetan medicine
  
• there is little knowledge of goji among Tibetan people
  
• where rarely sold in Tibetan markets, goji berries do not come from Tibet but rather mainly from central regions of China
  
• Tibetan people do not live to exceptional ages of 100 or more (attributed to lifelong consumption of goji berries), but rather have among the world's lowest life expectancies -- about 67 years
  
• although goji may grow wild and in sparse patches of a few, fertile low-altitude areas in south-eastern Tibet, most of Tibet and certainly the Himalayas are at high altitude (10,000 feet altitude and above) where weather and agricultural conditions are inhospitable for fruit cultivation
  
• commercial production of goji has apparently never occurred in Tibet
  
• uses of such terms as “Tibetan goji berry”, “Himalayan goji juice” and “goji berries from the Mongolian Himalayas” (usually conveyed on the label with a dramatic backdrop of snow-covered mountain peaks) for products manufactured and sold in the West are inaccurate at best, as the goji berries used for these products do not grow in Tibet or the Himalayas, and the Himalayan Mountains do not extend into Mongolia
  
• few benefits of using Tibetan or Himalayan names for goji products sold in the West return to Tibetans
  

10. If goji berries don't grow in significant quantities in Tibet or the Himalayas, where did the berries on the world market originate? Could goji be grown in places like Canada, the United States or Europe?

The Chinese government reports that the highest production region in China is the Autonomous Region (province) of Ningxia in north-central China along the banks of the Yellow River (8). Approximately 40% (13,000 metric tons in 2001, 8) of the national export crop is harvested in Ningxia, the country's smallest province. Other Chinese regions with significant production include Xinjiang, Qinghai, Sinchuan, Hebei, Gansu and Inner Mongolia.

Success in cultivation of berries depends on factors like genetic material, duration and weather conditions of the growing season, day-night temperature variation, adequate irrigation, soil quality, horticultural pest prevention tactics, etc. (4-chapter 9; 5). The Lycium genus is widespread, as more than 40 species related to goji grow in different world regions (4,9). None commercially, however, is known outside China.

As the successful goji growing region in China – Ningxia – has similar characteristics of the above agricultural factors as a Northern Hemisphere location on the same latitude (42nd parallel north) such as Oregon to Ontario or southern France, there seems to be no reason why goji could not be successfully cultivated in temperate regions of North America and Europe.

11. Often in goji marketing literature, one sees the terms “wild-crafted” or “wild-harvested” goji berries or products. What does this mean and are there organically certified goji farms?

Quoting from the TibetInfoNet article above:
“certified grown in the wild on the pristine Tibetan Plateau” appears to be completely bogus. But even if it was not, the additional claim that the berries grow “without pesticides or fertilizer” is patently absurd because the use of fertilizers and pesticides is widespread on the whole Tibetan Plateau, especially when crops are grown for market.”
There is also evidence that goji farms in China must use herbicides and pesticides to control infestations, although some claim the amounts are below detectable limits and so earn the farm and its produce “Green Food Status”, a designation assigned for agricultural training practices rather than organic certification (8). To date, no Chinese farms and no American manufacturers of goji juice or dried berry products have publicly provided evidence of their claimed organic certification (August 2007).

Nutrition, Antioxidant Qualities and Health Claims

12. What nutrient content does goji have?

Goji contains an exceptional nutrient content as a whole food (4,5)

• significant levels of carbohydrates, protein, dietary fiber, and linoleic acid, an omega-6 fatty acid (in seeds)
  
• excellent source of dietary fiber via high density of polysaccharides (10% or 3 g per serving of total 30 g recommended for daily fiber intake)
  
• vitamin A (carotenoid provitamins), B vitamins - thiamin, riboflavin, niacin – and vitamin C
  
• 11 essential and 22 trace minerals
  
• 18 amino acids with total content of 11 g per 100 g of dried fruit, an exceptional amino acid concentration
  Goji's micronutrient content is among the densest found in one plant food, as the few examples below illustrate (100 g dried fruit; 4)
  
• potassium, 1,132 mg, 24% of the Recommended Dietary Allowance
  
• iron, 9 mg (100% of the Dietary Reference Intake (DRI, US Institute of Medicine)
  
• copper, 2 mg (100% DRI)
  
• zinc, 2 mg (18% DRI)
  
• riboflavin (vitamin B2), 1.3 mg (100% DRI)
  

13. How does the micronutrient content of goji berries compare to other berries?

Goji (black), blueberry (blue), red raspberry (red).

Values for vitamin C, calcium and magnesium are in mg whereas those for selenium are in micrograms. Normalized to 100 grams of fruit, data are from Reference 4 for goji and World's Healthiest Foods for blueberry, http://whfoods.org/genpage.php?tname=nutrientprofile&dbid=84
and raspberry http://whfoods.org/genpage.php?tname=nutrientprofile&dbid=23.

These data reflect a consistent characteristic for the Ningxia goji berry: its nutrient density and diversity generally exceed those of more common berry species popular with North American consumers, such as cultivated blueberry (Vaccinium corymbosum), red raspberry (Rubus idaeus) or strawberry (Fragaria vesca).

Contrary to frequently quoted but unreferenced internet sources that goji contains “more vitamin C than oranges”, goji has approximately half the vitamin C content (29 mg per 100 g) as a fresh orange (53 mg per 100 g, ). This would still provide around 37% of DRI in one 100 g (3.5 oz) serving.

14. What phytochemicals are of interest in goji?

Supposing that “phytochemicals” are plant elements of scientific interest for human health but not yet confirmed with sufficient research evidence to call them “nutrients”, the main classes of goji phytochemicals would be antioxidant pigments from both the polyphenol (water-soluble phenolic acids) and carotenoid (lipid-soluble) pigment categories. By having both classes of pigments not usually present together in common berries, goji is exceptional with antioxidant protection which may be conferred upon human consumers.

Goji is a particularly enriched plant food source of the carotenoids (4), beta-carotene (12 mg per 100 g), zeaxanthin dipalmitate (162 mg per 100 g) and lycopene (1.4 mg per 100 g).

Other goji phytochemicals with growing research interest include phytosterols, scopoletin, terpenes and betaine (4,5), none of which is unique only to goji but can be found in many plant foods.

There is only one published report of the antioxidant radical absorbance capacity of dried goji – 30,300 ORAC units per 100 g (Brunswick Labs assay, 5), a value placing it among the highest reported for plant foods and some 6 times higher than cultivated blueberries or red raspberries (5,8, chart below). Goji contents of ellagic acid (86 mg per 100 g) and total phenolics (1309 mg per 100 g; both reported from one source, 5) are also among the highest values published for berry fruits.

Goji (black), cultivated blueberry (blue) and red raspberry (red) in ORAC units per 100 g.
Goji data from Reference 5; blueberry and raspberry data from Wu et al., J Agric Food Chem 52:4029, 2004.

15. Based on these goji phytochemicals, are there clear directions for research to pursue goji as a medicinal herb?

As goji is a phytochemical-rich plant food, its components individually or as a whole food could be of significant research interest.

One of its reputations from ancient Chinese myths – often stated by native Chinese of all ages -- is that goji is an eye-health food. A case can be made for this possibility, as at least a dozen goji components could aid eye health (10). But this premise has not been systematically studied and there is no human research yet available to support it.

16. In promotional literature for American-made goji juice products, it is often stated that goji polysaccharides have significant health value. What are polysaccharides and how are they important?

A significant history of Chinese research has been focused on goji polysaccharides showing immune-stimulating and antioxidant effects in vitro (literature summarized in 4).

Marketers of some goji products claim polysaccharides have specific physiological roles in vivo governing cell function, "master" control properties over other bioactive chemicals and cells, and characteristic spectral peaks defining one berry's physiological benefits as superior to another (11). These claims are a cornerstone of marketing messages for certain goji juice products.

Such statements, however, are

• entirely conjectural with no scientific basis established to date
  
• supported only by preliminary in vitro scientific evidence that does not replicate the fate of polysaccharides following ingestion of the whole goji berry as food in the living body
  not tested experimentally in either laboratory animals or human subjects
  
• non-compliant with regulatory guidelines for making health claims about a natural food product
  

Polysaccharides are long-chain sugars resistant to complete digestion in the upper intestinal tract where most foods are broken down by acids and enzymes to supply nutrients. Upon entering the colon, undigested polysaccharides from goji or any food source would become substrates for bacterial fermentation which yields health-promoting by-products like short-chain fatty acids (12). In this physiological process, goji polysaccharides are a good source of dietary fiber (12). No physiological role in vivo, however, has been identified for goji polysaccharides by scientific studies.

Studies using amplified polymorphic DNA fingerprinting or Fourier spectroscopy to distinguish nutrient advantages of one goji crop's region from another (discussed in chapter 8, reference 4), as claimed by some marketers of goji juice products (11), were never published in that context and have not been validated for that purpose by peer-reviewed science.

Conclusion

Goji berries are an unusually abundant source of essential nutrients, fiber, protein and antioxidant pigments -- a whole food most likely with valuable health-promoting properties.
Accordingly, health claims for goji berries or any products made from them are not scientifically validated at present. Neither are health claims about goji allowable as statements on food or juice labels or marketing literature for such products.

References

1. Starling S. Superfruits – superheroes of functionality, Functional Foods and Nutraceuticals, April 2007, http://ffnmag.com/ASP/articleDisplay.asp?strArticleId=1284&strSite=FFNSite&Screen=HOME
2. Gross PM. Superfruits take center stage, NPI Center.com, February 2007, http://www.npicenter.com/anm/templates/newsATemp.aspx?articleid=17826&zoneid=201
3. Bradley K. Fruits of the Future? Natural Products Insider, March 2007 http://naturalproductsinsider.com/articles/07mar12feat3.html
4. Gross PM. Zhang X, Zhang R (2006). Wolfberry: Nature's Bounty of Nutrition & Health. Charleston, SC: BookSurge Publishing.
5. Young G, Lawrence R, Schreuder M (2005). Discovery of the Ultimate Superfood: How the Ningxia Wolfberry and Four Other Foods Help Combat Heart Disease, Cancer, Chronic Fatigue, Depression, Diabetes and More. Orem, UT: Essential Science Publishing.
6. Goji berries more fad than fact, News.com Australia, June 2007, http://www.news.com.au/story/0,23599,21916251-2,00.html
7. Goji berries, UK Food Standards Agency, June 2007, http://www.food.gov.uk/multimedia/pdfs/gojiberriesrep.pdf
8. Wikipedia goji article, http://en.wikipedia.org/wiki/Goji
9. US Department of Agriculture Germplasm Resources Information Network, Lycium, http://www.ars-grin.gov/cgi-bin/npgs/html/taxlist.pl?Lycium
10. Gross PM. Goji's dozen friends of eye health, NPI Center.com, November 2006, http://www.npicenter.com/anm/templates/newsATemp.aspx?articleid=17095&zoneid=43
11. Mindell E, Handel R. (Ed. 1, 2003) Goji: The Himalayan Health Secret, Lake Dallas, TX: Momentum Media Health Series.
12. Teglund BC, Myers D. Nondigestible oligo- and polysaccharides (dietary fiber): their physiology and role in human health and food. Comprehen Rev Food Sci Food Safety 2002, 1:73-92.
13. CBC TV, Marketplace, Getting Juiced, Aired January 2007 (video/audio) http://www.cbc.ca/marketplace/2007/01/goji.html
14. PubMed goji references, http://pubmed.gov, search “wolfberry” or “lycium barbarum” or “lycium chinense”
15. FDA releases draft guidance on health claims approval process, Natural Products Insider, July 2007, http://naturalproductsinsider.com/hotnews/77h6111340.html; Guidance for Industry: Evidence-based review system for the scientific evaluation of health claims (Draft Guidance, June 2007), http://www.cfsan.fda.gov/~dms/hclmgui5.html; FDA Qualified Health Claims Guidance, July 2007, http://www.cfsan.fda.gov/~dms/lab-qhc.html
16. FDA review for false advertising about Lycium Barbarum Goji Juice, Dynamic Health Labs, http://www.fda.gov/cder/warn/cyber/2006/CL214e.pdf; Goji Juice by FreeLife or Himalayan Goji Juice, Healthsuperstore.com, http://www.fda.gov/cder/warn/cyber/2006/CL226e.pdf
17. Institute of Food Technologists, Expert Report, Current US Legal Standards for Health-Related Claims, March 2005 http://members.ift.org/NR/rdonlyres/69E560C7-9AEB-4DBF-8409-F5921FFEA4E2/0/HealthClaims.pdf
18. European Food Safety Authority, Scientific and Technical Guidance for Preparation and Presentation of the Application for Authorisation of a Health Claim, The FSA Journal 530:1-44, July 23, 2007; http://www.efsa.europa.eu/etc/medialib/efsa/science/nda/nda_opinions/
ej530_guidance_health.Par.0001.File.dat/nda_op_ej530_guidance_%20health_claim_en.pdf.pdf
19. Health Canada, Policy Paper: Nutraceuticals/Functional Foods and Health Claims on Foods, Final Policy Decision, November, 1998; http://www.hc-sc.gc.ca/fn-an/label-etiquet/nutrition/claims-reclam/nutra-funct_foods-nutra-fonct_aliment_e.html

Author Profile

Paul M. Gross, PhD received his doctorate in physiology from the University of Glasgow, Scotland and was trained in neuroscience at the Laboratory of Cerebral Metabolism, National Institutes of Health, Bethesda, MD. A Research Scholar for the Heart and Stroke Foundation of Ontario, he published 85 peer-reviewed journal reports and book chapters over a 25 year career in medical science, and was recipient of the Karger Memorial Award, Switzerland, for publications on brain capillaries. Dr. Gross is publisher of The Berry Doctor's Journal, http://berrydoctor.com where readers can obtain free information on berry science and nutrition. He is coauthor of a book on the goji berry with X. Zhang and R. Zhang, Wolfberry: Nature's Bounty of Nutrition and Health, 2006, Booksurge Publishing (Amazon.com).