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.E xpansion 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 aÃ§aÃ
Fig. 2 (above). 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.
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 -- gÇuqÇ (æ¸æ) -- simplified in English pronunciation as goji.
âGojiâ 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 Linnaeus' taxonomic textbook, Species Plantarum (1753), description of tomato is made first with its name, Solanum lycopersicum, or by literal translation of lycopersicum, âwolf-peachâ, followed a few pages later by the tomato cousin, Lycium barbarum, âwolfberryâ. By inference, botanists following Linnaeus' system may have adopted the name wolfberry directly from its botanical relationship with the âwolf-peachâ, tomato (8).
Wolfberry is the common name for plants of two closely related species: Lycium barbarum (Mandarin: å®å¤æ¸æ; Pinyin: NÃngxiÃ gÇuqÇ) and L. chinense (Mandarin: æ¸æ; Pinyin: gÇuqÇ), 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 "thornâ (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 âTibetan gojiâ and âHimalayan gojiâ 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 HimalayanMountains?
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
A fruitless search for the Tibetan goji berry
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 âTibetan goji berryâ, âHimalayan goji juiceâ and âgoji berries from the Mongolian Himalayasâ (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 â Ningxia â 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 âwild-craftedâ or âwild-harvestedâ goji berries or products. What does this mean and are there organically certified goji farms?
Quoting from the TibetInfoNet article above:
âcertified grown in the wild on the pristine Tibetan Plateauâ appears to be completely bogus. But even if it was not, the additional claim that the berries grow âwithout pesticides or fertilizerâ is patently absurd because the use of fertilizers and pesticides is widespread on the whole Tibetan Plateau, especially when crops are grown for market.â
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 âGreen Food Statusâ, 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 â 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 âmore vitamin C than orangesâ, 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 âphytochemicalsâ are plant elements of scientific interest for human health but not yet confirmed with sufficient research evidence to call them ânutrientsâ, 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 â 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 â 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.
17. There are many health claims associated with current American-made goji berry or juice products. Some say the fruit or its juice has miraculous properties, such as curing cancer and increasing longevity. How many of these claims are factual?
A: None. These are marketing statements with no scientific basis, blatantly falsified to induce purchases by unsuspecting consumers desperate for remedies.
The claim for a benefit against cancer by one manufacturer of a goji juice product was investigated by the Canadian Broadcasting Corporation television program called MarketPlace, revealing numerous misleading statements by the company and its promoter (13).
This same company and spokesperson have published a booklet stating that goji berries contain several phytochemicals providing specific health benefits (11)
- cyperone (âbenefits the heart and blood pressure, alleviates menstrual discomfort, used in the treatment of cervical cancerâ)
- solavetivone (âa powerful anti-fungal and anti-bacterial compoundâ)
- physalin (âactive against all types of leukemiaâ)
- betaine (âcalms nervousness, enhances memoryâ, âprotects DNAâ, among numerous other claims)
- beta-sitosterol (âanti-inflammatory agent, lowers cholesterol, treats sexual impotenceâ)
- germanium (âan anti-cancer mineralâ)
All these quoted claims are marketing fabrications with no foundations in science applying to mammalian biology or human health. Each of the above phytochemicals is only at an early stage of laboratory research with no confirmation of functional activity in mammals. Furthermore, there are no reports in available medical literature about cyperones, solavetivone. physalins or germanium being isolated from Lycium barbarum or related species (search PubMed, 14, August 2007).
18. What guidelines exist to protect consumers from false advertising about goji and other similar products?
Health regulatory bodies such as the US Food and Drug Administration (FDA) monitor such claims closely and issued a guide in July 2007 for the scientific information needed to support a health claim for any natural food product (15):
As part of its evidence-based review, FDA noted certain critical elements of a studyâdesign, data collection and data analysisâcan be flawed, making it impossible to draw a scientific conclusion. It warns: âFDA does not intend to use studies from which it cannot draw any scientific conclusions about the substance-disease relationship and plans to eliminate such studies from further review.â It further lists examples of questions it will use in reviewing various studiesâintervention, observational, etc.âfor certain scientific conclusions.
For studies making the grade, FDA will assign a high, moderate or low quality rating, based largely on the study design, data collection, data analysis, outcome measured and study population characteristics. The guidance explains the criteria behind each rating and provides examples of how it will judge those study factors.
In the end, FDAâs evaluation will consider the study type (e.g., intervention, prospective cohort, case-control, cross-sectional); methodological quality previously assigned; quantity of evidence (number of the various types of studies and sample sizes); relevance of the body of scientific evidence to the U.S. population or target subgroup; whether study results supporting the proposed claim have been replicated; and overall consistency of the total body of evidence. FDA will use this âtotality of scientific evidenceâ to determine whether studies submitted in a claim meet the SSA standard or are credible to support a qualified health claim for a substance-disease relationship.
- Other baseless claims for the health benefits of goji juice can easily be found
- Healthy immune system function
- Healthy mood (known for thousands of years as "The Happy Berry")
- Healthy libido
- Healthy aging and anti-aging; look and feel younger
- Healthy energy levels and resistance to fatigue
- Healthy blood pressure, cholesterol and homocysteine levels (supporting all around cardiovascular health)
- Healthy endocrine function
- Healthy liver function
- Healthy eyes
- Better sleep
- Protects DNA
- Reduces periodontal disease
- Improves digestion
- Relieves anxiety
- Relieves arthritis pain
- Improves memory
- Extends life
These and numerous other health benefits associated with consuming goji products (11) are all fabricated with no scientific evidence to support them, yet are used to induce purchases of goji products mainly via the internet and through direct sales. As part of its watchdog service against fraudulent health claims, the FDA has identified violations made by two goji juice distributors (16).
19. Have there been any well-designed clinical trials published showing use of goji as an intervention to modify disease?
There is one reference to a clinical trial done in China on patients with several types of cancer.
Cao GW, Yang WG, Du P. [Observation of the effects of LAK/IL-2 therapy combining with Lycium barbarum polysaccharides in the treatment of 75 cancer patients][Article in Chinese] Zhonghua Zhong Liu Za Zhi. 1994 Nov;16(6):428-31.
PubMed Abstract. Seventy nine advanced cancer patients in a clinical trial were treated with LAK/IL-2 combining with Lycium Barbarum polysaccharides (LBP). Initial results of the treatment from 75 evaluable patients indicated that objective regression of cancer was achieved in patients with malignant melanoma, renal cell carcinoma, colorectal carcinoma, lung cancer, nasopharyngeal carcinoma, malignant hydrothorax. The response rate of patients treated with LAK/IL-2 plus LBP was 40.9% while that of patients treated with LAK/IL-2 was 16.1% (P < 0.05). The mean remission in patients treated with LAK/IL-2 plus LBP also lasted significantly longer. LAK/IL-2 plus LBP treatment led to more marked increase in NK and LAK cell activity than LAK/IL-2 without LBP. The results indicate that LBP can be used as an adjuvant in the biotherapy of cancer.
As a full report of this study has not been published in English, it is impossible to understand critical aspects of the study design and other variables that would affect data interpretations from such a trial. No conclusions of anti-cancer activity can be made from such sparse information, yet marketers of some goji juice products inappropriately cite this study as though it were universally accepted by expert reviewers.
There have been no other clinical trials on goji reported in peer-reviewed publications.
20. What is the current status of research on goji?
Searching for âlycium barbarumâ, âlycium chinenseâ or âwolfberryâ on the US National Library of Medicine database, PubMed (14), finds 148 papers of interest. Eighty seven of these are for Lycium barbarum (1991 to August 2007) and 33 are for Lycium chinense (1963 to August 2007).
General categories of anti-disease research on goji over the above years are
- immune system
- eye diseases
- cardiovascular system
- metabolic syndrome
- neurological disorders
- antioxidant functions
There are only three publications to date from North American laboratories on this berry and four from Europe.
In the past year to August 2007, 20 new studies were cataloged on PubMed, 18 from laboratories in China and Hong Kong, one each from India and Austria, and none from other European countries, the United States or Canada.
Select 2007 publications on goji (wolfberry, Lycium barbarum), all from Chinese centers:
1. Xin YF, Zhou GL, Deng ZY, Chen YX, Wu YG, Xu PS, Xuan YX. Protective effect of Lycium barbarum on doxorubicin-induced cardiotoxicity. Phytother Res. 2007 Jul 11; [Epub ahead of print]
Synopsis. The objective of this work in rats was to test the hypothesis that Lycium barbarum protects against doxorubicin-induced cardiotoxicity through antioxidant-mediated mechanisms. Where control doxorubicin-treated animals showed signs of cardiac injury and higher mortality, those provided orally with 25 mg/kg/day of goji extract over 3 weeks had less myocardial fibril injury and improved overall heart function, indicating possible antioxidant effects against cardiotoxicity.
2. Zhu J, Zhao LH, Zhao XP, Chen Z. Lycium barbarum polysaccharides regulate phenotypic and functional maturation of murine dendritic cells. Cell Biol Int. 2007 Jun;31(6):615-9.
Synopsis. Lycium barbarum polysaccharides (LBPs) have been a common subject for in vitro or in situ research on goji, with some 35 reports listed on PubMed over 1991-2007. The tested assumption has been that goji polysaccharides may have a variety of immunomodulatory functions including activation of T cells, B cells and NK cells. In this study, bone marrow dendritic cells, which are antigen-presenting cells that may initiate a primary immune response, were stimulated by LBPs to produce a lymphocyte response in vitro. Such results provide evidence that the LBPs may have immune-modulating roles, but such an effect has not been shown following oral ingestion of goji berries nor has it been demonstrated conclusively in an in vivo model.
3. Li XM, Ma YL, Liu XJ. Effect of the Lycium barbarum polysaccharides on age-related oxidative stress in aged mice. J Ethnopharmacol. 2007 May 22;111(3):504-11.
Synopsis. This study examined age-dependent changes in the antioxidant enzyme activity, immune function and lipid peroxidation in aged mice provided daily oral doses over a month of Lycium barbarum polysaccharides (LBPs). The authors reported that endogenous lipid peroxidation, decreased antioxidant activities, as assessed by superoxide dismutase, catalase, glutathione peroxidase, total antioxidant capacity, and immune function were restored by oral LBPs. Unknown, however, is whether consumption of whole berries or goji juice would have similar results. The fate of ingested LBPs in the digestive tract, blood and organs can not be determined from these studies. It is not certain if the effects observed were elicited by LBPs or other physiological mediators.
4. Chan HC, Chang RC, Koon-Ching Ip A, Chiu K, Yuen WH, Zee SY, So KF. Neuroprotective effects of Lycium barbarum Lynn on protecting retinal ganglion cells in an ocular hypertension model of glaucoma. Exp Neurol. 2007 Jan;203(1):269-73.
Synopsis. One of the most enduring legends of eating goji is for its eye health benefit. These scientists tested whether goji could promote the survival of retinal ganglion cells against elevated intraocular pressure (a model of glaucoma) induced experimentally in rats. Oral administration of goji significantly reduced the loss of retinal ganglion cells in the model, providing evidence for protection against neurodegeneration during high intraocular pressure seen in glaucoma.
21. What is expected of manufacturers and marketers to meet regulatory requirements for making health claims about goji products?
Health regulatory bodies around the world are designing guidelines for food and beverage manufacturers to have accurate, scientifically-validated information on product labels and marketing literature.
In addition to the FDA guidelines (15), the Institute of Food Technologists published a report by scientific experts on functional foods (17), stating âExperts must agree that a claim is valid based on the totality of publicly available scientific evidence, including evidence from well-designed studies conducted in a manner consistent with generally recognized procedures and principles.â
âThe standard of scientific validity for a health claim includes two components: 1) that the totality of the publicly available evidence supports the substance/disease relationship that is the subject of the claim, and 2) that there is significant scientific agreement among qualified experts that the relationship is validâ (17).
Even if a health claim is allowed, its message may not be powerful enough for manufacturers to use on a label, such as the following FDA statement permitted for consumption of tomatoes to inhibit prostate cancer (from http://www.cfsan.fda.gov/~dms/qhclyco2.html):
"Very limited and preliminary scientific research suggests that eating one-half to one cup of tomatoes and/or tomato sauce a week may reduce the risk of prostate cancer. FDA concludes that there is little scientific evidence supporting this claim."
By this example, even for an intensely researched plant food such as tomato â cousin of the goji berry (4,8) â criteria for attaining a health claim are a long way from being acceptable.
The reasons for such strict regulations? In studies of foods, it's difficult â if not impossible -- to isolate the health benefit of a single nutrient (in this case, lycopene) when so many other nutrients may be at play following dietary intake, even in a well-controlled clinical trial. As a result, FDA concludes there has been insufficient credible evidence to support a link between tomato lycopene in any form (as a supplement or as part of whole food) and a lower risk of prostate cancer.
Likewise for currently marketed goji berries or juice, there is no health claim validated by acceptable human research criteria, as there have been no well-controlled clinical trials on goji, any of its nutrients or individual goji phytochemicals.
Bottom line: There's just not enough evidence to recommend that we eat tomatoes or goji to gain specific health benefits or prevent diseases.
Does that mean goji berry products are not worth consuming? Of course not. It simply means that regulatory agencies are not willing to let food or juice manufacturers make health claims that could confuse or mislead consumers.
The European Food Safety Authority has constructed similar criteria for health claim approvals (18), requiring manufacturers to show that
Â· the claimed effect is relevant to human health
Â· there exists a direct cause and effect relationship between eating the food and the health effect demonstrated
Â· the quantity and frequency of use of the claimed health food for the benefit must be demonstrated
Â· the study group used must represent the target population for which the claim is made
In Canada, manufacturers of food products claiming health benefits simply must meet the same stringent criteria as those for pharmaceutical companies and drugs (19).
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.
However, insufficient research criteria are satisfied to prove goji's health effects, and there are no well-designed clinical trials showing intervention by goji consumption against a disease.
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.
1. Starling S. Superfruits â 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 âwolfberryâ or âlycium barbarumâ or âlycium chinenseâ
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
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/
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
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).