In the Western world, Goji berries (Lycium barbarum) are one of the latest fruits to have medicinal claims made for them. However, these 15-25 mm long red berries have been part of the Chinese herbal medicine for centuries. Traditionally they have been used to treat inflammation, skin irritation, nose bleeds, aches, pains and as a sedative. They are also commonly used with other botanicals in Chinese medicine for poor vision, anemia, cough and for treating infertility.
Note on nomenclature
Lycium barbarum is known as wolfberries in China and the United States, and as goji berries in Tibet and Mongolia. Lycium chinense, L. europeaum and Fructus barbarum are synonyms for L. barbarum. They belong to the Solanaceae family. They grow wild in these countries but are also cultivated in China. Bernard King has tasted both the Chinese and Tibetan varieties and much prefers the Tibetan or Mongolian. He gave me a sample of dried Tibetan goji berries. They were delicious with a cranberry/sultana like taste. Highly recommended. In Tibet, the berries are never touched by hand as they will oxidize and turn black if touched while fresh. They are shaken onto mats, then dried in the shade.
A note of caution. It has been made known to me that a related species, Lycium ferocissimum (buckthorn) can be a weed in parts of New Zealand. Entry of Lycium ferocissimum, Lycium tenuispinosum and Lycium chilense into New Zealand is prohibited.
Claims are being made that eating them promotes long life, and in elderly people increases the effectiveness of the immune system, increases appetite and improves sleep. Most of the above claims are not backed by peer reviewed medical research. Yet there are some studies indicating that extracts of goji berries may hold promise in some medical conditions (see below). Dr Earl Mindell is a driving force behind Western interest in the medical properties of goji berries, particularly their anti-ageing properties, after observing the age of Tibetans and the use of goji berries in their diet. However, dietary calorie restriction is also likely to a factor in Tibetan diets and are known to increase lifespan, so what are the critical factor(s)? This is where epidemiological research is essential to determine which factor(s) best correlate with the life span.
Quackwatch (a website set up to assess medical claims) is critical of Dr Mindell, and indicates a number of important errors in his previous published work on herbal medicines. It states that Mindell claims to hold valid credentials in nutrition. Although he does have a bachelor’s degree in pharmacy from the University of North Dakota, his Ph.D. is from the University of Beverly Hills, an unaccredited school which lacks a campus or laboratory facilities. The Quackwatch review was written by Dr. Tyler, the Lilly distinguished professor of pharmacognosy (the science of medicines from natural sources) at Purdue University. On checking the medical literature, I have been unable to confirm claims that goji berries increase immune function in humans (there have been studies on mice using intravenous injections), or stimulate growth hormone release (the so-called “youth hormone”).
On the other hand, one human study has indicated that eating goji berries (50 g per day of dried berries for 10 days) increases levels of an enzyme (superoxide dismutase) which is involved in reducing free radicals in the body, and decreases lipid (fat) oxidation products. These results are an indication that oxidative stress is reduced by goji berries – oxidative stress is strongly suspected of being involved in ageing and a number of other human diseases. Another controlled study has shown a decrease in a number of minor symptoms of everyday living such as fatigue and sleeping problems (reviewed by D.S. Burke et al. Current Topics in Nutriceutical Research vol.3 pp. 259-266, 2005).
The Sloan-Kettering Cancer Center in New York summarizes the known medical properties of goji berries. The bark and the berry contain betasitosterol which can prevent cholesterol absorption in the gastrointestinal tract. Lycium barbarum polysaccharide has been shown to inhibit the growth of leukemia HL-60 cells (a study using cell cultures). One study reported that in 75 cancer patients, infusion into the blood stream of a combination of immune stimulation and a polysaccharide from goji berries improved regression of a number of cancers and improved remission. However, the treatment method used is not standard in Western medicine. A cerebroside (a type of fatty compound found in the brain and elsewhere) extracted from Lycium barbarum may help protect the liver from damage.
Studies in animals and in human cell cultures indicate that extracts of goji berries have antioxidant activity, enhance growth of immune cells, decrease insulin resistance (improving diabetes), have anti-tumour activity, inhibit damage to the sperm, decrease blood pressure and can decrease damage from a protein thought to be a cause of Alzheimer’s disease. Most of these studies have been to test the properties of a polysaccharide extracted from goji berries, but these studies do not indicate that eating goji berries will have the same effects. One of the functions of the gut is to breakdown polysaccharides into sugars, so it is unlikely that the polysaccharide ever reaches the blood stream. As well, absorption of large molecules such as polysaccharides from the gut into the blood stream is extremely limited.
Goji berries (as do blueberries and avocadoes) also contain zeaxanthin, required for good eye health (a lack of zeaxanthin and lutein are a cause of age-related macular degeneration resulting in blindness). Claims have been made that they are highly nutritious, with large amounts of Vitamin C, b-carotene (converted to Vitamin A in the body), Vitamins B1, B6 and E, most amino acids required for protein synthesis, minerals, antioxidants (including anthocyanins and other flavonoids) and essential fatty acids. Levels of these compounds in goji berries need to independently verified and compared with levels in other fruits, as most or all fruits contain antioxidants and other nutrients. The nutrient and anti-oxidant content may be the most important property of goji berries.
There is much more work to be done before goji berries can be recommended for treating human diseases (so far there appear to be only 3 studies actually using humans). Contraindicated for people on “blood-thinning” medication (warfarin).
Cultural conditions and availability of plants
Bernard King has Goji berry shrubs for sale (available also through Northern Branch NZTCA). These are sourced from the Himalayas, either Tibetan or Mongolian (similar properties). $10 per plant either direct from Bernard or from our branch, cheaper for bulk orders. The goji berry shrub is a scrambling shrub 2 m high by 3 m, requiring support – perhaps similar to raspberries. Grows fast with some berries possible in the second year and bearing heavily at 3-4 years.
Patrick Riddall at Awakeri in the Bay of Plenty initially germinated around 600 plants. This winter he is putting in around 3 to 4 acres of goji berries. Patrick has supplied the following cultural notes.
The goji bush is a very hardy plant that handles extremes in temperature and will survive just about anything. Optimum growth is in deep well drained fertile soil in full sun, they go better in full sun than partial sun. The only thing the Goji bush does not like is having it’s roots sitting in water. The roots like going deep and do not make good pot plants. They like regular watering for optimal growth although are very drought resistant once established. When planting them try to plant them in places were they get frost as this sets the fruit sugars and makes for sweeter fruit (my aside: they will survive –15C; so perhaps fruit from these plants will not be as good in Auckland and north). Very attractive to caterpillars.
Notes from Sheryl: This article was taken from the TreeCropper June 2006 – the newsletter of the New Zealand Tree Crops Association www.treecrops.org.nz A copy is available in our library – kindly donated by Merv Cooper.
The author Gordon Lees will be one of the keynote speakers at the 2007 TreeCrops conference 13th-15th April being held in New Zealand – the program looks exceptionally good. After doing a PhD on cheese bacteria in Melbourne, Gordon spent the next 30 years in the neuro-sciences working in medical institutes then spent the next 27 years at the University of Auckland in the Biochemistry Dept and later in the Depts. of Psychiatry and Pharmacology section of the medical school. He is now retired and is a Research Coordinator for the Tree Crops Association focusing on the medicinal properties of plants. We’re hoping to catch up with Gordon in New Zealand later in the year.
I recently attended the California Rare Fruit Growers meeting in Orange County, California where I got to taste fresh Goji berries. They were large, elongated orange berries – no sweetness in the ones I tried even though the books say they are. They were OK but I’d like to try other varieties. Michael Nave says that in the US they have random seedlings and there is a great deal of genetic diversity in the berries in China – it’s not clear what is being grown in the US. He has been growing goji berries from different sources and the quality of the fruit varies widely. Some are excellent and some are inedible. The dried fruit is promoted heavily on the internet and truth about the origin is often sacrificed in an attempt to get sales. Unfortunately even the alleged organic dried fruit from China is often laced with pesticides and colorants. Goji don’t like hot summers. Once they are established they can tolerate heat but the smaller plants don’t like it at all.