The current existing trends in the dieting world appear to be these so-called ‘superfoods’. The interest stems from the components in the food that are termed ‘bioactive’ (Kulczynski & Gramza-Michalowska, 2016). Goji berries is a fruit with a range of proposed health benefits, including and not limited to; antioxidant; cancer-fighting; immune boosting; blood glucose regulating; and energy boosting (Cui et al., 2011). But is it really?
Let’s dig a little deeper, where do they come from and how do they work?
The Goji berry is grown in Asia and produces an orange-red fruit that is used for traditional medicinal uses (Donno, Beccaro, Mellano, Cerutti, & Bounous, 2015). The Goji berry as we know it, is harvested and left to dry in the shade until the berry begins to shrink- it is placed in sunlight to dry out the outer skin of the fruit (Donno et al., 2015). They are known to contain a range of important nutrients, including: phenolic compounds; phytochemicals; and sugars (Donno et al., 2015). It is acknowledged by some scientists that the antioxidant component of goji berries may contribute to a range of health benefits and act as an antioxidant (Donno et al., 2015).
With so many claims surrounding this wonder berry we can’t investigate them all so today we’ll just focus on the Goji berry being a treatment for type-2 diabetes. Now that’s a big claim to make!
There are many complications that arise due to diabetes- it is common for an imbalance to occur between oxidative stress and antioxidant defence mechanisms, leading to damages of cell tissue (Luo, Cai, Yan, Sun, & Corke, 2004).
So where does Goji fit into the story? Goji berries are proclaimed to assist in reducing diabetic complications (such as high blood sugar) through protection against free radicals as a result of their high antioxidant properties (Luo et al., 2004).
It’s time to get a little scientific for those who are interested, sorry! The main component in goji berries most commonly tested are Lycium barbarum polysaccharides (LBP). These contribute about five to eight percent of the total fruit and are suggested to have an anti-diabetic effect (Amagase & Farnsworth, 2011). The actual function of LBP still isn’t well understood.
Let’s look at the evidence! Obesity is recognised as a large contributing risk factor for the development of Type 2 Diabetes (Franks & McCarthy, 2016). It is also commonly found that weight loss is a process that aids in the prevention of diabetes and lowers the risk of initial development (Franks & McCarthy, 2016).
A number of studies have been conducted on rat and rabbit subjects which all support Goji’s effect on diabetes, however this doesn’t provide reliable in relation to the effects on the human population. A number of these studies were only conducted for a short amount of time and it was also found that the researchers were employed by Goji berry producing companies.
One recent 2015 study conducted on humans concluded that LBP (a component of Goji berries) has the potential to be a useful aid (in conjunction with other medication) to manage Type 2 Diabetes (Cai et al., 2015). This study was again however over a short amount of time.
In summary, Goji berries have reported properties in treating diabetes however, these are not applicable to the human population as limited human trials have been conducted. This is an element that must be improved if goji berries are to be used as an effective treatment tool in diabetes. As there is currently no set clinical treatment dose, it is important that those with diabetes continue taking their diabetic medication until an effective treatment dose is determined.
This article was co-written with another 3rd year Curtin Uni student Matilda Retz who wrote a great investigative paper on this topic.
Amagase, H., & Farnsworth, N. R. (2011). A review of botanical characteristics, phytochemistry, clinical relevance in efficacy and safety of Lycium barbarum fruit (Goji). Food Research International, 44(7), 1702-1717. doi:http://doi.org/10.1016/j.foodres.2011.03.027
Cai, H., Liu, F., Zuo, P., Huang, G., Song, Z., Wang, T., . . . Sun, G. (2015). Practical Application of Antidiabetic Efficacy of Lycium barbarum Polysaccharide in Patients with Type 2 Diabetes. Medicinal Chemistry (Shariqah (United Arab Emirates), 11(4), 383-390. doi:10.2174/1573406410666141110153858
Cui, B., Liu, S., Lin, X., Wang, J., Li, S., Wang, Q., & Li, S. (2011). Effects of lycium barbarum aqueous and ethanol extracts on high-fat-diet induced oxidative stress in rat liver tissue. Molecules, 16(11), 9116-9128. doi:http://dx.doi.org.dbgw.lis.curtin.edu.au/10.3390/molecules16119116
Donno, D., Beccaro, G. L., Mellano, M. G., Cerutti, A. K., & Bounous, G. (2015). Goji berry fruit (Lycium spp.): antioxidant compound fingerprint and bioactivity evaluation. Journal of Functional Foods, 18, Part B, 1070-1085. doi:http://doi.org/10.1016/j.jff.2014.05.020
Franks, P., & McCarthy, M. (2016). Exposing the exposures responsible for type 2 diabetes and obesity. Science, 354(6308), 69-73. http://dx.doi.org/10.1126/science.aaf5094
Jin, M., Huang, Q., Zhao, K., & Shang, P. (2013). Biological activities and potential health benefit effects of polysaccharides isolated from Lycium barbarum L. International Journal of Biological Macromolecules, 54, 16-23. doi:https://doi.org/10.1016/j.ijbiomac.2012.11.023
Kulczynski, B., & Gramza-Michalowska, A. (2016). Goji berry (lycium barbarum): Composition and health effects – a review. Polish Journal of Food and Nutrition Sciences, 66(2), 67-76. doi:http://dx.doi.org.dbgw.lis.curtin.edu.au/10.1515/pjfns-2015-0040
Luo, Q., Cai, Y., Yan, J., Sun, M., & Corke, H. (2004). Hypoglycemic and hypolipidemic effects and antioxidant activity of fruit extracts from Lycium barbarum. Life Sciences, 76(2), 137-149. doi:https://doi.org/10.1016/j.lfs.2004.04.056
Richter B., Bandeira-Echtler, E., Bergerhoff, K., Clar, C., & Ebrahim, SH. (2006). Pioglitazone for type 2 diabetes mellitus. Cochrane Database of Systematic Reviews 2006, Issue 4. Art. No.: CD006060. DOI: 10.1002/14651858.CD006060.pub2
The National Health and Medical Research Council. (2009). The NHMRC additional levels of evidence and grades for recommendations of developers of guidelines. (Handbook). Retrieved from https://www.nhmrc.gov.au/_files_nhmrc/file/guidelines/developers/nhmrc_levels_grades_evidence_120423.pdf
Tognon, G., Berg, C., Mehlig, K., Thelle, D., Strandhagen, E., Gustavsson, J., . . . Lissner, L. (2012). Comparison of Apolipoprotein (apoB/apoA-I) and Lipoprotein (Total Cholesterol/HDL) Ratio Determinants. Focus on Obesity, Diet and Alcohol Intake. PLOS ONE, 7(7), e40878. doi:10.1371/journal.pone.0040878