I recently received an email from one of my customers asking if graviola leaves would cure his diabetes. In this case, I was unable to give him a direct answer because frankly, I had yet to come to my own conclusions on this subject.
I often come across articles on the internet saying that soursop can help with diabetes. I regularly read such articles in order to keep up to date with various studies and findings concerning soursop. However, in the majority of such articles, a couple of things tend to stand out: the posts often do not provide links to any of the related research, using unspecific phrases in their descriptions such as “a recent study shows that …”, or “soursop has been found to…”, and they tend not to mention which part of the soursop tree is used. Is it the leaves, or the fruit?
In other words, I was always left with the questions: “can graviola help with diabetes?”, if so “how does it work?” and “which part of the soursop plant helps?”
Naturally, I prefer to leave no stone unturned, so I connected to various databases, and sought out the actual research papers concerning Annona muricata (the latin name for soursop, or graviola - see more information here) and diabetes, hoping to come to my own conclusion.
I meticulously read through many laboratory studies that effectively show that graviola can have a positive impact on diabetes… in laboratory rats!
Before I delve into some of the case studies, a bit of background information is in store.
Diabetes mellitus (DM), generally referred to as diabetes, occurs when a person has high blood sugar levels over a prolonged period, resulting in serious health complications. Diabetes is caused because either the pancreas (Type 1 DM) is not producing enough insulin or the body is not responding properly to insulin (Type 2 DM).
Diabetes afflicts more than 380 million people worldwide and the World Health Organization expects this number to more than double by 2030. At today’s level diabetes takes more lives than AIDS and breast cancer combined and is a leading cause of kidney failure, blindness, cardiovascular problems and stroke.
Here are some of the main findings from each of the explored research papers:
A study conducted at the University of Yaounde in Camaroon used a group of streptozotocin-induced diabetic rats to test the impact of an Annona muricata plant extract on diabetes. Streptozotocin is a naturally occurring chemical that is particularly toxic to the insulin-producing beta-cells of the pancreas in mammals and is used to induce Type 1 diabetes in animals for the purpose of research. The study demonstrates that injecting diabetic rats with a soursop extract reduced the blood glucose levels in the rats and restored cholesterol and other fats, compared to the untreated diabetic rats. The study concludes that “…the antidiabetic activity of Annona muricata aqueous extract can be explained by its hypolipidemic effect [reduction of lipid fats in the blood], its antioxidant and protective action on pancreatic β-cells, which in turn improve glucose metabolism.” 
A similar study from the Department of Anatomy and Cell Biology at the Obafemi Awolowo University in Nigeria finds that soursop possesses anti-hyperglycemic activities. The study was again performed on laboratory rats, where “a significant difference exists between the blood glucose concentrations of treated and untreated hyperglycemic groups of rats.” 
Another study from the Obafemi Awolowo University concludes that the beta-cells of pancreatic islets (see next paragraph for definition) of diabetic rats regenerated after treatment with an extract of Annona muricata. 
Pancreatic islets are clusters of cells within the pancreas which work together to regulate blood sugar. A particular type of cell known as beta-cells sense sugar in the blood, and release a necessary amount of insulin required to maintain normal blood sugar levels. Type 1 diabetes occurs when the immune system mistakenly assume beta cells to be a “threat” and therefore destroys them. This means that the body can no longer produce the insulin required to transform food into energy. The above study shows that Annona muricata helps these cells to regenerate, thereby destabilizing blood glucose levels.
Yet another study carried out on rats at the Department of Pharmacology at the University of KwaZulu-Natal in South Africa finds that extracts of the graviola leaf has a beneficial effect on hepatic tissues which indirectly enhances the production of insulin and endogenous antioxidants in the body. 
The Department of Biochemistry and Pharmacology, School of Medicine, University of Marília in Brazil conducted a study on a close relative of soursop called Anonna montana, popularly known in Brazil as “false graviola” and came to similar conclusions, stating that “the use of A. montana may have beneficial effects in the prevention of diabetes mellitus and dyslipidemia and may thus contribute to the prevention of cardiovascular diseases.” 
After reading these studies, I thought to myself, “Wow, this is really incredible!”
I did not find a single study indicating that Annona muricata does not have a positive impact on blood glucose levels. An interesting point of note is that these studies focus on Annona muricata extracts taken primarily from soursop leaves. NOT the fruit, as many bloggers would have you believe, but from the plant itself. Just so you know, it is possible to make your own graviola extract simply by infusing the leaves.
Nevertheless, several questions did pop into my head: why are all of the above mentioned studies from African and South American universities? What do the Western institutions say about this? Why is the research relatively limited?
The first question, why do all of these studies come out of Africa and South America, was quickly answered. I came across several ethnographic studies which report the use of soursop in areas of Africa , the Caribbean (notably in Trinidad and Tabago) , and South America  as a natural, local remedy to fight diabetes. So it makes sense that local institutions would want to better explore this treatment.
The second question, “What do Western institutions say about this” was actually very disappointing. I checked the publicly available databases of major Western diabetes research institutions and could not find any mention of Annona muricata, graviola or soursop: The Diabetes Research Institute Foundation , nothing… The Institute of Diabetes and Regeneration Research in Germany , nothing… The Joslin Diabetes Center , zip… The University of California San Francisco Diabetes Center , nill… The American Diabetes Association , nada…
In other words, Annona muricata and diabetes seems to be totally ignored by Western Institutions.
Why is this? Obviously, I can only offer a guess. One possible explanation is that the research coming out of non-Western institutions is relatively recent, from 2008 onwards, and has yet to make its way to other parts of the world. The other is that because soursop does not grow in colder climates, it is relatively unknown among local populations and therefore has not yet been “discovered” by Western institutions.
The purpose of this article is not to promote soursop as a diabetes treatment. Its aim is instead to provide you with more information so that you can come to your own conclusion.
Personally, I believe that the research is promising. All of the above mentioned studies indicate that soursop/graviola has a beneficial impact on blood sugar levels, and may therefore help to treat diabetes. Keep in mind that all of these studies were performed in a laboratory environment on rats, not human patients, so they should not be considered as “medically conclusive”.
For those of you looking for a homeopathic diabetes regime, graviola leaves may be a good way to go. Here is an article with recommended serving suggestions when using soursop products for their health benefits. Just speak to your physician before trying!
Diabetes Research Institute Foundation: http://www.diabetesresearch.org/what-is-diabetes
 Florence NT, Benoit MZ, Jonas K, Alexandra T, Désiré DD, Pierre K, Théophile D. Antidiabetic and antioxidant effects of Annona muricata (Annonaceae), aqueous extract on streptozotocin-induced diabetic rats. J Ethnopharmacol [Internet]. 2014 Feb 3;151(2):784-90. doi: 10.1016/j.jep.2013.09.021. Epub 2013 Sep 25. Available from: http://www.ncbi.nlm.nih.gov/pubmed/24076471#
 Adeyemi DO, Komolafe OA, Adewole OS, Obuotor EM, Adenowo TK. Anti hyperglycemic activities of Annona muricata (Linn). Afr J Tradit Complement Altern Med. 2008 Oct 25;6(1):62-9. Available from: http://www.ncbi.nlm.nih.gov/pubmed/20162043#
 Adeyemi DO, Komolafe OA, Adewole OS, Obuotor EM, Abiodun AA, Adenowo TK. Histomorphological and morphometric studies of the pancreatic islet cells of diabetic rats treated with extracts of Annona muricata. Folia Morphol (Warsz) [Internet]. 2010 May;69(2):92-100. Available from: http://www.ncbi.nlm.nih.gov/pubmed/20512759#
 Adewole SO, Ojewole JA. Protective effects of Annona muricata Linn. (Annonaceae) leaf aqueous extract on serum lipid profiles and oxidative stress in hepatocytes of streptozotocin-treated diabetic rats. Afr J Tradit Complement Altern Med. 2008 Oct 25;6(1):30-41. Available from: http://www.ncbi.nlm.nih.gov/pubmed/20162039
 Barbalho SM, Soares de Souza Mda S, dos Santos Bueno PC, Guiguer EL, Farinazzi-Machado FM, Araújo AC, Meneguim CO, Pascoal Silveira E, de Souza Oliveira N, da Silva BC, Barbosa Sda S, Mendes CG, Gonçalves PR. Annona montana fruit and leaves improve the glycemic and lipid profiles of Wistar rats. J Med Food. 2012 Oct;15(10):917-22. doi: 10.1089/jmf.2012.0088. Epub 2012 Aug 2. Available from: http://www.ncbi.nlm.nih.gov/pubmed/?term=soursop+diabetes+brazil
 Karou SD, Tchacondo T, Djikpo Tchibozo MA, Abdoul-Rahaman S, Anani K, Koudouvo K, Batawila K, Agbonon A, Simpore J, de Souza C. Ethnobotanical study of medicinal plants used in the management of diabetes mellitus and hypertension in the Central Region of Togo. Pharm Biol. 2011 Dec;49(12):1286-97. doi: 10.3109/13880209.2011.621959. Available from: http://www.ncbi.nlm.nih.gov/pubmed/22077164
 Lans CA. Ethnomedicines used in Trinidad and Tobago for urinary problems and diabetes mellitus. J Ethnobiol Ethnomed. 2006 Oct 13;2:45. Available from: http://www.ncbi.nlm.nih.gov/pubmed/17040567