Ask a Dietitian: Can Soursop Fight Cancer?

Hello Mr. S,

Soursop is a prickly fruit found in parts of Africa, the Caribbean, South America, and Southeast Asia. It is also also known as graviola, custard apple, cherimoya, guanabana, and Brazilian paw paw. Many people are interested in the link between soursop and cancer.

Photo by Digi_shot via flickr Creative Commons

The sweet flesh of the soursop fruit can be eaten on its own or used to make custard, juice, candies and ice cream. One cup (250 mL) of soursop pulp has 150 calories and is an excellent source of fibre and vitamin C. Fibre is helpful for keeping bowel movements regular and preventing colorectal cancer. Vitamin C is an antioxidant that helps strengthen the immune system. Soursop may also be used as a remedy for viruses, parasites and stomach aches in some parts of the world.

Note that soursop seeds are toxic. In some cultures, the seeds, leaves, roots and bark are used as a poison to kill off insects.

Soursop extract is sold as a supplement in some health food stores and online. A handful of websites that sell soursop capsules claim it can cure cancer or help cancer treatments work better. But what does the research say?

We don't know how much soursop is safe, but we know lots of it is toxic. Drinking tea made from the leaves, eating the fruit, or taking soursop supplements can kill nerve cells in the brain and other parts of the body⁴. Taking too much soursop can also cause movement disorders similar to Parkinson's disease⁵. In one study, people with Parkinson-like symptoms were asked to stop eating soursop and drinking soursop tea. After 2 years, 57% of the people either didn’t get worse (were stable) or saw improvements in their walking, speed of movement, and reflexes⁵.

The effect of soursop on cancer cells has never been studied in humans. In the laboratory, some of the chemicals in soursop may help kill cancer cells^1-3, but the way cells work in a lab is not the same as the way cells work in our bodies. The human body is much more complex!

Because it has never been studied in humans, we don’t know if soursop is effective or safe for fighting cancer. We don’t know if it will interact with treatments such as chemotherapy. But we do know that too much of it can be harmful to your health.

Soursop is not safe for humans as a supplement or as a food or drink in large amounts. I recommend you avoid soursop supplements and tea. If you eat soursop pulp, desserts, or drink the juice, try limiting it to ½ cup a few days a week. Talk to your doctor if you are noticing any symptoms like loss of balance, shaking, feeling stiff or movement problems. Always talk to your oncologist before taking any supplements or herbs.

If you are looking for foods that help fight cancer, the evidence supports choosing a variety of vegetables and fruits in bright colours, having high fibre foods like beans, lentils and whole grains, and eating healthy fats from olive oil, nuts and avocado. Variety is always the healthiest choice when you are choosing foods because you get a wider assortment of nutrients.

For more information on what to eat during and after cancer treatment, that here are lots of recipes and tips on the ELLICSR Kitchen page. You can also check out some of these trusted resources:

• Memorial Sloan Kettering: Graviola
• WebMD
• Cancer Research UK

Have a nutrition question you want answered? Tweet me @80twentyrule.