I have a guilty secret. I simply can’t drink my herbal teas without sweetener. I’ve tried weaning myself off it but I just don’t enjoy it without some sweetness. And I don’t want to use sugar, partly because I don’t want to put on weight, which is a risk factor for cancer, and partly because sugar can be a fuel for cancer.

If you’ve read my book, you’ll know that I favour stevia. I know that stevia, like most other sweeteners, disrupts gut bacteria and therefore isn’t particularly good for me. But it does have some advantages for me: unlike some of the sugar alcohols, it doesn’t cause digestive problems and it has some anti-cancer properties (1). So, I’ve been using stevia for a while now.

Just recently, though, I’ve been looking at Monk fruit as an alternative. The supermarkets are stocking it and it seems to be popular. But I wasn’t sure how healthy it was compared with stevia.

Monk fruit (Siraitia grosvenorii) is a small green melon that’s found in southern China, where it’s known as Lo Han Guo. It was named after the monks who first grew it several centuries ago. It’s been used in Traditional Chinese Medicine (TCM) since then for coughs and colds, sore throats, and for minor stomach and digestive problems.

Extracts of monk fruit were found to be 150-250 times sweeter than sugar, but they have no calories or carbohydrates and don’t raise blood glucose levels. That makes them ideal for anyone watching their weight or wanting to avoid sugar.

For some people, stevia has a slightly bitter aftertaste. Most people find that monk fruit has a slightly fruity taste, which is preferable.

The health benefits of monk fruit

Monk fruit may also be really helpful if you have Type II diabetes. An animal study found that, after several weeks of use, monk fruit helped improve the insulin response in diabetic animals and reduced damage to the kidneys (2).

Monk fruit is also antioxidant. In a laboratory study, it was shown to reduce the oxidation of LDL (‘bad’) cholesterol, which means that it could reduce the risk of heart attacks (3).

For those of us who have been through chemo, another animal study tested an extract of monk fruit on mice that had been treated with cyclophosphamide and were immunosuppressed (their white blood cell count was reduced). The results showed that immune function had been significantly improved (4).

Another mouse study showed that monk fruit could reduce liver enzymes in animals that had liver damage, showing that it has a protective effect on the liver (4).

There is also some evidence that monk fruit has anti-cancer effects. A study of mice with pancreatic, colon and laryngeal cancers who were treated with monk fruit extracts showed that monk fruit reduced the growth of the tumours and increased their survival times (5).

How does monk fruit affect gut bacteria?

Unlike almost every other sweetener on the market, monk fruit has recently been shown to be actively good for our gut bacteria. Researchers have found that it has prebiotic effects. That means that it feeds the ‘good’ bacteria in our gut and helps them grow (6).

Is monk fruit safe to use?

Monk fruit is considered a food. In the US, food ingredients are evaluated by the FDA and monk fruit has been approved as Generally Recognised as Safe (GRAS). There haven’t been any negative health effects reported on it. Animal trials have not shown any dangers for pregnant or breastfeeding mothers, and it’s safe for diabetics, because it doesn’t raise blood sugar or insulin levels (7).

It’s also safe to use it in baking because it’s stable at high temperatures (7).

Most monk fruit granulated sweeteners are blended with erythritol, which is a sugar alcohol, to bulk them out. Erythritol doesn’t usually cause any digestive problems because it’s metabolised in the small intestine and never reaches the large intestine. However, if you have Small Intestine Bacterial Overgrowth (SIBO), you may well experience discomfort. In which case, look for liquid monk fruit, which is available online. Neither monk fruit nor erythritol cause tooth decay. Check the ingredients before buying a granulated monk fruit sweetener because I’ve read that some manufacturers use other bulking agents and those may be problematic for you.

The negative effects of stevia

Aside from the effects of stevia on the gut microbiome, one thing that you may not be aware of with stevia is that it has been shown in an animal study to have a contraceptive effect (8), although another more recent animal study found that it didn’t (9). However, a laboratory study showed that it does have an effect on progesterone, one of the female hormones, and that could potentially have an effect on female fertility (10). That could explain why natives of the Amazon, where stevia originated, reputedly used it as a contraceptive. At my age, that isn’t an issue for me. But perhaps that is important for you.

Looking at all the evidence, I’m pretty satisfied that monk fruit is a better option than stevia for sweetening my tea and for baking.

I hope that you’ve found this a useful review too. If so, you would find much more helpful advice on nutrition and many other ways to support yourself on your cancer journey in my book. If you’d like to buy the book, click on the button below.

References

1.       Marcinek K, Krejpcio Z. Stevia rebaudiana Bertoni: health promoting properties and therapeutic applications. Journal für Verbraucherschutz und Lebensmittelsicherheit. 2015;11(1):3-8. doi:10.1007/s00003-015-0968-2

2.       Suzuki YA, Tomoda M, Murata Y, Inui H, Sugiura M, Nakano Y. Antidiabetic effect of long-term supplementation with siraitia grosvenori on the spontaneously diabetic goto–Kakizaki rat. British Journal of Nutrition. 2007;97(4):770-775. doi:10.1017/s0007114507381300

3.       Takeo E, Yoshida H, Tada N, et al. Sweet elements of Siraitia Grosvenori inhibit oxidative modification of low-density lipoprotein. Journal of Atherosclerosis and Thrombosis. 2002;9(2):114-120. doi:10.5551/jat.9.114

4.       Gong X, Chen N, Ren K, et al. The fruits of Siraitia Grosvenorii: A review of a Chinese food-medicine. Frontiers in Pharmacology. 2019;10:1400. doi:10.3389/fphar.2019.01400

5.       Liu C, Dai L-H, Dou D-Q, Ma L-Q, Sun Y-X. A natural food sweetener with anti-pancreatic cancer properties. Oncogenesis. 2016;5(4):e217. doi:10.1038/oncsis.2016.28

6.       Norris J. A new low-calorie sweetener may also have prebiotic potential. Medical News Today. https://www.medicalnewstoday.com/articles/could-a-low-calorie-sweetener-also-improve-gut-bacteria. Published August 11, 2022. Accessed November 28, 2022.

7.       Food Insight. Everything you need to know about monk fruit sweeteners. Food Insight. http://foodinsight.org/everything-you-need-to-know-about-monk-fruit-sweeteners/. Published October 27, 2021. Accessed November 29, 2022.

8.       Planas GM, Kuć J. Contraceptive properties of stevia rebaudiana. Science. 1968;162(3857):1007-1007. doi:10.1126/science.162.3857.1007.a.

9.       Saenphet K, Aritajat S, Saenphet S, Manosroi J, Manosroi A. Safety evaluation of aqueous extracts from Aegle marmelos and Stevia rebaudiana on reproduction of female rats. Southeast Asian J Trop Med Public Health. 2006;37 Suppl 3:203-205.

10.    Shannon M, Rehfeld A, Frizzell C, et al. In vitro bioassay investigations of the endocrine disrupting potential of steviol glycosides and their metabolite steviol, components of the natural sweetener stevia. Molecular and Cellular Endocrinology. 2016;427:65-72. doi:10.1016/j.mce.2016.03.005