China provides the world with an abundant supply of natural therapies. Many of these herbal ­substances are classified as “functional foods,” which means that they are consumed for daily nutritional requirements but also possess unique medicinal properties.

Monk fruit, a gren fruit that looks like a melon, is named after the group of monastic practitioners who popularized its use as both a natural sweetener and a medicine. It is the latest nutritional treasure to emerge from the Far East. 


Background


Monk fruit, scientifically known as Siraitia grosvenorii, first surfaced in Chinese culture in the 13th century.1 Buddhist monks who were the medical practitioners of that era cultivated this member of the gourd family for many uses, primarily for the treatment of respiratory illnesses.

The species name was chosen in honor of Gilbert Grosvenor, who was president of the National Geographic Society and funded an expedition in the 1930s to find the living plant in its native habitat of southern China.2


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Monk fruit made its way into the United States in the early 20th century, but serious research into the fruit’s potential as a sweetening agent did not being until after 1975.1



Science


An estimated 150 million Americans use so-called sugar-free or low-calorie supplements, and that number has tripled over the past two decades to create a $1.5-billion industry.3

Until the introduction of the natural sweetener stevia, all of the artificial sweeteners in the United States were synthetic and therefore popular targets of the health-food movement for their potential toxicities.


The refined products of monk fruit are 200 to 300 times sweeter than traditional table sugar.1 Although research is ongoing, early in vitro and animal testing indicate that serum glucose levels are actually lowered by consuming this supplement, most likely due to its stimulation of pancreatic insulin secretion.

Bench research studying diabetic mice compared blood glucose levels of untreated animals with those exposed to four weeks of S. grosvenorii supplementation.4 Corresponding reductions in total cholesterol were found as well as an increase in HDL.

A similar but longer trial measured serum glucose levels as was hepatic function, and the antioxidative effect on lipid peroxidation resulted in similar findings.5 While still hypothetical, there is also an assumed simultaneous reduction in cellular insulin resistance. 


As noted earlier, one of the most common uses of monk fruit mentioned in Chinese literature is as a treatment for respiratory illness. Thought to exert a combination of analgesic, antihistaminic, and expectorant activities, teas made from monk fruit remain staples in the treatment of colds, bronchitis, and pneumonia.6 However, there are no current clinical trials exploring these effects.


Monk fruit is also being studied as an anticarcinogenic agent. In laboratory testing, the active chemical component group of S. grosvenorii that appears to show promise in this capacity is that of the cucurbitane glycosides.7

Under the theory that some cancer cells are triggered by viral insult, an extract of monk fruit was evaluated for its effect on Epstein-Barr virus early antigen activation. The monk fruit extract inhibited activation of viral antigen at equal or greater levels than did the control agent beta-carotene.

In a similar study, two monk fruit extracts were given to mice inoculated with a skin cancer cell line.8 There were fewer and slower-growing lesions in the mice fed the monk fruit extracts than there were in the control mice. 


Safety, interactions


After an extensive review, FDA issued a “Generally Recognized as Safe” statement for monk fruit.9 The summary statement stipulated that no toxicities were detected as a whole food (i.e., the fruit or dried pulp) or as a sweetener.


Cost, how supplied


Monk fruit is available as a refined liquid extract, a granular sweetener, and a dried fruit pulp. The granular sweetener costs approximately $10 for 40 single-serving packets. 


Summary


It is still too early to claim that monk fruit is an antioxidant with cancer-preventing capabilities. However, there appears to be little doubt that monk fruit is now a major player as a healthy sweetening agent.

As more mainstream literature discusses the negative aspects of artificial sweeteners, more health-care providers are coming to be on the alert for safer alternatives. Although sugar in any form will always be something that clinicians should urge patients to use in moderation, the increased availability of palatable, safe, and healthy substitutes is welcome. 


Sherril Sego, FNP-C, DNP, is a staff clinician at the VA Hospital in Kansas City, Mo., where she practices adult medicine and women’s health. She also teaches at the nursing schools of the University of Missouri and the University of Kansas. 

References


  1. Institute for Traditional Medicine. Sweet fruit used as sugar substitute and medicinal herb. Available at www.itmonline.org/arts/luohanguo.htm.

  2. Swingle, WT. Momordica grosvenori Sp. Nov. the source of the Chinese Lo han kuo. Journal of the Arnold Arboretum. 1941;22:197-203.

  3. Kinghorn AD, Soejarto DD. Discovery of terpenoid and phenolic sweeteners from plants. Pure and Applied Chemistry. 2002;74:1169-1179. Available at pac.iupac.org/publications/pac/pdf/2002/pdf/7407×1169.pdf.

  4. Qi XY, Chen WJ, Zhang LQ, Xie BJ. Mogrosides extract from Siraitia grosvenori scavenges free radicals in vitro and lowers oxidative stress, serum glucose, and lipid levels in alloxan-induced diabetic mice. Nutr Res. 2008;28:278-284.

  5. Suzuki YA, Tomoda M, Murata Y, et al. Antidiabetic effect of long-term supplementation with Siraitia grosvenori on the spontaneously diabetic Goto-Kakizaki rat. Br J Nutr. 2007;97:770-75.

  6. Hossen MA, Shinmei Y, Jiang S, et al. Effect of Lo Han Kuo (Siraitia grosvenori Swingle) on nasal rubbing and scratching behavior in ICR mice. Biol Pharm Bull. 2005;
28:238-241. Available at www.jstage.jst.go.jp/article/bpb/28/2/28_2_238/_pdf.

  7. Ukiya M, Akihisa T, Tokuda H, et al. Inhibitory effects of cucurbitane glycosides and other triterpenoids from the fruit of Momordica grosvenori on epstein-barr virus early antigen induced by tumor promoter 12-O-tetradecanoylphorbol-13-acetate. J Agric Food Chem. 2002;50:6710-6715.

  8. Takasaki M, Konoshima T, Murata Y, et al. Anticarcinogenic activity of natural sweeteners, cucurbitane glycosides, from Momordica grosvenori. Cancer Lett. 2003;198:37-42.

  9. U.S. Food and Drug Administration. Generally recognized as Safe (GRAS) determination for the use of luo han fruit concentrate as a flavor modifier and sweetener. Available at www.accessdata.fda.gov/scripts/fcn/gras_notices/grn000301.pdf.


All electronic documents accessed April 8, 2014.