Life Extension Magazine

Life Extension Magazine February 2014

Superfoods

Sweet As Sugar: Health Benefits Of Stevia And Xylitol

By Robert Iafelice

Sweet As Sugar Health Benefits Of Stevia And Xylitol  

In 1991, reacting to an anonymous trade complaint, the US Food and Drug Administration (FDA) deemed the sweetener stevia unsafe and issued an Import Alert, banning all stevia from entering the United States.1-3 While the FDA cited inadequate toxicological evidence of its safety, the ban was not based on any consumer complaints or reported adverse effects.2

Extracts of the South American stevia plant, called steviol glycosides , are up to 300 times sweeter than sugar and have little aftertaste, zero calories, and no effect on blood sugar.3 At the time of the FDA ban, supporters of stevia argued without success that stevia, with its long history of food use, should qualify as having GRAS (Generally Recognized as Safe) status in the same manner as coffee, tea, sugar, fruit, etc. A history of safe use is one condition that must be met to qualify for GRAS, and this was actually acknowledged in the FDA’s Import Alert for stevia!4 The FDA not only banned a safe and natural sweetener in stevia, but one that appears to provide health benefits as well, most notably for regulating blood sugar and blood pressure.3,5

The controversial ban on the importation of stevia in the US continued until 1995 when the Dietary Supplement Health and Education Act of 1994 forced the FDA to allow stevia to be imported and marketed as a dietary supplement, but not as a sweetener or other food additive purpose.1 The FDA’s policy to classify stevia to be safe for consumption as a “supplement,” but potentially harmful as a sweetener just added to the controversy and confusion.

In 2008, after a rigorous review of the scientific evidence, the FDA granted stevia sweeteners GRAS status.6 It was also approved by the European Union in 2011.7

Today, hundreds of foods and beverages throughout the world are sweetened with stevia sweeteners. Among these are Vitamin Water®, Coke Zero®, Sprite Green®, Gatorade’s G2® and Crystal Light®. Coca-Cola® and Pepsi Cola® have both disclosed their intentions to use rebaudioside A, the sweetest stevia extract, as a zero-calorie soft-drink sweetener in the US.3

Stevia May Help Control Blood Sugar And Insulin Levels

Health Benefits

While stevia has been documented to have medical purposes as an antimicrobial, anti-diarrheal, anti-tumor, diuretic, anti-inflammatory, and immunomodulatory actions, the scientific evidence is strongest, and its use is most promising for two indications: (1) high blood sugar/insulin resistance and (2) high blood pressure.3,5,8

Stevia May Help Control Blood Sugar And Insulin Levels

Extracts from stevia leaves have been used for centuries as a medicinal herb in the traditional treatment of diabetes in South America.5,9 Today, scientific evidence on stevia supports its historic precedent in the regulation of blood sugar and insulin.

Avoiding excess elevation of blood sugar and insulin after meals is perhaps the most important dietary measure you can take to reduce your risk for heart disease, cancer, and other age-related disorders. In a recent study in type II diabetic subjects, stevioside, one of the stevia extracts, reduced after-meal blood glucose levels by an average of 18%.10

When compared to sugar, stevia consumption before meals results in far lower after-meal glucose and insulin levels.11 Even when compared to aspartame, stevia resulted in lower post-prandial insulin levels.11 The comparison with aspartame is more impressive because the change in glucose and insulin levels cannot be due to a difference in calories, as with sugar. A key finding from this study was that participants eating stevia felt satisfied with fewer calories and did not eat more food throughout the day to compensate.11 This is an indication of stable blood sugar and insulin levels.

At the root of many cases of chronically elevated glucose and insulin levels is insulin resistance. In rats fed a fructose-rich diet for four weeks to induce insulin resistance, stevioside lowered high blood glucose levels in a dose-dependent manner and delayed the development of insulin resistance.12

Studies have evaluated the effects of stevioside on animal models of both type I and type II diabetes: elevated blood glucose levels were lowered, and less insulin medication was needed for the same effect. This research clearly demonstrates that stevia has the ability to increase cellular insulin sensitivity and help reverse insulin resistance.12,13

Interestingly, the mechanism for stevioside’s hypoglycemic effect in the latter group of rats with insulin dependent type I diabetes was determined to be slowing down gluconeogenesis (the synthesis of glucose in the liver from non-carbohydrate sources).13 Another plant compound very familiar to readers of Life Extension magazine®, chlorogenic acid from coffee beans, also down-regulates gluconeogenesis. Coffee sweetened with stevia may pack quite a one-two punch for blood sugar control!

The effect of stevia on blood sugar has only been observed when plasma glucose levels are elevated. It does not lower normal blood sugar levels in healthy individuals.5

Stevia is not just a safe sugar substitute, but a natural insulin sensitizer that may help maintain normal sugar and insulin levels in diabetics and nondiabetics alike. Since stevia extract also decreases oxidized LDL cholesterol14 and triglycerides,15 and lowers high blood pressure3,5—all metabolic risk factors—it has great potential for the treatment of metabolic syndrome.

Stevia May Lower Blood Pressure

A double-blind, placebo-controlled study demonstrated that oral stevioside taken at doses of 250 mg, three times a day for one year resulted in significant, lasting decreases in both systolic and diastolic blood pressure in patients with mild to moderate hypertension.16 A longer, subsequent study by the same research team that lasted two years and with an increased dose of stevioside ( 1,500 mg) replicated the decreases in blood pressure found in the initial study.17

The stevioside treatment was well-tolerated and no side effects were reported or detected. Moreover, the stevioside treatment group reported significantly higher quality of life scores than the placebo group.17 On the other hand, it was noted that more patients in the placebo group developed left ventricular hypertrophy,17 an abnormal thickening of the heart muscle often caused by high blood pressure.

Though the effect of stevioside was not better than drugs, it appears comparable and nearly everyone taking stevioside had significant lowering of blood pressure. As in the case of blood sugar, stevioside lowers elevated blood pressure, but not normal blood pressure.5

As a natural plant compound with no demonstrated side effects, stevia may offer an alternative or supplementary therapy for high blood pressure, and with possibly better compliance.

Xylitol: A Sweetener That’s Good For Your Teeth

Another sugar substitute with beneficial health properties that is growing in popularity is xylitol. While xylitol is a natural substance found in fruits and vegetables, it is also naturally produced in our bodies during normal carbohydrate metabolism. An average-size adult makes up to 15 grams of xylitol daily.18,19

Xylitol is classified as a sugar alcohol (like sorbitol, mannitol, erythritol, etc) because its chemical structure partially resembles sugar and partially resembles alcohol.20 It is actually a carbohydrate that looks and tastes remarkably like table sugar with 40% fewer calories and practically no aftertaste.21 It is used as a sweetener in chewing gums, mints, beverages, sweets, toothpaste and in tabletop granular form. It has been approved for use in foods, pharmaceuticals and oral health products in more than 35 countries worldwide, including the US.21

History Of Stevia

Stevia is a perennial shrub with over 200 species belonging to the Aster (sunflower) family and indigenous to South America.46 For centuries, the Guarani tribes of Paraguay and Brazil used the leaves of stevia, which they called ka’a he’e (“sweet herb”) to sweeten yerba mate tea and various foods. It was also used medicinally as a treatment for diabetes,47 hypertension, and obesity.5

Stevia has been used in Europe and Asia since the sixteenth century when it was discovered by the Spanish Conquistadors.48 The particular species used as a sweetener, Stevia rebaudiana Bertoni, was named after botanist Moises Santiago Bertoni, who “rediscovered” stevia and scientifically classified the plant in 1899, describing its sweet taste in detail. The compounds in the stevia leaf that give the plant its sweet taste, stevioside and rebaudioside A, were isolated in 1931 by French chemists.2

During World War II, England began to investigate stevia as an alternative to sugar, which was in short supply.49 In the 1970s, the Japanese began to use stevia to replace the banned artificial sweetener, saccharin. It became their chosen sugar alternative to sweeten food and beverages, so much so that Japan is now the largest consumer of stevia.2 Today, stevia can be found growing in China, South America, India, South Korea, Taiwan, and Israel, and is used in many countries around the globe.

Xylitol Fights Cavities

Though largely preventable, tooth decay (cavities) is one of the most prevalent chronic diseases among both adults and children, with 1 in 5 Americans reported to have untreated cavities according to the Centers for Disease Control (CDC).22 In 2010, roughly $108 billion dollars were spent on dental services in the US.23

By providing fuel for acid-forming bacteria in the mouth, sugar consumption sets up an ideal acidic condition that promotes decay and demineralization of teeth. Xylitol, conversely, is non-fermentable and does not feed acid-forming oral bacteria. Regular use of xylitol causes cavity-forming bacteria, most notably Streptococcus mutans (S. mutans ), to starve and die off by as much as 73%, decreasing the level of acidic byproducts formed when bacteria ferment sugars.24 Xylitol also increases salivary flow which helps to buffer these acids.25 A more alkaline environment is created, leading to less tooth decay and plaque, and enhanced tooth remineralization. Untreated cavities, especially small decay spots, can harden and become less sensitive from exposure to xylitol.26

Considerable research conducted since the early 1970s has established that consuming xylitol products results in reduction in tooth decay rates ranging from 30% up to levels in excess of 80%.27 What’s more, the protective effects of xylitol are long-lasting. In a study of nearly 300 children who chewed xylitol gum habitually for over two years and then stopped, some experienced a reduction in their tooth decay rate over the next five years.28 Xylitol-sweetened gum even reduces transmission of cavity-causing bacteria from mother to child.29

According to newer research, the number of exposures to xylitol throughout the day is more important than the quantity of xylitol.30 Consider chewing xylitol gum after each meal, sweetening your tea or coffee with xylitol granules and using xylitol toothpaste once or twice a day. Several dental associations, including the American Dental Association31 and the American Academy of Pediatric Dentistry,32 support the use of xylitol in caries control and prevention.

Xylitol Benefits Diabetes And Metabolic Syndrome

Because xylitol is slowly emptied from the stomach, and only about 50% of it is absorbed, it has neglible effects on blood sugar and insulin secretion.33,34 Xylitol has a considerably lower glycemic index (13) when compared with sucrose (65) and glucose (100).33 It even compares favorably with foods such as legumes and milk.35

In a recent animal study examining the antidiabetic potential of xylitol, animals fed xylitol had significantly better glucose tolerance (more stable blood sugar levels), less weight gain and significantly lower food intake (suppressed appetite) than both the sugar and control groups.36 Data from this study and others confirm that xylitol is an ideal low-calorie sweetener for people with diabetes, metabolic syndrome, obesity, and other metabolic disorders.34,36,37

Of course, like stevia, xylitol can be used by anyone to help maintain low blood sugar and insulin levels, thereby reducing risk of age-related disease.

Xylitol Helps Prevent Ear And Upper Respiratory Infections

Xyitol not only suppresses S. mutans, the cavity-promoting bacterium, but it also inhibits the growth of Streptococcus pneumoniae (S. pneumoniae), a major cause of middle ear infections and sinusitis.38,39 Owing to its unique structure, xylitol also has the ability to interfere with S. pneumoniae’s ability to stick to tissues and form colonies of bacteria called biofilms, making the germ more vulnerable to treatment.40

In clinical trials, xylitol given in the form of chewing gum or syrup reduced middle ear infections in daycare children by 30-40%.38,41,42 This safe and great-tasting sweetener offers the possibility of preventing ear infections in children and thus lessening the need for antibiotics.

Xylitol Strengthens Bone

Since xylitol appears to induce remineralization of tooth enamel, researchers are also now investigating its ability to remineralize bone tissue. Several animal studies show that xylitol increases bone density,43-45 suggesting that xylitol shows promise in the treatment or prevention of osteoporosis. Clinical trials are needed to confirm these potential benefits.

Summary

Stevia and xylitol are not only safe and tasty sugar alternatives, but also potent natural compounds that provide multiple health benefits.3,5,8,27,34,36-38,43-45 While both sweeteners improve glucose tolerance and reduce insulin needs, stevia can also lower elevated blood pressure while xylitol can help prevent cavities and ear infections, and possibly strengthen bones.3,5,8,27,34,36-38,43-45

Add some stevia to your favorite beverage and chew xylitol gum after meals. Enjoy the sweet taste and gain important health dividends as well.

If you have any questions on the scientific content of this article, please call a Life Extension® Health Advisor at 1-866-864-3027.

References

  1. Available at: http://www.accessdata.fda.gov/cms_ia/importalert_119.html. Accessed October 27, 2013.
  2. Available at: http://www.ianrpubs.unl.edu/epublic/pages/publicationD.jsp?publicationId=609. AccessedOctober 27, 2013.
  3. Ulbricht C, Isaac R, Milkin, et al. An evidence-based systematic review of stevia by the Natural Standard Research Collaboration. Cardiovasc Hematol Agents Med Chem. 2010;8(2):113–27.
  4. Available at: http://owndoc.com/pdf/Stevia.pdf. Accessed October 19 , 2013.
  5. Chatsudthipong V, Muanprasat C. Stevioside and related compounds: therapeutic benefits beyond sweetness. Pharmaco Ther. 2009;121(1):41-54.
  6. Available at: http://www.fda.gov/food/ingredientspackaginglabeling/gras/noticeinventory/ucm171539.htm. Accessed October 21, 2013.
  7. Available at: http://eurlex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2011:295:0205:0211:EN:PDF. Accessed October 22, 2013.
  8. Goyal SK, Samsher, Goyal RK. Stevia (Stevia rebaudiana) a bio-sweetener: a review. Int J Food Sci Nutr. 2010 Feb;61(1):1-10.
  9. Available at: http://healthfree.com/stevlife.html. Accessed October 30 , 2013.
  10. Gregersen S, Jeppesen PB, Holst J. Antihyperglycemic effects of stevioside in type 2 diabetic subjects. Metabolism. 2004;53(1):73-6.
  11. Anton SD, Martin CK, Han H, et al. Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels. Appetite. 2010;55(1):37–43.
  12. Chang JC, Wu MC, Liu IM, et al. Increase of insulin sensitivity by stevioside in fructose-rich chow-fed rats. Horm Metab Res. 2005;37(10):610-6.
  13. Chen TH, Chen SC, Chan P, et al. Mechanism of the hypoglycemic effect of stevioside, a glycoside of Stevia rebaudiana. Planta Med. 2005;71(2):108-13.
  14. Geeraert B, Crombe F, Hulsmans M, et al. Stevioside inhibits atherosclerosis by improving insulin signaling and antioxidant defense in obese insulin-resistant mice. Int J Obes (Lond). 2010 Mar;34(3):569-77.
  15. Park JE, Cha YS. Stevia rebaudianaBertoni extract supplementation improves lipid and carnitine profiles in C57BL/6J mice fed a high-fat diet. J Sci Food Agric. 2010 May;90(7):1099-105.
  16. Chan P, Tomlinson B, Chen YJ, et al. A double-blind placebo-controlled study of the effectiveness and tolerability of oral stevioside in human hypertension. Br J Clin Pharmacol. 2000;50(3):215-20.
  17. Hsieh MH, Chan P, Sue Y.M, et al.Efficacy and tolerability of oral stevioside in patients with mild essential hypertension, a two-year, randomized, placebo-controlled study. Clin Ther. 2003;25(11):2797-808.
  18. Available at: http://www.webmd.com/vitamins-supplements/ingredientmono-996-XYLITOL.aspx?activeIngredientId=996&activeIngredientName=XYLITOL. Accessed November 21, 2013.
  19. Available at: http://www.xylitol.org/questions-about-xylitol. AccessedNovember 21, 2013.
  20. Natah SS, Hussien KR, et al. Metabolic response to lactitol and xylitol in healthy men. Am J Clin Nutr. 1997;65:947-50.
  21. Available at: http://www.caloriecontrol.org/sweeteners-and-lite/polyols/xylitol. Accessed October 30, 2013.
  22. Available at: http://health.usnews.com/health-news/news/articles/2012/05/31/1-in-5-americans-has-untreated-cavities-cdc. Accessed October 29, 2013.
  23. Available at: http://www.cdc.gov/chronicdisease/resources/publications/aag/doh.htm. Accessed October 29, 2013.
  24. Bahador A, Lesan S, Kashi N. Effect of xylitol on cariogenic and beneficial oral streptococci: a randomized, double-blind crossover trial. Iran J Microbiol. 2012 Jun;4(2):75-81.
  25. Soderling E. Controversies around xylitol. Eur J Dent. 2009 April 3(2):81-2.
  26. Mäkinen KK, Mäkinen PL, Pape HR Jr, et al. Stabilisation of rampant caries: polyol gums and arrest of dentine caries in two long-term cohort studies in young subjects. Int Dent J. 1995 Feb;45(1 Suppl 1):93-107.
  27. Makinen KK. The rocky road of xylitol to its clinical application. J Dent Res. 2000 Jun; 79(6):1352-5.
  28. Hujoel PP, Makinen KK, Bennett CA, et al. The optimum time to initiate habitual xylitol gum-chewing for obtaining long-term caries prevention. J Dent Res. 1999;78(3):797-803.
  29. Isokangas P, Soderling E, Pienihakkinen K, et al. Occurrence of dental decay in children after maternal consumption of xylitol chewing gum, a follow-up from 0 to5 years of age. J Dent Res. 2000 Nov;79(11):1885-9.
  30. Milgrom P, Ly KA, Roberts MC, et al. Mutans streptococci dose response to xylitol chewing gum. J Dent Res. 2006 Feb;85(2):177-81.
  31. Available at: http://www.ada.org/6206.aspx. Accessed October 30, 2013.
  32. Available at: http://www.aapd.org/media/Policies_Guidelines/P_Xylitol.pdf.Accessed October 30 , 2013.
  33. Livesey G. Health potential of polyols as sugar replacers, with emphasis on low glycaemic properties. Nutr Res Rev. 2003 Dec;16(2):163-91.
  34. Salminen S, Salminen E, Marks V. The effects of xylitol on the secretion of insulin and gastric inhibitory polypeptide in man and rats. Diabetologia. 1982;22(6):480-2.
  35. Available at: http://www.xylitol.org/xylitol-nutritional-info-professional.Accessed October 31 , 2013.
  36. Islam MS. Effects of xylitol as a sugar substitute on diabetes-related parameters in nondiabetic rats. J Med Foods. 2011 May;14(5):505-11.
  37. Hassinger W, Sauer G, Cordes U, et al. The effects of equal caloric amounts of xylitol, sucrose and starch on insulin requirements and blood glucose levels in insulin-dependent diabetics. Diabetologia. 1981;21:37-40.
  38. Uhari M, Tapiainen T, Kontiokari T. Xylitol in preventing acute otitis media. Vaccine. 2000;19:S144-7.
  39. McEllistrem MC, Adams J, Mason EO, Wald ER. Epidemiology of acute otitis media caused by Streptococcus pneumoniae before and after licensure of the 7-valent pneumococcal protein conjugate vaccine. J Infect Dis. 2003 Dec 1;188(11):1679-84.
  40. Available at: http://www.blackwellpublishing.com/eccmid20/abstract.asp?id=84998. Accessed November 21, 2013.
  41. Uhari M, Kontiokari T, Koskela M, et al. Xylitol chewing gum in prevention of acute otitis media: double blind randomized trial. Br Med J. 1996;313:1180–3.
  42. Uhari M, Kontiokari T, Niemela M. A novel use of xylitol sugar in preventing acute otitis media. Pediatrics. 1998;102:879–84.
  43. Sato H, Ide Y, Nasu M, et al. The effects of oral xylitol administration on bone density in rat femur. Odontology. 2011 Jan;99(1):28-33.
  44. Mattila PT, Svanberg MJ, Pokka P, et al. Dietary xylitol protects against weakening of bone biomechanical properties in ovariectomized rats . J Nutr. 1998 Oct;128(10):1811-4.
  45. Mattila PT, Svanberg MJ, Knuuttila ML. Increased bone volume and bone mineral content in xylitol-fed aged rats. Gerontology. 2001 Nov-Dec;47(6):300-5.
  46. Available at: http://www.parc.gov.pk/articles/sugar_leaf.htm. AccessedNovember 22, 2013,
  47. Abudula R, Jeppesen PB, Rolfsen SE, et al. Rebaudioside A potently stimulates insulin secretion from isolated mouse islets: studies on the dose-, glucose-, and calcium-dependency. Metabolism. 2004 Oct;53(10):1378-81.
  48. Available at: http://www.holisticmed.com/sweet/stv-faq.txt. Accessed October 28, 2013.
  49. Available at: http://www.uofmhealth.org/health-library/hn-2169001#hn-2169001-uses. Accessed October 27, 2013.