Healthy potential for natural sweeteners

Much of the growth in the past decade for sweeteners has been in polyols and high-intensity forms. But has nature already provided a taste alternative to these refined sugars? Mark J Tallon, PhD, takes a health-related focus toward the challenges and opportunities facing the natural-sweetener market

The issue of whether 'natural' or 'synthetic' is better when it comes to food and beverage sweeteners may be a moot point, as there is now a strong sector of the market combining the natural with synthetic. Nature has been kind in its natural sweeteners, as many have healing properties beyond those of curbing our appetites. The following is a brief overview of some of the more common natural sweeteners including molasses, rice syrup, honey, lo han fruit and stevia, and the current research regarding their health and functional benefits beyond that of refined sugar.

Molasses is most commonly made from sugar cane, but can also be extracted from sugar beet and citrus. There are three major types and three grades of molasses based around the extraction process. The two most popular forms are high-test molasses (HTM) and blackstrap, of which both are primarily organic. During the boiling process to extract molasses, repeated boiling occurs, which removes most sugar content. Blackstrap has the lowest sugar content of all sources (its taste can be bitter). Although HTM has a high-sugar content compared to blackstrap (and thus tastes very much sweeter), its sugar composition includes the trisaccharide raffinose, which leads to a slower release of energy.

Previous studies have shown molasses to have numerous health benefits, including reduction of irritable-bowel-syndrome symptoms.1 The latest study from A-D Research Foundation (Carlsbad, US) tried to determine the possible clinical benefit of molasses-based dietary compositions — aqueous extract of the plant soma; a mixture of milk; plant derivatives; and a mineral formulation comprising apple cider vinegar, quinine, blackstrap molasses, sulfur and whole milk) in both primary and recurrent adult acute myelogeneous leukemia (AML).2

After three months of supplementation, clinical improvement and regression of AML were the outcome measures. The authors concluded treatment with the novel dietary compositions resulted in disease regression and the reversal of clinical manifestations following chemotherapy over two episodes of AML. 2 Therefore, further studies are warranted to evaluate this approach and to identify which active ingredient aided in the clinical management of AML.

Rice syrup
Rice syrup is a mild sweetener made from whole-grain rice that has been cultured and fermented with enzymes that break down its natural starch into complex carbohydrates, maltose and glucose. Rice syrup (brown and clear) is typically utilised in foods that have a harder texture, such as cookies, but delivers about half the simple-sugar content of refined white sugar. Brown rice syrup is a sweetener derived by culturing cooked rice with enzymes (usually from dried barley sprouts) to break down the starches, then straining off the liquid and cooking it until the desired consistency is reached. The final product is roughly 50 per cent soluble complex carbohydrates, 45 per cent maltose, and three per cent glucose.

Because of this unique carbohydrate composition, the application of rice syrup may extend to the medicinal needs of those suffering diarrhoea and the as-yet-unexploited area of energy-performance-drink market. Regarding the former suggestion, research carried out at Siriraj Hospital in Thailand assessed the effectiveness of an oral electrolyte solution made with rice-syrup solids (RSS).3 The results demonstrated that the RSS reduced faecal output, fluid, and sodium and potassium absorption more effectively than a comparable glucose-based solution for the treatment of infantile diarrhoea. The authors concluded that in some infants, the rapid, effective rehydration offered by this solution may prevent the need for hospitalisation.3

Honey is probably the most commercially accepted natural sweetener and offers the largest number of confirmatory studies of all sweeteners regarding its health-promoting influence. Although much of the research is related to wound healing, antimicrobial and gut disorders, there are now some novel directions taking shape in honey research.4,5,6

Recent work highlights the influence of natural honey on biological markers of artherosclerosis.7 This study investigated the effects of either dextrose, artificial honey or honey on plasma insulin, plasma c-peptide (CP), cholesterol (HDL and LDL), triglycerides (TG), and glucose (PG). The study was carried out on patients with hypercholesterolemia, hypertriglyceridemia, diabetes and a healthy control group for 15 days.7

In healthy subjects, dextrose elevated PG at one (53 per cent) and two (three per cent) hours, and decreased PG after three hours (20 per cent). Honey elevated PG after one hour (14 per cent) and decreased it after three hours (10 per cent). Elevation of insulin and C-peptide was significantly higher after dextrose than after honey. Honey reduced cholesterol, LDL and TG, and slightly elevated HDL. Honey consumed for 15 days decreased cholesterol (seven per cent), LDL (one per cent), TG (two per cent), CP (seven per cent), homocysteine (six per cent), and PG (six per cent), and increased HDL (two per cent).

In patients with hypertriglyceridemia, artificial honey increased TG, while honey decreased TG. In patients with hyperlipidaemia, artificial honey increased LDL, while honey decreased LDL. Honey decreased cholesterol (eight per cent), LDL (11 per cent), and CP (75 per cent) after 15 days. In diabetic patients, honey compared with dextrose caused a significantly lower rise of PG, suggesting honey is a better sweetener source for those with diabetes. In conclusion the authors state that honey reduces blood lipids, homocysteine and CP in normal and hyperlipidaemic subjects. Honey compared with dextrose and sucrose caused lower elevation of PG in diabetics. This provides some interesting evidence regarding the possible cardioprotective and antidiabetic effects of honey, and warrants further study.

Lo Han fruit (Momordica grosvenorii/Siraitia grosvenori)
Lo han fruit is a sweetener and a member of the squash family native to the mountains of China and Japan. Lo han fruit is suggested to be 300 times sweeter than sugar. Its active ingredients are primarily compounds classified as triterpene glycosides, which are not only responsible for the sweet taste but also some functional aspects. Recent work has provided a deeper analysis of lo han's bioactive composition,8 which gives a greater insight into some special triterpene glycosides known as mogrosides (particularly mogroside v). Lo han and its associated mogrosides have been shown to be safe when supplemented over a 28-90 day period.9 Following some work regarding absorption of sugars after lo han supplementation,10 researchers from the Huazhong Agricultural University (China) have taken a closer look at lo han's mogrosides.11 The purpose of this study was to investigate the influence of lo han extracts, particularly mogroside v, on pancreatic islets in insulin-dependent and normal, healthy mice.

The authors used an alloxan-induced diabetic mouse model. Alloxan is a drug used to induce diabetes in animals. It damages the insulin-producing pancreatic islet cells, and causes an increase in pro-inflammatory and a decrease in anti-inflammatory cytokine levels.11 Four weeks of lo han administration attenuated the early clinical symptoms, biochemical abnormalities and pathological damages in pancreatic islets. Furthermore, at low doses, mogroside regulated the immune imbalance observed in alloxan-induced IDDM mice.11 Lo han therapy had no effect on normal mice, except that low-dose mogroside marginally up-regulates IL-4 expression. The results revealed that lo han exhibited antidiabetic effects, presumably due to the presence of mogrosides, which may suggest lo han delivered as a sweetener may be beneficial to diabetics beyond a low-GI source for taste.

Also called sweetleaf, sweet leaf or sugarleaf, stevia is a genus of about 150 species of herbs and shrubs in the sunflower family (Asteraceae), native to subtropical and tropical South America and Central America. As a sweetener, stevia's sweet taste has a slower onset and longer duration than that of sugar, although some of its extracts may have a bitter or licoricelike aftertaste at high concentrations. Stevia is still getting a rough ride, as it is available as a dietary supplement but not safe to use in foods, according to the FDA, which makes little sense. This has prevented stevia reaching its full market potential given its many possible health attributes. Although studies are still showing positive and negative outcomes regarding its safety,12,13 it may achieve a resurgence as a dietary ingredient by isolating its most beneficial bioactive, which may point to not its steviosides but rather robodioside A, according to some unpublished work to be released in late 2007.

In conclusion, the natural-sweetener market is still producing some very interesting evidence for food fortification and taste modification. As the natural and organic sectors continue to grow, the marketers of natural sweeteners will ride these waves to success and integrate both novel science-based marketing and new food-technology manufacturing to extend natural sweeteners' acceptance throughout multiple food and beverage categories.

Mark J Tallon, PhD, is chief science officer of OxygeniX, a London-based consultancy firm specialising in claims substantiation, product development and technical writing.
Dr Tallon is also co-founder of Cr-Technologies, a raw-ingredients supplier.
Respond: [email protected]

1. Tunuguntla A, Sullivan MJ. Blackstrap molasses for the treatment of inflammatory bowel disease-associated anemia. South Med J 2004;97(8):794.
2. Grandics P. Complete remission achieved in a case of both primary and recurrent adult acute myelogeneous leukemia by a novel nutritional therapy. J Altern Complement Med 2006;12(3):311-5.
3. Jirapinyo P, Moran JR. Comparison of oral rehydration solutions made with rice syrup solids or glucose in the treatment of acute diarrhea in infants. J Med Assoc Thai 1996;79(3):154-60.
4. Ingle R, Levin J, et al. Wound healing with honey — a randomised controlled trial. S Afr Med J 2006;96(9):831-5.
5. Al-Jabri AA, et al. Antibacterial activity of Omani honey alone and in combination with gentamicin. Saudi Med J 2005;26(5):767-71.
6. Somal N, et al. Susceptibility of Helicobacter pylori to the antibacterial activity of manuka honey. J Royal Soc Med 1994;87:9-12.
7. Al-Waili NS. Natural honey lowers plasma glucose, C-reactive protein, homocysteine, and blood lipids in healthy, diabetic, and hyperlipidemic subjects: comparison with dextrose and sucrose. J Med Food 2004 Spring;7(1):100-7.
8. Dianpeng Li, et al. Cucurbitane glycosides from unripe fruits of Lo Han Kuo (Siraitia grosvenori). Chem Pharm Bull (Tokyo) 2006;54:1425-8.
9. Qin X, et al. Subchronic 90-day oral (Gavage) toxicity study of a Luo Han Guo mogroside extract in dogs. Food Chem Toxicol 2006;44(12):2106-9.
10. Suzuki YA, et al. Triterpene glycosides of Siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glucose level after a single oral administration of maltose in rats. J Agric Food Chem 2005;53(8):2941-6.
11. Xiangyang Q, et al. Effect of a Siraitia grosvenori extract containing mogrosides on the cellular immune system of type 1 diabetes mellitus mice. Mol Nutr Food Res 2006;50(8):732-8.
12. Ferri LA, et al. Investigation of the antihypertensive effect of oral crude stevioside in patients with mild essential hypertension. Phytother Res 2006; 20(9):732-6.
13. Nunes AP, et al.Analysis of genotoxic potentiality of stevioside by comet assay. Food Chem Toxicol 2006 Oct 27. Epub ahead of print.

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