Stevia is a natural sweetener obtained from the Stevia Rebudiana plant. This sweetener is almost 100-300 times sweeter than table sugar and is used as a substitute. While the overall consensus urges us to use less of any kind of sweeteners- be it sugar, honey, agave nectar, jaggery etc., in small amounts (½-1 tsp. per day). These sweeteners have come under fire due to the large amounts present in junk foods like biscuits, ice cream, chocolates, cakes, pastries and other desserts.

So how does stevia fare in the world of sweeteners? And how does this affect blood sugar?

Stevia is sweeter than sugar, but contains 0 kcal per serve (1 g). The leaf extract has been used to sweeten foods for centuries in its countries of origin-Paraguay and Brazil.

When consumed, stevia causes a suppression of plasma glucose levels and increases glucose tolerance. It regulates blood glucose by enhancing both insulin secretion and utilization. In addition to this hypoglycaemic effect, it also helps reduce oxidative stress. This stress produces free radicals that damage healthy cells. The body tries to detoxify or fight against free radicals by neutralizing them with antioxidants found in fresh, brightly coloured fruits and vegetables. In addition, stevia increases insulin effectiveness in cell membranes and improves glucose tolerance to digest carbohydrates. These mechanisms all contribute to the control of blood sugar- known as glucoregulation.

Out of the many varieties available, only Stevia Rebudiana has these therapeutic qualities. This variety is also rich in Beta Carotene, Thiamine, Riboflavin, flavonoids and terpenes (stevia contains 8 terpenes, the most common being stevioside and rebaudioside, which combined make up 5-10% of its sweetness). Being a zero-calorie sweetener is helpful for those who are overweight and/or diabetic and who need to keep a check on the calories they consume. Stevia is also beneficial as it contains phenols that help mop up the free radicals that cause cellular damage. The purified Rebaudioside A variety (a Steviol Glycoside) has been approved by the U.S Food and Drug Administration. Whole stevia leaves or extracts, though they are more natural than stevia products may affect the heart, kidneys and blood sugar levels adversely.

Types of Stevia:

Not all stevia is the same and some brands undergo extensive processing. The end product may be full of additives and artificial flavourings with only 1% of stevia present.

The three main commercial varieties of stevia are- green leaf stevia, stevia extracts and altered stevia (like Truvia).

Green leaf stevia and extracts:
This type of stevia undergoes the least processing. The stevia leaves are plucked, dried. They are then ground into a fine powder without any additives. This type has been used in South America and other countries like Japan as a natural sweetener for years. Since it does not contain any other sweeteners, green leaf stevia is 30–40 times sweeter than sugar. However, the FDA has not approved this variety for use in food. Crude Stevia Extracts are obtained from the sweeter part of the leaf- rebaudioside. But this too has not been given FDA approval.

High purity steviol glycosides:
According to the FDA, these are allowed to be marketed and added to foods in the United States. They carry a GRAS status- Generally Regarded as Safe. These extracts adhere to rules regarding purity and give details on which food grade alcohols have been used in their extraction. The extracts are removed using water or alcohol which do not alter the effectiveness of the plant’s compounds. The International Stevia council claims- “Stevia extracts are exactly the same compound outside the leaf as they are found in the leaf. The goal of this process is to extract and purify the natural substances (steviol glycosides) from the leaves of the plant.” (1)

The resulting extract contains 95% steviol glycoside which is 200-300 times sweeter than sugar.

Altered Stevia:
It is always important to check the ingredient list of a Stevia product. Brand names like Truvia contain Stevia in very small amounts. It is almost as good as any other processed sweetener and is not ‘natural’ any more. It under goes 42 steps of processing and contains added chemicals in the form of bulking agents, erythritol sweetener and so called natural flavourings. This makes it 200-400 times sweeter than regular table sugar. And while you may not be using too much, the manufacturers advise against excessive consumption as it could result in laxative effects. 

Compared to other artificial sweeteners like- Aspartame, the satiety level of consuming Stevia is much higher. This means one feels satisfied with the level of sweetness and tends not to overindulge. Other artificial sweeteners dull the sense of taste, resulting in a craving for more sugar or for foods that are sweet.

In India, the FSSAI – Food Safety and Standards Authority of India, has allowed Stevia to be used in various products. This notification was passed on November 13th, 2015. Stevia could then be present in flavoured drinks, desserts, dairy based products, jam and ready to eat cereals. (2)

Using Stevia as a sugar substitute
•    A pinch of Stevia is equal to 1 tsp. of table sugar.
•    Stevia can be used in beverages like- coffee, tea, juices and smoothies.
•    Depending on the brand and type, it can be used to sweeten desserts. Each brand has a specific sugar to stevia ratio, so be sure to check the amounts while using. Stevia comes in a powder as well as in a liquid form (with a dropper). For recipes using Stevia, it is important to note which form is being used.

References:
1.    http://www.internationalsteviacouncil.org/index.php?id=196
2.    Sweetener Stevia clears FSSAI hurdle | Business Standard News- www.business-standard.com

With inputs from:
1.    https://www.fda.gov/aboutfda/transparency/basics/ucm194320.htm
2.    http://healthyeating.sfgate.com/stevia-affect-blood-sugar-7359.html
3.    https://www.sciencedaily.com/releases/2017/04/170411104441.htm
4.    http://www.livestrong.com/article/505230-does-stevia-affect-blood-sugar/
5.    https://www.diabeteshealth.com/stevia-can-natures-sweetener-help-your-blood-sugar/
6.    https://draxe.com/stevia-side-effects/
7.    http://www.healthline.com/health/food-nutrition/stevia-side-effects#side-effects3
8.    http://food.ndtv.com/health/world-health-day-is-stevia-a-safe-alternative-to-sugar-1339758
9.    https://www.livescience.com/39601-stevia-facts-safety.html
10.    http://www.huffingtonpost.in/entry/stevia-what-is-it_n_5983772
11.    https://www.stevia.com/2016/10/03/stevia-nutrition-information/
12.    Nabilatul Hani Mohd-Radzman, W. I. W. Ismail, Zainah Adam, Siti Safura Jaapar, and Aishah Adam, “Potential Roles of Stevia rebaudiana Bertoni in Abrogating Insulin Resistance and Diabetes: A Review,” Evidence-Based Complementary and Alternative Medicine, vol. 2013, Article ID 718049, 10 pages, 2013. doi:10.1155/2013/718049
13.    Nutritional and therapeutic values of Stevia rebaudiana: A review. Vol. 7(46), pp. 3343-3353, 10 December, 2013 DOI: 10.5897/JMPR2013.5276ISSN 1996-0875 ©2013 Academic Journals .Gupta et al
14.    Potential Roles of Stevia rebaudiana Bertoni in Abrogating Insulin Resistance and Diabetes: A Review. Hindawi Publishing Corporation
15.    Evidence-Based Complementary and Alternative Medicine Volume 2013, Article ID 718049, 10 pages http://dx.doi.org/10.1155/2013/718049