Results from 1 afternoon of research on Stevia:
One thing I hate about information found online is often-times it lacks references to scientific studies/journal articles to support the claims that are made. A recent discussion among friends lead me to do my own research on sweeteners used in foods or as dietary supplements, specifically Stevia and Splenda vs sugar. I started with Stevia. Though there are MANY more articles to be read, here is the information I found from 4 articles in just one afternoon of reading.
These are my notes, from my own perspective. I am more than willing to provide copies of the full articles to anyone who wishes to read them entirely and make their own notes.
ARTICLE ONE
I am including this one first, because it addresses some key points as to why the FDA has only approved Stevia as a food supplement. It's important to know what TYPE of studies have been conducted thus far.
Journal Article from Pharmacology & Therapeutics, Volume 121, Issue 1, January 2009, Pgs 41-45
Title: Stevioside and related compounds: Therapeutic benefits beyond sweetness
Link will allow you to read the abstract only unless you have a valid login.
In short, the article discusses current knowledge about stevia, but concludes there are still “questions regarding chemical purity and safety” – which basically explains why the FDA has only approved stevia as a dietary supplement right now. I learned some key things from this article.
Shortcomings of the studies conducted thus far:
- Most were done on animals (rats and mice) not humans.
- Most involve extremely high levels of stevia, not necessarily the “average daily intake”.
- Studies have used different forms of steviocide (extract vs. pure compound) meaning there are various parts of the sweet component in the stevia plant (steviol, Rebausdioside A, etc.) and more research should be conducted on each part.
- Most studies have been done with oral administration, and intravenous studies should be conducted to draw additional conclusions.
- Though the article didn’t seem to discuss this area as much, it claims there are still uncertainties regarding safety and reproductive affects which prevent stevioside from being approved for use in pharmaceutics or as non-caloric sweeteners in foods.
In spite of the shortcomings of studies explained above, here are some basic conclusions:
- stevioside can lower blood glucose levels in both type 1 and type 2 diabetics, but does not appear to affect already healthy levels
- it also appears to lower blood pressure and cholesterol levels in people with high blood pressure or high cholesterol – again no effect on those with healthy or low conditions of either.
- Oral consumption of stevioside may be useful in promoting immunity against infection by microorganisms
- Stevioside could contribute to anti-diarrhea effects
- Stevioside in large amounts could effect therapeutic efficacy of drugs, or have a negative effect on the kidneys
- lower amounts of stevioside do not appear to promote cancer nor do they effect fertility
ARTICLE TWO
This article is older and seems to be less comprehensive than the one above, though concludes Stevia is safe.
Journal Article from Phytochemistry, Volume 64, Issue 5, November 2003, pgs 913-921
Title: Stevioside
Link is to the abstract only (unless you have a login for Science Direct):
This article discusses Stevioside which is the sweet component extracted from the stevia plant. It concludes stevia is safe when used as a sweetener, and no allergic reactions seem to exist.
Here are some quotes from the article I found interesting:
“The advantages of stevioside as a dietary supplement for human subjects are manifold: it is stable, it is non-calorific, it maintains good dental health by reducing the intake of sugar and opens the possibility for use by diabetic and phenylketonuria patients and obese persons.”
“In 1999 the JECFA clearly stated that there was no indication of carcinogenic potential of stevioside (WHO, 1999).”
“Although rather high concentrations of stevioside and Stevia extracts were shown to reduce the growth of some bacteria, the concentrations used for sweetening purposes are rather low. Therefore, the benificial effect of the use of stevioside would rather be due to the substitution of sucrose in the food by a non-cariogenic substance.”
ARTICLE THREE
This one is even less comprehensive, but also concludes Stevia is safe.
Journal Article from Food and Chemical Toxicology, Volume 46, Issue 7, Supplement, July 2008, Pages S1-S10.
Title: Overview: The history, technical function and safety of rebaudioside A, a naturally occurring steviol glycoside, for use in food and beverages
Link is to the abstract only, unless you have a login for Science Direct
This article discusses one of the components of Stevioside, which is the sweet part extracted from the stevia plant. As the abstract states: “This paper summarizes the information used to conclude that high purity rebaudioside A (rebiana) produced to food-grade specifications and according to Good Manufacturing Practices is safe for human consumption under its intended conditions of use as a general purpose sweetener.”
What does that mean? The article concludes Stevia is safe as a general purpose sweetener.
ARTICLE FOUR
This one was good because it laid out some basic facts about stevia in addition to summarizing some conclusions from various studies. I think it's important to note more studies should be done, because as the first article I read states...most (as is true regarding studies of OTHER sweeteners for that matter) involve using really high amounts of the substance, rather than what would be considered average consumption levels.
Journal Article from Food Chemistry, Volume 132, Issue3, 1 June 2012, Pgs 1121-1132
Title: Stevia rebaudiana Bertoni, source of a high-potency natural sweetener: A comprehensive review on the biochemical, nutritional and functional aspects
Link to abstract (can view full article if you have a login to Science Direct):
Interesting facts I learned about stevia from this article:
- 300 times sweeter than saccharose (another term for sucrose, or sugar)
- Thought to possess antioxidant, antimicrobial and antifungal activity
- It is thermostable at temperatures up to 200 degrees C – so you can cook with this and it won’t change. You have to get it up to 200 degrees C before it totally decomposes.
- Also contains folic acid, vitamin C, and all of the indispensable amino acids except tryptophan
- If taste is an issue for you, hot water seems to be the “tastiest” way to extract sweetness from stevia leaves, because is extracts the rebaudioside A component moreso than stevioside.
- While white sugar aggravates yeast and strep infections, stevia seems to inhibit certain bacterial growth and has been advocated for those susceptible to yeast/strep infections.
From this article’s concluding paragraph:
“Apart from the sweet contents, S. rebaudiana with its secondary plant constituents also offers therapeutic benefits, having anti-hyperglycaemic, anti-hypertensive, anti-inflammatory, antitumour, anti-diarrhoeal, diuretic, and immunomodulatory effects.”
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