Artificial sweeteners or non-nutritive sweeteners are often in the news and remain a bone of contention.
It was, therefore, most instructive to listen to Dr Bernadene Magnuson, Professor in the Department of Nutritional Sciences at the University of Toronto in Canada, speaking about “Sweeteners and Sweetener Safety” at a recent symposium on "Managing Sweetness" presented by Oldways. Oldways is an American organisation, based in Boston, which supports "Health Through Heritage".
In her introduction, the President of Oldways, Sara Baer-Sinnott (2012), explained that Oldways uses “a constructive, science-based approach that helps people lead healthy lives without sacrificing the pleasures of food and drinks they enjoy”. Subsequently, Prof Magnuson, one of the speakers, gave an overview of a variety of commonly used sweeteners and also addressed consumer concerns and safety issues.
Reasons for developing artificial sweeteners
The basic reasons why companies throughout the world have developed artificial sweeteners to replace sugar in the human diet are of course the obesity epidemic and the concomitant increase in diabetes mellitus. Prof Magnuson pointed out that low-calorie sweeteners (LCS) as they are called in Canada and the USA, have certain advantages compared to various types of sugar.
LCS do not affect blood glucose levels, they are many times sweeter than sugar so that much smaller quantities need to be used to achieve the same sweetening effect and they are not well absorbed by the human body thus limiting contributions to energy or toxicity.
Each LCS that is used commercially, has been subjected to very stringent tests. Firstly such products are tested for any hazards using a comprehensive battery of studies in many different species to determine the following:
- acute, sub-chronic and long-term toxicity
- the pharmacokinetics and metabolism
- carcinogenicity (i.e. does the compound cause cancer?)
- genetic toxicity (i.e. does the compound cause mutations?)
- reproductive toxicity, including teratogenicity (i.e. does the compound cause birth defects?)
as well as,
- clinical studies conducted in human subjects
Once all this data has been gathered, it is reviewed by a regulatory agency and the Acceptable Daily Intake (ADI) is determined. One such agency is the Joint FAO/WHO Expert Committee on Food Additives (JECFA), which is “an international expert scientific committee that is administered jointly by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organisation (WHO)”. It has been meeting since 1956, initially to evaluate the safety of food additives (JECFA, 2012).
The Acceptable Daily Intake (ADI) is defined by the WHO as “the amount that can be ingested daily over a lifetime without appreciable health risk”.
To calculate the ADI, the regulatory agencies such as the JECFA (2012), firstly calculate the NOEL (No-Observed Effect Level) from the results of long-term studies in 3 different species of animal and apply safety factors of 100 to account for differences between individuals and differences between humans and animals.
NOEL/safety factor = ADI (mg/kg/day)
Dr Magnuson (2012) emphasised that the ADI is “very conservative” and that is based on a level which has no effect, but has a “safety factor cushion”.
LCS approved in SA
According to Prof Magnuson (2012) the following LCS are listed as approved for use in food and beverages in South Africa:
- Acesulfame potassium- JECFA ADI - 15 mg/kg/day; Excreted unchanged in urine within 24 hours; No accumulation in the body
- Aspartame - JECFA ADI - 40 mg/kg/day; Not absorbed into the blood
- Cyclamate- JECFA ADI - 11 mg/kg/day; Incomplete absorption from the gut
- Neotame- JECFA and FDA ADI - 2 mg/kg/day; Derivative of aspartame, but unlike aspartame, Neotame can be used by individuals with phenylketonuria because very little phenylalanine is produced during metabolism
- Saccharin- JECFA ADI - 5 mg/kg/day; Not metabolised, but excreted in the urine
- Sucralose- JECFA ADI - 15 mg/kg/day; 85% is not absorbed, but excreted unchanged in the stools; absorbed Sucralose is excreted via the urine and no accumulation occurs
Two other LCS, namely Stevia and Monatin, are in the process of being approved by the Department of Health for use in South Africa.
Prof Magnuson (2012) pointed out that Stevia sweetener is produced by means of hot water extraction of so-called ‘steviol glycosides’ from the leaves of the Stevia rebaudiana shrub which grows in Uruguay. After extraction the Stevia Sweeteners need to be purified until they contain not less than 97% of steviol glycosides before the regulatory authorities will approve them for use by humans.
Unfortunately a number of extracts that do not meet the strict criteria of the JECFA are often sold as natural sweeteners. In general such poor quality Stevia sweeteners are not used in commercially produced foods manufactured by reputable food processing companies.
The JECFA ADI for Stevia sweeteners is 4 mg/kg/day. The glucosides in the Stevia extracts are not absorbed, but the glycosides are metabolised by the microorganisms in the gut to compounds called steviol which is absorbed in the human small intestine and is then excreted in the urine.
This new LCS is extracted from the root of the Sclerochitin ilicifolius plant which grows in the most northern parts of South Africa. The extract of this plant is purported to contain an intensely sweet substance.
Prof Magnuson (2012) reported that at present, toxicity studies are being conducted so that this LCS can be submitted to regulatory agencies worldwide for approval. We shall have to wait and see if this homegrown non-nutritive sweetener will be approved for human consumption.
It was evident from Prof Magnuson’s presentation that non-nutritive or artificial sweeteners, or LCS (Low-Calorie Sweeteners), are tested most stringently and need to meet very strict criteria before regulatory agencies such as the JECFA will permit their use in foods and beverages intended for consumption by human beings.
Next week we will address consumer concerns relating to the use of LCS in the modern diet.
(Baer-Sinnott B (2012). Managing Sweetness South Africa, Feb 2012. Opening address at Managing Sweetness, An Oldways Event in association with ADSA and SAAFoST, 23 February 2012. Sandton Convention Centre, Johannesburg. JECFA (2012). Food Safety and Quality(JECFA). www.fao.org/food/food-safety-quality/scientific-advice/jecfa/; Magnuson B (2012). Sweeteners and Sweetener Safety. Paper presented at Managing Sweetness, An Oldways Event in association with ADSA and SAAFoST, 23 February 2012. Sandton Convention Centre, Johannesburg.)
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