All food additives including artificial sweeteners approved by the FDA has been deemed safe for human consumption as long as the acceptable daily intake is not exceeded.
An acceptable daily intake (ADI) for each additive has been established and calculated according to current safety research. The ADI is defined as an intake that “individuals in a (sub)population may be exposed daily over their lifetimes without appre-ciable health risk” (World Health Organization). The ADI is calculated by dividing the maximum dose at which a study has not shown a negative effect in animal studies. The maximum no-effect dose is divided by 100 to calculate the ADI.
For example, a no-effect dose of 100 mg/kg body weight of the studied animal would translate into 1 mg/kg body weight in humans. The ADI is not likely to be exceed with normal consumption and even if it is exceeded someone consuming twice the ADI would still benefit from a safety factor of 50.
However, animal studies have shown that artificial sweeteners increase cancer and other adverse effect. This has been a great source of concern and controversy.
For example, despite of the fact that The National Cancer Institute made the summary statement: “There is no clear evidence that the artificial sweeteners on the market in the United States are related to cancer risk in humans” many are still afraid are still afraid that artificial sweeteners can cause cancer.
Below, the safety concerns for each available artificial sweetener are discussed.
Saccharin, a coal tar derivative initially synthesized in 1879, was the first non-nutritive sweetener to be commercially available in North America. It is not metabolized by the body and is excreted in the urine unchanged.
Saccharin has been shown in studies to increase bladder cancer in rats. This prompted its ban by the FDA and removal from the market however subsequent studies that looked into the association between saccharin and cancer failed to demonstrate any relationship. Some authors argued that very high doses of saccharin were used in the animal studies and that there are significant differences in both toxicokinetics and toxicodynamics between rats and humans. The ban has been lifted, but safety concern lingers resulting to decrease use of this substance.
Aspartame is commonly used as additive in carbonated beverages and beverage mixes, chewing gum, breath fresheners, and confectioneries. It is metabolized in the small intestine by the action of enterases and peptidases that hydrolyze aspartame to yield methanol and the 2 amino acids aspartic acid and phenylalanine. It provides 4 kcal/g. However, since aspartame is about 200 times sweeter by weight than sugar, only minute amount is needed to achieve the same level of sweetness hence will not provide significant amount of calorie.
The safety of aspartame and its metabolites has been established through extensive toxicology studies in laboratory animals, using much greater doses than people could possibly consume. Its safety has been further confirmed through studies in several human subpopulations, including: healthy infants, children, adolescents and adults; obese individuals with or without diabetes: and lactating women. In individuals with the genetic disease phenylketonuria, who have a decreased ability to metabolize phenylalanine, its consumption is discouraged since phenylalanine is one of aspartame’s metabolites.
A study published in 1996 suggests that an increase in the incidence of brain tumors in industrialized countries may be linked to aspartame consumption. However no cause-and-effect relationship can be concluded from this epidemiological study. Another case-control study investigating this relationship in children and children of mothers who consumed aspartame during pregnancy failed to show any association.
Aspartame has also been thought to provoke seizure. However several small randomized control trials did not show increased seizure events with aspartame consumption.
There are also safety issues concerning the aspartame’s metabolites (aspartate, phenylalanine and methanol). These metabolites have hypothesized to alter neurotransmitter balance that may affect even cognitive function. However no study in humans or even animals has substantiated this claim.
Acesulfame potassium (acesulfame-K) is often combined with other artificial sweeteners, such as aspartame, to intensify its sweetness and decrease its bitter taste (14). It is not a source of calorie. It absorbed by the gut and excreted in the urine unchanged.
Numerous toxicology studies did not show any evidence to suggest that it is not safe if consumed at the recommended daily intake. However, as with all artificial sweeteners, there is substantial lack of well designed studies in human.
Sucralose is structurally related to sucrose. They have the same discharride ring however 3 of the hydroxyl groups in sucrose is replaced with chlorine in sucralose. It produces no calorie. Only 25% of oral intake is absorbed, which is is excreted in the urine unchanged.
There are several human studies substantiating the safety of sucralose at the recommended amount of consumption.
There are no study showing that it can cause cancer.However, commercially available sucralose is mixed with bulking ingredients such as maltodextrin that may be carcinogenic.
Cyclamates, available in the Philippines as Magic Sugar has revieved much local attention in recent years due to rodent studies linking its use with increase incidence of bladder cancer. This prompted ban on this substance however this has been lifted and is now available for commercial use.
Subsequent animal studies demonstrated its good safety profile. This is generally supported by toxicokinetic studied in humans, however cyclamates are not completely metabolized and can be converted to cyclohexylamine, which is potentially carcinogenic and hypothesized to have adverse cardiovascular and metabolic effects.
Stevia is a herb that has been used in in South America. It has received much attention from the health conscious public and physician alike because it is supposed to be “all-natural” which gave it a much favorable connotation as safe. The stevia sweetener is a mixture extracted from the leaves of the herb and consists mainly of the glycosides (stevioside).
Animal studies studies have demonstrated its safety. Unlike most of the artificial sweeteners, stevia undergoes significant metabolism. Like aspartame, there are some soncern regarding the toxic potential of stevia’s metabolites.
It is important to remember that although, stevia is a plant extract, this does not guarantee its safety. Well designed human studies are still lacking.[pq]Artificial sweeteners appear to be safe when consumed below the acceptable daily intake.[/pq]
However there are limited human studies documenting its safety especially among pregnant women, people with kidney disease or liver disease. There are also limited data on the effect of chronic exposure to these additives at doses not exceeding the ADI.
– Dr. Allan Dampil