Topic

Primary Findings

Consumption levels of NNS

• Since manufacturers are not required to provide content information, there is no direct measurement of use
• From 2003 to 2004, 15.1% of the American population reported that they consumed foods or beverages containing NNS
• Consumption of NNS is increasing. In the American population, from 1998 to 2004, there was a 6.9% increase in NNS beverage consumption and an 81.2% increase in consumption of foods with NNS. Amount of NNS consumption has increased 37.7% and 14.2%, respectively.

NNS and appetite

• Earlier reviews report that acute exposure to NNS via non-energy-yielding vehicles augments hunger and that the sweetness of NNS enhances post-ingestive hunger. This has been found to be true of sodium chloride as well and now it is believed that, in general, oral exposure to a palatable stimulus in the absence of energy increases hunger.
• NNS have no effect on hunger when administered via nasogastric tube or capsules, indicating that changes in hunger may be due to orosensory stimulation. It is unclear if this translates to increased energy intake.
• When NNS are incorporated into energy-yielding foods or are part of a meal, no increase in hunger is evident.

NNS and energy intake

• It has been hypothesized that carbohydrate replacement (not addition) with NNS results in a relative increase in fat and protein consumption. However, in free-living individuals NNS are used as additions to the diet and not substitutions as evidenced by overall increased contribution of carbohydrate in the diet (as a percent of energy intake).
• The majority of evidence indicates that NNS have no short-term effects on energy intake
• Longer-term feeding trials generally indicate that the use of NNS result in no change or a reduction in energy intake (incomplete compensation).

NNS and BMI

• Intervention trials fail to document that NNS promote weight gain
• Observational studies are equivocal. Some studies show increased risk of weight gain associated with increased consumption of NNS, while others show that consumption of NNS facilitates weight management in individuals who have previously lost weight.
• There are many methodological differences amongst various studies, thereby confounding results and making comparisons among studies difficult.

Mechanisms of NNS and weight management

• NNS serve to maintain palatability of foods that are low in energy
• No data indicate that NNS modify energy balance independently of their influence on energy intake
• NNS, when substituted for NS, results in decreased carbohydrate intake; however most NNS are additions to the diet and not substitutions.

Mechanisms of NNS and appetite stimulation

• Cephalic phase stimulation: Neurally mediated physiological responses to prime the body to optimize digestion. Researchers disagree as to how cephalic stimulation affects hunger. The role of NNS is unclear and supportive evidence that NNS increase hunger via this mechanism is unsubstantiated.
• Nutritive and osmotic effects: Changes in the osmotic and nutrient properties of foods and beverages through substitution of NNS for NS has not been shown to affect satiety
• Gut peptide response: Failure of NNS to release peptides that augment satiety may result in increased energy intake; however, some NNS elicit the release of satiety peptides (sucralose) while others (aspartame) do not
• Palatability: NNS increase palatability which may result in over-consumption. Additionally these foods may be viewed as “healthy” and over-consumption may occur; however, there is inconclusive evidence that palatability influences absolute energy intake.

Theoretical mechanisms by which NNS may enhance energy intake or balance

• Loss of signal fidelity
• Activation of reward systems
• Training the palate to like sweetness
• None of these theories have been satisfactorily evaluated and no substantial evidence exists to support that NNS increases energy intake in free-living individuals.