Long-term food consumption and body weight changes in neotame safety studies are consistent with the allometric relationship observed for other sweeteners and during dietary restrictions.

In long-term safety studies with neotame, a new high-intensity sweetener 7000-13,000 times sweeter than sucrose, the percent changes (%Delta) in body weight gain (BWG) in Sprague-Dawley rats were several-fold greater than the %Delta in overall food consumption (FC). This study investigates the question of whether the changes in BWG were adverse or secondary to small, long-term decrements in FC. The hypothesis tested in Sprague-Dawley rats was that the relationship between long-term %Delta in FC and %Delta in BWG is linear and in a ratio of 1:1. The %Delta in FC were compared to %Delta in BWG after 52 weeks on study in one saccharin (825 rats), two sucralose (480 rats), two neotame (630 rats), and five dietary restriction (>1000 rats) studies. Non-transformed plotting of data points demonstrated an absence of linearity between %Delta in FC and %Delta in BWG; however, log-log evaluation demonstrated a robust (R2=0.97) linear relationship between %Delta in FC and %Delta in BWG. This relationship followed the well-known allometric equation, y=bxa where x is %DeltaFC, y is %DeltaBWG, b is %DeltaBWG when DeltaFC=1, and a is the log-log slope. Thus, in Sprague-Dawley rats at week 52, the long-term relationship between %Delta in FC and %Delta in BWG was determined to be: %DeltaBWG=3.45(%DeltaFC0.74) for males and %DeltaBWG=5.28(%DeltaFC0.68) for females. Sexes were statistically different but study types, i.e., the high-intensity sweeteners saccharin and sucralose versus dietary restriction, were not. The %Delta in BWG are allometrically consistent with the observed %Delta in FC for these high-intensity sweeteners, including neotame. BW parameters are not appropriate endpoints for setting no-observed-effect levels (NOELs) when materials with intense taste are admixed into food. An approach using objective criteria is proposed to delineate BW changes due to toxicity from those secondary to reduced FC.

Observations at the interface of mutation research and regulatory policy.

Between 1970 and 1975 developments in environmental mutagenesis proceeded with amazing speed. These developments were both structural and conceptual in nature. A new infrastructure was built and new concepts about how best to protect consumers from exposures to mutagens emerged. The internal dynamics within the Food and Drug Administration played an important role and is discussed with regard to modifications in testing protocols as well as changes in the overall approach used to protect consumers. It is clear that this exciting period in the early days of environmental mutagenesis has provided a base for growth and development of the field and continues to affect and guide future developments.

Soy isoflavones: a safety review.

Soy isoflavones have been a component of the diet of certain populations for centuries. The consumption of soy generally has been considered beneficial, with a potentially protective effect against a number of chronic diseases; because of their estrogenic activity, however, negative effects of isoflavones have been postulated. This review examines the literature associated with the safety of soy isoflavones, including dietary soy isoflavone exposure data of populations with high soy intakes, human studies in which soy protein or isoflavones were provided, and toxicologic studies investigating the potential genotoxicity, carcinogenicity, and reproductive and developmental toxicity of soy isoflavones. Whereas results in some studies are limited or conflicting, when viewed in its entirety, the current literature supports the safety of isoflavones as typically consumed in diets based on soy or containing soy products.