T Nation

what does that mean in plain English?

Anyone with physiology/biochem/med background, could you please comment on that article? What could it mean for us humans :-)?

Physiol Behav 2002 Feb 1;75(1-2):41-7
Effects of long-term ingestion of aspartame on hypothalamic neuropeptide Y, plasma leptin and body weight gain and composition.

Beck B, Burlet A, Max JP, Stricker-Krongrad A.

Centre de Recherches UHP/EA 3453, IFR no. 111, Systemes Neuromodulateurs des Comportements Ingestifs; 38, rue Lionnois, 54000, Nancy, France

The aim of this study was to determine the effects of the chronic ingestion of aspartame (ASP) on brain neuropeptide Y (NPY) concentrations, plasma hormones, food intake and body fat. Two groups of male Long-Evans rats, fed on a control (C) well-balanced diet, had to drink either a 0.1% ASP solution or water for a period of 14 weeks starting at weaning. Food intake and body weight were weekly recorded. At the end of the experiment, fat pads were sampled, leptin and insulin were measured in the plasma and NPY in several microdissected brain areas. Substituting ASP for water led to lower body weight (minus sign8%; P<.004) and lower fat depot weight (minus sign20%; P<.01) with no differences in energy intake or plasma insulin concentrations. Plasma leptin was significantly reduced by 34% (P<.05). Leptin concentrations were well-correlated with final body weight (r=.47; P<.025) and fat pad mass (r=.53; P<.01). NPY concentrations were 23% lower (P<.03) in the arcuate nucleus of ASP rats with no differences in other brain areas. The beneficial effects on body composition could be related to the decreased effects of NPY on lipid and energy metabolism, independently of insulin. The reasons for the NPY decrease (regulatory or toxicological) are not obvious. The constitutive amino acids of the ASP molecule might participate in the NPY regulation.

In layman’s terms, aspartame comsumption in rats leads to less fat storage over time even though caloric intact remained steady as compared to a control group wich gained more fat while eating the same number of calories but no aspartame. The aspartame fed rats had less body fat than control rats while both fed identical diet.

I know for a fact that aspartame causes brain tumors. Don’t use it. Use stevia, natural alternative. No Side Effects. And don’t trust what the FDA has to say because they banned Stevia after the introduction of Aspartame because they knew it would cut down sales of Aspartame. Other Chemical sweetners have same problems.



Cann’t help but ask: where did you get your “fact” on aspartame causing brain tumors? How many people do you know that have an aspartame caused brain tumor? Personally, I’ve been drinking 6-10 diet cokes a day for maybe 12-15 years and also use aspartame in any other number of foods, buy aspartame sweetner and use in oatmeal, home made protein shakes, etc etc, and have never experienced any kind of ill effects. In fact, at almost 45 yo, I feel in the best shape of my life. Though I admit, I do like sucralose also, but mix it 1/2-1/2 with aspartame.

Tim - Stevia is not the angel that you think. At least in lab rats it causes a negative effect on spermatozoa formation and acivity (it causes the balls to shrink and produce less). Other data imparts iffy effect on T as well.

(thick Austrian accent) “It is not a tumor!”

I’ll add more to this when I get home, but here is a start. Neuropeptide Y is a compound which is suggested to target the hunger areas of the brain to stimulate hunger. It aslo tends to slow down metabolic rate and if I remember correctly, it shifts the body towards favoring carbohydrate utilization versus fat utilization for fuel. If you reduce this compound in rats, they will tend to eat less and be leaner. Since the researchers controlled for food intake, the effects of Neuropeptide Y had to be mediated via other mechanisms. Neuropeptide Y and leptin are quite interlated in energy expenditure and food intake IN RATS (we hardly know anything about these compounds in humans). Neuropeptide Y also did not mediate its effects via leptin because the differences between leptin concentrations in the two groups where due primarily to differences in fat mass. (Leptin is produced and secreted by adipose tissue, thus the more fat you have, the more leptin). Also, insulin is another hormone which acts in conjuction with leptin and neuropeptide Y, but it did not seem to play a role in this case. So in conclusion, neuropeptide Y was decreased by aspartame ingesition and this led the rats to have less body fat, but was not due to changes in leptin or insulin. So, lowering neuropeptide Y likely caused in increase in resting energy expenditure and likely a shift towards favoring fat as fuel rather than carbohydrates. Why the researchers did not take a measure of energy expenditure and activity patterns of the rats, I don’t know, but they should have. With this information, you could really tell what the mechanism for change was. Does this mean anything for humans? Maybe, but I don’t think so.