|Solal Technologies placed in the Durban Mercury of 03 March 2011, in which the claim is made that “[T]oo much sugar may accumulate fat and make learning difficult”.|
The advert continues: “[S]tudies have shown that excessive sugar consumption can boost the body’s production of cortisol, a hormone that causes fat accumulation. Sugar excess is not good for the brain either.
A study published in the medical journal Neuroscience showed that sugar suppresses the brain’s neurotrophic factor, responsible for learning, memory and plasticity (the ability of the brain to learn new things”
Solal supports this advertisement with two references:
Gardner LB, Reiser S. Effects of dietary carbohydrate on fasting levels of human growth hormone and cortisol. Proc Soc Exp Biol Med. 1982 Jan;169(1):36-40.
Molteni R, Barnard RJ, Ying Z, Roberts CK, Gómez-Pinilla F. A high-fat, refined sugar diet reduces hippocampal brain-derived neurotrophic factor, neuronal plasticity, and learning. Neuroscience. 2002;112(4):803-14.
The first reference (Gardner et al.) refers to a study published in 1982. An Internet search for information for this reference brings up hundreds of similar anti-sugar claims, from a range of anti-sugar campaigners, all referring to the same reference.
The details of this article is “eye opening”: the study was conducted in male-only weanling carbohydrate-sensitive BUE rats. Yes, the rats were rendered carbohydrate-sensitive first, and results of this study are extrapolated to readers of the Mercury. [These may also be referred to as BHE rats.]
[These may also be referred to as BHE rats.]
It is significant that there have been no further studies conducted (since 1982) in animals or humans to corroborate this particular study’s findings.
The second reference (Molteni R, et al.) is just as highly misleading. The study was not only conducted in an animal model, but sugar (carbohydrate) was not investigated as the singular cause of brain changes. The diet investigated was specifically a high-calorie diet, a combination rich in saturated fat and refined sugar – in order to mimic the typical diet of most industrialized western societies.
Of course, my usual disclaimers: I do not claim that sugar is good or bad but that studies MUST be robust, and scientific evidence should be in general agreement before definitive claims can be made. Is it my belief that it is misleading to make claims regarding proof for a claim without indicating to scientifically naïve consumers that many excellent studies do not concur with the claims.