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DHA is shown to counteract the negative metabolic effects of fructose consumption in rats to restore memory and blood glucose/insulin levels.

May 31, 2016

A study of rats fed either fructose or fructose with DHA for 6 weeks was conducted at the University of California (2). The fructose only animals exhibited impairment to memory and adverse blood profiles (raised glucose, triglycerides and insulin). However, the fructose + DHA group had the same memory and blood profile as the control group.  These results suggest DHA may be protective against the adverse metabolic effects of fructose consumption.

At the end of 2012, a paediatric endocrinologist named Dr. Robert Lustig published a highly popular, though controversial, book called “Fat Chance: The bitter truth about sugar.” The theme of the book is the theory that fructose disrupts normal human metabolism, initiating metabolic syndrome and obesity (3). In a subsequent academic paper, Dr. Lustig provides evidence that fructose can have a similar effect to alcohol in the brain (4).

An article in the Sydney Herald reported on a study that appeared to indicate that the marine omega 3 fatty acid Docosahexaenoic Acid (DHA) could reverse impairment to memory caused by fructose consumption in laboratory rats (1). Previously, it had been shown that fructose-induced metabolic syndrome in rats reduced hippocampal-dependent memory (5). The new study (2) fed either fructose (15% in drinking water) or the same level of fructose but with 1.2% DHA to lab rats for 6 weeks.  (The fructose level is comparable to consumption of between 1 to 2 litre of a regular soda beverage per day by a 60kg adult). At the end of 6 weeks, a range of metabolic tests were carried out and the rats were tested for memory retention by measuring their performance in a Barnes maze. Rats with impaired memory take longer to negotiate the maze. These results were compared to those of a control group of rats who consumed neither fructose or DHA.

As expected, the fructose only rats took longer to get through the maze than the other groups and had significantly increased levels of blood glucose, blood triglycerides, insulin and insulin index. Remarkably, the fructose + DHA group exhibited none of these negative effects and had approximately the same memory retention and metabolic measures as the control group.

These results suggest that DHA can counteract the negative epigenetic changes to metabolism caused by fructose consumption. However, it has yet to be shown if these effects would be translated could be translated to humans.

References

  1. Berry S, “Fructose leaves you puzzled, and there’s something fishy about the solution”; The Sydney Herald, April 26th, 2016.
  2. Meng Q, Ying Z, Noble E et al.; “Systems Nutrigenomics Reveals Brain Gene Networks Linking Metabolic and Brain Disorders”; EBioMedicine April 2016. http://doi.org/10.1016/j.ebiom.2016.04.008
  3. Lustig RH, “Fat Chance: The Hidden Truth about Sugar, Obesity and Disease”; 2012, Fourth Estate
  4. Lustig RH “Fructose: it’s alcohol without the buzz”; Adv Nutr 2013; 4(2):226-35.
  5. Agrawal R & Gomez-Pinilla F; “Metabolic syndrome in the brain: deficiency in omega-3 fatty acid exacerbates dysfunctions in insulin receptor signalling and cognition”; J Physiol 2012; 590:2485-2499.