Female and male rats were fed an obesity-inducing high fat diet with or without polyphenolic-rich potato extracts (PRPE) for a period of ten weeks.
The McGill University researchers found that the mice given the extract diet demonstrated an enhanced capacity for blood glucose clearance while weight gain in this group was alleviated by up to 63.2%.
The mice started out with an average weight of 25g. Those given the control high-fat diet gained about 16g, while those given the same diet with potato extract put on just 7g.
Professor Luis Agellon, one of the authors behind the study published in the journal Molecular Nutrition & Food Research, said they had been “astonished” by the results.
“We thought this can’t be right – in fact, we ran the experiment again using a different batch of extract prepared from potatoes grown in another season, just to be certain.”
They said the results suggested the extract could be useful as part of a preventative dietary strategy against the development of obesity and type 2 diabetes.
Getting the daily dose
The extract was derived from 30 potatoes, but the researchers said they would not advise this level of consumption due to the calories that would entail. Instead they said a dietary supplement could achieve this dosage without the calorie burden.
Professor Stan Kubow, the study’s principal author, said in the French diet potatoes, not red wine, were the main source of polyphenols. In North America the potato was the third main source of the compound thought to be behind the potential health benefit.
“Potatoes have the advantage of being cheap to produce, and they’re already part of the basic diet in many countries,” he said.
Researcher seeks funding
The research team, which was planning to patent the Onaway and Russet Burbank potato extract, said it was now looking for food industry partners to fund further clinical trials.
This initial animal trial was financed by the Natural Sciences and Engineering Research Council of Canada, the Canadian Institutes of Health Research and the Canada Foundation for Innovation.
They said more data was needed to validate the benefits in humans and establish optimal dosages for men and women since metabolisms differed.
Last year the European Food Safety Authority (EFSA) rejected supplement firm Kemin’s health claim application for its potato extract Slendesta's ability to assist weight loss. The firm presented four unpublished human trials and a meta-analysis as evidence, but in its final opinion EFSA ruled that the data had not established a cause and effect relationship between consumption of the extract and reduction of body weight.
Source: Molecular Nutrition & Food Research
Vol 58, Iss 11, pp. 2235–2238, doi: 10.1002/mnfr.201400013
“Extract of Irish potatoes (Solanum tuberosum L.) decreases body weight gain and adiposity and improves glucose control in the mouse model of diet-induced obesity”
Authors: S. Kubow, L. Hobson, M. M. Iskandar, K. Sabally, D. J. Donnelly and L. B. Agellon