Acellular Carbs the New Frontier paradigm

Pubblicato: ottobre 21, 2012 in nutrition

Probably a neo-paradigmatic plug into the mistery of Human Nutrition


Comparison with ancestral diets suggests dense
acellular carbohydrates promote an inflammatory
microbiota, and may be the primary dietary cause
of leptin resistance and obesity

Ian Spreadbury

Gastrointestinal Diseases Research
Unit, Queen’s University, Kingston,
Ontario, Canada

Abstract: A novel hypothesis of obesity is suggested by consideration of diet-related
inflammation and evolutionary medicine. The obese homeostatically guard their elevated
weight. In rodent models of high-fat diet-induced obesity, leptin resistance is seen initially at
vagal afferents, blunting the actions of satiety mediators, then centrally, with gastrointestinal
bacterial-triggered SOCS3 signaling implicated. In humans, dietary fat and fructose elevate
systemic lipopolysaccharide, while dietary glucose also strongly activates SOCS3 signaling.
Crucially however, in humans, low-carbohydrate diets spontaneously decrease weight in a way
that low-fat diets do not. Furthermore, nutrition transition patterns and the health of those still
eating diverse ancestral diets with abundant food suggest that neither glycemic index, altered fat,
nor carbohydrate intake can be intrinsic causes of obesity, and that human energy homeostasis
functions well without Westernized foods containing flours, sugar, and refined fats. Due to being
made up of cells, virtually all “ancestral foods” have markedly lower carbohydrate densities
than flour- and sugar-containing foods, a property quite independent of glycemic index. Thus
the “forgotten organ” of the gastrointestinal microbiota is a prime candidate to be influenced
by evolutionarily unprecedented postprandial luminal carbohydrate concentrations. The present
hypothesis suggests that in parallel with the bacterial effects of sugars on dental and periodontal
health, acellular flours, sugars, and processed foods produce an inflammatory microbiota via
the upper gastrointestinal tract, with fat able to effect a “double hit” by increasing systemic
absorption of lipopolysaccharide. This model is consistent with a broad spectrum of reported
dietary phenomena. A diet of grain-free whole foods with carbohydrate from cellular tubers,
leaves, and fruits may produce a gastrointestinal microbiota consistent with our evolutionary
condition, potentially explaining the exceptional macronutrient-independent metabolic health
of non-Westernized populations, and the apparent efficacy of the modern “Paleolithic” diet on
satiety and metabolism.

Keywords: carbohydrate density, metabolic syndrome, nutrition transition, Paleolithic diet





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