Beyond the Paleolithic prescription: incorporating diversity and flexibility in the study of human diet evolution.

Abstract

"Evolutionary paradigms of human health and nutrition center on the evolutionary discordance or "mismatch" model in which human bodies, reflecting adaptations established in the Paleolithic era, are ill-suited to modern industrialized diets, resulting in rapidly increasing rates of chronic metabolic disease. Though this model remains useful, its utility in explaining the evolution of human dietary tendencies is limited. The assumption that human diets are mismatched to the evolved biology of humans implies that the human diet is instinctual or genetically determined and rooted in the Paleolithic era. This review looks at current research indicating that human eating habits are learned primarily through behavioral, social, and physiological mechanisms that start in utero and extend throughout the life course. Adaptations that appear to be strongly genetic likely reflect Neolithic, rather than Paleolithic, adaptations and are significantly influenced by human niche-constructing behavior. Several examples are used to conclude that incorporating a broader understanding of both the evolved mechanisms by which humans learn and imprint eating habits and the reciprocal effects of those habits on physiology would provide useful tools for structuring more lasting nutrition interventions."

[full text] 

Subjective satiety and other experiences of a Paleolithic diet compared to a diabetes diet in patients with type 2 diabetes.

Abstract

"BACKGROUND:

We found marked improvement of glycemic control and several cardiovascular risk factors in patients with type 2 diabetes given advice to follow a Paleolithic diet, as compared to a diabetes diet. We now report findings on subjective ratings of satiety at meal times and participants' other experiences of the two diets from the same study.

METHODS:

In a randomized cross-over study, 13 patients with type 2 diabetes (3 women and 10 men), were instructed to eat a Paleolithic diet based on lean meat, fish, fruits, vegetables, root vegetables, eggs and nuts, and a diabetes diet designed in accordance with dietary guidelines, during two consecutive 3-month periods. In parallel with a four-day weighed food record, the participants recorded their subjective rating of satiety. Satiety quotients were calculated as the intra-meal quotient of change in satiety during a meal and consumed energy or weight of food and drink for that specific meal. All participants answered the same three open-ended questions in a survey following each diet: "What thoughts do you have about this diet?", "Describe your positive and negative experiences with this diet" and "How do you think this diet has affected your health?".

RESULTS:

The participants were equally satiated on both diets. The Paleolithic diet resulted in greater satiety quotients for energy per meal (p = 0.004), energy density per meal (p = 0.01) and glycemic load per meal (p = 0.02). The distribution of positive and negative comments from the survey did not differ between the two diets, and the comments were mostly positive. Among comments relating to recurring topics, there was no difference in distribution between the two diets for comments relating to tastelessness, but there was a trend towards more comments on the Paleolithic diet being satiating and improving blood sugar values, and significantly more comments on weight loss and difficulty adhering to the Paleolithic diet.

CONCLUSIONS:

A Paleolithic diet is more satiating per calorie than a diabetes diet in patients with type 2 diabetes. The Paleolithic diet was seen as instrumental in weight loss, albeit it was difficult to adhere to."

[full text] 

Is Gluten a Cause of Gastrointestinal Symptoms in People Without Celiac Disease?

Abstract

"The avoidance of wheat- and gluten-containing products is a worldwide phenomenon. While celiac disease is a well-established entity, the evidence base for gluten as a trigger of symptoms in patients without celiac disease (so-called 'non-celiac gluten sensitivity' or NCGS) is limited. The problems lie in the complexity of wheat and the ability of its carbohydrate as well as protein components to trigger gastrointestinal symptoms, the potentially false assumption that response to a gluten-free diet equates to an effect of gluten withdrawal, and diagnostic criteria for coeliac disease. Recent randomized controlled re-challenge trials have suggested that gluten may worsen gastrointestinal symptoms, but failed to confirm patients with self-perceived NCGS have specific gluten sensitivity. Furthermore, mechanisms by which gluten triggers symptoms have yet to be identified. This review discusses the most recent scientific evidence and our current understanding of NCGS."

[link] 

Prevalence of gluten-free diet adherence among individuals without celiac disease in the USA: results from the Continuous National Health and Nutrition Examination Survey 2009-2010.

Abstract

"OBJECTIVES:

Clinical inference suggests the prevalence of non-celiac gluten sensitivity is substantially higher than that of celiac disease in the USA. Unfortunately, there are currently no data supporting these claims. The authors analyzed nationally representative data to estimate the prevalence of adherence to agluten-free diet among participants without celiac disease and also to characterize the demographics and general health status of these participants.

STUDY DESIGN AND SETTING:

The Continuous National Health and Nutrition Examination Survey (NHANES) 2009-2010 enrolled 7762 individuals representing the civilian, non-institutionalized, US population free of celiac disease. Participants responded to interviewer administered questionnaires regarding current adherence to a gluten-free diet. Prevalence estimates were computed using SAS survey procedures.

RESULTS:

There were 49 individuals who reported current adherence to a gluten-free diet reflecting a weighted prevalence of 0.548% (95% CI 0.206-0.889). The prevalence of a gluten-free diet was higher in females (0.58%) than males (0.37%), although this was not statistically significant (p = 0.34). Participants reporting a gluten-free diet were older (46.6 vs. 40.5 years, p = 0.005), had higher high-density lipoprotein, lower iron and lower body mass index.

CONCLUSIONS:

The estimated national prevalence of non-celiac gluten sensitivity is 0.548%, approximately half that of celiac disease. Future studies are merited in order to better understand the population burden of non-celiac gluten sensitivity."

[link]