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State of the Science: A Cultural View of Native Americans and Diabetes Prevention
The purpose of this article is to present a review of the literature on diabetes type 2 prevention interventions for Native American populations. The interrelation of the cultural role of food in Native American diets, educational policies related to food, outcomes of federal policies, and the historical background of diabetes are addressed. In addition, published studies of diabetes prevention interventions with Native American populations are examined. Lastly, exemplars of programs that represent best practices in the prevention of diabetes are described.
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Eating indigenously changes diets and lives of Native Americans
Bison and venison meatloaf? Cattail stir-fry? New movement brings Native Americans back to food of their ancestors
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Comparison with ancestral diets suggests dense acellular carbohydrates promote an inflammatory microbiota, and may be the primary dietary cause of leptin resistance and obesity.
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.
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Evolution of the diet from the paleolithic to today: progress or regress?
The changes in eating habits and decreased physical activity have been responsible for part of the high prevalence of chronic diseases such as hypertension or diabetes, currently observed in the so-called civilized societies. These diseases are less prevalent in previous civilizations and several decades of nutrition research have enabled better understanding of the eating habits of our ancestors, and have demonstrated the value of diet called "Mediterranean or Paleolithic". This review provides an update on the latest research. What dietary changes since the Paleolithic period, and finally how can we adapt our current diet? Several animal studies or human clinical demonstrate the value of historical research and nutrition.
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Evaluation of biological and clinical potential of paleolithic diet
Accumulating evidences suggest that foods that were regularly consumed during the human primates and evolution, in particular during the Paleolithic era (2.6-0.01 x 10(6) years ago), may be optimal for the prevention and treatment of some chronic diseases. It has been postulated that fundamental changes in the diet and other lifestyle conditions that occurred after the Neolithic Revolution, and more recently with the beginning of the Industrial Revolution are too recent taking into account the evolutionary time scale for the human genome to have completely adjust. In contemporary Western populations at least 70% of daily energy intake is provided by foods that were rarely or never consumed by Paleolithic hunter-gatherers, including grains, dairy products as well as refined sugars and highly processed fats. Additionally, compared with Western diets, Paleolithic diets, based on recently published estimates of macronutrient and fatty acid intakes from an East African Paleolithic diet, contained more proteins and long-chain polyunsaturated fatty acids, and less linoleic acid. Observational studies of hunter-gatherers and other non-western populations lend support to the notion that a Paleolithic type diet may reduce the risk of cardiovascular disease, metabolic syndrome, type 2 diabetes, cancer, acne vulgaris and myopia. Moreover, preliminary intervention studies using contemporary diet based on Paleolithic food groups (meat, fish, shellfish, fresh fruits and vegetables, roots, tubers, eggs, and nuts), revealed promising results including favorable changes in risk factors, such as weight, waist circumference, C-reactive protein, glycated haemoglobin (HbAlc), blood pressure, glucose tolerance, insulin secretion, insulin sensitivity and lipid profiles. Low calcium intake, which is often considered as a potential disadvantage of the Paleolithic diet model, should be weighed against the low content of phytates and the low content of sodium chloride, as well as the high amount of net base yielding vegetables and fruits. Increasing number of evidences supports the view that intake of high glycemic foods and insulinotropic dairy products is involved in the pathogenesis and progression of acne vulgaris in Western countries. In this context, diets that mimic the nutritional characteristics of diets found in hunter-gatherers and other non-western populations may have therapeutic value in treating acne vulgaris. Additionally, more studies is needed to determine the impact of gliadin, specific lectins and saponins on intestinal permeability and the pathogenesis of autoimmune diseases.
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Effects of a short-term intervention with a paleolithic diet in healthy volunteers
Objectives: Prevention of cardiovascular diseases by paleolithic or hunterer-gatherer diets has been discussed during recent years.
Methods: Our aim was to assess the effect of a paleolithic diet in a pilot study on healthy volunteers during 3 weeks. The intention was to include 20 subjects, of whom 14 fulfilled the study. Complete dietary assessment was available for six subjects.
Results: Mean weight decreased by 2.3 kg (P<0.001), body mass index by 0.8 (P<0.001), waist circumference by 0.5 cm (P=0.001), systolic blood pressure by 3 mm Hg (P=0.03) and plasminogen activator inhibitor-1 by 72% (P=0.020). Regarding nutrient intake, intake of energy decreased by 36%, and other effects were also observed, both favourable (fat composition, antioxidants, potassium-sodium rate) and unfavourable (calcium).
Conclusion: This short-term intervention showed some favourable effects by the diet, but further studies, including control group, are needed.
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Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a 2-year randomized trial
Background/Objectives:
Short-term studies have suggested beneficial effects of a Palaeolithic-type diet (PD) on body weight and metabolic balance. We now report the long-term effects of a PD on anthropometric measurements and metabolic balance in obese postmenopausal women, in comparison with a diet according to the Nordic Nutrition Recommendations (NNR).
Subjects/Methods:
Seventy obese postmenopausal women (mean age 60 years, body mass index 33 kg/m2) were assigned to an ad libitum PD or NNR diet in a 2-year randomized controlled trial. The primary outcome was change in fat mass as measured by dual-energy X-ray absorptiometry.
Results:
Both groups significantly decreased total fat mass at 6 months (−6.5 and−2.6 kg) and 24 months (−4.6 and−2.9 kg), with a more pronounced fat loss in the PD group at 6 months (P<0.001) but not at 24 months (P=0.095). Waist circumference and sagittal diameter also decreased in both the groups, with a more pronounced decrease in the PD group at 6 months (−11.1 vs−5.8 cm, P=0.001 and−3.7 vs−2.0 cm, P<0.001, respectively). Triglyceride levels decreased significantly more at 6 and 24 months in the PD group than in the NNR group (P<0.001 and P=0.004). Nitrogen excretion did not differ between the groups.
Conclusions:
A PD has greater beneficial effects vs an NNR diet regarding fat mass, abdominal obesity and triglyceride levels in obese postmenopausal women; effects not sustained for anthropometric measurements at 24 months. Adherence to protein intake was poor in the PD group. The long-term consequences of these changes remain to be studied.
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Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets
Both anthropologists and nutritionists have
long recognized that the diets of moderm-day hunter-gatherers
may represent a reference standard for modern human nutrition
and a model for defense against certain diseases of affluence.
Because the hunter-gatherer way of life is now probably
extinct in its purely un-Westernized form, nutritionists and
anthropologists must rely on indirect procedures to reconstruct
the traditional diet of preagricultural humans. In this analysis,
we incorporate the most recent ethnographic compilation of
plant-to-animal economic subsistence patterns of huntergatherers
to estimate likely dietary macronutrient intakes (% of
energy) for environmentally diverse hunter-gatherer populations.
Furthermore, we show how differences in the percentage of body
fat in prey animals would alter protein intakes in huntergatherers
and how a maximal protein ceiling influences the
selection of other macronutrients. Our analysis showed that
whenever and wherever it was ecologically possible, huntergatherers
consumed high amounts (45–65% of energy) of animal
food. Most (73%) of the worldwide hunter-gatherer societies
derived > 50% (≥56–65% of energy) of their subsistence from
animal foods, whereas only 14% of these societies derived > 50%
(≥56–65% of energy) of their subsistence from gathered plant
foods. This high reliance on animal-based foods coupled with
the relatively low carbohydrate content of wild plant foods
produces universally characteristic macronutrient consumption
ratios in which protein is elevated (19–35% of energy) at the
expense of carbohydrates (22–40% of energy). Am J Clin
Nutr 2000;71:000–000.
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