Lecture 11: Nutritional Transitions and the Paleo Diet

Nutritional Transitions and the Paleo Diet Lecture 11 Announcements Please check the days and times of your final exams to confirm that you don’t have any time conflicts. Please let me know if you have a time conflict with another class. Terms and Concepts to Know Cline Population s...

Nutritional Transitions and the Paleo Diet Lecture 11 Announcements Please check the days and times of your final exams to confirm that you don’t have any time conflicts. Please let me know if you have a time conflict with another class. Terms and Concepts to Know Cline Population substructure Selective sweep Polygenic adaptation Haplogroup Reference population How can genetic tests reinforce or undermine the idea that race is a genetically determined category? What about “racial medicine”? Dr. Dorothy Roberts https:// www.youtube.com/watch?v=KxLMjn4WPBY Today’s Objectives Summarize the components of a nutritious diet Review the history of agriculture and its health consequences Discuss paleo diets in the context of evolutionary mismatch Terms and Concepts to Know Macro vs micronutrients Health consequences of agriculture Paleolithic “Paleo Diet” and how it may differ from actual human diets from the Paleolithic Common characteristics of hunter- gatherer diets Today’s Objectives Summarize the components of a nutritious diet Review the history of agriculture and its health consequences Discuss paleo diets in the context of evolutionary mismatch Dietary Adequacy Extent to which food intake fulfills one’s nutritional requirements Typically assessed using a 24 hour dietary recall Six broad categories of nutrients need to sustain life Macronutrients Carbohydrates Protein Micronutrients Fats Vitamins Minerals Water Dietary Adequacy Carbohydrates Accounts for ~40-50% of daily calories among U.S. adults (Briefel & Johnson, 2004) Simple carbohydrates Monosaccharides Glucose, fructose, galactose Disaccharides Sucrose Complex carbohydrates Polysaccarides Starch Nonstarch polysaccharide Dietary fiber Dietary Adequacy Protein Composed of amino acids Body requires 20 different amino acids Essential amino acids 9 amino acids that cannot be synthesized by the body Arginine, cysteine, glutamine, glycine, proline, and tyrosine Fats Simple Triglycerides Composed of glycerol and fatty acid Saturated and unsaturated fatty acids Compound Phospholipids and lipoproteins Derived Cholesterol, steroids Dietary Adequacy Vitamins Not a source of energy, help the body use energy and carry out other metabolic activities Folate Type of Vitamin B Found in green leafy vegetables, citrus fruits, dried legumes Need for fetal development, spermatogenesis, production of neurotransmitters like serotonin Vitamin D Found in oily fish, liver, some plants and mushrooms, fortified dairy products Need for skeletal growth and maintenance and immune function Dietary Adequacy Minerals Inorganic elements that are key components in many biological molecules Calcium Needed for skeletal growth and development Found in dairy products, leafy greens, beans and nuts Iron Needed for hemoglobin (protein that carries oxygen in the blood) Found in meat, beans, and dark green leafy vegetables Today’s Objectives Summarize the components of a nutritious diet Review the history of agriculture and its health consequences Discuss paleo diets in the context of evolutionary mismatch The History of Agriculture https://youtu.be/Yocja_N5s1I?si=itSRc1BLxBYWEKX5 The Consequences of Agriculture for Human Health Shift toward carbohydrate-based diet The Consequences of Agriculture for Human Health Shift toward carbohydrate-based diet Skeletal signs of nutritional deficiencies in archaeological record Dental caries Pathological conditions of the skeleton Lower cortical bone thickness Reductions in skeletal growth Greater infant and childhood mortality Lower mean age-at-death The Consequences of Agriculture for Human Health Shift toward carbohydrate-based diet Skeletal signs of nutritional deficiencies in archaeological record Dramatic increases in population size The Consequences of Agriculture for Human Health Shift toward carbohydrate-based diet Skeletal signs of nutritional deficiencies in archaeological record Dramatic increases in population size Increase in infectious disease The Consequences of Agriculture for Human Health Shift toward carbohydrate-based diet Skeletal signs of nutritional deficiencies in archaeological record Dramatic increases in population size Increase in infectious disease Greater inequality The Consequences of Agriculture for Human Health Shift toward carbohydrate-based diet Skeletal signs of nutritional deficiencies in archaeological record Dramatic increases in population size Increase in infectious disease Greater inequality Variation in its affects due to differences in geography, politics, culture, and population size Lecture 11 Quiz True or false: While there are a few examples of how selective sweeps have shaped the human genome, most human genetic adaptations are polygenic adaptations. Today’s Objectives Summarize the components of a nutritious diet Review the history of agriculture and its health consequences Discuss paleo diets in the context of evolutionary mismatch What is the Paleolithic? Period that begins with hominins beginning to use stone tools ~3.3 million years ago Ends with the last glacial period (c 11,650 BP)  Human- Chimp LCA Early potential hominins: Definitive hominins Later hominins: Sahelanthropus Australopithecus anamensis Homo habilis Ardipithecus Australopithecus afarensis Homo rudolfensis Orrorin Australopithecus africanus Later Homo Paranthropus robustus including H. erectus, Paranthropus boisei H. neanderthalensis Paranthropus aethiopicus “Is There an Optimal Diet for Humans?” The Tsimane in Bolivia The Hadza in Tanzania The Shuar in Ecuador “Paleo Diet” Argues that a healthy diet should mimic the diet of Paleolithic hunter-gatherers Human digestion and nutritional needs are not adapted to diets that are common post agricultural revolution Specific macronutrient composition 35% of calories should come from protein 45% of calories should come from carbohydrates Mostly non-starchy fruits and vegetables with high fiber 28-47% of calories should come from fat Low saturated fat foods Avoid added sugar, dairy, grains, starchy tubers, and legumes Support for the “Paleo Diet” Archaeological evidence indicates that agriculture does not inherently lead to healthier populations Diets rich in added sugar, low fiber, refined carbohydrates are associated with metabolic disease Insufficient time for substantive genomic adaptations to contemporary diets Exceptions Lactase persistence Enhanced salivary amylase production in populations with starchy diets Health of Hunter-Gatherers Hunter-gatherer populations have low rates of chronic diseases such as Heart disease, hypertension, diabetes, cancer Expected Lifespan at Birth: 30-40 years old Due to high infant mortality from infectious disease Expected Lifespan at Age 15: 72 years old Critiques of the “Paleo Diet” There is no single Paleolithic diet Wide variation in macronutrient composition and plant- vs. animal-derived foods across populations Variation in Human Diets Critiques of the “Paleo Diet” There is no single Paleolithic diet Wide variation in macronutrient composition and plant- vs. animal-derived foods across populations Wide variation across seasons and years Critiques of the “Paleo Diet” There is no single Paleolithic diet Wide variation in macronutrient composition and plant- vs. animal-derived foods across populations Wide variation across seasons and years Archaeological evidence for consumption of some cereals, starchy tubers and legumes during Paleolithic Critiques of the “Paleo Diet” There is no single Paleolithic diet Wide variation in macronutrient composition and plant- vs. animal-derived foods across populations Wide variation across seasons and years Archaeological evidence for consumption of some cereals, starchy tubers and legumes during Paleolithic Not all aspects of modern diets are intrinsically unhealthy Common Characteristics of Hunter-Gatherer Diets Composed of a mix of meat, fish and plants More fiber in hunter-gatherer diet than typical American diet Most of the carbohydrates come from vegetables and starchy plants Low glycemic index -> a measure of the effects of a food on blood glucose levels  Nutrition Transition Shift: subsistence  wage/market economy Increased availability of market foods & energy Reduced activity & energy expenditure