Nutrition Flashcards
1
Q
Human Biology and Lifestyle Mismatch
A
- Human biology is the product of evolution of millions of years
- Earliest members of homo genus was 2 Mya
- We are genetically adapted to the environment of our ancestors who foraged
- 12,000 years ago: agriculture and farming caused a profound environmental change in diet and other lifestyle conditions which is a recent change
- We evolved based on our ancestors 2 mya not our current times of agriculture and farming 12,000 years ago so mismatch
- Mismatch pathway 1 – hunter gatherer to agriculture and farming causing overreliance
2
Q
GI tract
- Australopithecines
- Homo genus
A
- Australopithecines were herbivores
o Ate fruits and tubers
o Very long intestines with a large cecum to digest fiber
o Late australopithecines may have scavenged for protein - Homo genus are omnivores
o Fire for cooking so easier to chew/digest food
o Smaller intestine to save energy & invest in increased brain size
o Eating more energy rich meat so more energy for evolving brain
o Appendix is an atavism (means no longer used), vestigial organ, used to digest cellulose
3
Q
Appendicitis
A
appendix is easily infected because its no longer needed
o May be fatal so why hasn’t it been selected against
o Possibly rare until 19th century and then declined again so no time to be eliminated
o Infection
o Appendix is Left over from our past
4
Q
Domestication of Fire
-functions
A
- Fire was regularly used by: Neanderthals, erectus, sapiens
- Functions
1. Light, warmth, protection
2. Torch areas to gather animals (hunt), harvest cooked animals and vegetables
3. Cooking some foods that can only be digested after cooking so easier to chew, digest, metabolize
o Wheat, tubers, rice
o Killing germs and parasites (sterilize)
o Eat more types of food
o Spend less time eating = more efficient
o Resulted in larger brains, shorter intestine and smaller teeth because no longer need to digest raw food
5
Q
Fire and TB
A
- Lesions on paleolithic humans and ancient DNA revealed the coevolution with mycobacterium tuberculosis
- Most pathogens were transmitted from animals to humans but not TB
- Mycobacteria live in soil and water theoretically but get burned in fire so in soot that is breathed in
- Mycobacterium can cause opportunistic infections when infecting individuals with a weakened immune system
- Fire in enclosed space lead to
1. Smoke – inhaling smoke creates good environment for TB to grow
2. Inflammation
3. Bacterium spreads by coughing and sneezing - Coevolution with microbes = pathway #4
- An environmental microbe that rarely causes disease evolved and specialized in becoming an obligate pathogen
o A pathogen that cannot live outside of host
o Fire gave mycobacterium the opportunity to spread in humans
o Presence of inhaled smoke prevents the immune system from clearing lungs of pathogens
6
Q
Tuberculosis
A
- By beginning of 19th century TB had killed 1/7 of all people that had ever lived
- Now affects ¼ of human population
- Mycobacteria infect the lungs (90%) causing: chronic cough, blood containing sputum, fever
- Extrapulmonary TB (10%) on skin: in immunocompromised individuals, lymphatic system, bones, CNS
- Prophylaxis (prevention): vaccination
- Treatment: antibiotics
- Multiple strains of drug resistant TB now exist
7
Q
Diet Evolution
A
- A chimp spends ½ of his wakeful day chewing raw roots, fruits, leaves which requires extensive digestion
- Australopithecines were vegetarian: wild plants like roots, fruits, leaves
- Homo habilis became an opportunistic meat eater
- Homo erectus: true hunter for 2 mya
- Homo sapiens true mastery of fire
8
Q
Human Diet
-5 lines of evidence
A
- Humans have developed a greater brain mass and adapted the GI tract to provide an increased caloric intake: increased meat consumption
- Lines of evidence
1. Dental adaptations
2. Skull adaptations
3. Shorter GI tract
4. Bone remains suggesting meat eating
5. Anemia caused by lack of meat consumption
9
Q
Dentition - line of evidence for Diet
A
- Diet changes: herbivorous to omnivores
- Smaller teeth
- First molar in australopithecines = size of thumb nail
- First molar in sapiens = size of pinky nail
- Larger molars in herbivores and smaller in omnivores
10
Q
Skull adaptations - line of evidence for Diet
A
- In sapiens masseter & temporalis are smaller because reduce need to eat hard foods
- Evidence by the origin and insertion sites on bone landmarks have changed because don’t chew as much
11
Q
shorter GI tract - line of evidence for Diet
A
- Most great apes have GI tract adapted to the digestion of foods that require extensive digestion: roots and leaves
- Ape tract: stomach, appendix, colon are longer to process fibers
- Modern humans have a significant reduction in gut size: a reduced need to digest fiber rich food and greater reliance on eating meat
- More meat and fire use so less gut length needed
12
Q
Bone remains suggest meat eating - line of evidence for Diet
A
Mammalian bones found in association with early H. habilis populations have cut marks and other evidence of butchery (use of tools) suggesting the consumption of meat
13
Q
Anemia caused by lack of meat consumption - line of evidence for Diet
A
- Shards of the skull of a 2 year old child were found in Olduvai Gorge in Tanzania
- Possibly early homo habilis
- The remains suggest the infant suffered from a form of malnutrition seen in meat poor diets = meat deficient anemia
- The remains are dated 1.5 mya
- The bones have porotic hyperostosis, a disease that typically results from a lack of vitamins B12 in the diet
o Macrocytic anemia
14
Q
Hosteoporosis symmetrica
A
- Hosteoporosis symetrica is a pathological condition that affects bones of the cranial vault, and is characterized by localized areas of increased spongy or porous bone tissue
- Is a result from the enlargement of hematopoietic marrow as a result of micronutrient deficiency anemia
15
Q
Hematopoiesis
A
- All blood cells are descended from a single precursor cell called pluripotent hematopoietic stem cell
- In adults pluripotent hematopoietic stem cells are found primarily in red bone marrow
16
Q
Hemoglobin in RBCs
A
- Main function: transport O2 from lungs to tissues & CO2 from tissues to lungs
- Tetrameric structure is made of: 4 hemes (prosthetic group) and 4 globin (protein)
- Hemoglobin production requires various factors: iron (binds O2 in body), PLP (vit B6), zinc, nucleotides for proteins
17
Q
Anemia
- cause
- symtpoms of severe anemia
- abnomalities in erythrocyte production
- 2 types
A
- Cause: deficiency of RBC or hemoglobin or lack of things needed to make RBC or hemoglobin
- Symptoms of severe anemia: fainting, chest pain, angina, heart attack
- Abnormalities in the production of erythrocytes can be caused by:
1. Insufficient cofactors (nutrient deficiency): vitamin B12, folate, iron
2. Genetic abnormalities: congenital hemoglobinopathies (all heme disfunction in general), congenital membranopathies (shape of RBC), congenital thalassemia’s (quantity of globin produced) - 2 main types of anemia
1. Increased destruction of RBC (hemolysis)
2. underproduction of RBC
18
Q
2 main types of anemia
A
- Increased destruction of RBC (hemolysis): leads to more immature RBCs because trying to create more RBCs to compensate for increased destruction
- Underproduction of RBC: leads to less production of immature RBC because of overall underproduction and there are three types
o Microcytotic: MCV less than 80, less hemoglobin’s, iron/PLP/Zn deficiencies, thalassemia, microcytic anemia (small RBCs) caused by hemoglobin deficiency
o Normocytic: b/w 80 & 100 MCV, acute blood loss, bone marrow disorder
o Macrocytic: MCV over 100, characterized by nucleotide deficiency that causes macrocytic anemia (large RBC), B12 & folic acid deficiency
