Nutritional Anthropology 313

Why food is important?

humans developed complex ideologies about food… cooking culture, think about why food is important

Biocultural approach to food and nutrition

food that people eat is rooted in their culture, biology + culture… food adaptations

Nutritional Anthropology

concerned with understanding the relationships of biological and social forces in shaping human food use and nutritional status

Qualitative

descriptive, WHY

Quantitative

typically numbers (QUANT.), WHAT

Evolution

change, adaptation, etc. throughout generations

Natural selection

process where populations adapt and change

Cardiovascular system

refers to the heart, blood vessels, blood

How does the cardiovascular system connect to nutrition?

distributes nutrients absorbed from food (and oxygen from your lungs) to all body cells and tissues

• portal circulation

  • water and nutrients absorbed through the stomach or intestinal wall

  • enter intestinal capillaries into the veins and then the portal vein

  • transferred to the liver for processing and then released to general circulation

Lymphatic system

network of tissues and organs that help rid the body of toxins, waste, and other unwanted materials

How does the lymphatic system connect to nutrition?

• serve the small intestine

• pick up and transport most products of lipids (fats and oils) digestion and absorption

Nervous system

a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body and spinal cord to various parts of the body

How does the nervous system connect to nutrition?

exerts a profound influence on all digestive processes, namely motility, ion transport associated with secretion and absorption, and gastrointestinal blood flow

Endocrine system

system that controls the release of hormones that the body uses for a wide range of functions

How does the endocrine system connect to nutrition?

controls the release of hormones and enzymes required for digestion of food in digestive tract

Thyroid Hormones

aids in the control of the body’s rate of metabolism

Gastrin

acts to stimulate the production of digestive enzymes in the stomach

Insulin

helps regulate the amount of glucose in the blood

Immune system

many types of body cells and body components that work in cooperation to prevent or limit infection

How does the immune system connect to nutrition?

• influences the body’s ability to absorb nutrients and regulates the amount of “free” nutrients in the circulatory system (Innate (Nonspecific) Immunity)

Digestive system

consists of the GI tract plus some accessory organs

How does the digestive system connect to nutrition?

digestion involves the breakdown of food until it can be absorbed and assimilated into the body

3 stages of digestion

CGI

1. Cephalic

2. Gastric

3. Intestinal

Cephalic stage

• begins with gastric secretions in response to the sight and smell of food

• mechanical breakdown (CHEWING)

• chemical breakdown (DIGESTIVE ENZYMES)

• takes place in the mouth

1st stage

Gastric stage

breaks down food even further by mixing it with gastric acid until it passes into the duodenum, the 1st part of the small intestine; 2nd stage

Intestinal stage

when partially digested food is mixed with several enzymes produced by the pancreas to break down food before excretion (TAKING IN LAST OF THE NUTRIENTS BEFORE EXCRETION); 3rd stage

Omnivore

“all-devouring”

• organism’s physiologic capacity to both consume meat and plant foods equally

Omnivore’s dilemma

when you can eat anything, deciding what to eat would stir anxiety

• social class (fast food… good or bad?)

• availability

• environment (what’s available…)

• taste

Rules about food (Dietary Taboos)

• think about guinea pigs, cultural ideologies (religion, etc.)

• origins of prohibition —> human symbolic systems

Nutritional classification

• experimental science began looking at chemical explanations of food

• becoming reducible to chemical compounds and calories

Calorie classification

MACROS:

• protein

• carbohydrates

• lipids

Non-calorie classification

MICROS:

• water

• minerals

• vitamins

Classes of nutrients

• protein

• carbohydrates

• fat

• minerals

• water

• vitamins

Vitamins

essential organic substances needed in small amounts in the diet for normal function, growth, and maintenance of the body

• yield NO energy but participate in energy-yielding reactions

• considered essential because humans can’t synthesise them or their synthesis is decreased by environmental factors

5 requirements of minerals

1. naturally occurring

2. inorganic

3. solids

4. a definite chemical composition

5. an ordered internal structure

Major mineral

greater than 100 mg per day

Trace mineral

less than 100 mg per day

Bioavailability

degree to which an ingested nutrient is absorbed and is made available to the body

Carbohydrates

• main energy source for cells in the brain, nervous system, and red blood cells

• are readily available fuel for all cells, both in the form of blood glucose and glycogen

• stored in the liver and muscles

Carbohydrates are important for:

1. yielding energy

2. sparing protein from use as an energy source

3. regulating glucose

4. healthy gut

Monosaccharides

ONE, simple sugar units and serve as basis unit for all carbs

Glucose (dextrose)

• most common type of simple carbohydrate

• generally other carbs are eventually converted to glucose

Fructose

“fruit sugar”

Galactose

usually bonded to lactose (a sugar found in milk and other dairy products)

Disaccharides

formed when 2 monosaccharides combine

Sucrose

found naturally in sugar cane, honey, and maple sugar

Lactose

major source is milk products

Maltose

most of the starches we digest are converted to — in the small intestine

Polysaccharides

a carbohydrate (starch or glycogen) whose molecules consist of several sugar molecules bonded together

Amylose

comprises ~20% of digestible starch in human diet

Amylopectin

makes up ~80% of the digestible starch in the human diet

Glycogen

how animals (including humans) store glucose

Fats

solid at room temperature

Oils

liquid at room temperature

What are lipids important for?

1. providing energy

2. storing energy

3. insulating and protecting the body

4. transporting fat-soluble vitamins

Fatty acids

• consists of a straight chain of an even number of carbon atoms, with hydrogen atoms along the length of the chain with a carboxyl group (—COOH) at the end

• transported in the bloodstream as fatty acids attached to proteins

Triglycerides

lipids in foods are mostly in the form of ——

Glycerol

serves as the backbone for the 2 attached fatty acids

Phospholipids

2 fatty acid chains and a phosphorus-containing group are attached to the glycerol backbone

Sterols

4 interlocking hydrocarbon rings from a steroid

Protein

major part of lean body tissue

• ~17% of your body weight is protein

can be broken down to provide energy

What are proteins important for?

1. producing vital body structures

2. maintaining fluid balance

3. contributing to acid-base balance

4. forming hormones and enzymes

5. contributing to immune function

6. forming glucose

7. providing energy

8. contributing to satiety (satisfying appetite)

Amino acids

• building blocks of protein

• mostly carbon, hydrogen oxygen, nitrogen

What are the building blocks of protein?

amino acids

Each amino acid has:

1. a carboxyl group

2. an amino group

3. an R group specific to that amino acid

Peptide bonds

amino acids linked together by chemical bonds —> form proteins

What amino acid bonds form protein?

peptide bonds

Nutritional status

the current body status of a person, or a population related to their state of nourishment (the consumption and utilization of nutrients)

Desirable nutrition

when body tissues have enough of the nutrient to support metabolic function as well as surplus stores than can be used in time of need

Types of malnutrition

1. undernutrition

2. overnutrition

Undernutrition

when nutrient intake does not meet nutrient needs

Overnutrition

prolonged consumption of more nutrients than the body needs

Nutritional assessment is assessed by 2 methods

1. indirect

2. direct

What is the purpose of nutritional assessment?

1. identify people or populations at risk of being malnourished or who are malnourished

2. to develop health care programs that meet community needs which are defined by the assessment

3. to measure the effectiveness of nutritional programs and interventions once initiated

Indirect method

use indices that reflect community nutritional needs and status

• investigating and assessing the wide variety of factors that contribute to a person’s, household’s, or community’s nutritional status

Direct method

deal with the individual and measures specific criteria

4 direct methods

ABCD

1. anthropometric

2. biochemical

3. clinical

4. dietary

Types of dietary assessment

1. 24-hour dietary recall

2. food frequency questionnaire

3. food record (diary)

Food frequency questionnaire

• to obtain frequency and, in some cases, portion size information about food and beverage consumption over a specified period of time, typically the past month or year

• a finite list of foods and beverages (How often do you eat rice?)

• diet history

24-hour dietary recall

• to obtain detailed information about all foods and beverages consumed on a given day

Food record (diary)

• to obtain detailed information about all foods and beverages consumed over a period of one or more days

• self-reported account of all foods

Anthropometric assessment

the measurement of the body — typically height, weight, and various proportion measurements

What are the common measurements of anthropometric assessment?

• height, weight

• arm, waist, hip circumference

• skinfold thickness

Biochemical assessment

lab tests based on blood and urine can be important indicators of nutritional status

• measurement of individual nutrients in body fluids is most common along with hair, skin, nails

What are the common measurements for clinical assessment?

• blood spots or blood serum for hemoglobin or blood sugar

• stool examination for the presence of intestinal parasites

• urine dipstick and microscopy for nitrogen, sugar, and blood

Clinical assessment

simplest and most practical method of ascertaining the nutritional status of a person or group

Protein Calorie Malnutrition (PCM)

a condition from regularly consuming insufficient amounts of calories and protein

Kwashiorkor

a disease occurring primarily in young children who have an existing disease and consume a marginal number of calories and insufficient protein in relation to needs

• rounded stomachs

Marasmus

a disease resulting from consuming a grossly insufficient amount of protein and calories

Scurvy

a condition caused by a severe lack of vitamin C in the diet

Osteomalacia (rickets)

the softening and weakening of bones in children, usually because of an extreme and prolonged vitamin D deficiency

Adaptation

a change or process of change by which an organism or species becomes better suited to its environment

Intestinal microbiome

the microorganisms including bacteria, archaea, and fungi that live in the digestive tracts

What is the intestinal microbiome important for?

1. digestion of food and extraction of nutrients

2. modifying the host immune response

3. protecting against infection

4. regulating host metabolism

What are the key characteristics of a “healthy” gut?

1. richness

2. diversity

3. resilience

Richness

the total number of bacterial species in your gut microbiome

Diversity

the number of individual bacteria from each of the bacterial species present in your gut microbiome

Resilience

determines whether a particular change will permanently shift its table state or whether it will return to its initial homeostatic state following a disturbance

Ecological plasticity

ecology plays a dominant role in shaping the gut microbiome

Biological mismatch

concept that a previously advantageous trait may become maladaptive due to change in the environment