NUSCTX 10, Midterm 3 - UC Berkeley

What is a Healthful Body Weight?

Weight that is appropriate for your age and physical development

Weight that you can achieve and sustain without severely curtailing your food intake or constantly dieting

Weight that is based on your genetic background and family history of body shape and weight

Weight that promotes good eating habits and allows you to participate in regular physical activity

Weight that is acceptable to you

High-Fat, Low-Carbohydrate, High-Protein Diets

Types of diets that generally contain about 55% to 65% of total energy intake as fat, less than 100g of carbohydrate per day, with the balance of daily energy intake as protein

Moderate-Fat, High-Carbohydrate, High-Protein Diets

Types of diets that are balanced in nutrients which typically contain 20% to 30% of total energy intake as fat, 55% to 60% of total energy intake as carbohydrate, and 15% to 20% of energy intake as protein.

Low-Fat and Very-Low Fat Diet

Types of diets that contain 11% to 19% of total energy as fat, whereas very-low fat diets contain less than 10% of total energy as fat.

Muscle Energy Systems

Power

Speed

Endurance

Power

ATP

Anaerobic

Immediate Energy Sources

Speed

Glucose

Anaerobic

Glycogenolytic and Glycolytic Energy Sources

Endurance

Aerobic

Oxidative phosphorylation

Measuring Metabolism in vivo

Indirect Calorimetry

Biopsies

Arterial-Venous differences and tissue blood flow

Isotope Tracers

Glycolysis

The dissolution of sugar

Key to the non-oxidative and oxidative metabolism of glucose

Anaerobic pathway

Crossover Concept

30-60%

As % of VO2 max increases energy used from fat decreases and energy used from carbohydrates increases.

VO2

Maximum oxygen consumpton

Maximal Oxygen Consumption

Integrated functions of skeletal muscles

Lungs

Blood

Heart

Circulation

Endocrines

Brain

Autonomic nervous system

AMDR

Carbs: 45-65% of energy

Fat: 20-35%

Protein: 10-35%

n-6 PUFAs: 5-10:

n-3 PUFAs: 0.6-1.2%

EER

50% x BMR

Basal Metabolic Rate

Energy to maintain life processes.

Factors that affect it include: age, growth, height, % lean tissue, fasting, starvation, malnutrition, fever, hormones, and sleep.

70% of total energy use by body depends on lean body mass

Alcohol

Depressant

Goes to Acetyl Coa

Ethanol

A small two carbon alcohol

Absorbed into bloodstream

It's small size and alcoholic hydroxly group is soluble in both aqueous and lipid environments.

Can freely pass from bodily fluids into cells

Ethanol Oxidation

Alcohol Dehydrogenase

Microsomal Ethanol Oxidizing System

Alcohol Dehydrogenase

The most significant pathway responsible for the bulk of ethanol metabolism.

Microsomal Ethanol Oxidizing System

The second major pathway for ethanol metabolism.

Lipogenesis

Making fat from nonfat substances

Mostly occurs in liver cells

If excess calories are consumed, carbohydrates can be converted to fatty acids

Alcohol Breakdown

The major route of alcohol breakdown produces acetaldehyde, creates free radicals, and increases oxidative stress in the tissues.

Dopamine

The primary neurotransmitter in the brain pathway that mediates motivation and reward

Alcoholic Cirrhosis

An irreversible condition in which fibrous scar tissue replaces normal liver tissue and interferes with liver function.

Alcohol and Malnutrition

Alcohol might replace more nutrient-dense energy sources

Alcohol intake > 30% of calories results in decrease in macronutrient consumption

Alcohol may interfere with nutrient absorption by causing GI tract inflammation

Alcohol may decrease absorption of Vitamin C

A Standard Drink

12 oz beer, alcoholic lemonade, alcoholic carbonated drink

10 oz wine cooler

5 oz wine

1.5 oz hard liquor

Fetal Alcohol Syndrome

Head circumference < 10th percentile

Intellectual development

Attention deficit disorder

Impaired motor skills

Hyperactivity

Neurosensory hearing loss

Problems with reasoning and judgement

Learning disabilities

Inability to appreciate consequences

Impaired visual/spatial skills

Memory problems

Delayed development

Attachment concerns

Moderate Alcohol Consumption

Antioxidant

Cardiovascular system

Increase in HDL cholesterol

Excessive Alcohol Consumption

Obesity

Malnutrition

Liver cirrhosis

Mucosal damage

Decreases absorption due to inflammation

Effects of Rising Levels of Alcohol on the Brain

Impairment of:

Judgement

Reasoning centers

Speech centers

Voluntary muscular control

Reflexes

Respiration and heart action

Functional Foods

Provide health benefits beyond basic nutrition

Phytochemical

Substances found in plants that have health-promoting properties

Responsible for the health-promoting properties afforded by a variety of natural functional foods

Zoochemicals

Health-promoting substance found in animal foods

Food Synergy Level

Level 5

Level 4

Level 3

Level 2

Level 1

Food Synergy Level: Level 5

Dietary pattern "Prudent diet", "Western diet", other combinations of food groups

Food Synergy Level: Level 4

Food groups, whole grain, dairy, fruit, vegetables, meat

Food Synergy Level: Level 3

Whole grain, whole wheat, brown rice, rolled oats

Food Synergy Level: Level 2

Whole wheat bran, germ, endosperm; extract of fat-soluble portion

Food Synergy Level: Level 1

Bran or single phytochemical, specific nutrients of phytochemicals

Caratenoids

Some converted to vitamin A

Provide antioxidant protection

Some decrease the risk of macular degeneration

Flavonoid

Have been proposed to inhibit inflammation

Make capillary blood vessels stronger

Block carcinogens

Slow the growth of cancer cells

Phytoestrogens

Mimic effect of estrogen

Induce cancer cell death

Slow the growth of cancer cells

Reduce blood cholesterol

May reduce risk of osteoporosis

Malnutrition - Too Much

Obesity

Toxicity

Competition with other nutrients

Malnutrition - Too little

Starvation

Deficiences

(i.e. iron, iodide, vitamin A)

Starvation - Energy

First energy store used:

Glycogen

Starvation - Effects

Decrease in insulin

Decrease in leptin

Decrease in thyroid hormones

Decrease in BMR (energy expenditure)

Metabolic Adaptions to Prolonged Fasting

Glycogen depletion, N losses

Fatty acid oxidation, ketosis

Brain adapts to use ketones

Endocrine Consequences of Starvation

Behavioral changes

Decreases:

Growth hormones

Thyroid hormones

Reproductive hormones

Marasmus

i) The onset is earlier, usually in the first year of life

ii) Growth failure is more pronounced

iii) There is no edema

iv) Blood protein concentration is reduced less markedly

v) Skin changes are seen less frequently

vi) Liver not infiltrated with fat

vii) Recovery is much longer

Kwashiorkor

i) Onset is later, after the breast-feeding is stopped

ii) Growth failure not very pronounced

iii) Edema is present

iv) Blood protein concentration is reduced very much

v) Red boils and patches are classic symptoms

vi) Fatty liver is seen

vii) Recovery period is short

Kwashiorkor cont.

Frequently associated infections

Severe Vitamin A deficiency -> permanent blindness

Extreme protein deficiency

Disturbed water and electrolyte balance

Abnormal lipid transport: fatty infiltration of liver

Individual Nutrient Deficiencies

Iodine

Vitamin A

Iron

IND - Iodine

Developing world's most common cause of preventable brain damage

IND - Vitamin A

Leading cause of blindness

IND - Iron

Anemia, impairs development, work capacity, learning capacity, resistance to disease

Effects of Undernutrition During Pregnancy

Pregnant women's needs are higher

Affects fetal development

Fetus may deplete maternal nutrient stores

Results in death of woman and/or child

Effects of Undernutrition During Fetal and Infancy Stages

Poor growth and development

Pre-term delivery

Low birth weight

Premature death

Long-term health problems

Effects of Undernutrition During Childhood

Period of rapid growth rate, especially the brain and CNS

Often lead to permanent brain impairment

Stunted growth, impaired motor skills

Low resistance to infection

Effects of Undernutrition During Later Years

Require nutrient dense foods

Many with fixed income

Many forced to choose between medication or food

Low resistance to infection

General Effects of Semistarvation - Initial Stages

No visible clinical signs

May affect reproductive capacity

Weakened immune system

General Effects of Semistarvation - Consequences of Weight Loss

Fatigue, muscle soreness, irritability, hunger pains

Decrease in heart rate and muscle tone

Poor concentration and lack of ambition

Wasting

Loss of lean body tissue

Normal Response to Infection

Fever

Loss of appetite

Sleep, lethargy

Changes in trace elements, anemia

Failure of ketosis

Nitrogen loss

Results of Refeeding in Infection

Exclusively fat is gained; no lean body mass

Anabolic block

Results of Refeeding in Infection - Anabolic Block

Growth hormone

Testosterone, anabolic steroids

Resistance exercise

Combination therapies

Hunger

The physical feeling you experience when your body needs energy

Appetite

The desire to eat triggered by cravings, habits, the availability of food, other social and emotional factors

Brain and Gut

Send out neural and hormonal signals to one another

Food Intake - Cognitive Factors

Conscious control

Conditioning

Beliefs

Food Intake - Sensory Factors

Smell

Texture

Sight

Palatability

Concentration

Availability

Aversion

Food Intake - Satiety/Hunger Signals

Adipose

Gut hormones/nerves

Distension

Sensors

Food Intake - Brain Mechanisms

Signal sensory modulation

Reward and appetite

Peripheral Tissue Regulation of Hunger and Satiety

Signals go to the hypothalamus and originate from:

GI tract

Pancreas

Adipose tissue

Peripheral Tissue Regulation of Hunger and Satiety -GI Tract

Recent food intake

Peripheral Tissue Regulation of Hunger and Satiety - Pancreas

Energy reserves

Peripheral Tissue Regulation of Hunger and Satiety - Adipose Tissue

Energy reserves

Peripheral Tissue Signals

Nerves, circulating nutrients, hormones

Signals before and after food intake

Short Term Regulation of Food Intake

Gastric stretching

Circulating nutrient content

GI hormones

Short Term Regulation of Food Intake - Gastric Stretching

Stretch receptors

Short Term Regulation of Food Intake - Circulating Nutrient Content

Glucose

Amino acids

Fatty acids: weak

Short Term Regulation of Food Intake - GI Hormones

Ghrelin

CCK and Peptide YY

Ghrelin

Made in stomach, causes hunger, decreases after meal; levels high when body is in negative energy balance

CCK and Peptide YY

Made in small intestine, stimulated by presence of protein & fatty acids, signals brain to decrease food intake

Long Term Regulation of Food Intake

Signals energy reserves to brain

(e.g. insulin and leptin)

Leptin

Signals hypothalamus

Alters feeding behavior & hunger

Body temperature

Energy regulation

Product of ob gene

Deficiency of causes obesity

Fat Cells Adipose Tissue

Excess fat is stored in lipocytes, which expand in size until the fat is used for fuel

Low Insulin + Low Leptin

Signals to brain

Body has low glucose, low fat stores

Increase in food intake

Decrease in energy expenditure

High Insulin + High Leptin

Signals to brain

Body has high glucose, high fat stores

Decrease in food intake

Increase in energy expenditure

Regulation of Body Fat - Weight Loss

Decreased leptin->Hypothalamus->Increased energy intake and decreased energy expenditure

Regulation of Body Fat - Weight Gain

Increased leptin->Hypothalamus->Decreased energy intake and increased energy expenditure

Modulators of Food Intake

Cholecystokinin (CCK) -

Ghrelin +

Peptide YY (PYY) -

Leptin -

Neuropeptide Y (NPY) +

Cannabis +

Morphine -

Stress -

Portion Size Effect

One of the most powerful demonstrations of an external stimulus affecting human food intake

Neurochemical Systems Underlying Reward (food) in the Mammalian Brain

i.) A learning system that involves knowledge about the reward

ii.) A homeostatic "need" that is driven by a physiological regulatory system involved in energy balance

iii.) A hedonic "want" or "desire" system that is independent of physiological regulation, but that might drive the behavior toward the consumption of food just as strongly as the homeostatic one

Cholecystokinin

Hormone secreted in the duodenum

Responsible for the release of digestive enzymes and bile from pancreas and gallbladder

Hunger suppressant

Secretin

Hormone that inhibits the secretion of gastric acid from parietal cells of the stomach

Stimulates the production of bicarbonate

Disordered Eating

Variety of abnormal or atypical eating behaviors used to reduce weight

Eating Disorder

Psychiatric condition involving extreme body dissatisfaction and long term eating patterns harming the body

Binge Eating Disorder - Symptoms

Often overweight

A sense of lack of control during binging

Chaotic eating behaviors (eating too fast, too much, in private)

Negative self-esteem, poor body image

Often associated with depression, substance abuse, anxiety disorders

Binge Eating Disorder - Health Risks

Increased risk of overweight or obesity

Foods eaten during binging are often high in fat and sugar

Stress leads to psychological effects