major functions of water in the body
- carries nutrients and waste products throughout the body
- maintains the structure of large molecules such as proteins and glycogen
- participates in metabolic reactions
- serves as the solvent for minerals, vitamins, amino acids, glucose, and many other small molecules so that they can participate in metabolic activities
- acts as a lubricant and cushions joints and inside the eyes, the spinal cord, and, in pregnancy, the amniotic sac surrounding the fetus in the womb
- aids in the regulation of normal body temperature, as the evaporation of sweat from the skin removes excess heat from the body
- maintains blood volume
water balance
- the accounting of water inflows, outflows, and storage changes within a system over time
major water sources (water in)
- fluids (2000 ml - 8 cups)
- water content in food (500 ml - 2 cups)
- water produced from metabolism (300 ml - 1.25 cups)
beverages (550 - 1500 mL)
foods (700 - 1000 mL)
metabolism (200 - 300 mL)
total: 1450 - 2800 mL
body's major routes of water loss (water out)
insensible losses
- skin perspiration (750 ml - 3 cups)
- lung respiration (300 ml - 1.25 cups)
- feces (100 ml - 0.4 cup)
sensible losses
- urine (1650 ml - 6.75 cups)
kidneys (urine) (500 - 1400 mL)
skin (sweat) (450 - 900 mL)
lungs (breath) (350 mL)
GI tract (feces) (150 mL)
total: 1450 - 2800
moderate alcohol consumption for men
- less than or equal to 2 drinks (per day)
moderate alcohol consumption for women
- less than or equal to one drink (per day)
one drink when referring to an alcoholic beverage
½ oz pure ethanol
- 5 oz of wine
- 10 oz of wine cooler
- 12 oz of beer
- 1 ½ oz of liquor (80 proof whisky, scotch, rum, or vodka)
several factors that affect the body's ability to metabolize alcohol
- rate of stomach emptying
- intake of certain drugs
- type of beverage consumed
rate of stomach emptying affect on alcohol metabolization
- alcohol needs no digestion, quickly absorbed across the walls of an empty stomach, reaching the brain within a few minutes
- when stomach is full of food – alcohol has less chance of touching the walls and diffusing through → influence on the brain is slightly delayed
- carbohydrate snacks slow alcohol absorption, high-fat snacks slow peristalsis, keeping alcohol in the stomach longer
alcohol metabolization: women vs men
- women produce less alcohol dehydrogenase enzyme in the stomach → more alcohol reaches the intestine for absorption into the blood stream
- absorb more alcohol than men of the same size drink, more likely to become intoxicated on alcohol than men
type of alcohol consumed, effect on alcohol metabolization
- certain drinks have higher alcohol content than others
- different beverages influence gastric emptying and absorption rate
- carbonated drinks increase gastric pressure, speed gastric emptying (higher and earlier peak BAC)
- higher alcohol content / hard alcohol (higher concentration of ethanol, slower initial absorption but progresses quickly once in small intestine)
- diluted alcohol (reducing gastric irritation, speed up gastric emptying) – faster absorption than undiluted spirits
- sugary drinks – can slow the absorption of alcohol
potential health benefits associated with moderate consumption
- reduces blood clotting
- increases HDL
- reduces inflammation (CRP)
- improved insulin sensitivity
- lower dementia / Alzheimer's disease risk
polyphenols
- red wine, dark beer
- antioxidant effect
detrimental effects of alcohol when consumed in excess
- dehydration, loss of important minerals
- malnutrition (diet quality declines as alcohol consumption increases)
- displacing other important nutrients
- arthritis
- bone loss
- cancer
- fetal alcohol syndrome
- heart disease
- hyperglycemia
- hypoglycemia
- infertility
- kidney disease
- liver disease
- lung disease
- nerve disorders
- obesity
- psychological disturbances (depression, anxiety, insomnia)
MEOS (Microsomal Ethanol-Oxidizing System)
- enzyme system that metabolizes both alcohol and several other types of drugs
- handles about ⅕ of the total alcohol a person consumes
- high blood concentrations, repeated exposures to alcohol – alcohol stimulates synthesis of enzymes in the MEOS
- results in more efficient alcohol metabolism and tolerance to its effects
- drinking and using drugs at the same time – alcohol is prioritized for metabolism, drug more slowly (drug effect builds up, greatly amplified result)
Cirrhosis
- advanced liver disease in which liver cells turn orange, die, and harden, permanently losing their function (often associated with alcoholism)
- fatty infiltration of the liver (most advanced stage)
- 2nd leading cause for liver transplant
- 50% chance of death within four years
Wernicke-Korsakoff Syndrome
- a neurological disorder typically associated with chronic alcoholism and caused by a deficiency of the B vitamin thiamin (also called alcohol-related dementia)
- syndrome characterized by paralysis of eye muscles, poor muscle coordination, impaired memory, and damaged nerves
macronutrients
- required in gram quantities
- structure - polymer
- some are essential
- provide calories
carbs, lipids, protein
micronutrients
- required in mg quantities
- structure - individual molecule
- all are essential
- provide no calories
vitamins and minerals
fat-soluble vitamins
dissolve in fat or organic solvents
- vitamin A
- vitamin D
- vitamin E
- vitamin K
how solubility affects absorption: fat-soluble vitamins
- must first enter the lymph and then enter the blood
how solubility affects transport: fat-soluble vitamins
- require transport proteins to move around
how solubility affects storage: fat-soluble vitamins
- held in fatty tissues and the liver until needed
how solubility affects excretion: fat-soluble vitamins
- remain in fat storage sites in the body rather than being excreted
- more likely to reach toxic levels when consumed in excess
water-soluble vitamins
dissolve in water
- found in the watery compartments of food
- B vitamins
- vitamin C