Fluid and Water, Alcohol and Salt Flashcards
Name the 3 minerals/electrolytes in Salt
Sodium (Na)
Chlorine (Cl)
Potassium (K)
What form is the majority of dietary salt in?
Sodium Chloride - NaCl
Explain intake of Sodium (mg) Chloride (mg) and Sodium Chlorides (g) based on 1 mmol or 1g
1 mmol pf Sodium = 23mg
1 mmol of Chloride = 35.5 mg
Salt is NaCl in a ration of 1:1. The atomic mass of Salt is 23 + 35.5 = 58.5
1 g of Sodium = 2.5g of Salt
(58.5 / 23 = 2.54g)
Explain the physiological function of sodium in the body
Na + = Principle cation in extracellular fluid
Transporter - substrates, phosphates, amino acids, glucose and galactose
Excitability of muscle/nerve cells
Explain the physiological function of salt in the body
Maintaining acid-base equilibrium
Maintaining osmotic pressure
Control of body water balance metabolism is predominantly due to sodium
Explain sodium metabolism
Sodium concentration is tightly regulated by kidney excretion and retention
If sodium intake increases:
Water is retained and ECF volume rises, BP increases
‘Natriuretic’ factors increases sodium (and water) excretion
If Sodium intake falls:
Water is excreted and ECF volume falls, BP decreases
Vasoconstriction and other factors act to increase sodium and water retention
What is the RNI for sodium for adults 11+ years. How does this compare to children RNIs?
1.6g Sodium = 4g salt/day
In children, RNIs are lower to take account of lower body mass and kidney maturity
Explain why the DRV for salt is 6g/day
6g salt per day is estimated to reduce CVD risk by 10% and stroke by 13%
6g salt a day is higher than RNI
6g salt a day recommended by COMA and reaffirmed by SACN as an achievable popular goal, rather than an idea consumption level
Explain role of salt in health - salt produced by the body
Too little salt (uncommon) - caused by excess sweating may deplete salt but body soon adapts
Too much salt (very common)
Increases calcium excretion and may affect bone health
May directly stress a weekended heart
May aggravate kidney problems
raises blood pressure and may cause hypertension which is linked to increased CHD and stroke
What is the normal blood pressure level?
120/80mmHg
What blood pressure level is classed a hypertension?
Blood pressure greater than or equal to 140/90 mmHg
Explain some of the functions of salt in our food
Flavour
Texture
Spoilage
Explain what alcohol is functional and structure
One of the four macronutrients
Supplies energy
Considered a nutrient and drug
Ethanol - C2H5OH
Where does ethanol come from?
Fermentation of CHO by yeast
Naturally occurring process
C6H12O6 —> 2 C2H5OH + 2CO2
Explain absorption of alcohol
Rapidly absorbed (in blood <5 minutes)
Upper GI tract
Explain the process of metabolism for alcohol
Stomach ‘first pass’
Small proportion of total ingestion
1.8g/hour
Enzyme - stomach alcohol dehydrogenases (ADH)
Reduced in gastritis, H pylori infection, medication
Genetic differences in stomach ADH
Explain what ethanol and broken down into and the enzymes that do this
Ethanol to Acetaldehyde by the enzyme alcohol dehydrogenase
Acetaldehyde to acetate by the enzyme acetaldehyde dehydrogenase
Explain nutritional content of alcohol
Energy ~ 7 kcal/g
Metabolism requires thiamine (Vitamin B1)
Increased intake of alcohol require more thiamine
Body has limited thiamine reserves
Explain the impact on health on excessive alcohol intake
Liver damage, hepatitis and cirrhosis
GI tract damage, gastritis, pancreatitis
Cardiovascular disease, hypertension and stroke
Cancer e.g. mouth, oesophagus, breast, stomach
Brain damage, dementia, mental health, including depression
Obesity
Injuries following accidents, violence
Infertility, foetal alcohol syndrome
Explain the impacts on health to drinking alcohol
Increased HDL cholesterol
Increases insulin sensitivity
Decreases inflammation
Possible effects on those at risk of diabetes
Name the factors that affect alcohol consumption in the UK
Overall picture
Age
Gender
Income
Geographic location
What percent of Earth’s water is fresh?
2.53%
Explain how cholera spreads in water
Vibro cholerae - bacterium with flagellum
Lives in salt and fresh water
Only infects humans
Acute intestinal infection
1-5 day incubation period
Attaches to wall of gut and produces toxin
Gut wall produces diarrhoea
Dehydration
5-50% of cases results in death
Explain Cryptosporidiosis
Single celled parasite
Ubiquitous
Causes morbidity in healthy people, fatal to people with deficient immune system
Explain how water is treated in developed countries
Most methods of water treatment involve use of filtration at some stage to remove potentially harmful contaminants.
In developed countries, water treatment is carried out on a large scale.
In many developing countries that do not have the infrastructure in place to provide treated water the only practical method is to employ point-of-use treatments.
Why is fluid (water) important in our bodies?
Water makes up about 60-70% of body weight
Explain absorption and metabolism of water?
Digestion and absorption of water much quicker than food - liquids rapidly absorbed into the bloodstream.
Kidneys are continually producing urine, excess liquids are quickly eliminated via urine.
Water absorption can occur 5 minutesafter ingestion and peaks around 20 minutes after ingestion.
When water is drunk, it enters the stomach and quickly enters small intestine.
Nearly all water is absorbed into the bloodstream from small intestine.
Colon also absorbs some water.
Excess fluid absorbed in blood is filtered by kidneys, which produce urine that is transported to the bladder.
Explain excretion of water?
Urine: After the kidneys process water, much of it is excreted throughurine (1-2 l/day but can vary
Sweat: When body needs to control its temperature, water lost in form ofsweat. Usually 800-1000ml/day. In hot climate can be 500ml/hr but can be as high as 2500ml/hr
Stool:Contains a certain amount of water that helps make it heavy enough to exit the body
Lungs: Water vapour ~ 300ml/day. Increased in very dry air or if hyperventilating
Insensible losses = losses from skin and lungs. Make up about half of losses
Explain fluid requirements
Young infants: 150ml/kg
Toddlers: ~ 100ml/kg
Adult (18-60): 35 ml/kg
Adults (60 +) = 30ml/kg
Why do children have higher fluid requirements?
Body Composition
Higher surface to mass ratio
Increased respiratory and metabolic rate
Immature renal function
Decreased thirst sensitivity
Body cooling and heat tolerance
