HUNT141 Flashcards
Minerals and trace elements
essential, non-organic elements that dont provide energy, if absent in diet deficiency may appear
Sodium in diet
10% inherent, 15% discretionary, 75% processing.
AI for sodium
460-920mg/day required for the body
Sodium absorption
Well absorbed, not regulated, plasma levels controlled by kidneys.
Sodium function
Primary regulator of ECF volume, maintain acid-base balance, nerve impulse transmission, muscle contraction
Sodium secretion
> 90% sodium excreted in urine, sweat 10%
Sodium deficiency
Rare from diet however can be depletion from losses during disease state.
Sodium toxicity
- Acute illnesses are rare, whereas chronic illnesses more common.
Sodium and blood pressure
The kidneys capacity to excrete sodium declines with age.
- Globular filtration rate declines from age 30.
- Smaller increases in salt intake causes increased blood pressure
Hypertension
- High blood pressure can damage blood vessels increasing risk of heart disease and renal disease.
- Hypertension can be caused by: genetics, age, weight, smoking, exercise, stress, and diet.
DASH meaning
dietary approaches to stop hypertension
DASH 1 three diets
control (typical american diet), fruit and vegetable diet, fruit vegetble and low fat dairy products
DASH diet similarities
energy intake, protein and carbohydrates at similar levels (weight also constant)
DASH 1 outcomes
all three lead to a decrease
DASH 2
Clinical intervention trial which took 2 diet groups at 3 different levels of sodium (Low, medium, high)
DASH 2 diets
high fruit and vegetables, and low fat dairy
DASH 2 findings
no matter what sodium level the dash diet had the lowest blood pressure compared to the control diet, sodium content decreases therefore blood pressure decreases
Potassium foods
Fruit and vegetables
Potassium AI
2800 (f), 3800 (m
Functions of potassium
mportant in normal fluid and electrolyte balance, cell integrity, facilitates many reactions, nerve impulses, muscle contractions
Potassium absorption
passive diffusion, plasma levels are tightly controlled
Potassium excretion
Regulated primarily by kidneys, major route via urine however minor islost in faeces
Potassium deficiency
Rare from diet, depletion from losses and disease
Potassium toxicity
Rare from diet
Potassium and hypertension
inverse relationship as more potassium (higher intake of fruits and vegetables) leads to decrease risk of CVD
Hypertension - reductionist approach
single out nutrients based on pharmacological modelresulting in dietary supplements
Hypertension - holistic approach
changes in dietary patterns, looking at combinations of foods, nutrients and non-nurteints, difficult to define
Iron
4th most abundant element on earth, donates and accepts electrons readil
Iron - ferrous form
more soluble, reactive and bioavailable therefore used in supplements to treat iron deficiency
Functions of iron
haemoglobin, myoglobin, iron in enzymes, storage of iron (changes per person), transport iron
Iron in diet
different forms of iron including haem and non-haem
Iron RDI
8mg/day (M) 18mg/day (f)
Iron excretion
Not excreted
Factors affecting iron bioavailability
- Host-related factors
- Chemical form (haem vs non-haem Fe)
- Enhancers and inhibitors in meal.
Iron losses
menstruation and blood loss (blood noses), skin cells (epithelial, mucosa, urinary tract), bile
Iron - ham
Haem iron better absorbed however only present in animals (animals have both haem and non-haem while plants only have haem)
Iron absorption
5-35% of dietary iron is absorbed however the body acts as a buffer therefore can absorb more if body is low
Iron in bloodstream
Travels to liver, bone marrow and spleen
Hepicidin
Iron regulatory protein
ferroportin
controls flow of iron into plasma, iron exporter
Absorption of iron - Haem
broken down in cell to Fe2+
Absorption of iron - non-harm
broken into Fe3+ to Fe2+ then enters the cel
Absorption of iron - inside cell
cell secretes Fe2+ which then turns into Fe3+
factors affecting bioavailability of iron - host related factors
iron status, physiology, revent Fe intake, genes, disease
factors affecting bioavailability of iron - forms of iron
haem ion absorption (25-30%) vs non-haem absorption (5-15%)
factors affecting absorption of iron - enhancers
Meat fish protein factor (MFP) increases absorption, vitamin C keeps iron in Fe2+
factors affecting absorption of iron - Inhibitors
phytate, tannins, phenols, oxalic acid
Iron reutilisation
only 1-2mg iron absorbed a however making new RBC requires 20-25 mg iron/day therefore is reused
Iron deficiency - stage I
Deleted stores
Iron deficiency stage 2
IDE, no storage, decreasing RCB
Iron deficiency stage 3
iron deficiency anaemia, decrease in haemoglobin
Iron deficiency symptoms
decreased growth and cognition, fatigue, change in mood, increased hair loss
Causes of iron deficiency
combination of low intake and high requirements due to growth, blood loss and pregnancy
iron deficiency treatment
iron supplementation, changes in diet
Iron overload
- Acute iron toxicity
- Hereditary hemochromatosis.
- African iron overload.
- Other iron overload conditions.
zinc functions
- Important in biosynthesis nucleic acids, amino acids, proteins, hormones.
- Growth, immune function, vitamin A metabolism, reproduction, appetite.
Food sources of zinc
Dairy, meat, fish, poultry
Zinc RDI
14 mg/day (m), 8 mg/day (f)
Zinc absorption
15-35% of dietary zinc is absorbed, active transport at low or usual intake, passive diffusion at higher intakes
Enhancers of zinc absorption
dietary proteins, organic acids, vitamin C
inhibitors of zinc absorption
phytate, polyphenols, tannins, divalent metals (2+ charge) in high amounts usually via supplements
zinc regulation
tightly regulated both absorption and secretion involved
enterohepatic circulation of zinc
releases zinc into gut which is then reabsorbed
Zinc transporters
ZIP proteins (14), Zn T proteins (10)
Zinc deficiency
marginal zinc deficiency prevalent in some groups (toddlers, vegetarians, developing countries) due to low zinc in diet and high inhibitors
Zinc deficiency symptoms
growth retardation, hypogeusia, compromised immune function,hypogonadism, delayed sexual maturation, skin lesions, impaired wound healing, anorexia
Zinc deficiency recovery
rapid depletion however rapid recovery, individual responses vary
NZ soils low in
fluoride, selenium, iodine therefore our animals and crops have low levels
Strategies to increase dietary intakes of nutrients
fortification, supplementation, dietary diversification
Dietary diversification
adding different foods into narrow diets, increasing variation in a diet
Iodine function
adding different foods into narrow diets, increasing variation in a diet
Low iodine
Thyroid hormone cannot be made TSH increases to try make more TH causes stimulate growth of Thyroid (Goitre)
Dietary sources of iodine
Fish and seafood, iodised salt, eggs, milk, fortified bread
Iodine RDI
150 (m/f), 220 pregnancy
iodine absorption
100% absorbed, non regulated
Iodine excretion
90% in urine
Iodine storage
not stored however there is 3 months thyroid hormones stored
Iodophors
dairy industry used iodine to clean tanks therefore residual iodine contaminates dairy
reemergence of iodine deficiency due to
iodine disinfectant in dairy industry phased out, less salt, using rock salt (not iodised), processed foods and takeaways using non iodised salt
Iodine supplementation and cognitive ability
in children overall iodine supplements improved cognitive ability, no changes in adults
Increasing iodine in NZ - supplements
Pregnant and lactating women recommended to take iodine supplements
Iodine toxicity
thyrotoxicosis, excess thyroid hormone increasing hyperactivity leading to increased heart rate and dysfunction
Selenium dietary forms - organic
Se replaces sulfur in amino acids, selenomethionine, selenocysteine, all selenoproteins
Selenium dietary forms - inorganic
selenite, selenate
selenium functions
diverse number of enzymes and proteins, glutathione peroxidase, deiodinase for thyroid hormone (converts T4 to T3
glutathione peroxidase
prevent oxidative damage to phospholipids and cell membranes, antioxidant nutrient
Food sources of selenium
plant levels reflect soil content therefore NZ crops are low, grains (imported from australia), fruits and vegetables poor in sources, high in fish and organ meats
Absorption of selenium
80% absorbed, no regulation, organic through active transport while inorganic through passive transport
Excretion of selenium
50-60% of dietary selenium excreted in urine
Selenium deficiency
Keshan disease, cardiomyopathy in children and pregnant women
Toxicity of selenium
narrow window between having enough nad having too much, rare from diet however present in parts of china and venezuela from overdosing from selenised yeast supplement
Toxicity selenium symptoms
pallor, lassitude (lack of energy), irritability, indigestion and giddiness
Fluorine absorption
100% from diet
Fluoridation
addition of fluoride to water, decreases dental caries (0.7-1.0ppm)
Fluorosis
white specks on teeth due to high levels of fluoride
Dental caries
Carbs on teeth are broken down and fermented producing acid which breaksdown teeth
B vitamins (10)
B1 - thiamin
B2 - riboflavin
B3 - niacin
B5 - pantothenic acid
B6 - pyridoxine
B7 - biotin
B9 - folate
B12 - cobalamin
Thiamin deficiency
build up of pyruvate and lactate (vasodilators) as glucose isn’t converted to energy, causes heart failure, cerebral beriberi and psychosis (brain impacts)
Raboflavin deficiency symptoms
eneralised Vitamin B symptoms, inflamed eyelids, sensitivity to light, sore throat, cracks and redness at corners of mouth, painful smooth purplish red tongue
Niacin deficiency
Pellagra (diarrhoea, vomiting, death)
Pantothenic acid deficiency
rare
Biotin deficiency
rare
