Nutrients Flashcards
What is a nutrient and what are the 6 main groups of nutrients
a substance/chemical that is essential for life and reproduction
6 main groups:
- carbohydrate
- lipids
- protein
- vitamins
- minerals
- water
What are essential nutrients
these are nutrients that are not produced by the body and needs to be obtained from an external source (food) this is because:
1. organism cannot synthesise
2. organism can produce but not in sufficient quantities
what are the 4 most common micronutrient deficiencies
iron
iodine
vitamin A
zinc
what are the 8 micronutrients which are essential for crops and what are the effects of deficiency
boron
chlorine
copper
iron
manganese
molybdenum
nickel
zinc
deficiency of one or more of these affects both yield and quality of crops
What is the link between deficient crops and human deficiencies of nutrients
low trace elements in stable grains of essential nutrients for humans can lead to deficiency
What are the 2 groups of nutrients
Macronutrients
- large quantities needed (10-100g) per day
- carbohydrates, proteins and lipids
micronutrients
- minute quantities (micro/milligrams)
- vitamins, minerals and trace elements
what are catabolic and anabolic molecules and what is the link between the two
catabolic
- metabolic pathways that break down molecules into smaller units
- carbohydrates, lipids and proteins
anabolic:
- chemical reactions that synthesise molecules out of broken down ones
link:
- recycling of complex molecules
- both are balanced to help the body function
What are the 2 forms that carbohydrates are present in
simple carbohydrates:
- glucose
- fructose
- other sugars
compound carbohydrates:
- starch in plants
- glycogen in animals in the muscle and liver (polymers of glucose)
- metabolised to CO2 + H2O + energy
What is the structure of glycogen
branched biopolymer
- linear chains of glucose residues
- chains branching off every 10 glucoses
What is the structure of starch and what foods can are high in starch
structure
- large number of glucose units joined by glycosidic bonds
foods:
- potatoes
- wheat
- maize (corn)
- rice
What are the function of proteins to the body and what are they made from
proteins build body parts they are essential for:
- growth
- repair of worn-out tissues
- resistance against infections
made from amino acids
what are the 9 essential amino acids
histidine
isoleucine
leucine
lysine
methionine
phenylalanine
threonine
tryptophan
valine
all required from diet
proteins are found in the in animal and plant foods what is the difference between the two
animal proteins:
- complete proteins as they contain all amino acids
plant proteins:
- incomplete proteins as some are low in methionine, lysine and tryptophan
- there needs to be supplemented with grains, nuts, seeds and legumes
Lipids chemical properties, examples and what are they essential for
chemical property
- water insoluble (hydrophobic)
example:
- triglycerides
- phospholipids
- sterols (cholesterol)
essential for:
- brain
- nerves
- hormones
- absorption, transport and storage of fat soluble vitamins (A,D,E and K)
Triglycerides can be a fat or an oil depending on the bonds it has fats have what type of bonds?
saturated or monounsaturated (saturated = single bonds, unsaturated = contain at least 1 double or triple bond)
solidifies easy = solid at room temp
found in land animal sources
Triglycerides can be a fat or an oil depending on the bonds it has. Oils have what type of bonds?
polyunsaturated fatty acids (multiple double or triple bonds)
harder to solidify therefore liquid at room temperature
triglycerides as oils at room temp can be found in what sources
aquatic animals
- polyunsaturated fatty acids and their lipids
plant sources:
- mustard oil
- soybean oil
- sunflower oil
- corn oil
however:
- coconut and palm oil contain large portions of saturated and monounsaturated fatty acids therefore are solid at room temperature
what are the 2 groups of micronutrients
vitamins and minerals
Why are vitamins needed
cannot be synthesised in the body and are essential for metabolism and utilisation of carbohydrates, proteins and lipids
they also function as coenzymes
Which vitamins are water soluble and which are fat soluble
water soluble
- B complex vitamins (B1, B2)
- vitamin C
lipid soluble
- A
- D
- E
- K
What is the chemical names for Vitamin A
There are 3 forms of Vitamin A :
- retinols
- beta-carotenes
- carotenoids
What is Vitamin A needed for?
skin, hair, eyes (healthy vision), increases resistance to infection ( used in T cell differentiation)
Vitamin A deficiency can cause:
xerosis cutis (dry skin)
- retinoic acid needed for a growth factor for epithelial cells and control gene transcription
low resistance to infection
eye disorders (vit A deficiency is the leading cause of preventable childhood blindness
What are the different eye disorders which Vit A deficiency cause
xerophthalmia (loss of tears)
- loss of goblet cells in conjunctiva
- no mucus therefore debris accumulates in the eye forming Bitot’s spots due to dryness
keratomalacia
- atrophy of the corneal epithelial cells
- opaque cornea and blindness
night blindness
- retinal (Vit A) and opsin form rhodopsin in retina
- rhodopsin is a pigment for low light detection
Vitamin A toxicity (consumption of too much Vitamin A can be described from the case study of Douglas Mawson exploring the Antarctic with Mertz and Ninnis. How did vitamin A toxicity occur in this case study?
- Ninnis fell through a crevasse with sled and food
- forcing Mertz and Mawson to feed on their sled dogs for 10 days
- Husky’s liver contain extremely high levels of Vitamin A (100g is toxic to humans)
causing liver damage to Mertz and Mawson - between them they consumed 6kg
Vitamin A toxicity (consumption of too much Vitamin A can be described from the case study of Douglas Mawson exploring the Antarctic with Mertz and Ninnis. What were the symptoms they faced and why did Mertz suffer more?
symptoms:
- dizziness, nausea, abdominal pain, mucosal fissuring, skin/hair/nail loss, yellowing of the eyes/skin
- irrationality
mertz suffered more due to finding muscle tissue tough and difficult to eat therefore at more of the liver and softer tissues
- lost the will to move and went mad
- he died before making it to the base
Vitamin A toxicity (consumption of too much Vitamin A can be described from the case study of Douglas Mawson exploring the Antarctic with Mertz and Ninnis. What is the name for vitamin A toxicity and what does it affect?
Hypervitaminosis A
- increases bone resorption: bone fractures
- affects metabolism of other fat soluble vitamins (D, E and K)
- can disrupt mito function
What is the chemical name for Vitamin B1, where is it mostly found what is it essential for?
thiamine, found especially in the liver
essential for tissues with high oxidative metabolism (nervous system and heart)
involved in metabolism of acetyl CoA in mito
- when phosphorylated thiamine turns into its active form (thiamin pyrophosphate TPP)
- involved in turning pyruvate into acetyl CoA and in krebs cycle
B1 deficiency is caused by diets high in what food and what does it cause?
diets of mostly white rice and alcohols
- alcoholics have poor diet due to carbs coming from alcohol
causes:
- depression
- poor appetite
- skin problems
long term causes beriberi
What are the two types of beriberi and their symptoms
- dry beriberi ( neurological degeneration)
- numbness and confusion - wet beriberi (cardiovascular disease)
- tachycardia, cardiomegaly and congestive heart failure
other symptoms:
- muscular wasting and edema
Which food are rich in Vitamin B1
seeds
nuts
legumes
bread
meat
What is the chemical name for Vitamin B3 and what foods is it found in
chemical name:
- niacin and nicotinic acid
foods:
- meats
- seeds
- cereals
- vegemite
What is the role of Vit B3 and the end product which can be used by the body
converts carbohydrates into glucose for energy production
pathway to end product:
Niacin → nicotinamide → nicotinamide adenine dinucleotide (NAD) and NADP
What is the function of the end product of Vit b3
NAD and NADP are co-factors in enzymatic reactions (catabolism) required for ATP production
What is the function of Vit B3 in relation to cholesterol
B3 raises HDL cholesterol levels
- HDL are good cholesterols which take LDL’s to liver to be excreted
Protect against cardiovascular disease by lowering blood lipids
What can Vitamin B3 deficiency cause
- pellagra
- light sensitivity
- skin lesions (starts looking like sunburn but them blackens and peels over time)
- confusion and aggression
- ataxia
- dilated cardiomyopathy
- death
What are the symptoms of Pellagra
- inflamed skin (dermatitis)
- diarrhoea
- dementia
What is the chemical name of vitamin B12
cobalamin
What foods are a source of vitamin B12
- fish
- soy beans
- fortified cereals
- shellfish
- eggs
- red meat
- poultry
- liver
- crustaceans
- cheese
- dairy
- tofu
Is vitamin B12 water or fat soluble
water soluble
What is the 3 functions of vitamin b12
- cofactor in DNA synthesis and fatty acid and amino acid metabolism
- normal functioning of nervous system
- has a role in the synthesis of myelin
- maturation of developing red blood cells in the bone marrow
What does deficiency of vitamin B12 from diet cause
pernicious anemia (reduced number of red blood cells)
- DNA synthesis is inhibited due to lack of vitamin B12
causes:
- tiredness
- neurological and heart problems
What can cause the malabsorption of Vitamin B12 leading to deficiency
- atrophic gastritis
- thinning of stomach lining
- conditions that affects the small intestine
- crohn’s disease, celiac disease, bacterial growth, parasites
- immune system disorders
- Graves disease or Lupus
What is the molecular basis of pernicious anaemia
- intrinsic factor released by parietal cells which binds to vitamin B12 to be absorbed in the gut
- with no intrinsic factor no vitamin B12 can be absorbed
Lack of intrinsic factor is caused by antibodies against:
1. intrinsic factor itself inhibiting the binding to vitamin B12
2. H+/K+ ATPase in parietal cell in plasma membrane (destructs cell therefore no intrinsic factor is released)
What is the chemical name for Vitamin C
Ascorbic acid
What is the function of Vitamin C
- growth and repair of tissues
- collagen production
- prevents auto-inactivation of lysyl and prolyl hydroxylase (2 enzymes in collagen biosynthesis)
- antioxidant
What is the best source of vitamin C
Citrus fruits
What does vitamin C deficiency
Scurvy (ECM disease)
- bleeding gums
- bruising
- low infection resistance
- changes in personality
- lack of ability to heal wounds
What is the chemical name for Vitamin D and is it fat or water soluble
Calciferol
fat soluble
What does vitamin D act as
a hormone
What is the function of vitamin D
stimulates Ca2+ and PO4(3-) absorption in intestine
How can Vitamin D be synthesised from sunlight
cholesterol derivatives in skin when exposed to sunlight can synthesise pre vit D
however must be activated in the liver and kidneys by hydroxylation to vitamin D first before the body can use
What are good food sources for vitamin D
- eggs
- salmon
- cheese
- sunlight
- shiitake mushroom
- fortified foods
What is the pathway of vitamin D from synthesis to function
1.a. precursor in skin (7-dehydrocholesterol) exposed to sunlight forms vitamin D3
1.b. dietary vitamin D becomes vitamin D3 when ingested
- both go through to liver when enzymatically a hydroxyl group is added forming 25-OH-vitamin D3
- goes to kidney where another hydroxyl group is added forming 1,25-OH2-vitamin D3 (active vitamin D)
- Travels to intestine to promote Ca2+ and PO4(3-) absorption
What does vitamin D deficiency cause
- rickets (in still developing children)
- delayed growth
- bowed legs
- weakness and pain in spine, pelvis and legs - Brittle bones
- bone tenderness and susceptibility to fractures - Hypocalcemia
- low blood calcium levels
- causes muscle spasms - dental problems
What is the chemical name for Vitamin E and is it water or fat soluble
tocopherol or tocotrienols
fat soluble
Vitamin E is an ….
antioxidant
What are good food sources for Vitamin E
-sunflow, corn and soybean oil
- margarine
As Vitamin E is an antioxidant what is its role in the body
scavenges free radicals in membranes and are able to donate a hydrogen
tocotrienols also function to protect neurons from damage via antioxidant
How is vitamin E deficiency caused if it is only required in really low levels
caused by abnormalities in dietary fat absorption
What symptoms does vitamin E deficiency cause
- neurological problems
- neuromuscular problems
- anaemia (due to oxidative damage of red blood cells)
- muscle and heart problems
- nose bleeds
- skin infections
What is the chemical name for vitamin K and is it fat or water soluble
Phytonadione
fat soluble
What are good food sources of Vitamin K
Green leafy vegetables
- spinach
- kale
- lettuce
whole wheat products
animal foods
- meat
- fish
- eggs
Oils
- olive
- canola
- soybean
What is the role of Vitamin K in the body
- needed for complete synthesis of prerequisite proteins for blood coagulation
- controlling the binding of calcium in bones and other tissues
- modification of proteins allows for the binding of calcium ions
What are the symptoms of Vitamin K deficiency
uncontrolled bleeding
- bruising, gum bleeding, nose bleeding
stomach pains
weakened bones (osteoporosis)
calcification of arteries and other soft tissues
broad purpura (bleeding under skin)
