D1 Flashcards
(28 cards)
What is a nutrient ?
chemical substance found in foods that is used in the human body
what are the six classes of nutrients?
Carbohydrates / proteins / lipids / vitamins / minerals / water
what is the difference between essential and non-essential nutrients ?
Essential nutrient: cannot be synthesised by the body (water, vitamins, dietary minerals, some fa and aa)
Non-Essential nutrient: can be made by the body or replaced by another nutrient (carbohydrates, other minerals, some fa and aa)
State examples of essential minerals
Calcium (Ca)
Magnesium (Mg)
Iron (Fe)
Phosphorus (P)
Sodium (Na)
Potassium (K)
Chlorine (Cl)
explain the importance of minerals in human development
- Major constituents in structures such as teeth and bones (Ca, P, Mg)
- Important components of body fluids (Na, K, Cl)
- Cofactors for specific enzymes or components of proteins and hormones (Fe, P, I)
Deficiency = illness/disorder
What are vitamins ?
Chemically diverse carbon compounds that cannot be synthesised by the body. Their functions can vary as cofactors, antioxidants, hormones, many are essential
WATER soluble vitamins: need to be constantly consumed as any excess is lost in urine (B, C)
FAT soluble vitamins: can be stored within the body (A, D, E, K)
What is ascorbic acid?
A form of vitamin C that is required in a range of metabolic activities in all animals and plants. It is produced by some mammals, but not others that need a dietary supply.
most common food sources: citrus fruits, orange juice
What are the functions of Vit C in mammals?
Potant antioxidant / Immune function / Synthesis of collagen / Synthesis of lipoproteins
What are the consequences of Vit C deficiency?
SCURVY
- Skin decoloration and bruising
- Haemorrhaging
- Anemia
- Dental issues
- Exhaustion / fatigue
- Swelling of joints (edema)
What is Vitamin D?
Naturally synthesized by the body in presence of the sun.
Involved in the absorption of calcium and phosphorus, contributing to bone mineralization.
May be stored in the liver when levels are low.
Darker skin = slower production
What are the consequences of Vitamin D deficiency?
- Calcium and Phosphorus are not absorbed
- Osteomalacia (bones soften)
- Rickets (bones deform)
- Elderly and certain ethnicities more affected
What are the symptoms linked to rickets?
- Bone fragility & fracturing
- Atrophy / muscle weakening
- Dental problems
- Growth retardation
- Enlargement of liver / spleen
- Skeletal deformities
What does “conditionally non-essential” mean?
can be produced by the body, but at rateslowerthan certain conditional requirements (e.g. during pregnancy or infancy)
What is “protein deficiency malnutrition”
A shortage of one or more essential amino acids in the diet will prevent the production of specific protein
What are the 2 (cis)-polyunsaturated essential fatty acids?
Alpha linolenic acid: omega 3 fatty acid
linolenic acid : omega 6 fatty acid
(humans lack the enzyme required to introduce double bonds at the required position of the carbon chain)
state the sources and functions of omega 3 and 6
Omega 3
Source: fish, vegetable oils, walnuts
Function: make hormones regulating blood clotting, part of cell membrane, movement of artery walls
Omega 6
Source: sunflower, poultry, eggs, avocado, nuts, whole grains
Function: reduce risk of heart disease and cancer, lowers cholesterol
what are the dangers of trans fats?
- easily absorbed by the body
- cannot be used = build up
- more risks of CHD
- increase harmful LCL cholesterol
- decrease useful HDL cholesterol
What is Phenylketonuria? (PKU)
autosomal recessive genetic condition - caused by a mutation in the gene encoding for enzyme phenylalanine hydroxylase PAH = impaired metabolism of amino acid phenylalanine
in healthy people, PAH converts excess phenylalanine into tyrosine
What are the symptoms and treatments of Phenylketonuria?
SYMPTOMS: excess phenylalanine instead converted to phenylpyruvate = toxic build up in blood and urine. Leads to brain damage & mental retardation
TREATMENTS: strict diet restricting phenylalanine, low protein diet, diet should be supplemented with medical formula containing essential amino acids
What can cause malnutrition?
deficiency, imbalance or excess nutrients in a diet
How is appetite controlled?
- by a center in the hypothalamus
–> hormones made in the pancreas, stomach, intestine, adipose tissue send messages to the appetite control center of the brain to inhibit or stimulate it
Which hormones trigger a hunger response?
Ghrelin (stomach) Glucagon (pancreas)
Which hormones trigger a satiety response?
Leptin (adipose tissue) CCK (intestine)
What are the causes and consequences of overweight or obesity?
CAUSES
Obesity = BMI > 30
Increased energy intake
Decreased energy expenditure
CONSEQUENCES
Hypertension / Higher blood pressure = CHD
Excess weight = more strain on the heart that has to pump more blood = faster heart rate
High cholesterol = atherosclerosis = narrowing blood vessels
Type II diabetes: diet rich in sugars causing the progressive overstimulation of these cells by insulin = fat, liver and muscle cells become unresponsive to insulin (insulin insensitivity)
