[FMS] NAM - nutrition and health AND energy balance and body weight Flashcards
What is a macronutrient?
- Lipids
- Carbohydrates
- Proteins
- Alcohol
remember CALP
What is a micronutrient?
- vitamins
- essential minerals
- essential amino acids
- essential fatty acids
remember FAM V
^ called MICRO becuase Only needed in tiny amounts (~ g, mg or μg per day)
Who is responsible for deciding dietary reference values for food in the UK?
- The Food Standards agency (previously known as the Committee of Medical Aspects of Food Policy (COMA)).^ They are in charge of all dietary reference values for food, energy and nutrients for the UK.
How do the Food Standards Agency work out dietary reference values?
- the intake of X in groups of people with no deficiency
- the intake in groups of people with deficiency
- intakes that would cure clinical deficiency
- intakes that are associated with a marker of nutritional adequacy (enzyme saturation, tissue concentration).
- This allows you to work out the estimated average requirement (EAR).
Explain the EAR and RNI in terms of normal distribution
EAR = ESTIMATED AVERAGE REQUIRMENT - is the amount that will satisfy the needs of half the population.
This is not good enough so if you go two standard deviations about the EAR, you get the reference nutrient intake (RNI).
What are the 3 Dietary Reference Values (DRVs) and their definitions?
EAR - The national mean requirement of a nutrient
RNI - 2SD ABOVE EAR
LRNI - 2 SD BELOW EAR
What are the DRVs for Vitamin C (ascorbic acid)?
EAR for adults in the UK is 25mg
RNI for adults in the UK is 40mg
LRNI for adults in the UK is 10mg
- Do we find the average energy requirement and add two standard deviations?
No, you leave it at the estimated/average energy requirement.
What do we use DRVs for?
- For nutritional programmes for groups of people e.g. babies, pregnant women, children, adults, the elderly, ethnic groups
- For formulation of feeds for babies, schools, institutions
- For clinical nutrition ie patients on enteral or parenteral nutrition
Is the data obtained from the analysis of food accurate?
The data obtained from food tables will not have strict accuracy, e.g. fat content of milk varies with season
- Which groups are malnourished in the developed world?
- The main groups include:
- Elderly, at home on their own or in institutions
- Young people on junk food
- Some Asian women and children in traditional clothes
- Slimmers and people on fad diets
- Cancer and AIDS patients
- People with eating disorders
- Up to 40% of hospitalised patients
^ - These groups usually have specific deficiencies
- i.e. proteins, vitamins and minerals
How is BMI calculated?
Body mass index = weight/height^2 (kg/m^2)
What is a normal BMI
anything between 18.5 - 24.9
what is metabolic rate?
rate at which metabolism occurs kj/hour/kg
what is basal metabolic rate?
kj/hour/kg body weight, measured at rest
what mechanisms operate to control body weight
HYPOTHALAMUS - controls hunger and satiety
how does hypothalamus control satiety
LEPTIN - produced by adipose tissue, reflects size of fat stores
INSULIN - produced by pancreas, signals fullness of carb stores
POMC (PYY-36) - produced by intestines supresses the diet
how does hypothalamus control hunger
NPY- produced by brain
GHRELIN - produced by stomach
what is the prevalence of obesity
2/3 adults are overweight
in UK , 30% of adults are obese
consequences of obesity
- Cardiovascular disease
- Stroke
- Some cancers
- Hypertension
- Diabetes type 2
- Gallstones
- Dental caries
- Gout
- Infertility
- Sleep apnoea
- Surgical risk
- Psychological distress
what are the risks of CVD
- High blood cholesterol
- Hypertension
- Smoking
- Inactivity
- Obesity
What are the recommendations of the department of health?
- Total fat: 30-33 % of which, saturated fat: no more than 10%
- Protein: 10-15%
- Sucrose: no more than 10% (2014, no more than 5%)
- Alcohol: no more than 5%
What are solutions to poor diets and resulting health issues?
- Education
- Clear labelling of food products
- Support and provision of facilities for the deprived groups of the population
- School food schemes
- Role models
- Control of advertising
- Pressure on food industry
How Is Body Composition Measured?
Body density
Body water
Total body K
Methyl histidine or creatinine excretion
Skinfold measurements
^Biceps, triceps, supra iliac, sub scapular
Mid-arm circumference
How does bioelectrical impedance measure body composition?
- Electrical signal is sent through the body
- Travels quickly through lean tissue (high % water, therefore good conductor of electricity
- More slowly through fat lower % water , poor conductor of electricity.
How does air displacement plethysmography work?
Measure volume of chamber with and without subject, you can calculate body density and fat and fat free mass.
how much energy is derived from food (in terms of carbohydrates, fat, protein, and alcohol) ?
How do we get energy from food?
- The total energy = heat of combustion (energy you get if you set fire to the food).
- Digestible energy = energy absorbed.
- Metabolisable – Digestible minus that lost in urine sweat and skin – 50% lost as heat. Less than 50% used for ‘work’
energy requirments depend on?
- basal metabolic rate
- diet-induced thermogenesis
- physical activity
- Environmental temperature
- Growth, pregnancy, lactation
- Age
What are the short-term signals in the body when its balancing energy?
- the GI tract
- the hepatic portal vein
- the liver
^ They bring about the feeling of satiety through vagus and circulation
what are the methods for treating obesity
- high protein, keto diets
- intermittent fasting
-
Uncouplers and thyroid hormone treatment
- are dangerous and have been lethal (withdrawn)
-
Sibutramine
- increases concentration of serotonin and tends to reduce appetite (now withdrawn)
-
Orlistat (licensed in the UK)
- decreases fat absorption
-
leptin
- modest effect at high doses but obese have leptin resistance
OR have surgery:
- Liposuction
- Resection of intestine
- Stomach stapling
- Stomach banding
