The GIT Nutrition Flashcards
Nutrition
-The process of obtaining or providing food for good health
-Science that deals with nutrients and nutrition
What are the four categories of undernutrition?
- Wasting(low weight for height)
- Stunting(low height for age)
- Underweight(low weight for age)
- Vitamin and mineral deficiency
Wasting?
Usually indicates recent & severe weight loss,
* Due to insufficient food to eat and/or infectious disease e.g. diarrhoea
Stunting?
- Result of chronic or recurrent undernutrition
- Usually associated with poor socioeconomic conditions, poor maternal health & nutrition,
frequent illness, and/or inappropriate infant and young child feeding and care in early life. - Affects cognitive function
Underweight?
A child who is underweight may be stunted, wasted, or both
Vitamin and mineral deficiency(inadequate micronutrient intake)
Children & pregnant women in low income countries particularly at
risk of developing deficiencies in
* vitamin A
* Iodine
* Iron
Overweight and obesity?
- Person too heavy for his or her height
- Risk factor for cardiometabolic diseases
- Imbalance between energy consumption (too much) vs energy expended (too little)
Hidden hunger?
Presence of multiple micronutrient deficiencies
-Particularly iron, zinc, iodine and vitamin A
-Can occur without a deficit in energy intake
-Energy-dense, but nutrient-poor diet.
How many people are affected by hidden?
Affects > 2 billion people globally
-particularly in low- and middle-income countries
What causes hidden hunger?
Due to reliance on low-cost food staples & non diverse diet
Double burden of malnutrition?
Coexistence of undernutrition & overweight, obesity or diet-related
How does the double burden of malnutrition occur?
i. Within individuals -simultaneous presence of two or more types of
malnutrition, or multiple types over a lifetime (obese & deficient in
micronutrients)
ii. Households -different family members presenting with different types of
malnutrition (under and over nutrition)
iii. Populations/Communities/countries (usually due to socioeconomic factors), and across the life-course
What are the three assessments of nutrtional status?
- Clinical Knowledge
- Biochemical tests: blood/serum & tissue biopsies(urine, saliva and hair)
- Anthropometry
- Dietary Survey
Bioimpedience?
is about the electrical properties of your body or other biomaterials
Anthropometry?
-Skin fold thickness measurements
-Waist circumference determination
-Height
-Weight
-Body mass index computation (kg/mΒ²)
-A BMI of 25.0 to <30.0 is denotes overweight while a BMI >30.0 denotes obesity
-Arm circumference
-Head circumference
Dietary survey?
For this direct records of individuals diets are taken and inferences drawn
based on the nutrient composition of the dietary constituents
What are the dietary survey methods?
- Prospective Methods
- Retrospective Methods
Prospective Methods?
7 day food record or 72 hour record of nutrient
intake
-keeps diary & record all foods and beverages
consumed during the specified time period.
-The quantity of each component is also recorded
Retrospective Methods?
Dietary intake recall
-Either as a food frequency (per
day/week/month) or 24 hour recall. Further
details will be provided in the lab sessio
Limitations of methods especially recall (retrospective)
over/under estimation of food consumption
What are the quality control measures that are instituted?
i. Crosschecking. Use more than 1 method (e.g. 24h recall and food frequency) to avoid over/under
reporting.
ii. Validation. Check how a method actually assessed intake.
iii. Reliability. Check consistency of data.
Proximate analysis?
Determination of the macronutrients in food
What is trans fat?
Trans fat, also called trans-unsaturated fatty acids, or trans fatty acids, is a type of unsaturated fat that occurs in foods.
ο RDI vs RDA vs DV
RDI (Reference Daily Intake) is a population-adjusted RDA based on all ages and sex groups of RDA values.
Recommended Dietary Allowance (RDA): Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97β98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
The Daily Value (DV) is put on the labels of food products and is meant for the general population.
Instrument used to measure energy?
Bomb calorimeter often used to determine the energy content of food constituents
Digestibility?
Digestibility: quantification of the digestive process
provides a relative measure of the extent to which ingested food
and its constituent nutrients have been digested and absorbed
What happens to all undigested food?
Thus, only a portion of food is digested and absorbed by an individual
* The rest is excreted as faeces
What are the factors affecting digestibility?
- Food composition
- Host factors
-GIT anatomy
-GIT microbiome
-Age - Food characteristics
-Cooking
-ANFs
Determination of digestibility?
- In vivo methods
- In vitro methods
In Vivo methods?
- Direct/Conventional approach
- Indirect method/Indifference method or indicators/markers method
Direct/Conventional approach?
Determine feed or nutrient intake and faecal production
Nutrient digestibility equation?
Nutrient Digestibility= [(ππ’π‘πππππ‘ ππππ’ππ‘ ππ ππππ ππππ π’πππ β ππ’π‘πππππ‘ ππππ’ππ‘ ππ ππππππ )/
ππππ’ππ‘ ππ’π‘πππππ‘ ππ ππππ ππππ π’πππ] x 100
Apparent digestibility coefficients?
when faecal samples are collected
Apparent digestibility coefficients factors?
- Feces contain added components from the GIT (mucosal cells, secretions) & microbes.
- Microbial fermentation can also have an impact
True digestibility coefficient?
requires collection of samples from the ileum
In Vitro methods?
Use simulated process in the gastrointestinal tract
Which animals are of choice for digestibility trails?
Often rat and pig are animals of choice for
digestibility trials
What is the direct method for experimental animal models for digestibility?
Use metabolic cage
-Feed known amount of feed
-Collect faecal matter separately from urine
-Proximate analysis of feed and faeces
-Compute apparent digestibility coefficients
Nb for Crude protein determine N and multiple by 6.25
Which samples are collected for true digestibility?
For true digestibility, ileal samples are
collected
How does the rat GIT differ from the
pig and both vs the human?
Pigs and rats have a digestive system which is classified as monogastric, or nonruminant. Humans also have this type of digestive system. They have one stomach (mono = one, gastric = stomach). The monogastric differs from that of a polygastric, or ruminant, digestive system found in cattle and sheep.
Antinutritional factors (ANF)?
- Chemical substances present in food
- Alter the digestion and absorption of Nutrients
- Reduce the bioavailabity of food constituents
4.Cause nutritional deficiencies, poor growth and diseases
Mechanisms of action Digestive enzyme inhibition?
ο 1. Inactivation of nutrients
ο 2. Alteration of nutrient absorption pathways
ο 3. Direct/indirect effects on tissues once absorbed
Phytochemicals?
Plant-derived chemicals
Nutraceuticals?
phytochemicals with nutritional value and medicinal potential
Effects of cooking food?
-Improve digestibility of some macronutrients
-Decrease availability of some micronutrients
Effects of advanced glycation end products?
-Flavour
-βDigestibility
-Carcinogens
-Chronic disease
-Ageing
