Evaluation of Infant Feeding Flashcards
What is the natural biological food for a human infant?
Breast milk
When is the use of cows milk as the main drink not recommended?
Before 12 months
What is the composition of breast milk used as the basis of?
- Determining infant nutrient requirements during the first 6 months of life
- The regulations on permitted compositions of breast milk substitutes (infant formula)
What issues should be considered when using breast milk composition as the basis for recommended nutrient intake/composition of breast milk substitutes?
- Breast milk composition varies between and within mothers
- Method used to obtain breast milk samples may affect results
- Composition of EBM may differ from that of energy suckled from infant direct from breast
- Breast milk contains many bioactive substances
- Milk from different mammals varies considerably
Over what time frames does the composition of breast milk change within the same mother?
- Over the course of lactation
- During a day
- During a feed
In what respects might the methods for obtaining breast milk samples vary?
- Fore vs hindmilk
- Hand vs pump expressed
- Single vs pooled samples
What is the consequence of breast milk composition varying depending on the mother, time, and method of obtaining sample?
It is difficult to define a single reference concentration for many nutrients
What is the consequence of the composition of EBM potentially differing from breast milk suckled straight from the breast?
It has probably resulted in an overestimation of human milk, which was then applied to human formulas
Give 2 bioactive substances that breast milk contains?
- Hormones
- Growth factors
What is the limitation of breast milk containing bioactive substances when using it as a reference for infant formula?
These are difficult or impossible to mimic in infant formula
In what respect does milk from different mammals vary?
- Composition
- Configuration or quality of fat or protein
What is the consequence of milk from different mammals varying in terms of configuration or quality of fat/protein?
Infant formulas may contain the same total fat or protein concentration as human milk, but may still be significant different in type of nutrients
Give 2 examples of differences in the type of nutrients in formula milk compared to breastmilk?
- Stereo-isomeric differences in triglycerides influence fat and calcium absorption
- Different protein composition, e.g. alpha-lactalbumin, beta-lactoglobulin, can affect growth
What is the result of the problems with trying to make formula milk resemble breast milk as closely as possible?
Recently there has been a greater focus on trying to achieve the performance (health and developmental outcomes) of breastfed infants, rather than simply trying to mimic the composition of breast milk
How can data on the effectiveness and safety of interventions regarding infant feeding be obtained?
- Observational studies
- RCTs
What are RCTs considered the ‘gold standard’ for?
Demonstrating causal relationships between an intervention and outcome
What is the advantage of observational studies for evaluating infant feeding?
- Large sample size
- Can obtain results rapidly
What is the limitation of observational studies for evaluating infant feeding?
Because the type of infant feeding is not randomly assigned, they can show ‘associations’ between infant feeding and health outcomes, but they cannot demonstrate causation
What is the main problem with RCTs when evaluating infant feeding?
Healthy term infants cannot ethically or feasibly be randomised to breast-fed or formula fed, which prevents use of RCT for assessing the effect of any intervention against the ‘gold standard’ for infant feeding
What is problem with RCTs when evaluating breastfeeding?
Difficult to randomise breastfeeding mothers to different breast-feeding practices
What is the result of the problems with using RCTs to evaluate infant feeding?
Most data on the subject comes from observational studies
What are the methodological problems with observational studies into infant nutrition?
- Determination of feeding behaviour
- Definition of breastfeeding
- Outcomes
- Control for confounders
- Reverse causality
What are the problems with the determination of feeding behaviour in observational studies into infant feeding?
- Often retrospective
- Different sources of data, e.g. mother, HCP
What are the problems with the definition of breastfeeding in observational studies into infant feeding?
- Definitions are very variable, especially for exclusivity
- Range from ‘ever/never’ to detailed prospective records
What are the problems with outcomes in observational studies into infant feeding?
- Assessment not always blind
- Lack of consistent definitions or measurement methods
What are the problems with control for cofounders in observational studies into infant feeding?
- Variable definition and collection of data on confounders
- Direction of confounding differs in different populations and with time
Give an example of a confounding factor when comparing breastfeeding to formula feeding?
The choice of feeding mode is strongly related to social and demographic factors such as educational achievement and socio-economic status, which are in turn related to many of the health outcomes of interest
What is the problem with reverse causality in observational studies into infant feeding?
Alteration to feeding behaviour may be response to outcome, rather than cause
Give an example of where reverse causality may be a factor when comparing breastfeeding to formula feeding?
Mothers with a family history of atopy may breastfeed for longer to prevent the infant from developing atopy, but if the infant then develops atopy, it may be attributed to breastfeeding
What are the problems with the determination of feeding behaviour in observational studies into infant feeding?
- Often retrospective
- Different sources of data, e.g. mother, HCP
What are the problems with the definition of breastfeeding in observational studies into infant feeding?
- Definitions are very variable, especially for exclusivity
- Range from ‘ever/never’ to detailed prospective records
What are the problems with outcomes in observational studies into infant feeding?
- Assessment not always blind
- Lack of consistent definitions or measurement methods
What are the problems with control for cofounders in observational studies into infant feeding?
- Variable definition and collection of data on confounders
- Direction of confounding differs in different populations and with time
Give an example of a confounding factor when comparing breastfeeding to formula feeding?
The choice of feeding mode is strongly related to social and demographic factors such as educational achievement and socio-economic status, which are in turn related to many of the health outcomes of interest
What is the problem with reverse causality in observational studies into infant feeding?
Alteration to feeding behaviour may be response to outcome, rather than cause
Give an example of where reverse causality may be a factor when comparing breastfeeding to formula feeding?
Mothers with a family history of atopy may breastfeed for longer to prevent the infant from developing atopy, but if the infant then develops atopy, it may be attributed to breastfeeding
What are the current UK recommendations regarding breastfeeding and solid foods?
Infants should be exclusively breastfed for around 6 months before introducing solid foods alongside breastfeeding, which should continue ideally for up to 2 years
When are mothers who formula feed advised to introduce solid foods?
Around 6 months
