Lecture 22- Human nutrition Flashcards
1
Q
What are functional foods?
A
- “Foods that provide benefits beyond basic nutrition”
- Food innovation
- Connecting food with population health messages
- “healthy foods”
- Estimated worth of US $30-50 billion
- AUS $1 billion in 2003, growing 8-14% per annum
- Opportunity to grow the market in Australia
- Export opportunities
- National Centre for excellence in Functional Foods
2
Q
What are the opportunities for functional foods in terms of business?
A
- Opportunities for:
- Primary industry
- manufacturing/processing
- Retailing
- Minimally transformed foods
- Contain known bioactives (fruits & veg)
- Substantially & elaborately transformed
- Food & beverage ingredients
- Added bioactives
- Success depends on consumer responsiveness • Time poor consumers • Need for convenience • People are more interested / aware of what is in their food (publicity)
3
Q
What are some of the functional foods?
A
- omega 3
- probiotics
- high fibre
- energy drinks
- fortified alcohol
4
Q
What is the case with omega 3?
A
- Added Omega-3 DHA
- E.g. Dairy farmers kids milk has 75% RDI of Omega-3 in 250mL
- Omega-3 enriched eggs • Fed flaxseeds
5
Q
What about heart health functional foods?
A
• Contains plant sterols that lower LDl cholesterol, margerine and milk
- recent evidence suggests that similar effects can be gained from consuming lower doses of these sterols
- consumption of plant foods
6
Q
What about probiotics?
A
- advertised as the magic bullet
- contains microorganisms (bacteria etc.), GI tract targeted
- there are benefits when taking biotic
- reduce the severity of the diarrhea
- prevent the onset of diarrhea
- IBS= mixed evidence
- we discussed the microbiome, are they not all different?
- a better treatment, faecal transplant =cured 94% of infections, diarrhea,(antibiotics cure 27%)
7
Q
What about high fibre?
A
- important for GI tract
- can reduce incidence of some cancers and heart disease
- too much fibre?
- more than 50-60g per day can reduce mineral and vitamin absorption and causes GI discomfort
8
Q
What about energy drinks?
A
- Consumption is increasing
- Particularly in adolescents
- Higher in males
- Caffeine does improve attention
- Temporary
- Reduces memory
- Energy drinks:
- Decrease reaction time
- Increase alertness
- Improve memory & concentration
- Increase exercise endurance
-limited evidence that they improve energy, some ingredients have not been established as safe
9
Q
What is the case with fortified alcohol?
A
- Added alcohol in wine
- Alcohol + energy drinks
10
Q
Have many functional foods exaggerated the health claims?
A
- In Sept 2009 Dannon settled a case for US $35 million
- Exaggerated health benefits in yoghurt products (Activa)
- They had to change the labelling
- “clinically proven” etc.
11
Q
When does food preference in humans develop?
A
- Develop in utero?
- What is consumed in pregnancy may shape food preferences for baby
- Sensory stimuli can be perceived during the latter stages in utero
- Foods can ‘flavour’ the amniotic fluid & milk
- E.g. vanilla, carrot, garlic, mint, anise etc.
- Food experienced in utero are accepted better once born
- Nature Vs nurture
- Siblings raised the same way can have varied preferences
- Genetic influences on taste? (BUT not specific to foods)
- Role for both preference and aversion
- Religion, demographics, race, age, socioeconomics etc.
- Cannot discount the role of social activities and influences
- Classical conditioning
- Pavlov’s dogs
- Bad flavours or ill feelings lead to food aversions
- Reflex responses to tastes are present in the neonate
- Prefer sweet
- Reject sour and bitter foods
- Preference for salt develops at about 4 months old
12
Q
What do twin studies tell us about food preference?
A
- Studies of twins show:
- A substantial genetic effect on protein tastes (umami)
- Moderate genetic effect on veggies and fruits
- Small genetic effect on sweet tastes
- Preferences for dairy and starch are highly environment driven
13
Q
What is the problem of obesity like?
A
- Food selection has a strong adaptive value
- So does the storage of energy
- Advantage when resources are scarce
- In 2005, WHO reported that >400 million adults are obese
- Complex interactions between genetic, nutritional, metabolic, hormonal, medical, behavioural and environmental factors
- Role of food preferences?
- Particularly in children
14
Q
What are homeostatic signals?
A
- maintenance of physiological equlibrium
- Insulin
- Glucagon
- Catecholamines (eg. Epinephrine)
-going on all the time, maintain steady glucose level in the body
15
Q
What is homeorhesis?
A
-the adaption to these process to particular stage in life
- Pregnancy
- Lactation
- Growth
- co-ordinated changes in metabolism of body tissues to support a physiological state
16
Q
How is fat stored, how does this system work?
A
- if you consume dietary fat, made into glycerols, then nonesterified fatty acid and then into adipocyte for storage= same for glucose
- this process is positively influenced by insulin and negatively by epinephrin and glucagon (as you would need energy readily)
- the reverse can also happen when the stored fat is made into available
17
Q
What is the effect of feeding on plasma insulin, glucagon and glucose?
A
-insulin and glucagon keep the glucose low after food intake
18
Q
What happens in the cow after feeding with the insulin?
A
- really big difference when lactating or dry
- lactating has lower levels
- it differs across species
19
Q
What is the hyperinulinemic/euglycemic clamp?
A
• Technique to study insulin metabolism without altering glucose and glucagon
-you give insulin and maintain glucose so can tell that the difference is then due to the efficiency of the animals to maintain homeostasis
- hyperinsulinemic = high insulin
- euglycemic = glucose maintenance
- clamp = keep insulin and glucose constant
- Infuse insulin to increase plasma insulin while infusing glucose to maintain plasma glucose (glucagon won’t change)
20
Q
Why are these studies done?
A
- how well are things taken up into fat
- glucose uptake relative to the insulin
21
Q
What happens when inject glucagon?
A
- glucagon injection at time zero, then increase in glucose and eventually go back to steady state
- increase in insulin as well
22
Q
What also happens with glucagon injections?
A
-glucagon then increases the glucose but first have to break down the NEFA (non esterified fatty acids so it can be used by the body)
23
Q
What happens to NEFA when inject epinephrine?
A
- injection of epinephrine get an increase in plasma NEFA
- also in glucose
24
Q
What is the homeorhesis?
A
- Changing metabolism to support a physiological state
- Can be achieved through altering responses to homeostatic signals
- changing sensitivity (receptor related= to bind the hormone etc.)
- changing responsiveness (post-receptor related)
25
What happens in pregnancy and insulin?
- in non pregnant animal, the response rate is different
- the insulin is different
- at different stage of pregnancy this also differs
- how responsive the fat is to provide energy differs, less responsive in early pregnancy then later
26
What happens in pregnancy?
* Decreased sensitivity to insulin with respect to glucose utilisation (need more)
* Marginal changes in responsiveness to insulin of endogenous glucose production
* Decreased responsiveness to insulin with respect to NEFA metabolism
* Increased responsiveness to catecholamines
-more stress responsive when pregnant
27
What is the glucose uptake in pregnant and dry animals in their hind limbs?
- glucose uptake in the hindlimb
- in dry animal more readily uptaken
- when pregnant won't take it up as quickly since want circling glucose for the fetus
28
How do animals respond to an epinephrine challenge?
- dry animal doesn't really respond to the epinephrine
- the pregnant does
- lactating even more!
29
What about lactation in general?
* Decreased sensitivity and responsiveness to insulin with respect to glucose utilisation
* Decreased responsiveness to insulin of endogenous glucose production
* Decreased responsiveness to insulin with respect to NEFA metabolism?
* Increased responsiveness to catecholamines
30
What are the homeorhetic signals?
**• Bauman and Currie (1980)**
* somatotropin
* placental lactogen
* prolactin
**• Bines and Hart (1982)**
• somatotropin
31
What effect does somatotropin have?
- somatotropin (growth hormone)
- high yielding animal has more, and is more responsive
32
What about responsiveness to insulin?
-high yielding animal is also more responsive
33
What is true of milking cows?
- Negative energy balance is NOT more severe in TMR fed genetically superior cows (may not be the case for pasture cows)
- the cow produces more and doesn't expend more energy
34
What happens if inject bST (bovine somatotropin)?
- increase in productive input
- bigger decrease in energy balance so will need more energy input to not waste
- see more NEFA in plasma as need more energy
- become more sensitive to epinephrine (so more responsive to stress)
- they don't respond to insulin as much
35
What is the case with somatotropin?
* Increases responsiveness to catecholamines
* Reduces responsiveness with respect to glucose insulin stimulation of glucose utilisation by peripheral tissues
* Reduces effect of insulin in inhibiting hepatic glucose production
* Metabolic effects similar in lactating and growing animals
