Lecture 3701-lecture 28
15 November 2010
Joint efforts of Canadian and American experts intended to replace recommended nutrient intakes (RNIs)(Canada) and recommended dietary allowances(RDA)(USA)
Panels consist of experts on each nutrient are responsible for:
-reviewing the scientific literature concerning the specific nutrients are under study for each aspect of the lifespan
-considering the roles of nutrients in decreasing risk of chronic and other diseases and conditions
-evaluating possible criteria or indicators of adequacy and providing substantive rationales for choice of each criterion
-interpreting the current data on intakes in North American population
-estimating the average requirement for each nutrient or food component renewed
Subcommittees
Upper Reference Levels
-utilises risk assessment for estimating tolerable upper levels of nutrients at which there would be little or nor risk of toxicity or adverse effects
-assist the panels in applying the models to each nutrient or food component reviewed
Uses and
Interpretations of the DRIs provides guidance for:
-appropriate application of DRIs for assessing the intakes of individuals and groups
-appropriate application of DRIs in planning diets for individuals and groups
-other nutrient specific applications
-four values instead of one:
EAR-estimated average requirement-50 % chance of meeting requirement for a given nutrient for the individual-done by assessing groups for which scientific studies are required-exists for vitamin C for example
RDA-goal for the individual
New RDAs are not interchangeable with the RNIs currently used in Canada-although the same framework (EAR +2 SD) was used to derived RNIs there was often little data from which the nutrient requirements could be assessed and often the RNIs represented an informed judgement about what seemed to be an adequate intake
AI-Adequate Intake-used as goal for a person (~RDA)-if cannot assess groups must use AI-exists for calcium for example-used desirable daily calcium retention for setting AI- retention is classically measured as calcium balance(Intake-Losses) and assumes what is retained is in the bones though one can now measure bone mineral content
AI for calcium(male and female aged 19-30) is based on retention of 10-50 mg/day based on old balance studies current AI is 1200 mg/day -greater amounts required in those over 50 years of age due to less calcium absorption
AI-does not bear a consistent relationship to the EAR or RDA because it is set without being able to estimate the requirement and as such cannot be placed on the EAR or RDA.
UL-Upper tolerable Intake Level-assigned to many nutrients-a measure of toxicity-often based on case reports and not studies-refers to sustained intake and not a single doses (Magnesium is the exception)-2 grams/day for vitamin C and 2.5 grams per day for calcium
RDA=EAR + 2SD=very small risk of deficiency for a given nutrient for a given person-vitamin C RDA is 90 mg/day for men and 75 mg/day for women- smokers need an additional 35 mg/day (all values are averages)
Energy RDA=EAR
DRIs apply to healthy people
Average intake for a person over a period of time- not the intake for a given day
What is food labelling?
Main focus of current debate on non-genetically modified foods is what information is of significance to health of consumer and how to best get that information to the consumer
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Proposals for
nutrient content claims
-amount of nutrient in a food
-proposed that there be regulation of
compositional criteria and specific labelling requirements for all permitted nutrient
claims
-proposed to regulate compositional
criteria for nutrient content claims based on standardised reference patterns for a given
food
criteria now being established for:
calories-calorie free, low in calories,
reduced or lower in calories, source of calories
protein-source of protein, excellent source of protein, more protein
fat-fat free, low in fat, reduced or lower
in fat, 100 % fat free, naming the percentage fat free
saturated fatty acids-saturated fatty acid
free, low in saturated fatty acids reduced or lower in saturated fatty acids
trans-fatty acids-free of trans fatty
acids reduced or lower in trans fatty acids
polyunsaturated fatty acids- source of
omega 3 fatty acids or source of omega 6 fatty acids
cholesterol-cholesterol free, low in
cholesterol, reduced or lower in cholesterol
sodium-sodium-free or salt free, low in
sodium or salt, reduced or lower in sodium or salt, no added sodium or salt, lightly
salted
sugars-sugar-free, reduced or lower in sugar, no added sugar
fibre-source of fibre, high source of
fibre, very high source of fibre, more fibre
light- reduced in energy or reduced in fat
Proposals for
diet related health claims
Potassium sodium and reduced risk of high blood pressure
Calcium, vitamin D and regular physical
activity and reduced risk of osteoporosis
Saturated and trans fats and reduced risk
of heart disease
Fruits and vegetables and reduced risk of
some times of cancer
Sugar alcohols and dental caries
Food
labelling debates for genetically modified foods
Main focus of debate is on what the label should contain and to what extent such
labelling would affect trade of genetically modified food
A
government-appointed advisory body argued Monday against imposing mandatory labelling on
producers of genetically modified (GM) food, saying that it may be too costly and could
cause trade battles. Instead, the Canadian Biotechnology Advisory
Committee said, a voluntary system should be implemented for at least five years, but
only after an "agreed-upon standard" for GM content can be established. "We recommend
that it be evaluated in five years," a hefty report
(pdf) suggests to Industry Minister Allan Rock, convenor of the Biotechnology
Ministerial Coordinating Committee, "to determine whether it gives consumers
sufficient choice concerning the foods they purchase and, if not, that alternatives,
including mandatory labelling, be considered." One of the 20
members of the committee, Anne Mitchell, executive director of the Canadian Institute for Environmental Law and
Policy , "strongly" disagreed, the report acknowledges. The report says that
Ms. Mitchell proposed instead moving immediately to a mandatory system, and that she noted
that the majority of those reacting to the committee's interim report had also urged a
mandatory system. While the report
urges the government to implement a series of recommendations aimed at bolstering public
confidence in GM food, they stressed in a letter released to the public that there is no
evidence that the foods "pose any greater health or environmental risk than other
foods in the marketplace." The group
which has long been criticized by anti-GM campaigners as a tool of industry and government
acknowledges that its views are not universally accepted. "Positions are
polarized," they said, between those who believe that modification raises the
prospect of benefit to both farmer and consumer and those who believe it poses an
unacceptable, and unknown, risk to mankind and the planet. "The fact that
there are divergent views on such a complex issue is not surprising," the report
argues. "Nor should it be a reason for failure to take action that is in the public
interest namely, to capture the benefits of biotechnological innovation while
providing reasonable protection against potential harms." The group urged
that:
Despite these recommendations, the
committee stuck fast to its belief that GM foods are not known to pose any appreciable
risk to mankind. "Research and development of GM
organisms has been taking place for nearly 30 years with no evidence as yet of harm to
human health or the environment," the report says. But it then adds the caveat:
"Nevertheless, we urge an examination of existing standards to ensure that such
research is conducted in a precautionary manner." |