LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

PARALLEL SESSION 4B: DIET 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
We quantified the daily intake of nine qualifying and three disqualifying nutrients in the diets. The nine
qualifying nutrients were (the recommended daily value (RDV) is given in brackets): protein (57 g), fibre (25
g), calcium (800 mg), iron (14 mg), magnesium (375 mg), potassium (2000 mg), and vitamins A (800 µg), C
(80 mg) and E (12 mg). The three disqualifying nutrients were (maximum recommended value (MRV) given
in brackets): sodium (2400 mg), saturated fat (20 g) and total sugar (90 g) (efsa, 2009, 2010, 2012; EuropeanUnion,
2008). To quantify the daily intake of these 12 nutrients, we multiplied the daily intake of each
food product in the diet by the nutrient concentration of the food product. The nutrient concentration of food
products were taken from the online Dutch Nutrients Database NEVO (RIVM, 2011). Nutrient intake of
meals was scaled to daily intake by expressing it relative to a recommended daily energy intake of 2000 kcal
(efsa, 2009). Yearly diets were scaled to daily diets by dividing the intake of nutrients by 365.
To evaluate the nutritional quality of each diet in terms of individual nutrients, we compared the individual
scores of qualifying and disqualifying nutrients to the RDV and MRV respectively.
2.3. Calculation of the composite nutrient score of each diet
We developed the Nutrient Rich Diet 9.3 (NRD9.3) score to calculate the composite nutrient score of
each diet. The NRD9.3 score is an adaptation of the Nutrient Rich Food 9.3 (NRF9.3) algorithm
(Drewnowski, 2009), the latter reflecting the nutrient density of a given food product per 100 kcal. In contrast
to the NRF9.3 algorithm, the NRD9.3 algorithm is energy independent.
The NRD9.3 score consists of a Total Nutrient Rich9 (TNR9) and a Total Limiting3 (TLIM3) subscore.
The TNR9 subscore (Eq. 1) computes the percentages of RDV for the nine qualifying nutrients. Intake levels
of these nutrients were capped at 100% of their RDV. The TLIM3 subscore (Eq. 2) computes the percentages
of MRV for the three disqualifying nutrients. The NRD9.3 score (Eq. 3) of each diet was computed by subtracting
the TLIM3 subscore from the TNR9 subscore.
396
9
,
9 100
i nutrienti
capped
TNR Eq. 1
RDV
i1 i
3
3 100
i nutrient i
TLIM Eq. 2
MDV
i1 i
NRD9. 3 TNR9
TLIM
3
Eq. 3
where nutrienti is the amount (in g or mg or µg) of nutrient i in the diet, RDVi is the Recommended Daily
Value of nutrient i, MDVi is the Maximum Daily Value of nutrient i.
2.4. Comparison of the environmental impact of diets
Subsequently, we computed the Global Warming Potential (GWP) of each diet per FU. The impact of the
diets were reported in the reviewed articles. The impact derived from the reviewed articles was expressed as
GWP/day. In the present paper we compared this expression with GWP relative to the FUs ‘protein’ and
‘NRD9.3’.
Because overconsumption of qualifying nutrients lessens the environmental impact per unit of nutrient,
we explored the effect of capping qualifying nutrient levels to 100% of their RDV. We used this capping also
to compute the NRD9.3 score, which is based on capped scores for qualifying nutrients and uncapped scores
for disqualifying nutrients. The NRD9.3 score thus does not give credits to overconsumption of qualifying
nutrients, whereas it does account for overconsumption of disqualifying nutrients.
To test whether the environmental impacts of the FUs ‘protein uncapped’, ‘protein capped’ and ‘NRD9.3’
differed from the FU ‘day’, which was reported in the reviewed articles, we calculated the indexed GWP/FU
for each study and for each FU by setting GWP/FU to 100 for a diet without ASFPs. We regressed the indexed
GWP/FU to the fractional content of ASFP in the diet (assessed by animal source protein/total dietary
protein). By calculating the difference between the regression coefficient for ‘GWP/day’ and GWP per FUs
‘protein uncapped’, ‘protein capped’ and ‘NRD9.3’ and testing (by t-test) whether this difference differed
significantly from 0, we could conclude whether our functional units gave a different contrast between die-