The carbon footprint of breastmilk substitutes in comparison with breastfeeding

Abstract

Breastfeeding is one of the foundations of child health, development and survival. Breastmilk substitutes (BMS) are associated with negative influences on breastfeeding practices and subsequent health concerns and, as with all foods, production and consumption of BMS comes with an environmental cost. The carbon footprint (CFP) of production and consumption of BMS was estimated in this study. To illustrate regional differences among the largest producers and consumers, the CFP of BMS production in New Zealand, United States (USA), Brazil and France and the CFP of BMS consumption in United Kingdom (UK), China, Brazil and Vietnam were assessed. The CFP values were then compared with the CFP of breastfeeding arising from production of the additional food needed for breastfeeding mothers to maintain energy balance (approximately 500 kcal per day). The CFP of production was estimated to be 9.2 ± 1.4, 7.0 ± 1.0, 11 ± 2 and 8.4 ± 1.3 kg CO₂e per kg BMS in New Zealand, USA, Brazil and France, respectively, with the largest contribution (68-82% of the total) coming from production of raw milk. The CFP of consumption, which included BMS production, emissions from transport, production and in-home sterilisation of bottles, and preparation of BMS, was estimated to be 11 ± 1, 14 ± 2, 14 ± 2 and 11 ± 1 kg CO₂e per kg BMS in UK, China, Brazil and Vietnam, respectively. Comparison of breastfeeding with feeding BMS showed a lower CFP from breastfeeding in all countries studied. However, the results were sensitive to the method used to allocate emissions from raw milk production on different dairy processing co-products (i.e. BMS, cream, cheese and lactose). Using alternative allocation methods still resulted in lower CFP from breastfeeding, but only slightly for UK, Brazil and Vietnam. Care is also needed when interpreting findings about products that are functionally different as regards child health and development.

Keywords: BMS, Breastmilk substitute; CFP, Carbon footprint; Climate impact; Infant formula; LCA; LUC, Land use change; Lifecycle assessment; Sensitivity; Uncertainty.

Fig. 1

The three steps followed in this study when assessing the carbon footprint (CFP) of breastmilk substitutes (BMS), including system boundaries (hatched lines) and the location of the estimated CFP. Shaded boxes indicate processes not included in the assessment. BMS wasted after preparation was accounted for in the CFP of breastfeeding to estimate the amount of breastfeeding equivalent to 1 kg powdered BMS.

Fig. 2

Process steps in the production of powdered breastmilk substitute (BMS). In total, 13.7 kg of raw milk is used for producing 1 kg of BMS, of which 6.6 kg is allocated to the BMS and the rest to other co-products. Numbers represent the wet weight of inputs and co-products in the production of 1 kg of powdered BMS. The inputs in terms of energy used for each processing step is provided in Table S8 in Supplementary Data.

Fig. 3

Histogram showing variation in the consumption carbon footprint (CFP_Cons) for the China case as a result of varying the breastmilk substitute (BMS) recipe. Dashed and dotted lines represent the range including 50% and 95% of simulation outcomes, respectively, and the solid line represents the sample median. The carbon footprint of the baseline recipe is indicated by a red diamond.

Fig. 4

Difference in carbon footprint from breastfeeding (CFP_BF) and feeding breast milk substitute (BMS) (CFP_Cons). Values above zero mean that feeding BMS has a higher carbon footprint than breastfeeding, and vice versa. The comparison is presented for the default case (circles), for using fat-and-protein allocation (diamonds), and for excluding bottle sterilisation (shaded circles and diamonds). The whiskers show the 95% confidence intervals.

Fig. 5

Ratio between the carbon footprint of breastfeeding (CFP_BF) and feeding breast milk substitute (BMS) (CFP_Cons) under different assumptions on amount of BMS wasted at the consumer stage. Solid lines represent the comparison using the default dry mass allocation method and dashed lines the alternative fat-and-protein allocation method. Values above zero mean that feeding BMS has a higher carbon footprint than breastfeeding, and vice versa. The cases of United Kingdom, China, Brazil and Vietnam are represented by blue circles, red squares, yellow diamonds and green triangles, respectively. The symbols at the bottom of the diagram indicate the country-average, consumption-stage food waste used to estimate BMS waste levels in the default calculations.