Protein for a Healthy Future: How to Increase Protein Intake in an Environmentally Sustainable Way in Older Adults in the Netherlands

Abstract

Background Protein intake greater than the currently recommended amount is suggested to improve physical functioning and well-being in older adults, yet it is likely to increase diet-associated greenhouse gas emissions (GHGEs) if environmental sustainability is not considered. Objectives We aimed to identify dietary changes needed to increase protein intake while improving diet environmental sustainability in older adults. Methods Starting from the habitual diet of 1,354 Dutch older adults (aged 56–101 y) from the Longitudinal Aging Study Amsterdam cohort, mathematical diet optimization was used to model high-protein diets with minimized departure from habitual intake in cumulative steps. First, a high-protein diet defined as that providing ≥1.2 g protein · kg body weight−1 · d−1 was developed isocalorically while maintaining or improving nutritional adequacy of the diet. Second, adherence to the Dutch food-based dietary guidelines (FBDG) was imposed. Third, a stepwise 10% GHGE reduction was applied. Results Achieving a high-protein diet aligned with the FBDG without considering GHGEs required an increase in vegetables, legumes, nuts, whole grains, meat/dairy alternatives, dairy, and eggs and a reduction in total meat (for men only) and discretionary products, but it resulted in a 5% increase in GHGEs in men and 9% increase in women. When a stepwise GHGE reduction was additionally applied, increases in poultry and pork (mainly for women) and decreases in beef/lamb and processed meat were accrued, with total meat staying constant until a 50–60% GHGE reduction. Increases in whole grains, nuts, and meat/dairy alternatives and decreases in discretionary products were needed to lower GHGEs. Conclusions A high-protein diet aligned with FBDG can be achieved in concert with reductions in GHGEs in Dutch older adults by consuming no more than the recommended 500 g meat per week while replacing beef and lamb and processed meat with poultry and pork and increasing intake of diverse plant-protein sources.

Halving food-related greenhouse gas emissions can be achieved by redistributing meat consumption: Progressive optimization results of the NutriNet-Santé cohort

“…In our particular context, under all the considered nutritional and acceptability constraints and by accounting for the influence of anti-nutritional factors like phytate on zinc and iron bioavailabilities, total meat was maintained relatively stable, because of a decrease in whole grains and starchy foods (and thus a decrease in phytate), although it was qualitatively remodeled in disfavor of ruminant meat so as to reduce GHGe. In line with our results, a diet optimization study among old Dutch adults with 50% reduction in GHGs found unchanged total meat consumption with an increased contribution of poultry and pork and a decreased contribution of beef (52).…”

Advantages and limitations of the methodological approaches used to study dietary shifts towards improved nutrition and sustainability

“…76,77 Similarly, very few studies have considered the specific nutritional requirements of older Nutrition Reviews V R Vol. 00(0):1-20 adults, especially their relatively high protein needs (which could increase GHGEs when fulfilled), except when a multicriteria approach has been applied, as in the study of Grasso et al 78 More studies that take into account the dietary habits and nutritional requirements of children, adolescents, and older adults are needed to assess more finely the health dimension and to produce recommendations for more sustainable diets that are adapted for the various age groups.…”

“… 75 Only a few recent studies have looked at developing nutritionally adequate, GHGEs-reduced, and affordable school menus using mathematical optimization. 76 , 77 Similarly, very few studies have considered the specific nutritional requirements of older adults, especially their relatively high protein needs (which could increase GHGEs when fulfilled), except when a multicriteria approach has been applied, as in the study of Grasso et al 78 …”

Effect of personalized dietary advice to increase protein intake on food consumption and the environmental impact of the diet in community-dwelling older adults: results from the PROMISS trial

“…It has been previously argued that increasing protein intake based on current food consumption patterns is likely to have unfavorable consequences for the natural environment [18][19][20]. Globally, current food production and consumption are dominant drivers of climate change, eutrophication (excessive richness of nutrients in water), acidification (water or soil becomes too acid), and biodiversity loss and are a considerable drain on resources such as land, water, energy, and nutrients [21,22].…”

“…In the Netherlands, animal-based protein constitutes 60% of total protein consumed by young and older adults alike [ 25 , 26 ]. A theoretical high-protein diet, modelled based on actual food intake data of Dutch community-dwelling older adults, showed that increasing protein intake from 1.0 to 1.2 g/kg BW/d, with isocaloric replacement and no consideration of environmental sustainability, increased the contribution of animal-based protein to 65% of total protein and increased diet-associated greenhouse gas emissions (GHGE) by 12–14%, land use (LU) by 10–12%, and fossil energy use by 9–10% [ 20 ]. This study used diet optimization, which is a powerful tool to model realistic diets as it simultaneously combines a given set of nutritional and environmental constraints while staying as close to the habitual diet as possible.…”