Nutrient dense food for growing population needs
The growing worldwide population challenges worldwide food supplies. Nutrient-dense foods are crucial to support nutrient security in the future and yogurt contains high-quality proteins, a decisive macronutrient in this matter.
Consequently, the demand for yogurt and milk products is rising and the Food & Agricultural Organization (FOA) estimates that the demand for milk will increase from currently 700 to over 1000 billion kg in 2050.
In this context, improving efficiency in the dairy chain requires a nutritional and environmental impact by increased productivity of dairy cows for protein-rich milk and reduced greenhouse gas emissions while processing.
According to a Dutch research, cows are efficient convertors of human-inedible resources (low-quality proteins in grains and soy) into nutrient-dense milk and yogurt, containing essential micro-nutrients and high-quality proteins. The energy and protein efficiency of a dairy cow is already up to 25% with a return of 400% for the human-edible part.
Healthy diets and climate impact
Anyhow, the question of climate impact remains. Healthy diets can be achieved through various food combinations, which are associated with different environmental impacts, like greenhouse gas emission (GHGE).
A Danish study highlights the importance of examining these GHGE and nutritional status together when considering future dietary recommendations for a sustainable diet.
The GHGE and nutritional status of 8 different dietary scenarios (with different quantity of dairy products) were estimate, based on data of 71 highly consumed foods. For solid food items, an index was used to estimate nutrient density in relation to nutritional recommendation and climate impact: the Nutrient Density of Climate Impact (NDCI) index. NDCI index is calculated as the nutrient density divided by the CO2e for 100 g of food items. High NDCI index values were those with the highest nutrient density scores in relation to the GHGE.
The estimated GHGE for the average-dairy and non-dairy diets ranged from 4,340 to 4,826 g CO2e per day, with the highest GHGE in cheese-products and lowest GHGE in milk-products. For soy drink, the estimated values were 3,620 g CO2e per day. For the vegetarian and vegan diets, the estimated GHGE were 3,063 and 2,414 g CO2e per day, respectively.
However, when using the NDCI index (combining nutritional value and climate impact), the ranking of food items changes. Values for animal-based and plant-based products are more similar. This study shows that reducing consumption of food items with high or relative high GHGE is not necessarily the best approach to decreasing diet-related GHGE. If a product is replaced by food with lower energy density, the quantity needed to compensate for the caloric loss is greater than the quantity removed. This may result in a higher diet-related GHGE despite the lower GHGE per kg of the substituted product.
When optimizing a diet with regard to sustainability, it is crucial to account for the nutritional value and not solely focus on impact per kg product.
Source:
- Van Hooijdonk, T. et al., Microbiota and the gut–brain axis; Nutrition Reviews; 2015; 73(8): 48-54.
- Bruun Werner L et al. Greenhouse gas emissions of realistic dietary choices in Denmark: the carbon footprint and nutritional value of dairy products; Food Nutr Res; 2014; 58: 20687
