Meat and dairy will continue to play a major role in the world’s food production systems if we’re to deliver adequate nutrition to a growing world population.
That was the core message Dr Nick Smith of the Massey University-based Riddet Institute’s Sustainable Nutrition Initiative (SNI) delivered to the 400 farmers, horticulturalists, government and sector representatives at the Primary Industries NZ summit in Wellington last month. He said that while the world grapples with climate change and protecting water and other resources, there’s also the massive challenge of feeding a global population projected to jump from today’s 7.8 billion to nearly 10 billion by 2050.
We have a sad situation where 820 million people are currently malnourished or starving, while many more than that in developed nations are obese.
The Ridett Institute, described as New Zealand’s food science and nutrition centre of excellence, believes ‘nutrition for all’ should mean enough food produced to deliver:
- Sufficient energy, macronutrients and micronutrients
- Distribution and affordability, so all have access
- Sufficient production to cope with adverse events – a particularly apt measure this year given the COVID-19 pandemic.
“Regardless how sustainable it is or isn’t from climate change and other perspectives, it’s not sustainable if it falls at that first hurdle,” Dr Smith said.
Delving into markers for affordability and nutrition on a per individual basis, the SNI scientists and researchers developed a linear optimisation programme model using USA supermarket food data and recommended daily intakes of 28 nutrients.
“In particular, we wanted to know whether animal-based nutrients played a part of least-cost diets. Were they essential? The answer was ‘yes, absolutely’.”
The model found that a nutritionally adequate diet could be achieved at $US 1.98 per day. (Note: Such a restricted diet would not be recommended long-term.)
Animal-sourced nutrients, in particular from dairy, always featured in the least-cost diet.
“The reasons are largely about nutrient density. It is very challenging, particularly at large population scale, to achieve adequate nutrition without animal-sourced nutrients.”
As well as enhanced bio-availability (ability of the human body to use) of micro-nutrients and trace elements from meat, dairy and eggs, there is also much lower nutrient density in planted-sourced foods, meaning a person has to eat larger volumes.
Milk is an excellent source of calcium, essential fats and bioavailable protein. Meat is also important for bioavailable protein and bioavailable iron.
To investigate when a plant-sourced diet would kick in as lowest priced, SNI used the model to increase the price of animal-sourced nutrients as a component of an adequate diet.
“The price of meat had to double before it disappeared from the (most affordable) diet; the milk price had to increase eight times, and eggs tenfold,” Dr Smith said.
The cheapest plant food diet was $US3.61.
The SNI researchers are now working on inputting New Zealand supermarket data. It’s not as simple as making currency comparisons; “we know that food prices are substantially different here.
“I would expect to see the least cost diet point come up a bit but I would also expect to see the same foods represented in that diet,” Dr Smith said.
That linear model research was at a per individual basis. To test various scenarios for what is practical and/or optimal for globally sustainable future food systems, SNI developed the DELTA model. It’s freely available on-line, and includes the ability of users to alter different inputs and parameters to see for themselves the impact.
Data from 2018 shows that 10.6 billion tonnes of food biomass production occurred, but after taking into account the huge amounts of wastage in the system, plus the amount taken out for production of bio-fuels, the total food supply was 4.65 billion tonnes. And of that, 1.5b tonnes was used for animal feed.
Nevertheless, the model showed this was sufficient for the macronutrient requirements (protein, energy, dietary fat) for the current world population of 7.6 billion. Of course, we fall down on distribution of that food, with some countries/peoples enjoying far more than ‘adequate’ and some far less.
However, gaps in the recommended dietary intakes for micronutrients showed up – in particular a 36% deficit in calcium and a 31% deficit in vitamin E.
The DELTA model was then used to see if today’s food production could feed the projected 2030 population of 8.6 billion (one billion more people than now). Again, if our distribution systems were optimal, current food production could supply enough macronutrients. But big shortfalls in micronutrients appeared – calcium 43%, vitamin E 41%, iron 11%, potassium 12%, riboflavin 6%, vitamin A 9%, Vitamin B12 6%.
“For calcium, not only would we not be making the recommended daily intake, we’d also be falling short of the absolute minimum calcium requirement [for human health].”
Given that essential micronutrients such as vitamin B 12, riboflavin and the amino acid glycine come mostly from fish, dairy, meat and eggs, trying to transfer to plant-sourced only diets “means that starts to become really challenging from a global nutrition point of view”.
During question time, Dr Smith acknowledged the DELTA model does not take into account new technologies such as precision fermentation of micronutrients, ‘lab-grown’ proteins, or insect-based diets. That would involve assumptions and data not yet available.
The DELTA model was really about sparking international discussions about optimising global nutrition and food production, he said.
Though admitting lab-grown proteins was not his area of expertise, Dr Smith said what he did know, and what he’d gleaned from the experts at the Reditt Institute who were working in that sphere, indicated to him that “alternative processes like that are not likely to completely disrupt the global food system in the next 10 years, and maybe within 20-30 years, because of issues such as scalability and also social acceptance [of those foods].”