Sir, – In her article “Eating our way to nature recovery: buy and consume only what you need to stay healthy”, Prof Yvonne Buckley (Science, May 25th) advocates moving away from a diet reliant on animal protein to one more plant-based.
In the realm of food and nutrition policy, that is presently a given. However, strategies to increase the consumption of plant-based diets need to be evidence-based and need to be equitable. The article rightly identifies food waste as an enormous drain on the human food chain. It also argues, as an example, that free-range deer can play a role in meeting nutritional needs, citing its use as a food in some Scottish hospitals. But if the supply of free-range deer exceeds the demand for the product, as might happen if beef and lamb are phased down, then its price will rise and it will be affordable by only a small proportion of the population. Presently, wild venison mince costs twice the price of prime minced beef.
The article also advocates the foraging of nettles for nettle soup. But this is somewhat challenging. The nettle plant was once the third most popular plant-based textile material after flax and hemp and was a major element of the fabric of the German troops of the first World War. In its mature form, it is a fibrous plant. Thus there is a very short window in spring when the nettle is suitable for harvesting as a food. And while there are a few specialised farms for nettle production, the idea of foraging for nettles is somewhat elitist. Foraging for food requires time and local knowledge and quite simply, there are not enough wild nettles for everybody in the audience, as they say. I am food-savvy but would not know where to start in the pursuit of nettles as a regular component of my diet. And it is worth noting that popular recipe sources (the BBC Good Food and The Irish Times) include generous quantities of both cream and butter in their nettle soup recipes.
Like it or not, the future of plant-based foods will be technology dependent. The current evidence from a major French food consumption survey (NutriNet-Santé) shows that as one moves from omnivore diets to those of pesco-vegetarians then to vegetarians and finally to vegans, the proportion of caloric intake from highly processed foods rises. Quite simply, plant-based milks, meat analogues (burgers, sausages) and ready-to-eat plant-based meals are complex processed foods that require many ingredients to make them safe, stable, lasting, affordable and, of course, palatable.
We might prefer if plant-based diets were based mainly on home-made dishes involving lentils, peas beans and the like, but the same time pressure of modern family life and the many deficits of cooking skills and resources that has led to today’s higher intakes of convenience foods and ready-to-eat meals, will continue to apply as we progress to more plant-based diets. Major changes in any aspect of lifestyle will require trade-offs and increased reliance on technology to achieve a more dominant plant-based diet is one such trade-off.
Take, for example, the cow’s milk grown in cellular agriculture systems by the Singaporean company, Turtle Tree. Stem cells are isolated from untreated fresh cows’ milk, stimulated to differentiate into milk secreting cells, cultured in a 3D tubular architecture and, when perfused with nutrients, secrete milk which flows into the hollow tubes to yield real cows’ milk with not a moo to be heard. This 100 per cent cows’ milk can be used to make traditional dairy products such as cheese, yogurts, creams and butter. Some would think that this is a step too far and that nut-based milks are the way to go. But research shows that, globally, over 60 per cent of irrigated nuts are presently produced under what are defined as severe blue water stress, blue water being the potable form of global water. Increased use of such tree nuts will make this situation worse. Relocating tree nut agriculture to suitable climates with adequate rainfall might help, but don’t expect the support of Californian almond or Turkish hazelnut farmers.
The various elements of the human food chain have traditionally been considered within independent silos but there is now an unstoppable move toward the evolution of an integrated approach to human food needs in what is now referred to as a food systems approach. The International Food Policy Research Institute describes an ideal food system as one that “would be nutrition-, health-, and safety-driven, productive and efficient . . . able to deliver affordable food, environmentally sustainable . . . climate-smart, and inclusive”. Nettle soup, herbs cultivated in window pots and free range deer, as argued by Prof Buckley, may well have some role in food systems . But on a population basis, success will require a fully integrated food system with agreed trade-offs on new and existing technologies. All proposed solutions to the design of a future world with a plant-based diet must be evidence based and, above all, non-elitist. – Yours etc,
MICHAEL J GIBNEY,
(Professor Emeritus,
Food and Health,
University College Dublin),
Blackrock,
Co Dublin.