The proposed ‘planetary health diet’ that was developed in 2019 has several shortcomings in providing necessary nutrition to humans, according to a study published in a major medical journal.
The Lancet, the world’s foremost medical journal, published a paper in March outlining the nutritional shortfalls of the planetary health diet, which was envisaged as a ‘reference diet’ for the development of dietary guidance internationally.
Interestingly, The Lancet was itself involved in the development of this diet, through the EAT-Lancet Commission, a partnership between the medical journal and EAT, which describes itself as a “global, non-profit startup dedicated to transforming our global food system”.
The 2019 reference diet grabbed headlines by calling for large reductions in the consumption of meat, dairy, and other animal-sourced foods, while also recommending similarly large increases in the consumption of plant-sourced foods.
However, the article published in March by The Lancet Planetary Health – one of a number of journals published under The Lancet name – indicated that the planetary health diet may have been wide of the mark where human nutrition is concerned.
Speaking to Agriland, Prof. Alice Stanton of the Royal College of Surgeons in Ireland (RCSI), and director of human health at Devenish Nutrition, explained what March’s paper means for the original reference diet.
She said that the reference diet was “very influential because [it] indicated that if you ate the diet that [was] recommended, individuals would gain in human health and the planet would receive protection from climate change”.
“In particular, it was looking for a considerable reduction in animal source foods… It recommended that meat, dairy and eggs should be approximately halved from most of the national and international guidelines worldwide, to go from a minimum of 25% of animal sourced foods providing calories in the diet, to only 12%.”
“The article that was published in The Lancet [in March] is really significant, because many people had said that diet is not adequate, will not lead to human health, [and] will lead to lots of [nutritional] deficiencies,” Prof. Stanton added.
These deficiencies can, in turn, lead to issues such as anaemia, elderly fragility, and childhood stunting.
March’s paper in the The Lancet Planetary Health looked at six micronutrients – folate, vitamin A, vitamin B12, calcium, iron and zinc – and examined how well – or otherwise – the original reference diet provided those nutrients.
Prof. Stanton said: “What they come up with, for a minimally adequate diet, is back to the 25% of calories needing to come from animal source foods, if you’re going to have an adequate supply of those micronutrients.
“It’s a total reversal of the EAT-Lancet reference diet.
“I can’t see how it could be logical to disagree with this latest paper,” she added.
The nutrition shortfalls in the original reference diet are, according to Prof. Stanton, especially concerning where women of reproductive age are concerned, not just for the women themselves, but also their children.
“Women of child bearing age have a huge need for increased manufacture of red blood cells, and therefore they have huge iron needs.
We know that, currently, even in high income countries, 20% to 30% of women are iron deficient. The EAT-Lancet reference diet was going to make that worse.
“It’s not just that that will result in anaemia in the women. It is actually that their children, in utero, will be deprived of iron, and other micronutrients. The brains of those children and the bodies of those children, in utero, will not develop optimally,” the RCSI professor remarked.
She added: “It really does contribute to childhood stunting, and damaged children, so it’s really important that we consider adults, children, older people, and women of childbearing age, when we consider diets. We need to consider the average, plus those with additional needs.”
Prof. Stanton acknowledged that the sustainability of food production is important, saying: “We need to bear in mind the sustainability credentials of how food is produced, and how we manage the waste from that food, and we need to do that a lot better.”
She welcomed the discussion over how to promote both human health and planetary health through global food systems, but said that the EAT-Lancet reference diet “got it not quite correct in many ways”.
“It was very rigid, and it took the view that animal source foods were creating lots of emissions and therefore they should be removed or dramatically reduced. They didn’t put enough focus on improving the sustainable production of food,” she said.
“This is a really important debate, and we need to use the best evidence, and the best metrics possible, and they need to transparently evidence based, both in the relationship between food and human health, and the relationship between food production and environmental damage,” Prof. Stanton commented.