A switch from animal meat and dairy to plant-based substitutes is often considered to be an optimal way to reduce greenhouse gas emissions associated with diet.
The nutritional picture is, however, more complex. Some consumers view plant-based substitutes as a healthier option compared with animal-based meat and dairy, and some see these substitutes as ultra-processed and therefore to be avoided. Naturally, the truth is somewhere in between.
A new study explores the varying level of health content between different plant-based substitutes, presenting a potential solution for consumer confusion.
Assessing the plant-based landscape
The study aimed to assess the available literature on the health content and environmental impact of plant-based alternatives (with mycoprotein included in said definition, despite coming from the fungi – rather than plant – kingdom) in high-income countries, including plant-based meat, milk, cheese, egg and yoghurt alternatives. Overall, the study analysed 57 peer-reviewed studies and 36 grey literature articles.
To mitigate the potential that some of these studies were funded by the industry that produced said plant-based substitutes, a sensitivity analysis was performed. Indeed, studies funded by industry were more likely to find differences in nutrition than those funded by academia, but the overall trend was the same.
The studies which focused on plant-based meat revealed that most meat alternatives had lower saturated fat content, lower energy density, and more fibre than their animal-based cousins.
Health of UPF plant-based burgers
Earlier this year, the World Health Organisation (WHO) analysed the levels of health in ultra-processed plant-based burgers in Amsterdam, Copenhagen, Lisbon and London.
On the one hand, they found that plant-based protein (albeit low quality protein), dietary fibres and minerals, which can reduce non-communicable disease (NCD), were ‘abundantly’ present in the burgers. However, the burgers were also high in fat, salt and calories, which are directly linked to NCD, presenting a more ambiguous health picture. Overall, only 10% of the burgers analysed by the WHO were considered 'unhealthy'.
The lowest energy density and highest fibre content of all was mycoprotein, while cereal and grain based meats had the highest energy density similar to the levels found in meat and poultry, and the lowest fibre content, still significantly higher than meat and poultry.
Mycoprotein was also lowest in saturated fat, whereas nut and seed-based meats were found to be the highest (still lower than the saturated fat content of meat and poultry).
However, all plant-based meats contained more sugar than meat and poultry, and similar levels of sodium (with the exception of legume-based meats).
Mycoprotein had the lowest levels of sugar, whilst nut and seed-based meats had the highest.
In terms of micronutrients, some plant-based meats fared better than others. For example, while cereal and grain-based meat alternatives were higher in iron than their plant-based counterparts, animal-based meats generally came out on top when it came to vitamin B12 content. Legume and mycoprotein products usually match plant-based meat for protein.
The research also looked at plant-based drinks, finding, from 19 studies, that plant-based drinks usually had lower energy density and saturated fat and more fibre than their dairy-based counterparts.
The lowest energy density was found in coconut-based drinks, whereas the highest was cereal and grain-based (although still not significantly higher than dairy-based drinks). However, coconut-based drinks had the highest levels of saturated fat out of plant-based drinks assessed, compared to those based on cereals and grains, fruits and vegetables, and nuts and seeds, which had the lowest.
In contrast to plant-based meats, most plant-based drinks had lower levels of sugar than dairy milks, especially coconut, legume and nut and seed based drinks. Conversely, no plant-based drink matched the iodine content of dairy milks.
Plant-based yoghurts, on the other hand, showed a higher energy density and a higher sugar and fibre content than dairy-based, while having a lower saturated fat and sodium content.
Most plant-based cheeses assessed has a higher energy density and a higher saturated fat content than dairy cheese. Cheese based on nuts and seeds had the highest energy density, and cheese based on coconut oil had the highest saturated fat content (50% more than dairy cheese).
Health of plant-based steaks and cold cuts
A recent study on plant-based steaks and cold cuts found that they are sometimes low in protein, and additionally often contain more carbohydrates than their animal brethren.
However, plant-based steaks were found to be comparable with veal samples they were analysed against - in terms of essential amino acid content and digestibility. Plant-based cold cuts contained less salt and fewer amino acids than meat cold cuts.
However, both plant-based cheese based on nuts and seeds, and based on coconut oil had a generally higher fibre content than dairy cheese. Most plant-based cheese had a lower sodium and sugar content (although coconut-based cheese’s sodium content was similar to dairy).
So which plant-based alternatives came out on top? According to Sarah Nájera Espinosa, one of the researchers, swapping out meat for alternatives based on legumes such as peas and soy and fungi such as mycoprotein, as well as drinks for those based on legumes and vegetables such as potatoes, would not only reduce environmental footprints but boost healthiness.
However, some plant-based cheeses, such as those based on coconut oil, did not fare well in the study.
How healthy are plant-based meats?
As well as the nutritional content, the study also explored the general health affects of switching to a plant-based diet. In terms of plant-based meat, studies on making the switch to mycoprotein showed a positive response to making the switch, both in healthy and overweight adults. The studies of other plant-based meats also showed positive health outcomes, with reduced weight and risk of cardiovascular disease, and improvements in the gut microbiome.
However, when it came to plant-based drinks the results were more complex. Studies found that those consuming only plant-based drinks had a lower iodine content in their urine, and required supplementation. The higher sugar content of plant-based drinks when compared to dairy also led to dental decay.
How to improve consumer communication
While in a great many ways plant-based products are nutritionally superior to animal-based products, it is not that simple. Therefore, the study suggested that we can only use a plant-based transition as a tool to hit health targets if we are to be selective. The study warned against a blanket recommendation of plant-based alternatives, as some are significantly worse when compared to animal-based equivalents (for example, plant-based cheese has 50% more saturated fat that dairy-based).
Such variability has the potential to cause consumer confusion, which is why the study suggested front-of-pack labelling and information campaigns to help make nutritional content clearer.
“We advocate for better guidance in identifying healthy foods for consumers. Currently ‘plant-based alternatives’ are regarded as a homogeneous food group with very similar products, and this is a wrong assumption,” Nájera Espinosa told FoodNavigator.
“Whilst many could form part of a healthier and more sustainable diets when used to replace meat and dairy, it is important that it's clear to the consumer which foods and brands this entails. Currently people might assume all plant-based alternatives are healthy and they may overconsume the ‘not so healthy’ ones, whereas others would stay away from plant-based alternatives altogether as they think that ‘surely such ultra-processed foods are all unhealthy’ – [neither is] helpful if we want people to eat healthier and more sustainable.
“A simple, but clear and effective labelling system that would sub-categorised plant-based foods would likely take some doubts away and we think this would lead to higher uptake of plant-based foods that align with healthier and more sustainable diets.”
Regulations are also suggested, which could push plant-based alternatives to reformulate and ensure optimum nutritional quality. Some techniques, which can reduce sugar, improve palatability, and remove anti-nutrients and polyphenols, are already available.
Source: Nutrition Reviews
'Mapping the evidence of novel plant-based foods: a systematic review of nutritional, health, and environmental impacts in high-income countries'
Published on: 25 April 2024
Doi: https://doi.org/10.1093/nutrit/nuae031
Authors: S. N. Espinosa, G. Hadida, A. J. Sietsma, C. Alae-Carew, G. Turner, R. Green, S. Pastorino, R. Picetti, P. Scheelbeek