Nutritional quality of plant-based products surveyed by UK's Quadram Institute

Researchers from the Quadram Institute have carried out a comprehensive survey of the nutritional quality of plant-based products on sale in the UK.

Dr Maria Traka and her team in the Food & Nutrition National Bioscience Research Infrastructure (NBRI) looked at over 2,500 plant-based products and compared them with their animal-based counterparts.

They found that, in general, plant-based products were higher in fiber, but lower in protein, with a small percentage of the products supplemented with essential vitamins and minerals.

However, overall there is a huge amount of variation in the nutritional qualities of plant-based products on the UK market.  

This suggests that manufacturers could be doing more to improve certain plant-based products, both by enhancing the nutritional quality and by reducing environmental impact. More guidance is needed to support people making the switch to more sustainable, healthier diets.

As well as animal welfare, a common reason for switching to a plant-based diet is that it is more sustainable for the planet; plant-based food uses around 40% less water and emits 80% less greenhouse gases. Diets based on plants are also acknowledged as being healthier and associated with a reduced risk of developing chronic diseases.

All of this means that plant-based diets are on the increase. Around 2-3% of people in the UK are vegan, over half of whom have switched in the past five years. Also, 5-7% of the population describe themselves as vegetarian. Even more people, around 14%, are flexitarian, being mainly vegetarian but occasionally eating animal-based products. Overall the consumption of meat and meat-products in the UK is at its lowest levels since records began.

Food manufacturers have responded to this by developing a range of plant-based products that aim to match the taste and texture of popular animal-based foods. The number of these consumed has doubled in the UK in recent years, but how do these novel products stack up nutritionally?

To answer this question, the Quadram Institute’s food composition data experts in the Food & Nutrition NBRI used a brand database covering 98% of existing products to source back-of-pack nutrient information of any labelled plant-based, vegan, vegetarian or meat-free.

In total, 2,695 products were identified, including plant-based drinks, sausages, cheese and meat-free 'beef', 'chicken' and 'fish'. In total, 446 plant-based ready meals were also identified. Each food type was then paired with generic animal-based foods, or in the case of ready meals the nearest animal-based equivalents, and the nutrient contents from the product labels were compared.

In addition, the team calculated the nutritional quality of each food using the Nutri-Score system. This is an algorithm that considers a range of different factors to provide an overall score representing of nutritional quality. It is used to guide consumers in France and some other EU countries, similar to the UK’s traffic light labeling. Nutri-Score is especially useful for comparing foods from the same group. The team also looked at which products had been fortified or supplemented with vitamins and minerals.

The analysis has now been published in the journal Food Chemistry. The study was supported by the Biotechnology and Biological Sciences Research Council, part of UKRI.

They found that across all of the food groups, the plant-based products had higher levels of fiber than their animal-based equivalents.

This is positive news, as generally most of us don’t get enough fiber in our diet. While increasing the amount of minimally processed vegetables, fruits, grains and seeds remains the best way to up fibre intake, this study shows meat-free alternatives can also support this.

On the other hand, all of the groups except beef and ready meals had lower protein levels. This may not be a major concern as, at least in westernized countries, people on average consume more than enough protein.

But it may affect certain groups, such as older adults, people who are pregnant or breastfeeding, or with certain medical conditions, who are more at risk of protein deficiency, especially as the study found that beef alternatives generally have a lower percentage of essential amino acids to total protein content.

Innovations in protein sources, processing and absorption could potentially address the limitations of protein abundancy and bioavailability in novel plant-based products.

There is a growing concern that people switching to plant-based foods may become deficient in vitamin B12 and other essential minerals. Adding these to plant-based foods as supplements would help alleviate this.

The most commonly supplemented plant-based products were milks and creams, ready meals, yogurts and drinks. Vitamin B12 was the most widely supplemented nutrient, followed by calcium, vitamin D and iron.

But vitamin B12 was only added to 15% of products, with the majority of plant-based foods lacking any nutrient fortification.

This represents a missed opportunity, especially to increase  vitamin B12 levels for people following a vegan diet, as vitamin B12 is only found naturally in animal-based foods. Increasing supplementation in plant-based foods would help address this, but this does need to take into account the stability of those nutrients in the food, and how well the body absorbs them.

In terms of overall energy levels, there was very little difference between plant- and animal-based foods.

Importantly, many of the products would be classed as ultra-processed due to the inclusion of additives or the way they are made. While the consumption of UPFs is linked to poor health, not all of the foods that come into that category are unhealthy.

Nutri Score data provides a more detailed assessment of how healthy food. In this study it provided insights into how variable the nutritional quality of plant-based foods can be. In the beef, sausage, and chicken groups some plant-based products scored well but a small percentage had much lower quality scores than their animal-based counterparts. With the limited data provided by food manufacturers, this study also couldn’t fully assess any positive benefits from including plant-derived ingredients, including polyphenols and other phytonutrients that have long been associated with health.

“Overall, we’ve identified trends that plant-based foods are higher in fiber and lower in protein, but we can’t give an overall blanket answer to whether plant-based food products are healthier than their animal-based counterparts” commented Dr Traka. “This very much depends on each product’s formulation, so it’s important that manufacturers provide this information and share it correctly with consumers so that they can make informed decisions.”

“Currently there is a large amount of variation in how healthy these products are, but this presents an opportunity for food manufacturers to up their game and improve their formulations, including through fortification with essential vitamins and minerals,” added Dr Liangzi Zhang, first author of the study.