The health effects of alternative plant-based meats on inflammation
The Paper of the Month for February is from the Journal of Nutritional Science and is entitled 'Assessing the effects of alternative plant-based meats v. animal meats on biomarkers of inflammation: a secondary analysis of the SWAP-MEAT randomized crossover trial' by Anthony Crimarco.
Alternative plant-based meats have become increasingly popular with consumers over the last few years. Alternative plant-based meats (or plant-based meats) are vegan or vegetarian products that are designed to resemble the taste and appearance of traditional animal meats. For those in the United States, you likely have come across major brand names like Beyond Meat or Impossible Foods at your local super market, or even some chain restaurants. There are also increasingly more companies that are entering the market to introduce their plant-based meat products.
Traditionally, plant-based meats were marketed to vegan consumers. Vegans only account for ~5% of the total population in the United States. Companies and producers of plant-based meats have began to shift the focus of their products to non-vegan consumers. So, it would make sense that focusing on the other 95% of the population would generate a lot of interest and demand. But also concerns and criticisms about the health effects of these products.
Dietitians, researchers, and even some major players in the food industry have weighed their opinions on whether or not plant-based meats can really be considered a part of a healthy diet. The main concern is the fact that products are highly processed due to the number of added ingredients required to flavour them. This is understandably a concern, since there are a number of observational studies that have shown an association between highly processed foods and weight gain, or an increased risk for many chronic health conditions.
This was why my colleagues and I worked together to conduct a clinical trial at Stanford University to specifically compare the health effects of plant-based meats versus animal meats on cardiovascular risk factors (CVD) among generally healthy adults. After 8 weeks of consuming plant-based meats, our study participants experienced improvements in some of their CVD risk factors and even lost a little bit of weight. The improvements to their health were due to the modest improvements in diet quality: When our study participants substituted the plant-based meats over the animal meats that they would normally consume, they had an increase in daily dietary fibre and a decrease in saturated fat.
In light of these findings, we wanted to assess if there would be changes to biomarkers of inflammation as well. Afterall, if our participants had risk factors like LDL-cholesterol or TMAO (an emerging risk factor associated with inflammation) improve, we hypothesised there would be some improvements in their inflammation as well. We sent out our participants’ blood samples to a lab to have a number of biomarkers of inflammation measured. These included some of the most commonly associated cytokines with chronic diseases, like interlukein-6, tumor necrosis factor, and others. However, after analysing the data we found NO significant changes in any of the biomarkers of inflammation regardless of diet type or order.
We believe that it may due to the fact that 8 weeks is simply not enough time to see any changes in chronic inflammation. Afterall, the literature on healthy plant-based diets – as outlined from our National Dietary Guidelines – tends to indicate that it takes several months to notice any improvements in chronic inflammation. So it may not be that surprising that simply substituting some plant-based meat products in place of animal meats over an otherwise Standard American Diet would have much of an impact either. In order to further understand the potential health benefits or risks from consuming plant-based meats, longer duration clinical trials would be required. Finally, it’s important to note that plant-based meat products use different types of ingredients from one another. E.g. some products use pea protein, others may use soy etc. So it would also be beneficial to determine if the different plant-based meat products are better or worse for our overall health based on the specific ingredients that are used as well.