With meatless burgers heating up the food scene, it’s time to revisit the effects of a plant-based diet on our health, with an emphasis on microbiome impact.
An excellent review published in September 2019 reviewed effects of a plant-based diet on metabolism and cognition. After winnowing down the field, the researchers from Berlin and Leipzig in Germany ultimately included 32 clinical trials. The effects of plant-based diets on the body and the brain: a systematic review appeared in Translational Psychology.
Not surprisingly, there was robust evidence for benefits of plant-based diets versus conventional diets on weight, energy metabolism and systemic inflammation in healthy participants, obese and type-2 diabetes patients. The underlying mechanisms are grounded in the starkly contrasting menus of macro and micronutrients between the two.
Plant-based diets differ from omnivore diets in many ways
- Types of fatty acids (mono- and poly-unsaturated versus saturated and trans)
- Sugars (complex and unrefined versus simple and refined)
- Lower intake of saturated fatty acids, retinol, vitamin B12 and D, calcium, zinc and protein
- Higher intake of fiber, magnesium, iron, folic acid, vitamin B1, C and E in vegan compared to omnivore dieters
These differences alone benefit metabolism and help prevent chronic diseases such as obesity and Type 2 diabetes.
Plant-based diets and the microbiome
But importantly, novel microbiome-related pathways, by which plant-based diets modulate the gut microbiome towards a favorable diversity of bacteria species, are also evident.
One included study of 98 participants from the University of Pennsylvania concluded that a diet high in protein and animal fats was related to more Bacteroides, whereas a diet high in carbohydrates was linked with more Prevotella.
The astonishing news was how fast a change in diet elicited change in gut microbial enterotype: converting from a high-fat/low-fiber or to low-fat/high-fiber diet produced change in only 24 hours and remained stable over 10 days.
In another study, fermentation processes linked to fat and carbohydrate decomposition were related to the abundance of certain microbial species. The researchers found a strong correlation between fiber intake and Prevotella abundance in the microbial gut. The result may be better glycemic control and tempered inflammatory processes.
The German researchers include many recent studies on possible beneficial pathways involving the microbiome which will be helpful to all working in this sector of the food industry.
There were limited studies on effects of plant-based diets on cognition. However they conjectured that one underlying mechanism of how plant-based diets may affect mood could involve signaling pathways on the microbiome−gut−brain axis.
The new meatless burgers taste more like animal meat than the dry textured patties of old. Whether people will go back for more after the novelty wears off is another question. But without a doubt, foregoing meat is better for the planet (cattle heat up the planet and use vast amounts of land and water) and healthier for your body.
Our microbes prefer plants too; that may be a better reason to throw one on the grill.