Thinking of taking up a ketogenic or vegan diet? Doing so could do more than help you lose weight.
A new study published in Nature Medicine shows these two widely different diets can quickly alter the immune system, demonstrating how effective nutrition is in preventing disease.
Researchers at the National Institutes of Health (NIH) found that eating a vegan or keto diet changes the body’s immune system in distinct ways.
“Our data revealed that overall, a ketogenic diet was associated with a significant upregulation of pathways and enrichment in cells associated with the adaptive immune system. In contrast, a vegan diet had a significant impact on the innate immune system, including upregulation of pathways associated with antiviral immunity,” they wrote.
Vegan diets restrict any foods that come from animals, including dairy products and eggs. Keto, or ketogenic, diets are low in carbohydrates and may or may not rely heavily on animal foods. The idea is to get most of one’s calories from protein and fat while consuming less than 50 grams of carbs per day, eventually putting the body into ketosis. Ketosis is when your body starts burning primarily fat for energy.
In recent years, the keto diet has become more popular in the United States. The keto diet exploded in 2019, becoming a $9.57 billion market as celebrities, health magazines, and documentaries touted its efficacy. In 2020, it was the most Googled diet, with more than 25.4 million unique searches. In tandem, vegan diets have continued to gain popularity. According to a 2021 study, the number of Americans who follow a vegan diet grew by 600 percent from 2014 to 2018. The plant-based foods market increased by 29 percent from 2017 to 2019.
Both Diets Altered the Microbiome in 2 Weeks
To determine the effect of both diets, researchers observed people eating each diet exclusively for two weeks. Twenty study participants were allowed to consume as much food as they wanted from one diet for two weeks, followed by as much food as they wanted from the other diet for two weeks.Both diets included nonstarchy vegetables; the keto diet included animal-based products, including meat, poultry, fish, eggs, dairy, and nuts. The vegan diet included legumes, rice, root vegetables, soy products, corn, lentils, peas, whole grains, bread, and fruit. According to the study, the vegan diet was high in dietary fiber compared to the ketogenic diet. On the other hand, the keto diet was higher in fatty and amino acids.
While both diets benefited participants’ immune systems, they had varying effects on the body.
The vegan diet helped promote the body’s innate immune system and “promoted more red blood cell-linked pathways.” The keto diet aided the adaptive immune system, which contains a memory bank for antigens; the stronger it is, the better the body can fight viruses or pathogens it has previously been infected with. Specifically, the keto diet boosted protein levels in the blood plasma and a broader range of tissues, including the blood, brain, and bone marrow.
Both diets also induced changes in the microbiomes of the study participants, indicating that nutrition plays a vital role in how the body functions.
The most marked change the researchers identified was that the microbiome of those eating a ketogenic diet downregulated pathways involved in the biosynthesis of amino acids, perhaps because the ketogenic diet is higher in protein, which is made up of amino acids. Other changes were noted as well.
“Most microbial enzymes upregulated following vegan diet were associated with digestion of polysaccharides unique to plants, whereas microbial enzymes upregulated following ketogenic diet related to digestion of polysaccharides coming from both plant and animal,” the researchers wrote.
“Our study revealed that a 2-week dietary intervention can impose a striking shift in host immunity, superseding genetics, age, sex, ethnicity, race and even body mass index.”
The results indicate that food and tailored nutrition can be used as medicine for individuals dealing with specific ailments, the researchers noted.
“The authors suggest that it may be possible to tailor diets to prevent disease or complement disease treatments, such as by slowing processes associated with cancer or neurodegenerative disorders,” the NIH said in a statement.
The study authors also emphasized that more research is needed to better understand the full implications of nutrition’s role in managing conditions and whether these results would be echoed in a larger population.
