A recent study gives the undecided another reason to consider adopting a vegan or keto diet: these dietary changes can bring about rapid transformations in the immune system. Vegan diets, characterized by zero animal products and typically low-fat content, and keto diets, high in animal proteins and fats but low in carbs, were the focal points of the study.

Scientists scrutinized blood, urine, and stool samples in lab tests to uncover the impact these diets might have on the immune system. They asked 20 participants to try each diet for two weeks. The vegan diet influenced what is known as innate immunity, i.e., the body's consistent protective response against pathogens, while the keto diet altered adaptive immunity, or the body's defense against specific pathogens.

The fact that a two-week dietary intervention could reshape the immune system irrespective of age, gender, body mass index, ethnicity, or race was quite remarkable, says the study's lead author, Verena Link, PhD.

While the results suggest that nutrition can have a quick and dominant effect on immunity, the study was not designed to authenticate if this would directly improve fighting infections or prevent illness. It did not assess the participants' diets prior to the experiment, nor did it identify if the reported shifts in immune function were positive or negative.

In short, while rapid impacts on immunity occurred due to dietary changes, it is still too early to recommend these diets on this specific grounds. Long-term effects of each diet on immune health, particularly in larger populations, is still uncertain. Sustainability of these diets and their overall suitability to individuals also remains a matter of consideration.