What is Veillonella atypica, and why is she a ‘good’ bug?

ZOE runs the largest study of nutrition and gut bacteria in the world, with data from over 40,000 people. We publish our research in top scientific journals, including Nature Medicine.

Our scientists have found 15 “good” gut microbes that are associated with indicators of good health and 15 “bad” gut microbes that are linked with worse health. 

Veillonella atypica — or “Violet,” as we call her — is one of the 15 “good” bugs. In this article, you can find out more about Violet, why she’s a good bug, and what foods she likes and dislikes. 

Fast facts about your gut microbiome

  • Your gut is home to trillions of bacteria and other microbes that make up your gut microbiome.

  • These microbes mainly feed on fiber and chemicals called polyphenols, which give plants their color, and turn these into chemicals that help support your health and weight control. 

  • Your gut microbiome is unique and radically different from everyone else’s, unlike your DNA, which is 99% the same. Even twins only share 34% of the same microbes. 

  • At ZOE, we use the latest and most advanced biotechnology to analyze the bacteria in your gut from a poop sample.

  • Using this technology, the ZOE program tells you your unique microbiome composition — including which of the 15 “good” and 15 “bad” bugs are in your gut — in order to recommend the best foods for you.

Who is Violet?

Violet is part of a group of bacteria called Firmicutes. If you looked at her under a microscope, you would see that she is spherical, or round. 

Our scientists found Violet in the guts of a little under half of our study participants: 41%, to be precise. 

Other members of the Firmicutes group include Lactobacillus, which you may be familiar with already. They are “good” bugs in foods like yogurt.

Why is Violet a ‘good’ bug?

Violet is a common resident in the oral cavity and the gut. She produces propionate and acetate. These are chemicals called short-chain fatty acids, and they're important for good health.

In the oral cavity, Violet is involved in the formation of plaque and may also play a role in periodontal disease. 

One group of researchers found that marathon runners have higher levels of Violet in their guts after their runs. They also found that giving Violet to mice increases the animals’ running time. 

In our study, we saw links between having Violet in your gut and having higher insulin sensitivity, as well as lower levels of insulin after eating. 

Higher insulin sensitivity and lower insulin levels are good for your body. Too much insulin isn’t good for your health, as it increases your risk of obesity, type 2 diabetes, and heart disease.

What foods does Violet like and dislike?

Our scientists have found links between specific foods and the 15 “good” and 15 “bad” gut bugs.

In general, Violet likes whole grains, such as wholegrain pasta, as well as apples and spinach. She doesn’t like burgers, potatoes, or white pasta.

But the exact foods that will help Violet thrive in your body depend on the combination of bugs in your gut. Since every person’s gut microbiome is completely unique, there’s no one-size-fits-all diet that’s right for everyone. 

The ZOE program analyzes your entire microbiome and works out your unique “gut booster” and “gut suppressor” foods, so “good” bugs like Violet can flourish.

If you want to know the best foods for your body and your unique combination of gut bugs, take our free quiz


A YadA-like autotransporter, Hag1 in Veillonella atypica is a multivalent hemagglutinin involved in adherence to oral streptococci, Porphyromonas gingivalis, and human oral buccal cells. Molecular Oral Microbiology. (2015). https://onlinelibrary.wiley.com/doi/epdf/10.1111/omi.12091

Insulin: Too much of a good thing is bad. BMC Medicine. (2020). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7441661/

Meta’omic analysis of elite athletes identifies a performance-enhancing microbe that functions via lactate metabolism. Nature Medicine. (2019). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7368972/

Microbiome connections with host metabolism and habitual diet from 1,098 deeply phenotyped individuals. Nature Medicine. (2021). https://www.nature.com/articles/s41591-020-01183-8