What Does the World's Largest In-depth Nutritional Research Study Say About the Gut Microbiome?

May 12, 2022 7 min read

What Does the World's Largest In-depth Nutritional Research Study Say About the Gut Microbiome? - Layer Origin Nutrition

PREDICT 1 Study: The Link Between Gut Microbe, Diet, and Metabolic Illness

The concept of personalised medicine has been on the agenda for a while, with healthcare professionals moving towards a tailored and personalised clinical model. It’s an exciting prospect because it would mean clinical diagnosis would be faster based on your own unique situation, and treatments could be tailored to you, limiting side effects and boosting effectiveness[i].

But what if it was possible to modulate the human gut microbiome and, in turn, improve health through personalised advice? Now, it looks like that may be possible, thanks to the ground-breaking discoveries being made by the UK led PREDICT studies.

So far, the studies have suggested that a complex interplay exists between the inhabitants of the gut microbiome, diet, and health status. The researchers have even shown that specific microbes may also play a role in host responses and effects after meals (blood glucose and fat levels) which may have a long-term effect on health and weight[ii].

In this article, we take a look at the PREDICT 1 study, its key findings in relation to the gut microbiome, and introduce some of the key gut microbes that may play a significant role.

What is the PREDICT 1 Study?

If we could see into the future, there’s no doubt many things will have changed, and we see huge differences today compared to just 20 to 30 years ago. In the 90s, the text messaging revolution began. It felt new and exciting. Fast forward to 2022, and most of us can now send voice messages, use emojis to communicate, and video calling has even become the new norm.

What’s that got to do with anything? Well, technology has rapidly evolved which has had a huge impact on our personal and work lives. Plus, healthcare and medicine have also advanced massively. It appears that the way we eat may also be subject to change.

Metabolic illnesses have become a huge burden on health services across the western world and beyond. According to a worldwide survey conducted in 2015 across 195 countries, 604 million adults and 108 million children were obese[iii]. Those figures are staggering, and treatments are often based on a one size fits all approach, like calorie or carb counting, and diet and exercise plans.

But more recent research has shown that personalised recommendations can be made based on a person’s unique physiology, including the composition of their gut microbiome. Thanks to PREDICT (Personalised Responses to Dietary Composition Trial), the largest, in-depth nutritional research program in the world, researchers are learning more about individual responses to food as well as the impact of lifestyle factors.


The PREDICT 1 trial involved 1102 healthy twin and unrelated adults in the United Kingdom (plus 100 from a US cohort). Researchers assessed the postprandial metabolic responses, blood triglyceride, and glucose and insulin levels following the consumption of identical meals, both in a clinical setting and at home. The aim of the study was to assess how postprandial responses to meals were affected by a range of factors, including:

  • the gut microbiome
  • metabolic differences
  • meal context
  • genetics
  • meal composition
  • characteristics like age, gender, BMI

In this article, we are going to focus on the results collected from the study related to the gut microbiome, but first, let’s have a short gut microbiome recap.

Key findings from the PREDICT study

According to the ZOE research team, there are six major findings from the PREDICT studies, of which there have been six studies so far: 

  1. Humans have individual responses to the same foods.That means the way your body responds to high/fat carbohydrate meals, for example, may differ from someone else.
  2. The gut microbiome has an important role in metabolic health.The studies have found that a diverse microbiome alongside a diet rich in fibre, and plant-based foods help to nourish ‘good’ gut bacteria, enabling them to thrive. A low diversity diet with lots of processed foods has been associated with poor metabolic and long-term health.
  3. Dietary inflammation has a significant impact on health.That means what you eat can affect your health.
  4. Your genes may play a small role in your body’s response to the food you eat but it is possible to improve health through diet and lifestyle.Interestingly, the research has found that even identical twins may have a different response to the same foods.
  5. Extra calories are not the only cause of weight gain.
  6. Personalised nutritional advice can be created using machine learningii.

Why is the gut microbiome so significant?

The gut microbiome is a complex ecosystem consisting of trillions of microbes. Many of these microbes live in harmony with you and are critical for human health. That’s because the human gut microbiome has important roles in:

  • transforming dietary fibre into vital metabolites, such as short-chain fatty acids
  • the production of vitamins, enzymes, and other metabolites that may not be available via the diet or cannot be made by the human body
  • the metabolic response to food
  • supporting the immune system

The composition and diversity of the gut microbiome has been shown to have a major influence on both health and disease, including the risk of heart disease, type 2 diabetes, inflammatory bowel disease, obesity and cancer. The gut microbiome has also been shown to have a major impact on host metabolism both directly and indirectly through the diet. So, a low bacterial diversity has been found in individuals with chronic illnesses such as:

  • inflammatory bowel disease
  • type 2 diabetes
  • eczema
  • obesity
  • Crohn’s disease[iv]

The influence of food on the gut microbiome

The PREDICT 1 study has shown that the composition of the gut varies from person to person and that even identical twins can have vastly different gut microbiomes. In fact, every single one of us is unique when it comes to our gut microbes because we all have a unique set of genetic variants or strains of each microbial species in the gut. Interestingly, genes only have a small influence over the composition of your gut microbiome, which means you have the power to modify it through your diet.

The unique thing about the PREDICT 1 study is that through the analysis of microbiome data collected from stool samples, alongside health metrics such as blood pressure, age, and body mass index as well as diet and postprandial responses, researchers were able to identify 15 ‘good’ and 15 ‘bad’ bacteria strains.

By ‘good’ and ‘bad,’ the researchers mean 15 bacterial strains that are associated with good or positive health markers and 15 that are linked to poor or bad health. The PREDICT 1 study found a strong link between diet quality and the composition of the gut microbiome. They found that certain compositions were strongly linked to healthy and unhealthy foods or dietary patterns, and these were also associated with specific health markers, such as those for obesity.

The study found that the microbes associated with good health outcomes were found in individuals who followed a diet high in healthy plant-based foods and fibre but also in people who consumed healthy animal-based foods like oily fish, shellfish, eggs, and yoghurt. It was similar for the abundance of ‘bad microbes, too. Here, the researchers saw a pattern in people who consumed unhealthy plant and unhealthy animal-derived foods and their microbiome composition.

The key here is to eat a balanced and diverse diet because individuals who ate meat could also display a ‘healthy’ gut microbiome as long as their diet was varied. That’s not all, the study also established a link between what a person’s gut microbiome looks like (healthy or unhealthy) and specific cardiometabolic biomarkers, such as:

  • blood pressure
  • fasting glucose
  • fasting lipids
  • HbA1c
  • Inflammation

What that means is that certain microbes can affect your risk of developing some chronic conditions including, heart disease, diabetes, and even obesity. According to the PREDICT 1 study, a healthy diet is one that has a variety of foods that are associated with a lower risk of chronic disease. A diet such as this, or one that is high in plant-based foods, means individuals who consume it are more likely to have a greater abundance of ‘good’ gut microbes and a lower risk of illness. 

The 15 ‘good’ gut microbes (not the ones you expected)

The PREDICT 1 study has identified 15 good gut microbes that are linked to positive diet and health indicators. They are:

  1. Faecalibacterium prausnitzii
  2. Eubacterium eligens
  3. Oscillibacter sp 57 20
  4. Romboutsia ilealis
  5. Haemophilus parainfluenzae
  6. Firmicutes bacterium CAG 95
  7. Oscillibacter sp PC13
  8. Veillonella dispar
  9. Roseburia sp CAG 182
  10. Veillonella atypica
  11. Clostridium sp CAG 167
  12. Veillonella infantium
  13. Bifidobacterium animalis
  14. Prevotella copri
  15. Firmicutes bacterium CAG 170 

Over the next few weeks, we’re going to be bringing you an in-depth look at the 15 bacterial species labelled as ‘good’ by the PREDICT 1 study. So, get ready to be amazed at the purpose, functions, and even the names of some of these incredible microbes. 


The PREDICT series of studies, including PREDICT 1, is the largest, in-depth nutritional program in the world. The PREDICT 1 study helped to define links between a person’s diet, gut microbiome, and cardiometabolic health biomarkers from a cohort of 1100 participants.

The findings from the study have shown how important the gut microbiome is in determining human health, as well as showing that it is able to be modified, through diet, making it the perfect target for personalised nutrition.

Remember, you can support your own gut microbiome and help to improve its diversity with our PureHMO® human milk oligosaccharide prebiotics. Take a look at our range here. 



[i] England, N., 2022. NHS England » Personalised medicine. [online] England.nhs.uk. Available at: <https://www.england.nhs.uk/healthcare-science/personalisedmedicine/> [Accessed 5 May 2022].

[ii] 2. ZOE Science. Rethinking the future of nutrition. ZOE Science; 2020 p. 25-28.

[iii] Saklayen MG. The Global Epidemic of the Metabolic Syndrome. Curr Hypertens Rep. 2018 Feb 26;20(2):12. doi: 10.1007/s11906-018-0812-z. PMID: 29480368; PMCID: PMC5866840.

[iv] Valdes A MWalter JSegal ESpector T DRole of the gut microbiota in nutrition and health BMJ 2018; 361 :k2179 doi:10.1136/bmj.k2179

6 Responses

Layer Origin Customer Support
Layer Origin Customer Support

May 26, 2022

Re: Marie

Hi Marie, we hear you and this is exactly why we do not advocate our customers to buy probiotics (we are a prebiotic company). We are dedicating to providing solutions to feed the bacteria in our gut so they can grow well and stay. We will do a follow up article about how our food/diet influences the growth of those beneficial microbes. More information are being collected from the original research groups. Stay tuned.- Layer Origin

Layer Origin Customer Support
Layer Origin Customer Support

May 26, 2022

Re: Robert,

Hi Robert,

We can not upload the whole article to our website since the journal has the copyrights. But you are welcome to find the original version here (https://www.nature.com/articles/s41591-020-0934-0) (only downloadable through University network)

Or you can email support@layerorigin.com to get a copy

Layer Origin

Robert Kemp
Robert Kemp

May 25, 2022

No answer to my question after one week – I guess Layer doesn’t care about their customers.

Robert Kemp
Robert Kemp

May 18, 2022

Where is the published paper with the 15 “good” bacteria listed?


May 18, 2022

These studies are great to reference and fascinating to read. But, I find with all these, they ultimately lead to heavy marketing to eat “X microbe” purchased in “X supplement” because “clinical trial said X.” That being said I think Layer Origin offers a high quality product and they are on the right track of “feeding” your existing personal biome vs shoving unwanted guests in it ;)

It would be great if these studies instead included info on how/what influences the microbes robust growth “naturally” and what throws them out of whack (sunlight exposure, blue light exposure, cell phone exposure, toxin exposure, our grossly sedentary lifestyles, etc).

As someone with severe IBD who has tried thousands of dollars worth of probiotics in the past twenty years and had hundreds of tests with so said X probiotic of the moment to compare and contrast…I can confidently say “a pill of lab made microbes,” (in most cases) will not "fix your gut” or in my case influence any blood tests of lipids, glucose, A1c, crp, etc…

Humans are out of the natural loop of existing and I don’t think I will see true evidence of microbiomes (galaxy-in-a-body) being “fixed” by a simple supplement while I am in this galaxy. I hope I am proven wrong!

Daren Purnell
Daren Purnell

May 18, 2022

excellent summary, thanks for sharing

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