This article was written by one of The Food Medic team; registered dietitian – Maeve Hanan
The importance of good gut health and a diverse gut microbiome is gaining more and more attention. This article will explore the advice that you should specifically aim for at least 30 different types of plants per week to boost gut health.
What is a healthy gut microbiome?
This is the trillions of microbes (mainly bacteria) found in your intestines that function as an organ and significantly impact health.
There’s no such thing as a ‘perfect gut microbiome’ because this varies so much between people, and is impacted by so many factors.
Factors that impact the gut microbiome include (1):
- birth delivery method i.e. vaginal or C-section
- whether you were breast or formula fed as a baby
- exposure to antibiotics
Current research indicates that a healthy gut contains diverse bacteria and higher levels of health promoting bacteria (like Bifidobacteria and Lactobacillus) as compared with potentially harmful gut bacteria (like E.coli and Staphylococcus) (1).
Having a healthy, diverse gut microbiome has been seen to impact immunity and body size, as well as reducing the risk of a number of medical issues including food allergies, gut and metabolic diseases (2). More research is emerging in this fascinating area all the time.
Why 30 plants per week?
A fascinating study from 2018 compared the gut microbiome of over 10,000 volunteers, mainly from the US, UK and Australia (3). This study had a number of important findings, including those who consumed more than 30 types of plants per week were more likely to have a healthier, more diverse gut microbiome, as compared with those consuming less than 10 types of plants per week.
Interestingly, this plant diversity was seen to be more important than following a vegan or plant-only diet (3).
Other studies have also found that consuming a variety of plants in the diet is associated with improved gut health (4).
It’s likely that fibre plays a big role in why plant diversity is so good for your gut. Certain types of fibre can be fermented and used to feed healthy gut bacteria (5). This fermentation process also produces short chain fatty acids (SCFA) which feeds and protects cells in the gut lining and may also be beneficial when it comes to immunity and metabolic health (6). Fibre also helps with the movement of stools through the digestive system.
As well as fibre, plant-based foods can contain a variety of important nutrients such as vitamins, minerals, antioxidants, carbohydrates, proteins and fats. The nutrient composition varies between different plant-based foods, hence consuming a wide variety leads to varied intake of nutrients.
Examples of different plant-based foods
Based on this landmark study, Dietitian Dr Megan Rossi (A.K.A. The Gut Health Doctor) came up with the term ‘plant points‘. All plants count towards your plant points with 1 point per portion, with herbs and spices getting 1/4 point each.
When we think of ‘plant-based foods’ the main foods that come to mind are often fruit and vegetables. But there are many other foods that fall into this category as well.
Different types of plant based foods include:
- beans and pulses e.g. chickpeas, lentils
- grains – e.g wheat [i.e. flour, bread, pasta and couscous], oats, quinoa, rice, buckwheat etc.
So when aiming for at least 30 different types of plants per week it’s best to aim for a variety within all of these types of types.
As always when it comes to nutrition, this guideline might not suit everyone. The aim behind the recommendation is to increase the diversity of plant-based foods in the diet, so it might be more realistic for many people to aim to work on this more gradually. For example, if you currently usually consume 5 different types of plants each week a good starting point could be aiming for 7-8 per week, then 9-10 etc.
As the research the 30 plants per week recommendation is based on was carried out in adults who were mainly based in the US, UK and Australia this might also not be applicable to people of different ages, or with different cultural and economic backgrounds.
It might also not be appropriate for those with certain medical conditions. For example, those who are malnourished and need to prioritise their energy and macronutrient intake. Similarly, it might not work for those with IBS who are working to find their triggers or are sensitive to fibre or FODMAPs (a group of fermentable carbohydrates).
For those who struggle with disordered eating, there’s a risk that this could become a rigid rule and that lower-energy higher-fibre plant-based foods could be used to bulk out the diet as a form of restriction.
So although aiming to include a wide variety of plants in the diet is a good idea for many people, it’s always important to consider your individual circumstances and to get one to one advice from a Registered Dietitian if you need some support with this.
Having a diverse intake of plants in the diet can play an important role in developing a healthy and diverse gut microbiome, which is likely to have a knock-on beneficial impact on overall health.
The advice to aim for 30 plants per week comes from a fascinating study which found this to be linked with improved gut health as compared to consuming less than 10 types of plants per week.
So for many people, aiming for at least 30 different plants per week may be good for their gut. This can be achieved by eating a variety of fruit, vegetables, beans, pulses, nuts, seeds and grains.
But when it comes to nutrition, there’s never a ‘one fits all’ answer, so there are situations where aiming for this may not be a good idea. Always seek individual nutritional advice where needed.
- Rinninella, E., Raoul, P., Cintoni, M., Franceschi, F., Miggiano, G. A. D., Gasbarrini, A., & Mele, M. C. (2019). What is the healthy gut microbiota composition? A changing ecosystem across age, environment, diet, and diseases. Microorganisms, 7(1), 14. [accessed April 2022 via: https://pubmed.ncbi.nlm.nih.gov/30634578/]
- Valdes, A. M., Walter, J., Segal, E., & Spector, T. D. (2018). Role of the gut microbiota in nutrition and health. Bmj, 361. [accessed April 2022 via: https://www.bmj.com/content/361/bmj.k2179]
- McDonald, D., Hyde, E., Debelius, J. W., Morton, J. T., Gonzalez, A., Ackermann, G., … & Knight, R. (2018). American gut: an open platform for citizen science microbiome research. Msystems, 3(3), e00031-18. [accessed April 2022 via: https://pubmed.ncbi.nlm.nih.gov/29795809/]
- Heiman, M. L., & Greenway, F. L. (2016). A healthy gastrointestinal microbiome is dependent on dietary diversity. Molecular metabolism, 5(5), 317-320. [accessed April 2022 via: https://pubmed.ncbi.nlm.nih.gov/27110483/]
- Chassaing, B., Vijay-Kumar, M., & Gewirtz, A. T. (2017). How diet can impact gut microbiota to promote or endanger health. Current opinion in gastroenterology, 33(6), 417. [accessed April 2022 via: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6005665/]
- Blaak, E. E., Canfora, E. E., Theis, S., Frost, G., Groen, A. K., Mithieux, G., … & Verbeke, K. (2020). Short chain fatty acids in human gut and metabolic health. Beneficial microbes, 11(5), 411-455. [accessed April 2022 via: https://pubmed.ncbi.nlm.nih.gov/32865024/]