The Microbiome Group

04/09/2026

I learnt a fascinating fact about plums recently.

Read on to find out what it was!

Some of the facts below are not that surprising, given the dark purple colour of most plums we eat:

🍏 Plums are nutrient-dense fruits packed with polyphenols and fibre.

🌿 Polyphenols are beneficial because they act in a prebiotic-like way, aiding the growth of beneficial gut bacteria while reducing potentially harmful species. Some studies on inflammatory bowel disease, bone health, and cancer also highlight the strong antioxidant activity of plums, supporting gut and overall health.

🔥 The anti-inflammatory effects of polyphenols help reduce intestinal inflammation, protecting the gut lining and supporting healthy digestive function.

🥗 Plums are rich in fibre, which supports digestive regularity. Soluble fibre in the pulp dissolves into a gel-like mass that traps fats, sugars, bacteria, and toxins, aiding their removal from the body and helping regulate blood sugar. Insoluble fibre in the skin adds bulk to the stool and gently scrubs the intestinal lining, promoting bowel regularity and easing constipation.

But this is what surprised me and what you shouldn’t do:

✅The bloom on the outside of a plum is a wild type of yeast that is a rich source of B vitamins! Who would have known that? So, whatever you do, don't wipe it off.

✅And B vitamins are vital for energy production, so yet another health benefit of these delicious autumn fruits.

✅So, make sure you buy some for your fruit bowl on your next shop!

References:
Kaulmann, A et al (2016). Mol Nutr Food Res. Inflammation related responses of intestinal cells to plum and cabbage digesta with differential carotenoid and polyphenol profiles following simulated gastrointestinal digestion

https://pubmed.ncbi.nlm.nih.gov/26990368/

✏️ Melody
📷 Melody eating a plum

28/08/2026

Brussels sprouts are making a comeback, especially in Melbourne where the weather is still cold.

They used to be known as the stinky vegetable that no one wanted to eat.
Now they are being roasted and served as a side dish in most restaurants. This version was tossed together with whatever I had in the kitchen - cranberries, apricots, hazelnuts and some sesame seeds and eaten warm but you could make it a cold dish too.

Brussels sprouts are cruciferous vegetables in the Brassica family along with broccoli, cauliflower, kale and cabbage among others. When these vegetables are chopped or chewed, they release sulforaphane, a phytochemical known for its antioxidant properties.

Some people tend to avoid sulphur rich foods altogether as they can cause gas and abdominal pain. This is linked to our gut microbiome composition, when we have high levels of sulfate reducing bacteria that produce hydrogen sulphide gas.

Interestingly, a small study in 2017 found that healthy adults eating a high brassica diet (mainly broccoli and cauliflower) for two weeks had a reduction in sulfate reducing bacteria. As close relatives sharing the same sulphur compounds, Brussels sprouts are likely to work the same way.

Brussels sprouts also contain fructans, a fibre our digestive enzymes cannot break down. They travel to the colon intact, where our gut bacteria ferment them into short chain fatty acids like butyrate, which feeds the cells lining the gut.

That is also why sprouts can cause a bit of gas! The same fermentation that feeds your beneficial bacteria is what produces it, and how much you notice depends on the bacteria already living in your gut, which is why we look at the individual gut microbiome as a baseline.

To understand how microbiome analysis may help you, get in touch (link in the bio).

✏️ 📸 by Vicky

REFERENCES
https://doi.org/10.1002/mnfr.201600992

IMAGE: A pale blue bowl of roasted Brussels sprouts, halved and charred at the edges, tossed with dried cranberries, apricot, hazelnuts and sesame seeds in a glossy dressing, shot from above on a rustic wooden table with cutlery resting alongside.

26/08/2026

I came across this study recently which I thought was worth sharing given so many people are dealing with fatigue and other symptoms from Long Covid (LC).

This was a randomised, double-blind, placebo-controlled trial that looked at whether the probiotic VSL #3 could ease fatigue in people with LC. Forty-eight patients completed the study, split between VSL #3 and placebo, over four weeks followed by a four-week follow-up period.

The trial classified patients as responders based on a set improvement threshold on the Chalder fatigue scale (CFS), and significantly more people hit that bar on VSL #3 than on placebo. In fact, the results showed that people taking VSL #3 saw a much greater drop in fatigue scores (24.24% vs. 6.06%). The benefit was still there a month after supplementation stopped and other improvements in gastrointestinal symptoms and overall quality of life were also noted.

Stool testing showed a rise in Bifidobacterium and Lactobacillus in the treatment group, and among the people who responded best to treatment, Ruminococcus and Coprococcus also increased. These bacteria produce short chain fatty acids, which play a key role in gut barrier integrity, immune function and regulating inflammation.

The trial also found that not everyone responded the same way, and those differences appeared to be linked to each person's baseline microbiome.

While this was a small, single centre trial, and more research is needed, it adds further weight to the role of the gut microbiome in helping to improve Long Covid symptoms such as fatigue.

For anyone dealing with fatigue and other Long Covid symptoms, get in touch with us to learn how microbiome analysis could help with your recovery.

✏️ 📸 by Vicky

REFERENCE:
https://www.frontierspartnerships.org/journals/british-journal-of-biomedical-science/articles/10.3389/bjbs.2026.16993/full
Image shows a screenshot of a journal title page for a study on VSL #3 probiotic supplementation in Long Covid.

20/08/2026

18/08/2026

Some of the best foods for your gut bacteria are the ones people are often told to avoid.

A comment on my recent fig post asked about oxalates, so here is some additional information. Many of the foods highest in oxalates, such as spinach, almonds, dark chocolate, are also some of the richest polyphenol sources for your gut microbes. Avoiding them because of oxalate sensitivity often means missing out on feeding our beneficial bacteria.

For those with a history of calcium oxalate kidney stones, or impaired kidney or liver function, managing dietary oxalate is an important part of clinical care. For others, high oxalate foods can trigger uncomfortable gut symptoms and brain fog.

The gut microbiome plays a central role in oxalate degradation. When we consume foods high in oxalates, certain gut bacteria produce the enzymes needed to break them down before they cause problems. Specialist bacteria, particularly Oxalobacter formigenes, do this in the colon before oxalate reaches the bloodstream. Certain Lactobacillus and Bifidobacterium species contribute too.

When these bacteria are depleted, often due to antibiotic use, gut infection or prolonged microbiome imbalance, oxalate accumulates and symptoms follow. A compromised gut barrier compounds this further, allowing more oxalate to pass through than it should.

Microbiome repair is one of the most effective ways of improving oxalate sensitivity. Restoring the bacteria that degrade oxalate, increasing beneficial bacteria and improving gut barrier integrity will help to clear oxalates from the body more effectively.

The goal for most people is not permanent restriction. It is restoring the gut ecosystem, so a diverse, plant-rich diet becomes well tolerated again.

DM me if you’d like to know more about how microbiome repair could help you.

✏️ 📸 by Vicky

IMAGE Three photos of high-oxalate foods: dark chocolate; baby spinach leaves and raw almonds with brown skins.

REFERENCES
Nazzal et al. (2021)
https://doi.org/10.1038/s41598-021-95992-7

13/08/2026

Fresh and sun-dried tomatoes, a good basil pesto, extra virgin olive oil. Three ingredients, one of my favourite simple summer dishes.

These ingredients are not only delicious, they bring together a diverse mix of fibres, polyphenols, and plant compounds to support your gut microbiome.

Tomatoes (both fresh and sun-dried) provide polyphenols and lycopene, while basil contributes its own distinct phytochemicals - including compounds with potential antimicrobial and anti-inflammatory properties.

Olive oil, particularly extra virgin, adds more health benefits with its polyphenol content, which has been shown to interact with gut bacteria and support beneficial species.

When these foods are combined, you're not just adding nutrients, you're increasing plant diversity within a single meal. Plant diversity is one of the dietary factors research has more consistently linked to a resilient, diverse gut microbiome.

What's more, it's simple to make, especially if you buy the pesto, and simply delicious.

A couple of easy ways to bring this combination into your meals:

✅Toss chopped fresh tomatoes with a small amount of sun-dried tomatoes, basil pesto, and extra virgin olive oil.

✅Add the mix to whole grains, beans, or sourdough for an easy way to layer up plant diversity or add as an accompaniment to a fish dish.

Let me know in the comments if you make this and if you enjoy it as much as I do.

✏️ 📸 by Melody
REFERENCES
Garcia-Mantrana I, Selma-Royo M, Alcantara C, Collado MC (2018) Shifts on gut microbiota associated to Mediterranean diet adherence and specific dietary intakes on general adult population. Front Microbiol 9: 890.
https://doi.org/10.3389/fmicb.2018.00890

Collins EJ, Bowyer C, Tsouza A, Chopra M (2022) Tomatoes: an extensive review of the associated health impacts of tomatoes and factors that can affect their cultivation. Biology 11(2): 239.
https://doi.org/10.3390/biology11020239

10/08/2026

Radicchio is one of the most polyphenol-rich leafy salad vegetables. A comparison of different chicory varieties found the anthocyanins (the polyphenols that give red radicchio its colour) were largely absent in the green ones, like Belgian endive, and its total phenolic content was markedly higher too.

A review of 22 human studies, published earlier this year, found polyphenol-rich diets were consistently linked to higher levels of Bifidobacterium, Faecalibacterium and Lactobacillus species; all key beneficial gut bacteria. Several of the included studies also reported greater microbiome diversity.

Many studies now show polyphenols support gut microbiome health, and the microbiome in turn releases the health-promoting properties from polyphenol-rich foods. That’s why our treatment plans include a focus on polyphenol-rich foods, especially for clients who can’t yet tolerate prebiotic-rich foods, such as onions, garlic or pulses (legumes.)

Radicchio is a useful low FODMAP option for individuals with IBS. Monash University runs the lab testing most FODMAP guidance is built on, and radicchio stays low FODMAP up to a fairly generous serving, around 75g or two cups shredded.

Sign up to our email list for more ingredients that support microbiome health. Link in bio www.themicrobiomegroup.com/subscribe

✏️ 📸 by Viola

REFERENCES
Innocenti et al (2005) Evaluation of the phenolic content in the aerial parts of different varieties of Cichorium intybus L. J Agric Food Chem 53: 6497-6502 https://doi.org/10.1021/jf050541d

Toderescu et al (2026) Dietary Polyphenols as Modulators of Bifidobacterium in the Human Gut Microbiota. Nutrients 18: 782 https://doi.org/10.3390/nu18050782

IMAGE: Radicchio leaf with its deep magenta fanning out from a pale, veined core.

31/07/2026

Back in May I promised an update on the tomato ‘probiotic’ experiment. Well the results are in! It’s the biggest crop I’ve ever grown.

From just four plants (four different varieties, because: microbiome diversity!) this is just one picking. They have been giving me a daily supply for a few weeks now, with many more still to ripen.

I can’t tell you whether it’s the heatwaves, the bacteria, or both. What the label doesn’t say is which species or strain of bacteria and fungi are actually in the product. In clinical practice, strain specificity is the difference between a probiotic supplement has proven efficacy for a particular action, through clinical trials and one that has no proven benefit.

I’ll use this ‘soil probiotic’ again next year. Partly for the yield, partly because I’m curious what a second season tells me.

Head to our profile for the original post from May (also in comments below), which shares the original research and explains why I chose this product in the first place.

Make sure you are following us for more ideas on supporting your microbiome health.

VIDEO: a slideshow of different varieties of tomatoes in a white bowl and on the vine: yellow, red and chocolate cherries and a striped heritage plum variety.

✏️ 📸 by Viola

20/07/2026

I’ve been in Bali for a much needed break and was blown away by the food.

So many plant based options to boost our beneficial gut bacteria. While I do eat seafood I found myself requesting vegetarian or vegan meals fairly often.

Here is a snapshot of the highlights!

13/07/2026

When I was a child, we would go strawberry picking on the way to see my aunt and uncle every summer.

This year I even grew my own and managed to eat them before the birds did!

Apart from evoking great childhood memories for me, they are a brilliant food from a gut health perspective.

They provide fibre, vitamin C, and a range of polyphenols that can help feed beneficial gut bacteria and support a more diverse microbiome. Like many brightly coloured berries, they combine flavour and function in a really enjoyable way.

They’re also wonderfully easy to eat in lots of gut-friendly ways. I love them eaten fresh or tossed into a salad with mint and a drizzle of extra virgin olive oil.

As I live near Wimbledon, strawberries and cream are practically part of the tradition at this time of the year as well!

A few simple ways to enjoy strawberries:
🍓Eat them fresh on their own or with plain yoghurt.
🍓Add them to oats, chia pudding, or overnight oats.
🍓Use them in a simple fruit salad with mint and a squeeze of lemon, if well tolerated.

However, for anyone with a histamine intolerance, strawberries can be a tricky food because they may trigger unpleasant symptoms in some people, so should be avoided.

Fortunately, I’ve seen histamine intolerance change over time in some clients, especially when the gut and immune system are better supported via targeted microbiome testing which I routinely organise for my clients at the Microbiome Group.

If you would like to discuss microbiome testing to support your immune and microbiome health, please get in contact with me.

REFERENCES
Meiners F, Kreikemeyer B, Newels P, Zude I, Walter M, Hartmann A, Palmer D, Fuellen G, Barrantes I. Strawberry dietary intervention influences diversity and increases abundances of SCFA-producing bacteria in healthy elderly people. Microbiol Spectr. 2025 Feb 4;13(2):e0191324.

Sánchez-Pérez S, Comas-Basté O, Duelo A, Veciana-Nogués MT, Berlanga M, Latorre-Moratalla ML, Vidal-Carou MC. Intestinal Dysbiosis in Patients with
Histamine Intolerance. Nutrients. 2022 Apr 23;14(9):1774.

✏ by Melody
📸 by Vicky