Your microbiome is like a bustling metropolis, teeming with activity and life. And just like any city, it needs the right resources to thrive. It is home to more than 38 trillion organisms including bacteria, viruses, fungi, parasites and yeasts. Like finger prints we all have a unique gut microbiome. So, if you want to perform at your best or achieve body composition goals such as fat loss and muscle gain you need to give your gut the attention it deserves.

However it's not just about numbers. The gut microbiome is a complex and fascinating ecosystem, with a vital role to play in your overall well-being. From your moods to your cravings, metabolism, immunity, glucose metabolism and even fat storage, these gut bacteria are calling the shots.  

You may not have realised but over 40, our gut microbiome changes, and one of the reasons is the decrease in estrogen. As you can see in the diagram below as estrogen and progesterone decrease our gut microbe diversity reduces and our gut lining thins. This leads to increased intestinal permeability (or sometimes referred to as leaky gut) which can result in chronic inflammatory conditions and digestive symptoms like bloating, gas and constipation. This is all very common in the menopause transition period which is the period of perimenopause to menopause to post menopause, which can span over a 10-12 year period starting around 40.

Your gut microbiota has two dominant bacterial divisions competing for control: Firmicutes and Bacteroidetes. These tiny powerhouses have a big impact on our weight, regulating how much energy we absorb from our food. Firmicutes are a little greedy, absorbing more energy and leaving us with more calories. Bacteroidetes, on the other hand, are very savvy, taking only what they need and leaving the rest. By balancing these bacterial factions, we can take control of our weight and health. It's like a game of microbiota chess! Firmicutes, the dominant bacteria in some gut biomes, have been linked to inflammation, weight gain, and other health issues. A healthy and balanced microbiome can help manage metabolism and keep inflammation in check.

When we eat, our bodies go through a complex digestive process. Short chain fatty acids (SCFAs) are produced when indigestible fibers ferment in our gut. And these little guys pack a big punch when it comes to protecting us against inflammation, retaining our muscle mass, and even reducing our insulin resistance. It's like having a secret weapon in our bodies that we didn't even know about. And the best part? It's all natural and the gut microbiome changes quickly in response to what we eat – beginning just hours after a meal. It doesn’t take months.

So next time you're enjoying some fiber-rich foods, remember that you're not just filling up your belly - you're giving your body the tools it needs to function at its best. And that's something to feel good about.

Dietary fibre is the preferred food or 'fuel source' for your gut microbes and it helps them function in several different ways:

  • it stimulates the growth of beneficial bacterial populations in the gut
  • it stimulates the production of beneficial compounds called 'metabolites', such as short-chain-fatty-acids (SCFAs), which can induce mucosal healing and suppress inflammation, helping to keep your gut wall healthy (and you healthy!)
  • it provides a binding surface to increase the number of beneficial bacteria in the colon (large intestine), which is a good thing!

When fibre in your diet is low, bacteria can feed on the mucus layer (lumen) which protects your gut wall. This is also exacerbated in the menopause transition as we no longer have the protective effect of estrogen. Our mucus layers decrease and open themselves up to intestinal permeability.

When your diet is rich in fibre, the number of mucus-degrading bacteria decreases, and the mucus layer (lumen) protecting the gut wall, is re-established which all helps to heal the gaps or leaky gut. The diagrams below shows on the left healthy intestinal cells with a nice amount of protective mucus and on the right you can see leaky gut where there is less protective mucosa and gaps forming between the cells which allow foreign substances to enter the blood stream.

healthy gut

Your gut is also a powerhouse that regulates your hormones like a boss. Estrogen, thyroid stimulating hormone (TSH), serotonin (our feel good hormone) and stress hormones are all under its command. In fact, it's so influential in managing sex hormones that scientists have coined the term “microgenderome” to describe the dynamic interplay between the gut microbiome and sex hormones.

Estrogen, the hormone that makes us feel like our best selves, is quite the traveler. Once it's produced, it takes a journey through our bloodstream and eventually ends up in our liver. But that's not the end of the story. Our gut bacteria have a special collection called the estrobolome. This group of microbes can actually modulate the metabolism of estrogen through an enzyme they create called beta-glucuronidase. This enzyme can convert inactive estrogen back into active forms, sending it back into circulation. It's like a superhero team-up between our gut bacteria and our hormones!

The estrobolome plays a crucial role in maintaining hormonal balance. But when our bacteria becomes unbalanced it can lead to conditions like PCOS and endometriosis. And as we age, the reduction of our sex hormones can cause a shift in our gut microbiome diversity, putting us at risk for metabolic disease. Maintaining diversity in our microbiome can help keep our hormones in check and prevent these conditions.

Research has shown that a healthy gut microbiome can give your performance a serious boost. Think increased metabolism, more energy during exercise, and quicker recovery post-workout. So let's get those microbes firing on all cylinders and see what kind of results we can achieve. Your gut will thank you, and so will your performance.

So what do we need to do to help our gut microbiome thrive.

Don’t cut out or go too low with your good quality carbs, think wholegrains and vegetables. Aim for 25-30grams of fiber each day.

Eat 30 different plant foods each week. This can include vegetables, fruits, nuts, seeds and wholegrains. Diversity of plants means greater microbiome diversity.

Learn which foods contain prebiotics and probiotics and try to incorporate some into your diet. Prebiotic foods include barley, oats, unripe bananas, apples, onions, garlic, leek, legumes, asparagus, nuts and seeds, chicory root and Jerusalem artichokes.

Add in some probiotic foods such as fermented foods which include greek yogurt (with live cultures), kefir, miso, kimchi and sauerkraut.

Cut down on ultra processed foods as refined sugary foods promote firmicutes in the gut and when these take over inflammation and weight gain seem to follow.

If you are lactose intolerant or struggling with breaking down lactose which is common in the menopause transition period you may like to try probiotic kefir. It has higher levels of bacteria who feed on the lactose (milk sugar) and break it down, making it very low in lactose and generally well tolerated.

If you are still worried about that, try a good quality lactose free or soy yoghurt with live cultures instead (Note: these products do not have proven strains but do contain live strains that may have some benefit).

Practical Summary

what to do

  • 2 serves fruit/day - medium piece of fruit


A serve is equal to:

  • 1 x apple, pear, orange, banana
  • 2 x small pieces of fruit e.g. 2 kiwis, plums, or nectarines
  • 1 cup of chopped, frozen or small fruit e.g. watermelon, berries or grapes

what to do

  • 5 serves of vegetables or salad per day (as much diversity and colour as possible).
  • One serve is equivalent to 1/2 cup of vegetables or 1 cup of salad


  • Swap to wholegrain (high protein wholegrain bread, oatmeal, quinoa, wild rice, brown rice, buckwheat, rye, barley, millet, spelt varieties)
  • 1 serve is equivalent to 1 slice bread or 1/2 cup cooked wholegrains.

what to do

  • 30g nuts/seeds each day which is equivalent to about 15 almonds
  • Include legumes


  • If legumes are not tolerated start with 1/4 cup cooked or try 1/2 cup cooked legume pasta

what to do

  • Include prebiotic and probiotic foods daily


  • Sometimes a prebiotic supplement is an easy way to get diversity and boost the good guys. There are plenty on the market.
  • One I particularly like is Microbiome Essentials. You can use code RHODA for a discount.
microbiome essentials

If we feed our gut microbiome it in turn nourishes us. If you change what you eat today, your gut microbiota will be different tomorrow. It is so cool we have the ability to alter our microbiome for the better.

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About Rhoda ...

Rhoda is an award-winning dietitian, mature age model, and CEO of Sayvana Women.  

She is the creator of the Elegant Eating Solution, an affordable program that helps women avoid weight regain and feel great about themselves, without restrictive eating.

Elegant Eating is based on the science of protein leverage and follows the unique R.E.M.A.P approach to successful aging.

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