Are Spices Good for your Gut Health?

It's a question we're asked regularly - are spices good for your gut health?  And we couldn't think of a better person to ask than Dr Laura Wyness!  She's an award winning freelance Registered Nutritionist and our go-to for all nutrition science information!

How your diet and culinary spices can benefit your gut health:-

1. Why is gut health important?

Microbes are found throughout the body, mainly on external and internal surfaces of our skin, mouth and our gastrointestinal tract.  These microbes help look after us on a daily basis by performing thousands of functions in our body.  

An estimated 40 trillion microorganisms live within your gastrointestinal tract (Sender et al 2016).  These microbes play a key role in digestion, as well as having many other benefits for our health and wellness.  Our gut microbes help strengthen our immune system and have a function in producing vitamins, managing hormones and communicating with our nervous system and brain (Rossi, 2019).  Our gut microbes could even be linked with our mental health and mood (Bonaz et al 2018). 

2. Can using culinary herbs and spices benefit our gut microbes?

There’s been very little research done to explore the impact of culinary herbs and spices on the gut microbiome.  One small study, involving 31 healthy adults, found that a daily intake of 5g of mixed spices for two weeks had a positive impact on bacteria in the gut (Lu et al 2019).  Another recent small study with 15 healthy adults, looked at the impact of a single serving of mixed spices Indian curry consumption.  The results suggested that even a single meal containing mixed spices can modify the gut microbiome within a day or two (Khine et al 2021).  

Whilst this research sounds promising, more studies are needed in this area to better understand the impact of herbs and spices on our gut microbes.  

3. Variety is the spice of life

Including lots of variety in your diet, especially different plant foods – vegetables, fruits, wholegrains, nuts, seeds, legumes and herbs and spices - is one of the best ways of looking after your gut microbes.  People who regularly eat 30 or more different types of plant foods in a week have a more diverse microbiome than those who eat 10 or fewer types of plants per week.  This was one of the findings from the largest published study to date (The American Gut Project, 2021) which looked at how diet and lifestyle affects the human gut microbiome. 

Having a variety of plant foods in your diet will help you get all the nutrients your body needs to function and feel well.  This is due to the range of dietary fibres and beneficial phytochemicals plant foods provide. 

Including different herbs and spices is a great, and simple, way to increase the variety of plants in your diet, particularly the contribution of phytochemicals.  

4. Phytochemicals

Phytochemicals is the sciencey term for plant chemicals.  One of the most studied type of phytochemicals are the polyphenols.  These are found in a wide range of plant foods such as berries, coffee, tea, olives, onions, broccoli, flaxseeds and rapeseed oil.

The richest source of polyphenols is from culinary spices and herbs, with the highest levels found in: cloves, peppermint, star anise, oregano, celery seed, sage, spearmint, thyme, capers, basil, curry powder, ginger, cumin, cinnamon and caraway (Perez-Jimenez et al 2010).

It’s thought that around 90% of polyphenols pass from the stomach, through the small intestine and into the large intestine undigested.  It’s in the large intestine where the magic starts to happen.  Here, the polyphenols help increase the amount of beneficial gut bacteria such as Bifidobacterium and Lactobacillus, which provide anti-pathogenic and anti-inflammatory effects (Correa et al. 2019). 

When you’re adding spices to your food, I’m sure you’re more likely to be thinking about flavour than increasing the beneficial bacteria in your intestines!  The flavour that herbs and spices provide can be really useful, especially when it comes to reducing salt. 

5. More flavour, less salt. 

Average salt intake among UK adults are currently 40% higher than the Government’s recommended maximum of 6g of salt a day (PHE, 2020).  Too much salt in our diet leads to high blood pressure, which is the main cause of strokes and a major cause of heart disease.  

Emerging evidence that suggests a high-salt diet can alter the gut microbiome too.  Some researchers think that reducing the salt in our diet is likely to have a beneficial impact on our gut microbiome (Chen et al 2020).  However, most of this evidence so far, has been from studies of animal models rather than studies involving humans.  

Salt is often added to food to enhance the flavour, but using more herbs and spices, means less salt is needed, whilst still getting lots of flavour.  

In general, culinary spices help add variety to your diet and beneficial polyphenols.  They help excite your taste buds and may even keep your gut microbes happy, so enjoy!

About Dr Laura Wyness:-

Dr Laura Wyness is an award winning freelance Registered Nutritionist who specialises in nutrition writing, workplace wellness and nutrition communications. She loves clarifying nutrition science into clear consumer messages and enjoys providing personalised nutrition advice to individuals looking to make positive changes to their diet.