Which foods contain probiotics?

Probiotics are live microbes that benefit your health when you consume them. 

Many people assume all fermented foods contain probiotics. In reality, most fermented foods don’t have probiotics, though they can still be part of a healthy diet.

With that bit of terminology out of the way, let’s dig into fermented foods and how they might support your health. 

In this article, we look at 14 fermented foods and drinks you might want to add to your diet. 

We also explain how to check whether a product contains live microbes, and we describe the risks to be aware of. 

Are fermented foods healthy?

Most of the foods and drinks we cover below are fermented by bacteria that produce lactic acid. 

This acid helps ward off ‘bad’ microbes and keep food edible for longer. It’s why these foods have been popular globally for thousands of years.

Scientists now believe that fermented foods have benefits beyond their extended shelf life.

During fermentation, microbes metabolise (break down) compounds in food. As they do this, they produce a diverse range of new compounds with anti-inflammatory and antioxidant properties. Some of these may have health benefits.

The new compounds also contribute to the distinctive tart, tangy and sour taste of fermented food. 

Importantly, some fermented foods contain live microbes, which may support a healthy gut microbiome. The gut microbiome is the trillions of microbes that live in your gut. 

In general, experts agree that including fermented foods in your diet is likely to support good health. 

Although scientists are still researching the topic, there’s some evidence that fermented foods and foods that contain live microbes may:

• support gut health
• reduce the severity of food allergies
• support immune health
• improve blood sugar levels
• benefit heart health
• strengthen bones

Some studies even suggest that fermented foods might support better mental health, but the evidence is patchy so far.

Fermenting foods can also:

• make certain nutrients easier for your gut to digest and absorb
• improve the food’s flavour and texture

So, how can you tell if a food or drink contains live microbes?

What to look for on the label

Fermented foods don’t always contain live microbes. So, look for products with labels that say ‘live microbes’, ‘live cultures’ or ‘active cultures’ to be sure.

High temperatures kill most bacteria. Because pasteurisation involves heating, pasteurised products won’t contain live bacteria. 

Similarly, tinned foods tend to be heated before they’re packaged. 

This is important to remember when you’re making meals with fermented foods: if you cook them, the microbes will die.

So, to keep these microbes alive: 

• add in fermented foods at the end of the cooking process
• have them as a side dish
• enjoy them in cold dishes, like salads, wraps and sandwiches

Types of fermented food

Next, we’ll look at 14 popular fermented foods. For some, we’ll include links to research that suggests possible health benefits. 

We should note: while scientists do believe that fermented foods in general probably support good health, the evidence for specific foods and drinks isn’t as strong – scientists need to do more studies. 

Let’s start with fermented dairy products.

1. Yoghurt

Although yoghurt is a fermented food, it doesn’t always contain live microbes. Greek or ‘natural’ yoghurts normally do, but check their labels.

Thanks to its popularity, yoghurt has been the subject of a fair amount of research. 

For instance, there’s some evidence that regularly consuming yoghurt might:

• improve gut symptoms, like bloating
• protect the heart by reducing blood pressure and cholesterol levels
• reduce the risk of some cancers

2. Some cheeses

Cheese is made by fermenting milk, but not all cheeses contain live microbes. As always, it’s important to check labels. 

Cheeses that are heated during processing tend to have few or no live bacteria. Some types that do often contain live microbes include:

• mozzarella
• Gouda
• Edam
• cheddar
• Camembert
• provolone
• Swiss
• Gruyère
• cottage cheese

In general, experts think that cheese can be a good addition to a healthy diet. For instance, a meta-analysis found that eating cheese is associated with a reduced risk of heart disease. 

The scientists calculated that consuming around 40 grams per day was linked to the greatest reduction in risk.

3. Buttermilk

Buttermilk is a fermented dairy drink. Historically, it was a byproduct of making butter, but nowadays it’s produced separately. 

It has a similar nutritional profile to whole milk, and you can drink it straight or add it to cooking. 

Buttermilk has a tart flavour due to the lactic acid produced during fermentation, so it can work well in savoury foods like salad dressings and mashed potatoes.

Many buttermilks today don’t contain live cultures, so check labels before you make a purchase. 

4. Kefir

Kefir is another fermented milk product. It's traditionally made by adding ‘kefir grains’ to cow’s or goat’s milk.

These grains are actually cultures of yeast (a fungus) and lactic acid bacteria. 

You can find non-dairy versions of kefir, too, like soya milk kefir. You could also try making your own. 

Some people like to add kefir to smoothies, juices or overnight oats. Alternatively, you can replace milk with kefir in recipes – though remember, if you cook kefir, the microbes will sadly perish.

Kefir has more research behind it than many other fermented foods. The studies are promising, even if the field is still relatively new. 

For example, one study involving people with type 2 diabetes suggests that kefir might help lower blood sugar levels, but we need more research to be sure. 

5. Water kefir

For a milk-free version of kefir, you can add kefir grains to sugar water. People often add fruits and spices to this lightly sparkling, slightly tart beverage.

Note: Shop-bought versions often contain quite high levels of sugar and other additives. So, as always, giving the label a glance is a good idea.

6. Kimchi

Kimchi is a fermented Korean side dish. Generally, cabbage is the main ingredient, alongside chilli flakes, ginger, garlic, radish, onion, salt and pretty much any other vegetable to hand. 

Because kimchi contains live cultures and a variety of veg, it has two-pronged benefits: delivering beneficial live bacteria and the fibre that your gut bacteria feed on. 

As with kefir, health claims about kimchi abound.

It's still early days, but research shows shows that kimchi might help with metabolic health, including body weight and blood fat levels. 

This potent side works particularly well with rice and noodle dishes.

7. Sauerkraut

Particularly popular in Europe, sauerkraut is another cabbage-based fermented dish. It works well as a side with many savoury foods, like sausages, sandwiches and salads.

Research has shown that eating sauerkraut can lead to improvements in the diversity of the gut microbiome.

Some of these changes include increasing the number of the beneficial bacteria Lactobacillus plantarum, Lactobacillus brevis and Faecalibacterium prausnitzii.  

Look for unpasteurised sauerkrauts in the refrigerated section of the supermarket to make sure you get one with live microbes. 

Or you could try making your own sauerkraut. 

8. Miso

Miso is a paste made from fermented soybeans. This Japanese staple may be white, yellow, red or brown.

Thanks to its salty flavour, miso works well in a range of dishes. You might enjoy it in soups, broths, marinades, stir-fries, sauces and dressings. 

To keep the bacteria alive, try to add in miso after cooking, if possible.

Scientists are currently investigating whether miso might offer health benefits, including reducing inflammation and protecting against obesity, cancer, type 2 diabetes and other conditions. 

9. Tempeh

Tempeh originated in Indonesia, and it’s popular around the world as a meat substitute because of its high protein content.

Tempeh is made by soaking soybeans, removing their outer layer, then cooking them. 

Once the beans have cooled, they’re mixed with mould spores. As the beans ferment, they join together to form a cake-like product.

With an earthy, mushroomy taste, tempeh is an excellent replacement for meat in a variety of dishes.

10. Natto

Rounding off our trio of Asian fermented soybean products, we have natto, another Japanese staple. Unlike miso and tempeh, natto is made using the whole bean. 

In Japan, many people eat it cold with rice for breakfast. Like Marmite in the United Kingdom, natto seems to split the crowd. This is because it has a strong flavour and a stringy, sticky texture. 

Natto seems to be less popular in the UK than other fermented soya products, but it packs in around 5 g of fibre per 100 g.  

11. Kombucha

Kombucha is sugar-sweetened tea fermented with a symbiotic culture of bacteria and yeast, called a scoby. 

It can be made with either green or black tea, and some types are infused with mint or lemon. 

Once again, there are many suggested health benefits, but scientists need to do more conclusive research.

Kombucha can be a good alternative to standard fizzy drinks because it's typically lower in sugar. Thanks to the tea, it also contains plant chemicals, such as polyphenols. 

If you want to have a go at making kombucha, you can try this recipe. 

12. Sourdough bread

During the pandemic, many of us started baking, sparking a sourdough revival of sorts. With its sharp taste, sourdough adds a zing to any sandwich.

This bread begins with a sourdough starter: a culture of bacteria and yeast. While it certainly does contain microbes, none are likely to survive the baking process.

Still, some research suggests that even dead microbes can offer health benefits.

If you have irritable bowel syndrome (IBS), you may be thinking about FODMAPs. These are short-chain carbohydrates, and when they reach your gut, they don’t get absorbed. 

For people with IBS, foods with high levels of FODMAPs can lead to symptoms.

There’s some evidence that using sourdough starter yields bread with fewer FODMAPs. When the dough is left to 'prove' for a long time (typically over 12 hours), the yeast and bacteria break down the flour's carbs, including FODMAPs. 

You might try your hand at spelt sourdough, because spelt has fewer FODMAPs than regular wheat.

13. Kvass

Kvass is an Eastern European beverage traditionally made from stale rye bread and flour. Nowadays, people also make it using fruits and root vegetables, like beetroot.

This drink has a sweet and sour flavour and a small amount of alcohol. Not all versions contain live bacteria, so check the label.

14. Apple cider vinegar

Apple cider vinegar is made by fermenting apples with yeast. Again, not all products contain live microbes. The vinegar should look cloudy, and the label should say ‘unfiltered.’

There’s been a lot of hype about apple cider vinegar over the last few years.

Alongside the benefits of consuming live microbes, there’s some evidence that this vinegar might support cardiometabolic health. 

It may specifically have beneficial effects on fasting blood glucose and HBA1c levels in people with type 2 diabetes. However, apple cider vinegar should not replace diabetes medication. 

It's also highly acidic, which increases the risk of acid reflux for some people, as well as the erosion of tooth enamel. 

What about probiotic supplements?

Probiotic supplements come as capsules, powders or liquids. They may also support your gut and overall health. 

Not all probiotic supplements are equal, though, so check the label to make sure the product contains a range of live microbes. 

Are there any risks?

For most people, fermented foods shouldn’t cause any problems. 

But it’s important to store these products correctly, and don’t consume them after the use-by date.

In some cases, fermented foods might make you feel a little bloated. So, if you’re new to fermented foods, add them to your diet gradually to give your gut time to adapt.

Also, if you have histamine intolerance, fermented foods may not be suitable for you. 

Summary

Foods that contain live microbes can help support your overall health when they’re part of a well-rounded, healthy diet.

Fermented foods are diverse, and their microbial colonies and beneficial compounds can add exciting new flavours and textures to your menu.

As a bonus, many fermented foods are plant-based, so they offer additional nutrients, like fibre and plant chemicals.

In general, fermented foods are safe for most people and widely available in shops. But remember to check labels to make sure the product contains live bacteria.

To learn more about bloating and other gut health topics, visit Symprove’s Gut Hub.

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