Prebiotics vs probiotics: Which do I need?

According to Bowel Research UK, nearly three quarters of UK adults buy the same foods every week. This lack of food diversity may increase our risk of gut issues. Poor gut health can significantly impact our quality of life and yet simple dietary changes, such as changing what we routinely buy and picking some key foods, can make all the difference.

Understanding what pre- and probiotics are is a useful starting point. These gut health essentials serve distinct, yet related roles, helping to nourish and balance our digestive system. A simple analogy is to think of your gut as a garden – probiotics represent the plants and flowers, and prebiotics are the fertiliser you feed them. Read on to learn more about pre- and probiotics, how they differ, how they benefit us and, if you decide to supplement, whether they should be taken together or separately.

Discover our full range of health benefit guides and check out our guide on what probiotics are and what they do and all you need to know about how diet affects your gut health.

What’s the difference between prebiotics and probiotics?

Probiotics are beneficial live micro-organisms, such as bacteria (e.g. Lactobacillus and Bifidobacteria) and certain yeast (like Saccharomyces Boulardii). When administered in adequate amounts, probiotics confer a health benefit on the host. These beneficial microbes can be found in foods like fermented dairy (including yogurt and kefir) as well as fermented vegetables such as kimchi and sauerkraut. Pasteurising and cooking these foods may kill most probiotics, so look for raw, unpasteurised products and where appropriate minimise the application of heat. You need to consistently consume sources of probiotics in order to sustain their benefits. It’s worth saying that probiotics are not the same as your natural gut microbes: the latter is a unique ecosystem of trillions of micro-organisms, while probiotics are specific forms of beneficial microbes that may temporarily support gut health.

Prebiotics are the food or fuel source for these live microbes, and are needed by them to increase in number, diversity and to thrive. Your body doesn’t digest prebiotics, instead they are metabolised by your gut microbes. Examples include non-digestible fibre, resistant starch as well as plant compounds, like polyphenols. Prebiotics can be found in foods like onion, garlic, leeks, asparagus, banana and oats as well as cooked and cooled pasta and potatoes. If you suffer with irritable bowel syndrome (IBS) you should be aware that many prebiotics are classed as FODMAPs and as such you will need to seek professional guidance when following a low FODMAP diet. Prebiotics not only support probiotic microbes, they also (very importantly) provide a food source for all the trillions of natural microbes that live in your gut.

Benefits of prebiotics and probiotics

There is still much for us to learn in this area, although it is recognised that prebiotics:

• act as a ‘fertiliser’ promoting the growth and diversity of natural gut microbes as well as probiotic microbes,
• provide the source material for the production of anti-inflammatory short chain fatty acids (SCFAs),
• may help control blood sugar, appetite and weight,
• may increase the absorption of some micronutrients, like calcium, iron and zinc.

Probiotics work alongside your natural gut bacteria to support health and balance. Their other benefits may include:

• improve IBS symptoms, traveller’s diarrhoea and the duration of antibiotic associated diarrhoea,
• may help lower blood pressure and improve cholesterol levels,
• may reduce inflammation by promoting the production of anti-inflammatory compounds called short chain fatty acids (SCFAs),
• may enhance immunity and be of benefit in the cold or flu season and during stressful periods.

Discover more benefits from our guide, what are probiotics and what do they do?

Should you take prebiotics and probiotics together?

Functional supplements that combine prebiotics and probiotics are known as synbiotics and are designed to work synergistically to optimise benefits. By combining the good microbes with their specific food source, the product aims to enhance gut health, metabolism and immunity and may be more effective than having one or other on their own.

In your diet you can get both pre- and probiotics by combining foods like kefir with raspberries, overnight oats with yogurt and banana or serve a buttermilk dressing over a green salad.

Are prebiotics or probiotics better for you?

The answer to this is they both are. The billions of beneficial microbes that live in the gut work tirelessly to ward off infection and support our wider health, supporting them with probiotics helps maintain balance and diversity. These microbes are unable to do their hard work without the presence of prebiotics from your diet. Therefore, eating fermented foods and enjoying a diverse variety of plant foods through the week helps maintain a healthy gut.

When might I take probiotics?

Including fermented foods in your regular diet is the key to healthy gut maintenance, however, on occasions a supplement may be helpful, such as:

• After a course of antibiotics,
• When experiencing traveller’s diarrhoea or a specific digestive upset,
• To support your digestive system during times of dietary change or extreme stress.

When might I take prebiotics?

Your regular diet should be your main source of prebiotics, although a supplement may help when:

• Your diet is low in fibre and diversity,
• You’re working on increasing microbial diversity,
• You’re taking probiotics.

Enjoyed this? Read more of our health guides

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Kerry Torrens BSc. (Hons) PgCert MBANT is a BANT Registered Nutritionist® with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including Good Food.

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