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The health benefits of fermented food

Patsy Westcott / 09 October 2018

Fermentation is one of the hottest food trends right now – but why all the fuss about this ancient method of food preservation?

sourdough bread
Sourdough breads harness wild yeasts floating in the air and lactic acid bacteria found naturally in flour to make dough rise.

Fermented foods have been part of our diet ever since our ancient ancestors cottoned on to the idea that fermentation helped to preserve food. With the advent of canning, refrigeration and freezing, it fell out of favour. But new findings about its potential role in fostering healthy gut bacteria have turned the spotlight on this tried-and-tested method of halting food spoilage. In fact, some experts now argue that fermented foods should be included in official nutrition guidelines.

According to a review in Critical Reviews in Food Science and Nutrition, fermented foods could help to lower cholesterol, improve immunity, help thwart the development of cancer, protect against allergies, atherosclerosis (hardening and narrowing of the arteries), diabetes, osteoporosis and obesity, and ease symptoms of lactose intolerance (sensitivity to the milk sugar, lactose).

It’s quite a list. As well as the more exotic or unusual foods such as Korean kimchi, German sauerkraut or the Caucasian Mountains’ milk-based kefir, there are several everyday foods closer to home that have the same health benefits – plus they’re easier on the purse.

5 fermented foods to put on the menu


Sourdough breads harness wild yeasts floating in the air and lactic acid bacteria found naturally in flour to make dough rise. This helps to stabilise or increase levels of nutrients, such as folates and vitamin E –linked with a lower risk of heart disease and stroke – and improve bioavailability of minerals such as magnesium, needed for a healthy nervous system.

Rye sourdough may be especially protective against Type-2 diabetes and heart disease thanks to certain blood-glucose-balancing amino acids and biologically active small protein fragments produced during fermentation.

Mass-produced commercial sourdough loaves aren’t always the real deal though: seek out an artisan baker, community bakery or make your own.

Try our sourdough starter recipe

Recipe: multi-seed sourdough bread


Cheese and other fermented dairy foods – think yogurt, kefir, buttermilk – have some of the biggest health benefits, especially for the heart and brain. Blue, mould-fermented cheeses such as Roquefort, beloved by our cousins over the Channel, are thought to be particularly heart-friendly. In fact, experts suggest this may partially explain the French Paradox, the fact that although the French consume a high-saturated-fat diet, they have low levels of heart and circulatory disease. Their secret could lie in the action of chemical by-products of the mould Penicillium roqueforti (also used to make Italian Gorgonzola, English Blue Stilton and Danish Blue), which act like natural statins.

There is a but, though: the NHS recommends ‘at risk’ groups – including, sadly, people aged 65-plus, as well as those with long-term medical conditions or weakened immune systems – to steer clear of blue and soft, mould-ripened cheeses such as Brie and Camembert. Why? ‘They aren’t ripened for long enough to kill the food poisoning bug, listeria,’ explains Dr Paul Cotter, an internationally acclaimed expert on fermented foods, from the University of Cork.

Other experts, such as Professor Tim Spector, of King’s College, London, are less cautious, pointing out that the Italians and the French don’t ban these cheeses for older people. The good news, says Dr Cotter, is that, ‘This caveat doesn’t generally extend to other cheese/fermented foods, which typically contain enough natural acids and other chemical compounds to kill listeria and other bugs. Indeed, this was the reason why the practice of fermenting foods began millennia ago.’


Strictly speaking ‘drupes’ (fruit with a single stone), olives have been a cornerstone of the Mediterranean diet for centuries. Rich in biologically active compounds with antioxidant, anti-inflammatory and hormone-like properties, the olives that we eat are the product of fermentation with gut-friendly probiotic lactic acid bacteria and/or natural yeasts. Olive consumption is thought to be a key factor to the benefits of the Mediterranean diet, which reduces the risk of chronic diseases, such as heart disease and dementia. Research is ongoing into developing low-salt, probiotic olives as a potential new superfood.

10 healthiest Mediterranean foods


Essential to flavour, the fermentation of cocoa or cacao beans is the first step in chocolate production. Writing in Nutrition and Metabolism in 2016, experts highlighted ‘cocobiota’, by-products of fermentation, for their antifungal, cholesterol-lowering and infection-fighting properties, as well as their ability to promote short chain fatty acids (SCFAs), which help to improve gut health. Dark and preferably raw is the best choice.

The surprising health benefits of chocolate


Believe it or not, your morning cuppa is fermented. Black tea, produced by fermenting the leaves of the plant Camelia sinensis, is a source of natural antioxidants – by-products formed during fermentation that are responsible for colour, taste, flavour and aroma, as well as some potential health benefits. These include helping to ward off cancers, oral health problems, heart disease and stroke, and diabetes – as well as helping to detoxify, improve urine and blood flow and boost the immune system.

The health benefits of tea and coffee

What is fermentation?

A process that harnesses bacteria, yeasts and other micro-organisms to convert sugars and starches in food and drink to acids. Fermentation can happen naturally or be induced by adding a ‘starter culture’. The bacterial and yeast species contribute to the flavour and texture of the food or drink.

How does fermentation change food?

It improves the digestibility of proteins and carbs, increases our body’s ability to absorb and use vitamins, minerals and plant nutrients, and helps to maintain a healthy balance of gut bacteria. It also kills off or inhibits harmful bacteria, such as E.coli, increases shelf life and enhances both the aroma and flavour of food.


The opinions expressed are those of the author and are not held by Saga unless specifically stated. The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.