Fermentation has been used to preserve foods for thousands of years. Some of these foods will be familiar, such as yoghurt, sauerkraut and crème fraîche. Others, such as kimchi (Korean fermented vegetables), kombucha (a drink made from fermented tea), miso (a Japanese flavouring made from fermented soya beans) and kefir (a fermented milk drink), are less well known.
Fermented foods can contain ‘probiotics’ – live bacteria and yeasts that are thought to have health benefits. This may make these foods a useful addition to our diets.
There are many health claims about them, from preventing cancer to reducing cholesterol and obesity, but most aren’t supported by research. There is some evidence linking certain probiotics with benefits for some digestive problems. More studies are needed to understand how the benefits of individual probiotics seen in clinical trials translate to eating these in foods – for example, we need to know how much we’d need to eat to see any benefit, or which foods are the best sources.
There are many health claims about fermented foods, but most aren’t supported by research
Although there is still much to learn about fermented foods, for most people there is no harm in trying them. Just remember that any benefit is an ‘add-on’ to a healthy balanced diet; they can’t counteract the effects of an otherwise unhealthy diet.
Check nutrition labels carefully and remember that fermented foods should be ‘live’ so need to be kept in the fridge. If they’re from a supermarket shelf, be wary – heat treatment that may be used to preserve these foods destroys probiotics.
Some of these foods, such as sauerkraut, kimchi and miso, are often salty, so check the label and choose reduced-salt versions if possible. A food is classed as ‘high’ in salt if it contains more than 1.5g (0.6g sodium) per 100g and ‘low’ if it has 0.3g (0.1g sodium) or less per 100g. If you’re buying yoghurt, choose low-fat versions without added sugar.
To find out more, or to support British Heart Foundation’s work, please visit www.bhf.org.uk. You can speak to one of our cardiac nurses by calling our helpline on 0808 802 1234 (freephone), Monday to Friday, 9am to 5pm. For general customer service enquiries, please call 0300 330 3322, Monday to Friday, 9am to 5pm.
British Heart Foundation is a registered Charity No. 225971. Registered as a Company limited by guarantee in England & Wales No. 699547. Registered office at Greater London House, 180 Hampstead Road, London NW1 7AW. Registered as a Charity in Scotland No. SC039426