Eat well
British Heart Foundation warns that many gut-friendly foods come with a heart health catch
The British Heart Foundation is urging people to look more closely at some popular gut-friendly foods which, while beneficial for the microbiome, may also come with hidden risks for heart health when eaten in excess.
We have issued advice to help people protect their hearts when making food choices to keep their gut healthy and feed their ‘good’ gut bacteria. This includes:
Many people now choose foods marketed as prebiotic, probiotic or good for the gut in other ways. Our advice highlights that there’s no harm including these foods as part of a healthy diet - they can be a positive thing to do for your health - but many of these foods come with a catch that can raise your risk of cardiovascular disease.
Tracy Parker, our Nutrition Lead, said: “We encourage everyone to choose foods that can keep their gut microbiome healthy. The benefits are clear, and we are continuing to improve our understanding of how a gut-friendly diet may help our hearts.
“A lot of these products can contain high levels of salt or sugar though, so it is important to be aware of the potential drawbacks. By ensuring you check package labels for added salt and sugars, and eat each in moderation, you can make sure the risks do not outweigh the benefits for your heart health.”
What to watch out for:
Kimchi
Fermented foods like kimchi are rich in probiotics, the healthy bacteria produced during fermentation that can help support a diverse and healthy gut microbiome.
However, traditional kimchi is often made with a lot of salt, so it can raise blood pressure if eaten frequently or in large quantities. High blood pressure is known to increase your risk of having a heart attack or stroke. To help keep your salt intake low, we advise enjoying kimchi in small portions and checking labels for lower-salt varieties.
Kombucha
Kombucha, a fermented tea, also contains probiotics and can help your gut in a similar way to kimchi. It can be a healthier alternative to sugary or fizzy drinks and has become a popular choice for people looking to introduce fermented products into their daily routine.But many commercial kombucha products contain added sugars. Eating too much sugar can lead to weight gain, which in turn can increase the risk of a heart attack or stroke or other cardiovascular disease. That’s why we encourage people to choose lower sugar varieties, often labelled as ‘No added sugar’.
Fruit Yoghurts
Plain yoghurt also naturally contains probiotic live cultures that can boost levels of helpful bacteria in the gut. Yoghurt is also a good source of calcium and protein. However, many flavoured or fruit-based yoghurts contain added sugars and may have fewer live cultures than plain versions.
We recommend choosing plain yoghurt with “live and active cultures” mentioned on the label to ensure you are buying a low sugar option that is good for your gut. You can add whole fruit at home for a healthier way to add sweetness.
Smoothies
Smoothies made with whole fruits provide prebiotic fibre that feeds the beneficial gut bacteria and supports digestive health. They also offer a range of vitamins and antioxidants, especially when prepared with a variety of plant-based ingredients.But blending breaks down the structure of fruit, releasing “free sugars” that behave like added sugars in the body and cause faster rises in blood sugar levels. Regularly consuming too much sugar can lead to weight gain, which can increase the risk of developing type 2 diabetes, heart and kidney disease.
Only one 150ml serving of any smoothie counts towards your 5-a-day, so we recommend sticking to that portion size. It can also be good to add nuts or seeds for extra protein and fibre, which can help keep blood sugar levels more stable.
Sauerkraut
Much like kimchi, sauerkraut is a fermented food and so naturally very rich in healthy probiotics. However, also like kimchi, traditional sauerkraut relies on lots of salt for fermentation, which may be a concern for anyone watching their blood pressure. Some shop bought versions are also pasteurised, which removes most of the live bacteria.
To avoid overdoing the salt, it's worth checking the label and eating small portions only. If you want the beneficial probiotics, make sure you are getting unpasteurised sauerkraut - it’s generally fine for most healthy adults. Look for phrases like “raw”, “unpasteurised” or “contains live cultures” on the packaging.
How the gut microbiome could affect your heart health
Beneficial gut bacteria produce short-chain fatty acids during digestion, which are linked to reduced inflammation, better metabolism and better heart and circulatory health. People also need these ‘good’ bacteria to digest polyphenols – chemicals naturally found in plants that are thought to have antioxidant properties and may lower blood pressure.
On the other hand, ‘bad’ bacteria in the gut produce chemicals that cause problems in the heart and blood vessels by increasing inflammation and altering how cholesterol is processed in the body. These bacteria thrive on diets high in fat and red meat. We are continuing to fund research on the effect of these bacteria on heart health.
‘Good’ bacteria benefit when you eat varied diets high in prebiotics – non-digestible fibres that act as food for these bacteria. Prebiotics can be found in foods like wholegrains (including oats), beans and lentils, bananas and onions.
Probiotic foods – those which contain healthy bacteria – also ensure your gut microbiome is varied and healthy by adding helpful bacteria to those already in the gut. These foods include kimchi, sauerkraut, live yoghurt, kefir and kombucha.