Trendy fermented food and drinks diets can trigger a host of nasty side effects and breed antibiotic-resistant bugs, an expert has warned. Kombucha, k
Trendy fermented food and drinks diets can trigger a host of nasty side effects and breed antibiotic-resistant bugs, an expert has warned.
Kombucha, kimchi and natural yoghurts have been flying off shelves for years thanks to claims about their reported health benefits.
They are thought to improve digestion, cut inflammation, boost the immune system and even help people lose weight.
But most people aren’t aware they can trigger allergy-like symptoms, according to Manal Mohammed, a lecturer in medical microbiology at the University of Westminster.
Writing in The Conversation, Ms Mohammed said the most common reported side effects were headaches, bloating and migraines.
Products like kombucha, kimchi (shown) and natural yoghurts have been flying off shelves for years thanks to claims about their reported health benefits
Trendy fermented food diets can actually trigger a host of nasty side effects and breed antibiotic-resistant bugs, health experts have warned. Pictured: Organic yoghurt is filled with probiotics
They occur because food rich in probiotics contain histamines. For most people, their bodies will produce specific enzymes which naturally digest them.
But some people do not produce enough of these enzymes, and the histamines are absorbed into the bloodstream where they trigger reactions.
Symptoms include itching, headaches or migraines, fatigue, hives, diarrhoea, nausea and vomiting, according to Ms Mohammed.
In rare cases, it can cause low blood pressure, irregular heart rate and sleep disorders.
Ms Mohammed also warned that elderly people and those with compromised immune systems were at risk of contracting serious infections by eating the foods.
She pointed to the case of a 65-year-old diabetic patient whose liver abscess had been caused by consumption of probiotics – live bacteria.
The case was reported in the British Medical Journal (BMJ) Case Reports at the time in 2017.
It is estimated that only about one in one million people who take probiotics will develop an infection.
Supplements of ‘good bacteria’ can enhance weight loss in dieters, scientists find
Scientists studied a group of overweight children taking supplements.
All of them were also given an exercise regime and diet plan.
Results showed youngsters using probiotics lost a ‘significantly’ higher number of pounds compared to those who didn’t.
Critics said it’s too early to jump to conclusions considering the study is yet to be published in a journal.
However, it’s the latest of a swathe of evidence suggesting the gut microbiome could play a powerful role in weight regulation.
The research, carried out by Fuzhou Children’s Hospital in China, involved 54 obese children between six and 14 years old.
Thirty were randomly assigned to take probiotic pills and 24 were in the placebo group. The trial lasted 12 weeks.
Researchers, led by Professor Rui-Min Chen, analysed various measurements of the children’s weight and metabolic health.
Those who had been treated with probiotic supplements lost significantly more weight – but the authors did not quantify how much.
The children in the probiotics group also had better metabolic health, measured by level of inflammatory proteins and blood glucose levels.
Ms Mohammed has also warned that fermented foods freely available on supermarket shelves can carry antibiotic-resistant superbugs.
She wrote in The Conversation: ‘The most common antibiotic resistance genes carried by fermented foods are against erythromycin and tetracycline, which are used to treat respiratory infections and some sexually transmitted diseases.
‘Researchers found resistant probiotic strains in commercially available dietary supplements, which could mean resistance to several common types of antibiotics used to treat serious bacterial infections.
‘Research has also found six probiotic Bacillus strains found in food products (including kimchi, yogurt and olives) are also resistant to several antibiotics.’
The most common reaction to fermented foods is bloating and an increase in gas. This occurs as the probiotics kill off harmful gut bacteria.
While this is typically considered a good thing, some people experience severe bloating which causes them pain and interferes with their day or sleep.
Fermented food or drink is given its flavour or texture through microorganisms such as bacteria or yeast.
Kombucha, for example, is tea left to brew with sugar, bacteria and yeast, while kefir is milk cultured with bacteria and yeast to thicken it and add a slight ‘fizz’.
These types of ‘trendy’ foods have been around for centuries. Sauerkraut — the traditional German pickled cabbage — is a fermented food, as is balsamic vinegar and traditional sourdough.
It can improve the nutritional properties of food by breaking down nutrients, making them more ‘bio-available’ — easier for us to absorb.
In effect, the bacteria pre-digest the foods, and this can mean we take on more vitamins and minerals than we would in their unfermented state.
You might, for example, absorb more nutrients, such as zinc or iron, from fermented soya such as tempeh than you would from the same amount of soya beans.
But the popularity of certain fermented foods really stems from our emerging understanding about how the mix of our gut bacteria affects health — including our immunity, weight and mood.Because of the way they are prepared, some fermented foods contain live ‘good’ bacteria and yeasts known as probiotics.
The health benefits a probiotic offers when eaten depends on its species and its strain, as well as the number of the micro- organisms present.
Some fermented foods — such as kefir, kimchi and sauerkraut — are what’s known as synbiotics.
This means that as well as containing probiotic ‘good’ bacteria, they also contain prebiotics. These aren’t a type of bacteria themselves, but are carbohydrates we can’t digest which act as food for the ‘good’ bacteria.
However, despite the trend for everything from skin cream to cola describing itself as ‘fermented’, not all fermented products are equal or healthy — salami, for instance, is high in fat and salt.