A healthy immune system is vital for shielding us from a number of diseases, and one way to accomplish this is to include probiotics in our diets.
With viruses such as Covid-19 having ravaged the globe, the importance of probiotics has gained even more significance.
Many studies have found that these 'good bacteria' can help balance gut flora, helping produce protective substances, which may spur the immune system to fight off bugs.
Here's a lowdown on the friendly bacteria that live in our intestines, stomach and gastrointestinal tract.
What are probiotics?
The World Health Organisation defines probiotics as "live microorganisms which when administered in adequate amounts confer a health benefit on the host".
Probiotics fundamentally are live 'friendly' bacteria in food or supplement form that have the ability to alter the balance of our own gut bacteria.
The health benefits of probiotics
There are thousands of research articles on the benefits of probiotics. These include improved protection against gastroenteritis, reduced inflammation (hence the link to Covid-19), and boosting immunity.
In addition, recent research found probiotic bacteria could help control the development and progression of colorectal cancer. While there's also some evidence probiotics are helpful for reducing cholesterol, there's only limited evidence that they're beneficial for reducing blood pressure and helping psoriasis and chronic fatigue syndrome.
Many chronic health conditions, including Type 2 diabetes, obesity, inflammatory bowel disease and bowel cancers, have been linked with an imbalance of gut bacteria. The right proportion of gut bacteria plays a role in giving us defences against viruses such as Covid-19.
Probiotics in food
Probiotics are found in many fermented foods, including kefir (fermented milk), kombucha (fermented sweet tea), kimchi (spicy fermented cabbage), tempeh (fermented soya bean patties), miso (fermented soya bean paste) and sauerkraut (fermented cabbage), as well as yoghurt.
Probiotics can also be found in supplements and special drinks such as Yakult.
Experts suggest it's good to combine probiotics with prebiotics - dietary substances that boost numbers of 'friendly' bacteria and promote their activity. The most accessible prebiotics are tea, onions, garlic and banana. These have been proven to help rebalance our gut microbiota. Prebiotics are like fertilisers for live probiotic microbes already in the gut.
Who should take probiotics?
People whose diets tend to be low in fibre, fruit and vegetables and high in animal protein should have these gut-boosting bacteria for nourishment.
However, people who get their fill of five-a-day fruit and vegetable, and consume two to three daily servings of fibre-rich foods like wholegrain bread, pasta and rice, or high-fibre breakfast cereal, plus a few servings of fermented foods a week, should have a healthy gut microbiota. Everyone else should consider adapting their diets or taking a probiotic supplement.
One may take supplements if their diets are lacking in immunity-boosting microorganisms.
Having said that, it's easy to get ample probiotics in your diet by including natural sources, boosting them with prebiotic foods, and ensuring you eat plenty of dietary fibre from whole grains, fruit, vegetables, legumes and yoghurt.
What probiotics should you take?
Probiotics containing lactobacilli and bifidobacteria are the most well-researched and have the best safety and efficacy records.
However, product quality varies, with some probiotic products being very well researched and others not.
Any health concerns?
People who are immuno-suppressed (those taking immuno-suppressant drugs linked to organ transplants) should avoid probiotics because even 'good' bacteria, which would be harmless in most people, has the potential to cause infection in those with a suppressed immune system.
Besides this category of individuals, probiotics don't cause harm, even in young children. In fact, foods containing natural probiotics have been eaten by people around the world for thousands of years.