By medical nutritionist Dr Sarah Brewer, an expert in food, herbs and supplements
Probiotics are live bacteria which provide health benefits. While most of their effects occur within the intestinal tract, probiotics also stimulate immunity and new research suggests they even influence our psychological health.
The most commonly used probiotic organisms are strains of Lactobacillus and Bifidobacterium. These have been researched and show clinical benefits although no health claims are currently authorised within the EU – not because they have no benefits, but because the bacteria first need to be genetically sequenced to ensure the right claim is attached to the right strain.
Why are probiotic bacteria beneficial?
Probiotic bacteria produce beneficial substances such as lactic acid (which discourages the growth of less acid tolerant bacteria such as those which cause food poisoning), natural antibiotics (bacteriocins which suppress the growth of harmful bacteria) and stimulate immune cells so they are better able to fight infections.
The results from 12 trials, involving 3,720 children and adults found that probiotics almost halved the chance of experiencing an upper respiratory infection, shortened the cold by almost two days, and reduced the need for antibiotics by over a third as well as reducing days off work or school.
Lack of probiotic bacteria in the intestines disrupts digestion of fibre, increases production of gas and bowel irritants, and has been linked with a number of health problems, including food intolerance, bloating, flatulence, diarrhoea and constipation. It also increase the chance of developing long-term intestinal problems such as irritable bowel syndrome, diverticular disease, and possibly even inflammatory bowel disease.
Replenishing your probiotic strains
Dietary sources of probiotic bacteria include live bio yoghurts, fermented milk drinks and probiotic supplements in tablet or capsule form. These are held in suspended animation through modern techniques which allows them to reactivate within the bowel.
When buying supplements, select one that provides a blend of at least four strains of different bacteria for optimum benefits. The best supplements individually identify each strain so that, for example, instead of plain Lactobacillus acidophilus or Bifidobacteria lactis, you will see specific strains such as L. acidophilus La-14 and B. lactis HN019. This will help you select the strains with the best research evidence to support their use.
Then look at how many of each strain are present, which is usually shown as CFU (colony forming units). For general use, doses of five billion CFU or 10 billion CFU are common. If taking for a diagnosed condition such as IBS, you can take 20 billion CFU or more.
Medical guidelines from the National Institute for Health and Care Excellence (NICE) recommend that probiotics used to manage IBS should be taken for at least four weeks.
Taking oral probiotic supplements appears to be safe with few side effects reported. They should only be used under medical supervision if you have reduced immunity, however.
About Dr Sarah Brewer
Dr Sarah Brewer is a medical nutritionist and an expert in food, herbs and supplements. She qualified from Cambridge University with degrees in natural sciences, medicine and surgery. After working in general practice, she gained a master’s degree in nutritional medicine. Sarah is a licensed medical doctor, a registered nutritionist and a registered nutritional therapist.
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