Probiotics are bacteria and yeasts that occur naturally in the human body and benefit it rather than causing disease. They usually play a role in digestion, and prevent disease by crowding out harmful bacteria; some help burn fat or even balance hormones. Research is also starting to suggest that they could have a role in urinary and vaginal health, allergy and cold prevention, treating skin conditions such as eczema, and oral health. Some even think they could help with mental health issues and neurological disorders.
It's particularly important to replenish your inner fauna during and after a course of antibiotics (which, as you probably know but a reminder never hurts, you should only take when you have to and then finish the entire treatment to avoid breeding drug-resistant bacteria). However, regularly taking probiotics or eating probiotic foods helps maintain a healthy and diverse internal micro-community to keep your gut healthy. Probiotic bacteria are impacted by all kinds of things, including chemicals in tap water, emotional stress, antibiotic residues in conventional foods, and even a diet high in grains and carbs.
Most probiotics fall into two main categories. Lactobacillus, found in fermented foods such as yoghurt, helps prevent diarrhea and can mitigate lactose intolerance. Bifidobacterium, found in some dairy products, can ease irritable bowel syndrome symptoms. Other probiotics include Bacillus subtilis, which elicits a potent immune response; Streptococcus thermophilus, reportedly useful in preventing lactose intolerance; Bacillus coagulans, that improves nutrient absorption and can reduce inflammation and symptoms of arthritis; and Saccharomyces boulardii, good against inflammation and IBS. Probiotics were discovered in the early 20th century by Elie Metchnikoff, who observed that rural Bulgarians were very long-lived and theorized that the bacteria in sour milk might be a contributing factor.
If you're going to take a supplement, look for the highest number of strains and CFUs (colony forming units) you can tolerate. However, there's a lot to be said for getting your probiotics by including natural sources such as fermented foods in your diet.
Recent research has "discovered" that some people are sensitive to probiotics and even yoghurt will make them nauseous. There is hope, however; in most cases, taking small doses as part of a large meal -- not just a bit of toast or a few bites of sandwich -- will solve the problem. I can personally recommend keeping a bottle of Rawkstar's excellent water kefir on hand and having a few sips whenever you manage to put together a substantial dinner.
Read more:
Food Matters
Harvard
MedicineNet
Versión en español: this post is also available in Spanish.
Esperanta traduko: this post is also available in Esperanto, because Dana is a language geek.
