Читать книгу Nutrition For Dummies - Carol Ann Rinzler - Страница 38

A little more than 100 years ago, Ilya Ilyich (Elie) Metchnikoff, a Russian scientist, decided that humans who died young had succumbed to the effects of “putrefying bacteria” in their intestines. Searching for a remedy, Metchnikoff ended up with Bulgarian peasants, a significant number of whom lived well into their late 80s. Historians may argue that the only way to have lived long in Bulgaria was to avoid Bulgarian politics, but Metchnikoff credited the national longevity to yogurt, the first time someone recognized the benefits of probiotics, a discovery that won him the Nobel Prize in physiology and medicine in 1908.

The National Institutes of Health (NIH) defines probiotics as “live microorganisms that are similar to the beneficial microorganisms found in the human gut.” The most common probiotics in our food are members of the Lactobacilli family, such as the ones in Metchnikoff’s magic Bulgarian yogurt. Probiotic microbes are also active in other fermented food, including kefir, tempeh, some pickles, sauerkraut, and kimchi. (Note: Heat kills these microbes, so to be useful they must be live as noted on the labels for many yogurts.) Recently, a new term has entered the conversation: prebiotics. As you can assume, the “pre” means something that comes before probiotics — in this case, dietary fiber your body cannot absorb but which serves as food for those protective probiotic microbes. (See Chapter 8 for more on dietary fiber.)

While food is your best natural source of prebiotics and probiotics, the hot market right now is in supplements: probiotic tablets, capsules, powders, lozenges, and gums whose worldwide sales are expected to rise from $2.5 billion in 2018 to an astronomical $74.69 billion by 2025. And no wonder. Healthwise, proponents claim a slew of benefits for probiotics, including the prosaic but highly welcome ability to prevent or ease diarrhea due to an infection or treatment with antibiotics that wipes out normal bacterial colonies in the intestines. In 2014, a metanalysis for 24 different trials showed that probiotics also helped prevent a life-threatening intestinal inflammation in newborn premature infants.

Some studies also suggest that probiotics may alleviate symptoms of digestive disorders such as irritable bowel syndrome (IBS) and improve and perhaps relieve depression, but no evidence supports claims that they strengthen your immune system or make it easier for you to lose weight. And there’s this: Probiotic products are supplements, which means the Food and Drug Administration (FDA) regulates them as food, not drugs, so they don’t have to prove that they’re safe or effective. (See Chapter 13 for more on supplement safety.) That matters because with all the hoopla surrounding a “natural” product, there is a clear lack of data regarding the possible risks of long-term use of these supplements.

The bottom line: Probiotics are a promising field of research, and one day they may be used to treat or help prevent many disorders. But right now, not enough evidence exists to recommend their widespread use.