Probiotics: Should You Take One?

By Lisa Andrews Med RD LD


You can’t go anywhere (a party, your gym, the grocery store or work site) without hearing someone talking about their gut health. Whether they’re complaining about IBS or experiencing traveler’s constipation, people have certainly become more comfortable talking about their gastrointestinal issues. Along with that discussion typically comes the topic of probiotic supplements. Some people swear by them, whiles other are not so sure. Are they worth the money?

Probiotics are strains of live bacteria and yeasts that have health benefits. Our guts house millions and millions of bacteria known as the microbiome. The majority of our microbiome is in our large intestine and everyone’s bacteria will vary based on genetic factors, environment and components in our diets. 1 For example, studies show that eating an all animal-based diet for one day versus all plant based can alter gut bacteria drastically. 2 The long-term use of artificial sweeteners such as Sucralose (Splenda), Aspartame (NutraSweet) and Saccharin (Sweet n Low) has also been found to negatively impact the diversity and balance of gut bacteria. 3

Some of the conditions that probiotics may be beneficial for include IBS, bowel regularity/constipation, Crohn’s disease, diarrhea and/or vaginal infections, to name a few. In addition, having a thriving microbiome has been linked with reduced inflammation, improved nutrient utilization, weight management, blood sugar control and reduced risk of heart disease. 3, 1

Fermented foods contain probiotics and include yogurt, kefir, kimchi, sauerkraut and miso. These are healthy foods to include in our diets, thought the amount of probiotic can vary widely. Probiotic supplements do not require FDA approval prior to being marketed to the public. Products often contain mixed strains of bacteria versus a single strain, which can make it difficult to choose which product will work for which condition.

Here are a few conditions where they may be of help:

  1. Atopic dermatitis: Several studies and meta-analysis show that probiotics used during pregnancy reduce the risk of atopic dermatitis in infants. Strains that include Lactobacillus Bifidobacterium,and Propionibacterium showed the most promise. In children between the ages of 6 months and 9 years, use of probiotics with single strains or mixtures which included Lactobacillus, Bifidobacterium, and Propionibacterium strains significantly reduced the risk of atopic dermatitis from 34.7% in the control group to 28.5% in the probiotic group. 5

  2. Antibiotic associated diarrhea (AAD): Antibiotic use often disrupts intestinal gut flora and reduction in microbiome diversity, leading to diarrhea. Meta-analysis studies show that use of several strains of probiotics may be helpful. According to a 2015 article by Szajewska, “In a systematic review and meta-analysis of 21 RCTs in a total of 4,780 participants, treatment with Saccharomyces boulardiicompared with placebo or no treatment reduced the risk of AAD in 3,114 adults treated with antibiotics from 17.4% to 8.2%”. Data suggest that beginning probiotic treatment with Lactobacillus rhamnosus GG or Saccharomyces boulardii within the first 2 days at the start of antibiotic use helps cut the risk of AAD in children and adults aged 18 to 64, but not in elderly adults. 6

  3. Irritable Bowel Syndrome (IBS): IBS is a common gastrointestinal condition with symptoms of gas, bloating, abdominal pain, constipation and/or diarrhea. Several meta-analyses studies have evaluated the role of probiotics in the treatment of IBS. A meta-analysis of 23 RCTs in over 2,570 patients found that for the most part, probiotics reduced the risk of IBS symptoms continuing or not improving by 21%. The strain of bacteria needed to treat IBS depends on the symptom. In a meta-analysis of 10 RCTs with over 875 adults, pain scores significantly improved in those treated for 4 to 6 weeks with use of probiotics containing Bifidobacterium breve, Bifidobacterium longum, or Lactobacillus acidophilus species compared with placebo use. More research is needed in this area. 7

  4. Hypercholesterolemia: high levels of LDL cholesterol (“lousy” cholesterol) are a risk for cardiovascular disease. A review of 30 RCTs with over 1600 subjects (primarily adults over the age of 18) showed that those treated with probiotics for 3 to 12 weeks had a 7.8 mg/dL reduction in total cholesterol and 7.3 mg/dL drop in LDL cholesterol than those given placebo. Benefits of probiotics were slightly better in studies that went for 8 weeks or more and in subjects with total cholesterol levels of 240 mg/dL or higher at baseline. Lactobacillus acidophilus, a mixture of Lactobacillus acidophilusand Bifidobacterium lactis, and Lactobacillus plantarum were linked with significant reductions in total and LDL cholesterol levels. 8

  5. Obesity: Probiotics are also under investigation in the treatment of obesity, though results of studies have been mixed. A 2017 systematic review of 14 clinical trials, in 1,067 overweight or obese individuals found that probiotics (mostly Lactobacillus given at various doses for 3 weeks to 6 months) greatly reduced body weight and/or body fat in nine trials, had no effect in three trials, and increased body weight in two trials. 9 A diet high in fiber from a variety of plant sources including fruits, vegetables, whole grains, legumes, nuts and seeds is certainly a step in the right direction in improving the gut microbiome of those struggling to lose weight.

For clients experiencing the above conditions, a probiotic may be beneficial. Like other supplements, probiotics are not regulated by the FDA. Reading labels and being knowledgeable about the various strains of probiotics available for each condition may help dietitians provide their clients with an informed decision of which one to use.


1. Valdez, Ana. Role of the gut microbiota in nutrition and health. BMJ 2018; 361 doi: (Published 13 June 2018)

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  1. Huang R, Ning H, Shen M, Li J, Zhang J, Chen X. Probiotics for the treatment of atopic dermatitis in children: a systematic review and meta-analysis of randomized controlled trials. Front Cell Infect Microbiol 2017;7:392.

  2. Silverman MA, Konnikova L, Gerber JS. Impact of antibiotics on necrotizing enterocolitis and antibiotic-associated diarrhea. Gastroenterol Clin North Am 2017;46:61-76. [PubMed abstract]

  3. Ford AC, Quigley EM, Lacy BE, Lembo AJ, Saito YA, Schiller LR, et al. Efficacy of prebiotics, probiotics, and synbiotics in irritable bowel syndrome and chronic idiopathic constipation: systematic review and meta-analysis. Am J Gastroenterol 2014;109:1547-61

  4. Shimizu M, Hashiguchi M, Shiga T, Tamura HO, Mochizuki M. Meta-analysis: effects of probiotic supplementation on lipid profiles in normal to mildly hypercholesterolemic individuals. PLoS One 2015;10:e0139795.

  5. Crovesy L, Ostrowski M, Ferreira D, Rosado EL, Soares-Mota M. Effect of Lactobacillus on body weight and body fat in overweight subjects: a systematic review of randomized controlled clinical trials. Int J Obes (Lond) 2017;41:1607-14