Probiotics stick around for a while, though for how long isn’t precisely clear. You have to keep taking them to continue to reap the benefits. Further, getting a wide variety of strains into your system is beneficial. “Periodically mixing up your probiotic supplement is also a good way to ensure that you get different health-building strains in your health regime,” says Dr. Cook.
This story has played out before, most notably with vitamin supplements, which decades of research have revealed to be completely unnecessary for most adults and, in some cases, dangerous, correlating with higher rates of lung, breast and prostate cancers. But that has not stopped marketers from pushing another nutritional craze. According to a National Institutes of Health survey, the number of adults in the U.S. taking probiotics or their cousins, prebiotics (typically nondigestible fibers that favor the development of gut bacteria), more than quadrupled between 2007 and 2012, from 865,000 people to nearly four million. San Francisco–based business consulting firm Grand View Research estimates that the global probiotics market exceeded $35 billion in 2015 and predicts that it will reach $66 billion by 2024.
"I usually recommend Garden of Life, BioK or Megafoods brand," says Shapiro. "I also recommend starting with about 30 billion CFU and making sure your supplement has at least 12 different strains. And if you don't eat a diet high in fruits, vegetables, nuts, seeds, and whole grains that provide fiber for the probiotics to live off of, make sure you're the one you are taking contains prebiotics as well.
Most probiotics are like what is already in a person's digestive system. Some probiotics have been used for a very long time throughout history, such as in fermented foods and cultured milk products. These don't appear to cause illness. But more study is needed on the safety of probiotics in young children, the elderly, and people who have weak immune systems.
"The name itself is derived from the Latin 'pro-' meaning 'for' and the Greek '-biotic' meaning 'life,'" explains Jeannel Astarita, skincare expert and founder of Just Ageless NYC Wellness and Medspa. "Probiotics are the helpful bacteria that live primarily in your gut and play a crucial role in your overall health by fighting pathogens and yeast that lead to a weakened immune system."
The science on what probiotics do is still emerging. There is some hard evidence that suggests eating probiotic foods and supplements can have a beneficial effect on health. Other evidence suggests probiotics benefits are limited to those individuals in good health and should be avoided by those who suffer from certain serious health conditions. There is no research that demonstrates the risks or the benefits of probiotic supplements on children.
However, it is not just digestive woes that probiotics can help address. A clinical case series followed 300 patients who took a probiotic mixture of L. acidophilus and L. Bulgaricus. They documented that 80% of acne patients had some degree of clinical improvement, particularly effective in inflammatory acne. Later, an Italian study involving 40 patients found L. Acidophilus and B. Bifidum supplementation produced better clinical outcomes in acne as well as better tolerance and compliance with antibiotics .
Even if some of the bacteria in a probiotic managed to survive and propagate in the intestine, there would likely be far too few of them to dramatically alter the overall composition of one's internal ecosystem. Whereas the human gut contains tens of trillions of bacteria, there are only between 100 million and a few hundred billion bacteria in a typical serving of yogurt or a microbe-filled pill. Last year a team of scientists at the University of Copenhagen published a review of seven randomized, placebo-controlled trials (the most scientifically rigorous types of studies researchers know how to conduct) investigating whether probiotic supplements—including biscuits, milk-based drinks and capsules—change the diversity of bacteria in fecal samples. Only one study—of 34 healthy volunteers—found a statistically significant change, and there was no indication that it provided a clinical benefit. “A probiotic is still just a drop in a bucket,” says Shira Doron, an infectious disease expert at Tufts Medical Center. “The gut always has orders of magnitude more microbes.”
Yogurt: It can contain Streptococcus thermophilus, Lactobacillus bulgaricus, L. acidophilus, and Bifidobacterium bifidum. Research has shown links with yogurt to have positive effects on the gut microbiota and is associated with a reduced risk for gastrointestinal disease and improvement of lactose intolerance (especially among children), type 2 diabetes, cardiovascular disease, allergies and respiratory diseases, as well as improved dental and bone health.
Prebiotics are fuel for the good bacteria (probiotics) in your gut; without prebiotics, probiotics can’t do their job. There are tons of prebiotics in whole fruits and vegetables, including onions, garlic, bananas, asparagus, and artichokes. If you’re worried you’re not getting five to 20 grams per day (more on prebiotic-rich foods here), consider taking a prebiotic supplement, usually a powder or drink mix.
In addition to the impact on our immune systems, our digestive systems are the second largest part of the neurological system. It’s called the enteric nervous system and is located in the gut. This is why it’s called the second brain — the gut is responsible for creating 95 percent of the serotonin and may have significant impact on brain function and mood.
Most of the high-quality probiotics that are available on the market today share the same annoying pitfall: they need to be refrigerated. If losing your supplements in the abyss of your fridge isn’t exactly your idea of a good time, the Garden of Life Dr. Formulated Once Daily Women’s Probiotic is just for you! This probiotic comes with a Shelf Stable Potency Promise, meaning there is no need for refrigeration.
A popular dish in Japan consisting of fermented soybeans, natto contains the extremely powerful probiotic bacillus subtilis, which has been proven to bolster your immune system, support cardiovascular health and enhance digestion of vitamin K2. Natto can also contain vitamin B12, which is usually lacking in vegan diets. It’s also one of the highest plant-based proteins.