Before buying this, I didn't realize that some strains of bacteria used in probiotics produce histamines. When I discovered this, I looked up which ones do, and all three I discovered are used in this one. If you're sensitive to histamines or have leaky gut (which makes you sensitive to histamines), then this is not for you. According to an article on bullet proof, an overload of histamines "leads to increased inflammation and many other symptoms including: skin irritation, hives, throat tightening, increased heart rate, nasal congestion, migraines, fatigue, heartburn, reflux, and weight gain." I'm sure this can work for some people, but probably only despite the histamine-producing bacteria.

The U.S. Clinical Guide to Probiotic Products1, Canadian Guide to Probiotic Supplements2 and the WGO Global Guidelines for Probiotics and Prebiotics3 provide suggested effective amounts of specific strains for treating certain health conditions, such as constipation or IBS. All 37 products listed the species of bacteria they contained, but only 14 listed amounts of individual strains. We found that 9 of those 14 products provided beneficial bacteria at effective levels. The Center for Responsible Nutrition recommends4 the industry move toward specifying strains as a best-practice because whether a product works and for what purpose depends on its strains.
Probiotics: Health benefits, facts, and research Every human on the planet has microbes living in their body. While bacteria get a bad reputation, many can promote good health. Probiotics are a type of 'good bacteria' that provide health benefits for the host. The health benefits of probiotics include treatment of diarrhea and irritable bowel syndrome. Read now
If this happens, it's time to consider switching to a new probiotic. Other reasons a probiotic may not be the right fit: SIBO or Candida. If you have either of these conditions, the strain of the probiotic could potentially make your symptoms worse. Remember, if you think a probiotic is not helping, seek the advice of a functional medicine provider to help you navigate the choices out there.
Renew Life offers a powerful, high potency blend of 10 specially selected Lactobacillus and Bifidobacterium strains designed to help restore your body’s good, natural ora. Their probiotics come in a special capsule designed to survive stomach acid and make it intact into the intestines to deliver the probiotics more effectively where they are most needed.
That’s why adding probiotics and prebiotics to your diet provide the best possible outcome from a bacterial perspective. It isn’t always easy to eat naturally prebiotic-enriched foods, however, because they are often distasteful to eat in quantity. Would you enjoy eating several cups of raw onion or garlic every day? Probably not. Other foods that contain prebiotic fiber, such as bread and bananas, are high in calories. Consuming hundreds of calories of these foods every day is counterproductive if you’re trying to lose weight.
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.” 

In October 2013, the International Scientific Association for Probiotics and Prebiotics (ISAPP) organized a meeting of clinical and scientific experts on probiotics (with specialties in gastroenterology, pediatrics, family medicine, gut microbiota, microbiology of probiotic bacteria, microbial genetics, immunology, and food science) to reexamine the concept of probiotics. They define probiotics as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host." They also differentiated between products containing probiotics and those containing live or active cultures and established the following criteria: 

Some yogurts contain the aforementioned bacteria; however, because they are sensitive to oxygen, light, and dramatic temperature changes, make sure to look for yogurts with “live and active cultures.” Many commercial yogurts are heat-treated or pasteurized, resulting in the loss of these valuable cultures. Learn more about the smart way to shop for probiotics.

If you get sick often, probiotics might be the immune booster you've been looking for. The Cleveland Clinic says they've been shown to strengthen immunity by enriching and replenishing the good bacteria in the body. And when you eat foods with probiotics regularly, it's easier for your body to produce vitamins and enzymes that help keep your intestines happy.
There is one Voluntary Certification Program by which a supplement manufacturer can choose to be evaluated. ConsumerLab.com (CL) is the leading provider of independent test results and information to help consumers and health-care professionals identify the best quality health and nutrition products. Products that have passed their testing for identity, strength, purity, and disintegration can print the CL Seal of Approval on their product. This is one step toward being confident that one is getting the amount and type of probiotic promised by the manufacturer.

Candida yeast species, on the other hand, can cause numerous infections in and on you. Although they are usually present in controlled amounts, Candida overcomes your usual defenses and establishes itself when conditions are favorable, such as when you take antibiotics and many beneficial bacteria, which normally would control Candida, are killed. Unlike the Saccharomyces yeasts, which are not invasive, Candida species form hyphae, finger-like projections that penetrate tissues, causing deep infections that are difficult to eliminate. Candida is also able to weaken your immune defenses.
Following a healthy and active lifestyle and eating a balanced diet are the best ways to foster a bountiful gut flora. Taking care of your gut flora can help with things like irritable bowel syndrome and chronic constipation, among other things. Even if you’re not sold on pursuing probiotics for your allergies, they’re good to consider if you’re experiencing any gastrointestinal issues.

Bottom line: Probiotics are a promising field of research and may one day be used to treat or help prevent many disorders. But there’s not enough solid evidence to recommend their widespread use. Vague claims that probiotics "support good digestive health" are meaningless. Larger, longer and better studies are needed to test specific strains for specific conditions and to determine the proper doses and regimens.
As with other types of supplements, scientists are still discovering the full potential of probiotics. However, when taken regularly, it is believed that they help support digestive health by helping maintain the balance of beneficial and non-beneficial bacteria in your digestive tract. Having a natural balance of good bacteria in the digestive tract can help defend against occasional digestive issues. In addition, probiotics play an important role in supporting immune health, since 70% of the body's immune system is found in the digestive tract.∗
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