Scientists have known for years that probiotics are friendly bacteria that help keep our digestive systems in balance, and that antibiotics usually wipe them out, causing an imbalance that interferes with digestion and potentially leads to other health problems. Patients are often advised to take probiotics, sometimes in the form of yogurt, to replenish friendly bacteria.

In addition to helping our digestive systems, recent studies have also revealed that probiotics have further wide-ranging benefits. They include:

Cancer. UCLA researchers gave mice either only anti-inflammatory gut bacteria, or anti-inflammatory and inflammatory microbes in proportions normally found in the intestines. They found that mice fed the beneficial bacteria produced microbes known to prevent cancer.  The good bacteria also reduced gene damage. They suggested ingesting probiotics like yogurt or probiotic supplements could help prevent cancer from developing.

In another study, researchers used mice designed to have hepatocellular carcinoma (HCC), the most common form of liver cancer. Mice given probiotics showed a 42 percent reduction in tumor size and a 52 percent reduction in the growth of blood vessels — the means tumors use to grow and spread — when compared to untreated mice. The study, which was published in the Proceedings of the National Academy of Sciences, found that probiotics increased anti-inflammatory bacteria in the gut, which may help block tumor growth. 


Weight loss. A study published in the British Journal of Nutrition found that probiotics could help women lose weight and keep it off. Overweight subjects underwent a 12-week weight-loss diet, followed by a 12-week period aimed at maintaining body weight. Throughout the 24-week period, half the participants took two pills daily containing probiotics from the Lactobacillus rhamnosus family, while the other half received a placebo. After 12 weeks, women in the probiotic group lost almost twice as much weight as those in the placebo group.

Researchers from Washington University School of Medicine found that your weight may depend, in part, on the microbes in your gut. They put gut bacteria from thin and fat people into mice whose guts were bacteria-free. Mice who received bacteria from obese people gained more weight than those who got "thin" microbes, even though they ate the same amount of food.

Heavy metal poisoning. During a study at Lawson Health Research Institute's Canadian Centre for Human Microbiome and Probiotic Research, scientists gave probiotics to pregnant women and found they reduced the absorption of arsenic by up to 78 percent and the absorption of mercury by 36 percent. Arsenic and mercury are common environmental toxins found in water and food, and exposure is associated with some cancers and lowered IQs in children.

Allergies. An analysis of 23 randomized studies at Vanderbilt University Medical Center found probiotics improved the symptoms of people with seasonal allergies, such as sneezing and a stuffy nose, in 17 of the studies. Researchers theorize probiotics change the composition of bacteria in the intestines in ways that modulate the body's immune response and stop it from reacting to pollen and other allergens. The study was published in the journal International Forum of Allergy & Rhinology.

Probiotics can eliminate cow's milk allergy in some infants, according to research conducted by the University of Chicago and Italy's University of Naples. Infants fed a formula containing Lactobacillus rhamnosus GG (LGG), a specific type of probiotic found in many supplements, modulated their immune response, and allowed some infants to develop a tolerance for milk. In addition, the probiotic also significantly changed the makeup of the babies' gut bacteria, producing higher levels of a bacteria that help maintain a healthy balance in the gut.

In another study, researchers from Murdock Children's Research Institute gave children with peanut allergies either a daily dose of a probiotic (Lactobacillus rhamnosus) together with a peanut protein, or a placebo. While the amount of the probiotic remained the same throughout the trial, the amount of peanut protein was gradually increased every two weeks. After a maximum maintenance dose of 2 grams was reached, it was maintained until the end of the 18-month trial. Researchers found that an astonishing 80 percent of the children were able to tolerate peanuts compared to only 4 percent in the placebo group — a rate 20 times higher than the natural rate of resolution for peanut allergy.

High blood pressure. Helping control high blood pressure may be as easy as eating yogurt, which contains probiotics, or taking probiotic supplements. A study published in the journal Hypertension found that those who took probiotics daily for more than two months experienced an average drop of 3.6 mmHg in systolic blood pressure (the top number), and a 2.4 mmHg drop in diastolic blood pressure (the bottom number). "We believe probiotics might help lower blood pressure by having other positive effects on health, including improving total cholesterol and low-density lipoprotein, or LDL, cholesterol; reducing blood glucose and insulin resistance; and by helping to regulate the hormone system that regulates blood pressure and fluid balance," said researcher Jing Sun.

Depression. A study at the University of Toronto found that giving patients suffering from chronic fatigue syndrome (CFS) a two-month course of probiotics significantly reduced their depression and anxiety. Experts said the "good" bacteria encouraged by the probiotics boosted the production of L-tryptophan, the "feel good" neurotransmitter.

Another study, this one from the Netherlands' Leiden University, studied healthy people to see if probiotics might influence their moods. Those who took probiotics, which included Bifidobacterium and Lactobacillus, were significantly less prone to sad moods than those who took a placebo.