Probiotics are live bacteria and yeasts that are good for your health, especially your digestive system. We usually think of bacteria as something that causes diseases. But your body is full of bacteria, both good and bad.



Probiotics are live bacteria and yeasts that are good for your health,especially your digestive system. We usually think of bacteria as something that causes diseases. But your body is full of bacteria, both good and bad.Probiotics are often called "good" or "helpful" bacteria because they help keep your gut healthy.

Probiotics are naturally found in your body. You can also find them in some foods and supplements.

The root of the word probiotic comes from the Greek word pro,meaning "promoting," and biotic, meaning "life." The discovery of probiotics came about in the early 20th century, when Elie Metchnikoff, known as the "father of probiotics," had observed that rural dwellers in Bulgaria lived to very old ages despite extreme poverty and harsh climate. He theorized that health could be enhanced and senility delayed by manipulating the intestinal microbiome with host-friendly bacteria found in sour milk.



Probiotics May Improve Cognitive Function

One scientist’s team from Iran is the first to show how a daily dose of probiotics for 3 months could be effective for improving memory and thinking abilities in individuals with Alzheimer's disease.

The team found that Alzheimer's patients who consumed milk enriched with beneficial live bacteria every day for12 weeks showed significant improvements in cognitive functioning.

Senior study author Prof. Mahmoud Salami, from Kashan University in Iran, and colleagues recently published their findings in the journal Frontiers in Aging Neuroscience.

Probiotics are defined as live microorganisms that are "helpful" to human health. These include bacterial groups such as Lactobacillus and Bifidobacterium, as well as yeasts, including Saccharomyces boulardii.

According to the National Center for Complementary and Integrative Health, probiotics can act in a number of ways.They can help create a favorable community of microbes in the gut, for example,and help stimulate immune response.

Research has shown that these friendly microorganisms - many of which are added to food products, topical medications,and dietary supplements - may help protect against numerous infections and diseases, including irritable bowel syndrome (IBS), eczema, certain allergies, colds, and tooth decay.

Previous animal studies have also shown probiotics to improve learning and memory - an association that has been attributed to beneficial alterations in the gut microbiome that affect the brain. Whether probiotics have the same effect in humans, however, has been unclear.

For this latest study, Prof. Salami and team set out to determine the effects of probiotics on the cognitive functioning of 52 men and women aged 60-95 who had been diagnosed with Alzheimer's disease.


Researchers found older adults with Alzheimer's who drank probiotic-enriched milk showed improvements in cognitive functioning.


Participants were randomized to one of two groups. One group was required to drink 200 milliliters of normal milk every day for 12 weeks, while the other group drank 200 milliliters of milk containing four probiotic bacteria: Lactobacillus acidophilus, Lactobacilluscasei, Lactobacillus fermentum, and Bifidobacterium bifidum.

Fast facts about Alzheimer's

  • More than 5 million adults in the United States are living with Alzheimer's
  • Every 66 seconds, someone in the U.S. develops the disease
  • Alzheimer's kills more people than breast cancer and prostate cancer combined.

Before and after the 12-week study period, researchers collected blood samples from the participants, and the subjects' cognitive functioning was assessed using the Mini-Mental State Examination (MMSE) scale.

As part of this examination,subjects are required to complete a number of tasks that test learning and memory, such as naming objects, counting backward, and copying a picture.

Compared with participants who consumed the untreated milk, those who received the macrobiotic-enriched milk demonstrated significant improvements in cognitive functioning, the team reports.

Subjects who consumed the treated milk saw average MMSE scores increase from 8.7 to 10.6(out of a possible 30) during the 12-week study period, while scores dropped from 8.5 to 8.0 for those who drank the untreated milk.

The researchers stress that all participants remained severely cognitively impaired, but their findings are the first to show that probiotics might lead to some cognitive improvements.

"In a previous study, we showed that probiotic treatment improves the impaired spatial learning and memory in diabetic rats," notes Prof. Salami, "but this is the first time that probiotic supplementation has been shown to benefit cognition in cognitively impaired humans."

On assessing the participants' blood samples, the researchers found that subjects who consumed probiotics had lower triglycerides levels, lower levels of "bad" very low-density lipoprotein (VLDL) cholesterol, and reduced high-sensitivity C-reactive protein - a marker of inflammation.

Additionally, participants who received probiotics showed a reduction in two measures of insulin resistance and the functioning of insulin-producing beta cells in the pancreas - HOMA-IR and HOMA-B.

The team says these findings indicate the cognitive benefits of probiotics may be down to the metabolic changes they provoke. "We plan to look at these mechanisms in greater detail in our next study," notes Prof. Salami.

Walter Lukiw, a professor at Louisiana State University who was not involved in the study, hails the team's findings as "interesting and important,"noting that they provide further evidence of a link between the gut microbiome and cognitive functioning.

"This is in line with some of our recent studies which indicate that the GI [gastrointestinal] tract microbiome in Alzheimer's is significantly altered in composition when compared to age-matched controls, and that both the GI tract and blood-brain barriers become significantly more leaky with aging, thus allowing GI tract microbiological (e.g. amyloids, lipopolysaccharides, endorphins and small non-coding RNAs) to access central nervous system compartments," he adds.



Probiotics Reduce Blood Sugar Levels

The study involved people who were following the DASH diet, which is recommended for people with high blood pressure. The people on this diet who also consumed probiotics, which are considered "good" bacteria, had a decrease in several measures of blood sugar levels over a three-month period,according to the findings. People with consistently high blood sugar levels mayor may not go on to be diagnosed with diabetes; a diagnosis can depend on the results of several tests.

Although more research is needed, the findings suggest that adding probiotics to the DASH diet could be used in the future to help protect against diabetes, said Arjun Pandey, a researcher at the Cambridge Cardiac Care Centre in Ontario and the author of the study

Pandey presented his findings here on Sunday (Nov. 13) at the American Heart Association's Scientific Sessions annual meeting. The findings have not been published in a peer-reviewed journal.

In the study, 80 people with high blood pressure were placed on either the Dash diet or the DASH diet plus probiotic-rich foods. About 15 percent of the participants had prediabetes, Pandey noted, which means their blood sugar levels were elevated but were not considered high enough to warrant a diagnosis of diabetes.

The DASH diet, which stands for Dietary Approaches to Stop Hypertension, is one of the most effective non-drug-related methods for improving certain aspects of heart health, including lowering blood pressure, Pandey told Live Science.

The people in the study who added the probiotics to their diet did so by replacing certain components of the DASH diet with probiotic-rich components,Pandey said. For example, instead of just consuming any type of low-fat dairy product, as recommended by the DASH diet, a person could eat a low-fat probiotic yogurt, he said.



Before the study participants started the diets, the researchers measured the people's hemoglobin A1C, fasting blood sugar levels and blood pressure.They took the measurements again at the end of the study.

The hemoglobin A1C test measures how much hemoglobin, a protein found in red blood cells, is linked with sugar molecules, according to the American Diabetes Association (ADA). The more sugar molecules that are present in a person's blood, the more linked-up hemoglobin molecules there are, the ADA says. The fasting blood sugar test measures a person's blood sugar levels before he or she has eaten anything that day.

Before the diets began, there were no differences in the measurements between the two groups, Pandey said.

After three months, both groups had similarly lower blood pressure measurements, Pandey said. In other words, adding probiotics did not appear to be associated with a change in blood pressure, specifically.

But adding probiotics did have a significant link with the participants' blood sugar measurements, Pandey said. 

At the three-month mark, the people who had followed only the DASH diet(with no added probiotics) had lowered their hemoglobin A1C, on average, by 3.4percent. In comparison, those who had followed the DASH diet plus probiotics had lowered their hemoglobin A1C, on average, by 8.9 percent.

Adding probiotics to the DASH also had a stronger link with the participants' fasting blood sugar levels, according to the study. The DASH-plus-macrobiotics group lowered their fasting blood sugar levels by 10.7percent, on average, compared with an average reduction of 3.3 percent in the group that followed only the DASH diet. 

Although the study doesn't prove a cause-and-effect link between probiotics and lower blood sugar levels, one possible explanation for how probiotics could lower blood sugar levels is through a compound called butyrate, Pandey said. In the gut, certain bacteria produce butyrate, which may play a role in insulin sensitivity, he said. When insulin sensitivity is higher, the body does abetter job of absorbing sugar from the blood, therefore lowering blood sugar levels.

Pandey noted that there were several limitations to the study, including the small number of study participants and the short duration of the study. To validate the findings, the research should be carried out in a larger, more diverse group of people for a longer time period, Pandey said.


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