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The Gut-Brain Link to Depression and Obesity

It wasn’t long ago that conventional medicine debated the existence of the gut-brain axis, the connection that links your emotions, intestines and brain.

The medical community couldn’t dispute it for long, however, given that about 90 percent of serotonin, a chemical that sends messages from one side of the brain to the other, is produced in the human gut.

Obesity and diabetes are serious conditions that harm many parts of your health, including your gut. (Remember, gut health problems could be a warning sign of type 1 diabetes?)

Eating a high-fat diet, a direct contributor to obesity and diabetes, creates greater emotional problems and direct shifts in the makeup of bacteria in the gut too, according to findings from the Joslin Research Center (affiliated with Harvard Medical School).

In their work with mice, Joslin researchers had long studied the damage done by diabetes, obesity and other metabolic health problems in their work with mice fed high-fat diets.

One variable stood out in their previous research: Obese mice that had been fed high-fat diets showed far more signs of emotional problems (depression, anxiety and obsessive behaviors) than animals fed healthier diets.

For their newest study, researchers took a different approach by giving mice behavioral tests commonly used to screen drugs for depression and anxiety. They learned mice that were fed high-fat diets experienced greater amounts of depression and anxiety.

However, when scientists took steps to change the gut health makeup of obese mice by giving them antibiotics their emotional health improved.

Taking that gut bacteria shift one step further, Joslin research also discovered the gut microbiomes of obese mice triggered emotional problems when they were transplanted in germ-free mice. And other germ-free mice that received gut bacteria from obese mice given antibiotics showed no signs of emotional problems either.

Where the gut-brain link really came into play was when researchers examined parts of the brain that govern metabolism and emotions, according to Dr. C. Ronald Kahn, Chief Academic Officer who leads the Section on Integrative Physiology and Metabolism at Joslin.

Like other tissues, these areas of the brain became insulin-resistant in test animals fed high-fat diets and this resistance was mediated partly by their microbiomes, Dr. Kahn said.

The Joslin team also found alterations in the gut health of mice were linked to the production of some chemicals that send signals across the brain too.

Now, scientists are studying specific populations of bacteria involved in the gut-brain axis that may govern this process, with an eye on creating healthier metabolic profiles in the brain.

Interestingly, Dr. Kahn points out the problems of using antibiotics as “blunt tools that change many bacteria in very dramatic ways.”

“Going forward, we want to get a more sophisticated understanding about which bacteria contribute to insulin resistance in the brain and other tissues. If we could modify those bacteria, either by putting in more beneficial bacteria or reducing the number of harmful bacteria, that might be a way to see improved behavior.”

Fortunately, there’s a growing body of evidence that shows probiotics like EndoMune Advance Probiotic may be a safe and proven tool for treating behavioral issues among mice and humans and provide some extra help to fight obesity too.

Can Yogurt Treat Depression?

Yogurt is a delicious and nutritional treat people often confuse as a remedy for all sorts of health conditions (often with the sneaky help of science).

But can yogurt treat depression, one of the most pervasive, frustrating and common health problems affecting more than 16 million adults in America annually?

A recent study appearing in Scientific Reports concluded feeding mice a proprietary strain of Lactobacillus reuteri in yogurt made from live cultures was enough on its own to reverse depressive symptoms in stressed out mice.

A team of scientists at the University of Virginia’s School of Medicine came to that finding after studying the gut health of tiny mice and discovering the depletion of Lactobacillus reuteri triggered the onset of depression.

To take it a step further, that loss of Lactobacillus reuteri was responsible for spiking levels of kynurenine (a metabolite in blood) that bring on depressive symptoms. Once mice were fed Lactobacillus reuteri with their food, however, their stress levels returned to nearly normal, scientists said.

This research does represent evidence that the gut-brain axis – the link between your brain, emotions and intestines – is very much a reality, and maintaining a healthy balance among all three is critical for good physical and mental health.

University of Virginia scientists were so pleased with these results on mice, they plan to turn their attention to human subjects, specifically with multiple sclerosis patients who struggle with depression too.

However, one probiotic strain may not be enough to do the trick. Other studies have found probiotics formulated with Bifidobacterium longum may have a similar beneficial effect on treating depression.

What’s more, there’s no guarantees the yogurt you’ll find in a grocery store will contain exactly the right amounts or combinations of beneficial bacteria that make much of a difference on balancing your emotions.

But, there is growing evidence that a probiotic containing multiple strains of beneficial bacteria – think EndoMune Advanced Probiotic — may be a more effective solution for treating depression and a safer one given all of the side effects associated with antidepressants.

Treating IBS-Related Depression With Probiotics

Most symptoms associated with irritable bowel syndrome (IBS) — gas, cramping, diarrhea and constipation — are very uncomfortable, very embarrassing and very painfully obvious.

Considering the pain and discomfort you may be feeling, however, you may not be paying as much attention to one specific symptom — depression — as it really deserves.

Plus, taking drugs like mesalazine may be good for treating some IBS symptoms, but they don’t address the real problem: Restoring a healthy balance of bacteria in the gut.

Not only can taking a probiotic be a safer way to restore and protect that gut bacteria balance, it may also treat the symptoms of depression associated with IBS too, according to a recent study published in Gastroenterology.

Researchers at McMaster University in Canada studied the effect that prescribing a probiotic formulated with a proprietary blend of Bifidobacterium longum (one of the 10 species of beneficial bacteria found in EndoMune Advanced Probiotic) has on treating depression.

Over the course of 10 weeks, scientists monitored the health of 44 patients, half of whom took a probiotic while the rest were given a placebo.

After just six weeks, nearly two-thirds of patients in the probiotic group felt greater relief from their depression based on falling scores based on the standard Hospital Anxiety and Depression Scale (HADS), versus just seven in the placebo group.

More evidence that those falling HADS scores were real: Functional Magnetic Resonance Imaging tests that showed changes in various sectors of the brain related to mood control.

Other good things could be taking place behind-the- scenes that moderate your mood levels, thanks to probiotics. For example, as much as 90 percent of your body’s serotonin, a chemical that works as a neurotransmitter in the brain, is produced in the gut.

Taking a probiotic is one important and safe way to protect and enhance the diversity of beneficial bacteria in your gut naturally, without a drug.

Probiotics: A drug-free way to treat Alzheimer’s

Alzheimer’s disease is one of the most devastating health problems facing America today. Not only does this mind-robbing condition affect more than 5 million Americans today, with the Baby Boomer generation heading to retirement, that number is expected to triple by 2050.

Although there is no cure for Alzheimer’s, just a handful of FDA-approved drugs relieve symptoms, but only for the short-term. What’s more, they come with an array of side effects, including headaches, nausea, weight loss, diarrhea and constipation.

Fortunately, modern medicine has begun to embrace the gut-brain axis — the connection that links your brain to your intestines and emotions. Over time, probiotics have proven their value as a non-drug tool ideally equipped to maintain that important balance, and treat problems like depression.

One day very soon, neurologists may be using probiotics to treat Alzheimer’s, based on a recent clinical trial featured in Frontiers in Aging Neuroscience.


Neurological testing

Over the course of the 12-week, double-blind clinical trial, Iranian researchers split 52 Alzheimer’s patients (between ages 60-95) into two groups. One received 200 milliliters of milk enriched with three strains of Lactobacillus (acidophilus, casei and fermentum) and Bifidobacterium bifidum, while a control group was given milk without beneficial bacteria.

(Lactobacillus acidophilus and Lactobacillus casei and Bifidobacterium bifidum are three important ingredients of EndoMune Advanced Probiotic.)

At the beginning and end of the trial, blood samples were taken and all patients were given Mini-Mental State Exams (MMSEs) that measured their cognitive ability on specific tasks like remembering dates, copying pictures, counting backwards and naming objects.

No surprise, patients who received the probiotic mixture improved on their previous MMSE results after 12 weeks, while those in the control group had lower scores.

Patients in the probiotic group also benefitted in other measurable ways, with lower levels of trigylcerides, high-sensitivity C-Reactive Protein (hs-CRP) and Very Low Density Lipoproteins (VLDL) as well as drops in two common measures used to gauge insulin resistance and the production of insulin in the pancreas.

“These findings indicate that change in the metabolic adjustments might be a mechanism by which probiotics affect Alzheimer’s and possibly other neurological disorders,” said senior study author Dr. Mahmoud Salami, according to a press release.


Multi-species power

Arguably, the real benefits Alzheimer’s patients received in improved cognitive skills and healthier blood levels may stem from the multiple species of bacteria, not just one.

In fact, it’s possible giving Alzheimer’s patients a multi-species probiotic like EndoMune Advanced Probiotic with 10 proven strains of bacteria every day may have yielded even greater results.

Beat depressing thoughts with multi-species probiotics

Reflecting on life’s lessons about a difficult time in your life can be beneficial, and even instructive.

Looking back, however, can become unhealthy if your mind gets stuck ruminating, and replaying the same situation over and over again, causing you to focus more on what you might’ve done rather than how to solve the issue or avoid it.

When taken to an extreme, according to the American Psychological Association, ruminating doesn’t offer new insights at all. Instead, it can feed depression and make it harder for you to shake negativity.

There are lots of strategies you can use to beat the rumination cycle, using cognitive skills you can learn on your own, or with the help of a licensed therapist or a trusted friend.

A new study appearing in Brain, Behavior, and Immunity identified a familiar weapon — multi-species probiotics — which can also be helpful in breaking the depression-rumination cycle too.

Psychologists at the Leiden Institute of Brain and Cognition (located in the Netherlands) tested the effect of probiotics containing proprietary strains of various beneficial bacteria, including Lactobacillus acidophilus, Lactobacillus lactis, Lactobacillus casei, Bifidobacterium bifidum and Bifidobacterium lactis on 40 healthy patients.

(These five strains represent half of the beneficial bacteria contained in EndoMune Advanced Probiotic.)

Half of the patients received a drink made of lukewarm water or milk containing probiotics or a placebo for four weeks. At the beginning and end of the study, patients completed questionnaires that measured their sensitivity to depression.

Patients who were given the multi-strain probiotic experienced significantly fewer ruminative thoughts, compared to those assigned the placebo.

“Even if preliminary, these results provide the first evidence that the intake of probiotics may help reduce negative thoughts associated with sad mood,” says Dr. Lorenza Colezato, co-researcher of the study in a press release.

“As such, our findings shed an interesting new light on the potential of probiotics to serve as adjuvant or preventive therapy for depression.”

Considering the results of a recent study that identified specific beneficial bacteria in your gut responsible for the production of serotonin, as well as more evidence of the gut-brain axis, these results were not unexpected.

In addition to multiple species of beneficial bacteria, EndoMune Advanced Probiotic and EndoMune Jr. contain no artificial colorings, sugar, dairy products, preservatives or gluten and both are certified kosher.

Healthy Bugs Prevent Depression and Gut Distress

This month I am discussing some new, exciting research on the effect of probiotics on the gut-brain axis(1). Before proceeding, I think it is best to explain the relationship between the intestines and the brain.

We have all experienced the effect of this axis. Most of us have been in a situation where we become very anxious about an upcoming event – making a presentation, taking an exam – and, as a result, developed a terrible gut pain or “knot.”

As quickly as the pain surfaced, it similarly eases when the stressful event resolves. When this happens, we don’t develop an ulcer or any other structural intestinal problem. So what physically happened to cause this pain?

The brain releases chemicals that travel through the blood stream (or nerves) to the gut.  The major nerves between the brain and intestines are called the vagus and the sympathetic nerves. The “knot” commonly experienced during stressful events is a result of the nerve endings releasing chemicals that cause spasms of the intestines and activation of the intestinal pain fibers.

Now, let’s get really geeky to explain how this happens in more detail. The gut-brain axis consists of:

(1) Vagus and sympathetic nerves that send messages to:

  • Stimulate or inhibit stomach and intestinal secretions
  • Increase or decrease stomach and intestinal motility
  • Enhance or decrease appetite
  • Transmit pain sensation from the gut to the brain
  • Alter our mood …positively or negatively

2) Hormones secreted by the brain and gut that stimulate or suppress the hunger and satiety centers in the brain affecting dietary intake. It is very common for people to attribute weight loss to stress. Their appetite seems to have just “disappeared.”

What really happened was that the emotional stress sent hormones and nerve signals to the intestines causing the following:

  1. Disruption of the healthy intestinal balance of the bacteria.
  2. Multiplication of the unhealthy bacteria, causing intestinal inflammation.
  3. Release of chemicals by the inflamed intestines, stimulating the satiety center in the brain – resulting in loss of appetite.
  4. Once the stress is resolved, both the healthy bacteria and appetite will return.

Be Happy…Take a Probiotic!

With this brief background, we will explore more clearly how intestinal bacteria can be impacted by stress and how probiotic bacteria can improve our mood. It is a two way street.

A research article published this month in the prestigious medical journal Proceedings of the National Academy of the Sciences discusses how probiotic bacteria may lessen anxiety and depression and help to maintain a positive attitude(3).

The point of the study was to determine how bacteria dwelling in the gut can effect the brain, and thereby influence mood and behavior. Since there are special neurotransmitters in the brain that impact mood, the researchers sought to evaluate whether these receptors could be modified by probiotics.

The researchers split their rodent subjects into two groups. One lot was fed a special broth containing Lactobacillus rhamnosus. The other group was fed an ordinary diet not fortified with microbes.

The mice were subjected to a battery of tests that measured their emotional state. The results indicated that the mice fed Lactobacillus performed more activities in a maze which indicated confidence and less anxiety. They were able swim in a container farther indicating a more positive mood.

Direct measurements of the animals’ brains supported the behavioral results. Levels of cortisone, a stress hormone, were significantly lower in the bacteria-fed mice than they were in the control group.

In addition, the number of neurotransmitter receptors was higher in the mood altering portion of the brain. Stimulation of these receptors results in sensations of relaxation and euphoria.

Finally, to prove that the vagus nerve is responsible for transmitting signals from the gut to the brain, the study was done again. But in the second study, the vagus nerve was severed in both groups of mice. The results of the repeat study revealed that the behavior in the two groups of mice was the same. The probiotic fed mice didn’t demonstrate the same activities which had been associated with confidence, less anxiety and a more positive mood. The damaged vagus nerve couldn’t transmit the benefits of the probiotics to the brain.

At this point you may say “well that is very interesting but we are not mice.  Are there studies in humans that also show similar results?”

A recent study in the British Journal of Nutrition(4) assessed whether a daily dose of a Lactobacillus and Bifidobacterium probiotic taken for 30 days could influence the psychological impact of everyday life events in normal human volunteers.

By using standardized psychological tests, the scores of the probiotic treated group had lower values for depression, anger-hostility and physical complaints.

The authors concluded that the beneficial effects of the probitotics may be explained by competitive exclusion of harmful gut bacteria and a decrease in inflammatory signals via the vagus nerve to the brain!

Take Home Message

If you are feeling a little “blue” or just want to feel positive about life, consider taking a beneficial probiotic like EndoMune. The best part of these studies is that there were no adverse effects of probiotics – no need for a black box!


(1) Gut-brain axis. Romijn JA, Corssmit EP, Havekes LM, Pijl H. Curr Opin Clin Nutr Metab Care. 2008 Jul;11(4):518-21.

(2) The new link between gut-brain axis and neuropsychiatric disorders. Fetissov SO, Déchelotte P.Curr Opin Clin Nutr Metab Care. 2011 Sep;14(5):477-82.

(3) Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Bravo JA, Forsythe P, Chew MV, Escaravage E, Savignac HM, Dinan TG, Bienenstock J, Cryan JF.Proc Natl Acad Sci U S A. 2011 Sep 20;108(38):16050-5.

(4) Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects. Messaoudi M, Lalonde R, Violle N, Javelot H, Desor D, Nejdi A, Bisson JF, Rougeot C, Pichelin M, Cazaubiel M, Cazaubiel JM. Br J Nutr. 2011 Mar;105(5):755-64.

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