Lactobacillus is a strain of friendly bacteria. In general, all of the probiotics you probably hear a lot about are helpful bacteria that keep bad bacteria in check and also help to regulate a surprising range of body functions. Some bacteria, however, are especially friendly.

These are the psychobiotics. These are Lactobacillus bacteria that beneficially help to regulate your brain, not just your gut. They can improve your self-esteem, and help you lose weight by losing fat even while you gain muscle. That’s what a clinical trial in Italy revealed.

Psychobiotics: Feel-Good Bacteria

Lactobacillus psychobiotics don’t just help your digestive functions work better. They also help you lose weight and  feel better about yourself. Nine Italian medical doctors recruited 48 women to participate in a three-week study. They recruited women who had various combinations of too much weight and too much body fat.

There were 13 women who had both normal weight and a normal percentage of body fat. There were 11 women who were not overweight, but whose bodies were overfat. And there were 24 women who were both mildly to seriously overweight as well as overfat.

In addition, the women were given a series of physical and psychological examinations. They underwent body composition analysis, psychological profiles, and eating behavior assessments.

Furthermore, they were also given psychological tests such as the body uneasiness test (BUT), an evaluation of body image perception (IC), and a test called the EDI-2 to identify unhealthy eating behaviors. Then the women were given either a placebo or a special probiotic mixture.

The probiotic mixture included Streptococcus thermophilus, Bifidobacterium animalis, Streptococcus thermophiles, Bifidobacterium bifidum, Lactobacillus delbrueckii spp. Bulgaricus, Lactococcus lactis subsp. Lactis SGLc01, Lactobacillus plantarum (which is a name you will see again a little later in this article), Lactobacillus reuteri SGL01. What difference did taking 3000 mg of these probiotics every day for three weeks make?

Psychobiotics Help Women Lose Weight, Lose Fat, and Gain Muscle

The mixture of psychobiotics not only helped women lose weight. Additionally, it helped them lose weight by losing fat even though they gained some weight by adding muscle.



In women who had normal weight but high body fat, there was both a significant decrease of weight and a significant reduction in body-mass index (BMI) while there was a significant increase in total body weight.

In other words, the women taking psychobiotics not only lost fat, they gained muscle. In the women who both weighed too much and had too much body fat, the result of using psychobiotics was significantly lower weight and significantly lower BMIs.

They lost around the waist and hips. In addition, they also lost fat and gained muscle. The women who didn’t need to lose weight or body fat didn’t lose them just because they took psychobiotics. These friendly bacteria don’t make changes that aren’t needed.

However, all of the women in the study had better orocecal transit time, which is a fancy way of saying their bowels moved better. They had less constipation, less bloating, and less gas. But the most telling change was improvement on the psychological tests that measured body image.

Women who were overweight or overfat began feeling significantly better about the way they looked in just three weeks.[1]

Psychobiotics Make You Feel Better About the Way You Look

The idea that psychobiotics can help you feel better about the way you look is not so strange when you consider all the ways that probiotics can lift your mood.

Here are some of the key facts that have emerged from psychobiotics research:
  • One of the undisputed facts about the use of probiotics is that they can relieve both constipation and diarrhea. It turns out that also makes these strains useful as psychobiotics. This property is important because a reduction in bowel irregularity (both constipation and diarrhea) leads to a reduction in pain all over your body. Stool consistency is correlated to pain perception.[2]
  • Consumption of psychobiotics increases the absorption of tryptophan.[3] This is the amino acid the brain uses to make serotonin, the antidepressant chemical. In addition, psychobiotics release chemicals that prevent the brain from breaking down serotonin too fast.[4]
  • Psychological stress increases the permeability or “leakiness” of the lining of the gut.[5] Psychobiotics help preserve the integrity of this lining by tightening the tiny junctions between its cells. As a result, this keeps waste products out of the bloodstream. In turn, keeping waste products out of the bloodstream lowers inflammation, and lowering inflammation reduces depression.[6]
  • Psychobiotic probiotics increase the production of antioxidants.[7] They increase production of gamma-aminobutyric acid (GABA).[8] GABA is the brain’s “downer” chemical that counteracts “upper” chemicals like glutamate, from aspartame and certain protein foods.
  • In addition, Psychobiotic probiotics increase the absorption of nutrients that are important to the brain.[9]
  • Psychobiotics have important effects on stress hormones. They reduce production of stress-induced increases in adrenocorticotropic hormone (ACTH),[10] corticosterone,[11] adrenaline, and noradrenaline.[12] As a result, these hormonal changes reduce the activity of the hypothalamic–pituitary–adrenal (HPA) axis, which is hyperactive in depressed patients.[13]
  • Also, psychobiotics increase expression of brain-derived neurotrophic factor,[14] a growth factor crucial for brain plasticity, memory, and neuron health[15] that is abnormally reduced in patients suffering from depression.[16]
  • Psychobiotics reduce the production of the inflammatory substances interleukin-1-beta (IL-1β) and interleukin-6,[17] which are associated with depression.

Even More Proof That Psychobiotics Improve Mood and Self-Esteem

These findings tell us how probiotics could influence mood, but what is the proof that psychobiotics actually do improve mood disorders in real people?

Researchers in New Zealand found that a significant majority of 212 women suffering postpartum depression found relief from anxiety and depression after taking psychobiotics during and after pregnancy.[18]  Additionally, a clinical study in Japan found that taking Lactobacillus helped restore sleep to study volunteers who had insomnia.[19]



Clinical studies suggest that Lactobacillus is probably better for treating mild depression than major depression, and that the longer you have been depressed, the longer it will take for the probiotic to work.[20]

Furthermore, there is a growing body of evidence that Lactobacillus makes consistent, moderate desirable changes in lifting mood even in people who do not need medical attention.

Here are some more examples:

  • One study with 124 psychologically healthy volunteers who suffered “bad mood” found that most reported a “good mood” after 20 days of taking psychobiotics.[21]
  • A study of 35 people who had been diagnosed with chronic fatigue syndrome found that taking Lactobacillus psychobiotics eased anxiety and depression after two months.[22]
  • Another study of people aged 60 to 75 found that taking Lactobacillus psychobiotics reduced somnolence (dozing off) and psychological measures of anger and hostility.[23]
  • In addition, a study of 44 psychologically healthy young adults found that taking Lactobacillus psychobiotics reduced brooding, dark thoughts.[24]
  • A study of students found that taking probiotics reduced anxiety about exams and lowered the number of cases of colds and flu around exam time.[25]
  • People who are inclined to social anxiety have fewer symptoms when they consume more probiotic foods rich in psychobiotics.
  • And a study of healthy young adults found that drinking dairy products cultured with psychobiotics led to lower scores on tests measuring self-blame and higher scores on tests involving problem-solving.[26]

What Is Special About Lactobacillus plantarum?

Clinical testing of psychobiotics for improving mood and cognition has used a variety of strains of both Lactobacillus and Bifidobacterium. A variety of strains of psychobiotics, the greatest variety possible, is a desirable feature in any probiotic supplement.



However, there is a good reason to favor products that include a particular species of Lactobacillus known as Lactobacillus plantarum.   What’s so special about Lactobacillus plantarum?

It’s something very basic. This strain is the most likely to survive passage through the digestive acids of the stomach on its way to the colon. It’s the most easily absorbed of all the psychobiotics. And this hardy psychobiotic has some potential applications that other strains do not:

  • A combination of Lactobacillus plantarum and Bifidobacterium animalis reduces brain inflammation in people who have multiple sclerosis (MS).[27]
  • Lactobacillus plantarum has promising preliminary results as part of supportive diet for autism.[28]
  • Lactobacillus plantarum has been helpful in managing anorexia.[29]

It’s not that Lactobacillus plantarum is the only species of the psychobiotics that you should take. The thing to remember about Lactobacillus plantarum is that any probiotic you take should include it. This especially friendly probiotic is the most likely to make the journey to your colon where it is needed, and offers some unique protective features.