According to Dr Perlmutter, a neurologist studying the gut and the brain,
The following five probiotics are the most effective for brain health and mood:
- Lactobaccilus plantarum: Found in kimchi, sauerkraut, and other cultured vegetables, this bug is one of the most beneficial bacteria in your body. It survives in the stomach for a long time and performs many functions that help regulate immunity and control inflammation in the gut. It also helps fortify the gut lining, fending off potential invaders that might compromise the intestinal wall and sneak into the bloodstream. In fact, L. plantarum’s beneficial impact on the gut lining is perhaps its most important attribute, for it reduces gut permeability, thereby reducing the associated risks for leaky gut—including an increased risk for virtually every brain disorder. Moreover, L. plantarum can quickly digest protein, and this has the ultimate effect of preventing food allergies and even treating such allergies when they arise. Its been shown in experimental animal studies to protect engineered mice from having clinical symptoms of multiple sclerosis and even reduce the inflammatory response typical of that condition. Finally, L. plantarum has an uncanny ability to absorb and maintain important nutrients such as brain-friendly omega- 3 fatty acids, vitamins, and antioxidants. All of these actions make L. plantarum essential for fighting infection and taking control of any pathogenic bacteria.
- Lactobaccilus acidophilus: L. acidophilus is the darling of fermented dairy products, including yogurt. It keeps the balance of good vs. bad bacteria in check and in doing so, aids your immune system. In women, it helps to curb the growth of Candida albicans, a fungus that can cause yeast infections. L. acidophilus has also gained fame for its ability to help maintain cholesterol levels. In the small intestine, L. acidophilus produces many beneficial substances that combat pathogenic microbes, including acidolphilin, acidolin, bacteriocin, and lactocidin.
- Lactobaccilus brevis: Sauerkraut and pickles owe a lot of their benefits to this bug, which improves immune function by increasing cellular immunity and even enhancing killer T cell activity. It’s so effective in combating vaginosis, a common bacterial infection of the vagina, that it’s added to pharmaceuticals used to treat it. L. brevis also acts to inhibit the effects of certain gut pathogens. Perhaps best of all, it has been shown to increase levels of that all-star brain growth hormone BDNF.
- Bifidobacterium lactis (also called B. animalis): Fermented milk products like yogurt contain this gem, which is well documented to have a powerful effect on preventing digestive ills and boosting immunity. It’s also known to be helpful in knocking out food-born pathogens like salmonella, which causes diarrhea.
- Bifidobacterium longum: Just one of the 32 species that belong to the genus bifidobacterium, this is one of the first bugs that colonize our bodies at birth. It has been associated with improving lactose tolerance and preventing diarrhea, food allergies, and the proliferation of pathogens. It’s also known to have antioxidant properties as well as the ability to scavenge free radicals. In laboratory mice, B. longum has been shown to reduce anxiety. Like L. acidophilus, B. longum also helps maintain healthy cholesterol levels.
Dr Perlmutter recommends the above bacteria as his go-to supports. However, the list of which bacteria will work is apparently related to who is advising as one study using just Lactobacillus and bifidobacterium bacteria, daily for 12 weeks, made moderate improvements in patients' scores for mental tasks.
In studies with mice given probiotics improve learning and memory and also reduce. A study by Kashan University of Medical Sciences and Islamic Azad University in Iran studied the same with people.They did a 12 week trial with 52 women and men (60 to 95), who had Alzheimers disease.
The people who benefited were in the group given milk with Lactobacillus acidophilus, L. casei, L. fermented and Bifidobacterium bifidum.
Then there is yet another study that refers to specific probiotics by the catchy title, "psychobiotics". This study used yet again, another set of bacteria.