Story at-a-glance

• Recent research reveals lactobacillus rhamnosus (LGG) protect the liver against oxidative damage caused by acetaminophen. Animal studies have also shown this bacterium helps protect against alcoholic liver disease and nonalcoholic fatty liver disease
• LGG protects the liver by activating Nrf2, a biological hormetic that upregulates intercellular antioxidants, thereby lowering inflammation, improving mitochondrial function and stimulating mitochondrial biogenesis
• People who consume probiotics on a regular basis (in the form of yogurt, kefir or supplements, for example) tend to have lower blood pressure than those who do not consume probiotics
• Animal research also suggests the probiotic lactobacillus marinus effectively prevents salt-sensitive hypertension
• Recent research also shows regular consumption of kefir lowers blood pressure, improves intestinal structure and decreases inflammation in the central nervous system

Your intestinal bacteria are part of your immune system and researchers have discovered that microbes of all kinds play instrumental roles in countless areas of your health. Beneficial bacteria also control the growth of disease-causing bacteria by competing for nutrition and attachment sites in your colon.

This is of immense importance, as pathogenic bacteria and other less beneficial microbes can wreak havoc with your health if they gain the upper hand. It can also affect your weight. Moreover, your gut microbiome — which contains 100 times as many genes as your body’s total genome — is involved in important chemical reactions that your gut enzymes cannot perform, including fermentation and sulfate reduction.

Importantly, your gut microbiome helps generate new compounds (bacterial metabolites) that can have either a beneficial or detrimental impact on your health. Among the most recent research published are studies showing beneficial gut bacteria, also known as probiotics, benefit your liver function and help lower blood pressure.

Probiotics Influence Liver Function

While a lot of research has focused on the influence gut bacteria have on your gastrointestinal health, recent research presented at the 2018 Experimental Biology meeting in San Diego reveals probiotics also impact your liver function. This study focused primarily on a probiotic called lactobacillus rhamnosus GG (LGG), which is found in many commercial probiotic supplements.

Mice were first given food with added LGG for two weeks, and were then given a toxic dose of acetaminophen, known to cause serious liver damage by increasing oxidative stress. Interestingly, the animals pretreated with LGG had far less liver damage than untreated mice when given an acetaminophen overdose.

According to lead author Bejan Saeedi, doctoral candidate at Emory University,1 "Administration of the probiotic LGG to mice improves the antioxidant response of the liver, protecting it from oxidative damage produced by drugs such as acetaminophen.” Earlier animal studies have also shown LGG helps protect against alcoholic liver disease and nonalcoholic fatty liver disease, the latter of which is primarily driven by diets high in sugar and processed foods.

Earlier research by the same team reveals the mechanism behind this finding. It appears LGG protects the liver against oxidative damage by activating Nrf2, a biological hormetic that upregulates superoxide dismutase, catalase and other intercellular antioxidants. Nrf2 not only lowers inflammation, but also improves mitochondrial function and stimulates mitochondrial biogenesis. Aside from consuming LGG-containing probiotics, Nrf2 can also be activated by:

• Consuming Nrf2-boosting food compounds such as sulforaphane from cruciferous vegetables, foods high in phenolic antioxidants, the long-chained omega-3 fats DHA and EPA, carotenoids (especially lycopene), sulfur compounds from allium vegetables, isothiocyanates from the cabbage group and terpenoid-rich foods
• Performing high-intensity exercises that activate the nitric oxide (NO) signaling pathway, such as the NO dump exercise
• Multiday water fasting and intermittent fasting
• Molecular hydrogen
• CBD oil

Probiotics Help Normalize Blood Pressure

Other recent findings suggest regularly consuming probiotics can help relieve hypertension (high blood pressure). One previous analysis2 of nine studies that scrutinized associations between probiotics and blood pressure found that people who consume probiotics on a regular basis (in the form of yogurt, kefir or supplements, for example) tended to have lower blood pressure than those who did not consume probiotics.

On average, their systolic blood pressure (the top number in a reading) was 3.6 millimeters of mercury (mm Hg) lower and their diastolic blood pressure (the bottom number) was 2.4 mm Hg lower. The most significant benefit appeared to be among those whose blood pressure was higher than 130/85, and probiotics that contained a variety of bacteria lowered blood pressure to a greater degree than those containing just one type of bacteria.

Another animal study3 published last year found the probiotic lactobacillus marinus effectively prevents salt-sensitive hypertension by modulating TH17 cells. (Other research has found high salt intake inhibits lactobacillus marinus, thereby contributing to hypertension.) According to the authors:

“In line with these findings, a moderate high-salt challenge in a pilot study in humans reduced intestinal survival of lactobacillus spp., increased TH17 cells and increased blood pressure. Our results connect high salt intake to the gut–immune axis and highlight the gut microbiome as a potential therapeutic target to counteract salt-sensitive conditions.”

Blood Pressure Effects of Kefir Assessed

Findings presented at the 2018 Experimental Biology conference found similar effects on blood pressure using kefir, specifically. Here, rats were divided into three groups. The first group, consisting of hypertensive rats, received kefir on a regular basis for nine weeks. The second group, which was also hypertensive, did not receive kefir. The third control group had normal blood pressure and were given regular chow.

After nine weeks, blood and stool samples were analyzed to evaluate changes to the animals’ microbiome. Blood pressure was also measured, and neural changes in the hypothalamus, which plays a role in the regulation of blood pressure, were analyzed. Compared to groups two and three, the treatment group that received kefir had:

• Lower blood pressure
• Improved balance of beneficial bacteria in the gut
• Improved intestinal structure with decreased intestinal permeability
• Lower levels of endotoxins (byproducts of bacterial disintegration that contribute to inflammation)
• Lower levels of inflammation in the central nervous system

According to the authors, “Our data suggests that kefir antihypertensive-associated mechanisms involve gut microbiota-brain axis communication during hypertension.” In other words, signals sent from the gut to the brain influence blood pressure, and by improving the gut microbiome, blood pressure was normalized naturally.

Probiotics Impact Your Health in Numerous Ways

In recent years, mounting research shows your gut microbiome has a truly profound influence on your health and well-being. Aside from improving liver function and lowering blood pressure, beneficial bacteria have been shown to:

Modulate your immune response and boost immune function

Help your body produce vitamins and absorb minerals

Aid detoxification of pesticides

Control asthma and reduce risk of allergies

Lower your risk for periodontal disease by more than 50 percent4

Influence the activity of hundreds of genes, helping them to express in a positive, disease-fighting manner5,6

Benefit your mood and mental health7

Boost weight loss8 and lower your risk for obesity9

Lower children’s risk of behavioral problems and autism

Lower your risk for both Type 110 and Type 2 diabetes11

Reduce inflammation

Improve sleep quality12

Mediate your risk for certain types of cancer, especially colon cancer.13 Butyrate, a short-chain fatty acid created when microbes ferment dietary fiber in your gut, has been shown to induce programmed cell death of colon cancer cells,14 and cultured milk products may reduce your risk of bladder cancer by about 29 percent15

Ward against malnutrition16,17

Boost growth factor hormone production18

Reduce the number and length of infections suffered by athletes19

Prevent and control vaginitis in women

Lower risk of premature labor in pregnant women20

Lower risk of inflammatory bowel disease

Lower risk for recurrent bladder and ear infections

Improve and prevent chronic diarrhea

Get Into the Habit of Eating Fermented Foods Every Day

For all of these reasons, and more, I recommend a diet rich in whole, unprocessed foods along with cultured or fermented foods. A high-quality probiotic supplement can also be a helpful ally to restore healthful balance to your microbiota — especially when taking antibiotics. Keep in mind, however, that there’s a great difference between traditionally fermented foods and commercially processed and pasteurized foods to which probiotics are simply added.21

The latter is not nearly as effective or beneficial as the former. Fortunately, preparing your own fermented foods at home is quite easy, and very cost effective. For instructions, see my previous interview with Caroline Barringer,22 a Nutritional Therapy Practitioner and an expert in the preparation of the gut-nourishing foods prescribed in Dr. Natasha Campbell-McBride's Gut and Psychology Syndrome (GAPS) Nutritional Program.

As a general guideline, eat about a quarter-cup to half-cup (2 to 4 ounces) of fermented vegetables or other cultured food, such as raw yogurt or kefir, with one to three meals per day. Regularity is important if you’re looking for health benefits. As noted in the meta-analysis23 mentioned earlier, which found probiotics reduce blood pressure, this really is the key.

Those who consumed probiotics for less than two months didn’t show any positive impact in their blood pressure readings, and the evidence clearly suggested that regular consumption can make or break the success of probiotics for easing hypertension.

Bear in mind that since cultured foods are efficient detoxifiers, you may experience detox symptoms if you introduce too many at once. So, start with very small servings — as little as a teaspoon of fermented vegetables, for example, or even just a spoon or two of the juice — and slowly work your way up. This way your intestinal microbiota has the chance to adjust.

Five Strategies to Improve Your Gut Health

Aside from eating fermented or cultured foods and taking a high-quality probiotic supplement if needed, a number of other factors will also have a bearing on the composition of your gut microbiome. Below are six suggestions for how you might support and nourish the beneficial microbes in your gut:

Only consume organic foods. Genetically engineered foods are loaded with glyphosate that can cause leaky gut and disrupt cellular communication through the shikimate pathway. Your optimal choice would be to grow your own food but for many that’s not possible. Your next best bet is to buy certified organic or biodynamic foods to avoid glyphosate and other toxic agrichemicals.

Avoid antibiotics. The average child in the developed world will likely receive 10 to 20 courses of antibiotics before his or her 18th birthday. This, coupled with the low therapeutic doses added to animal feed, and therefore many of our foods, may be shifting our gut microbes into an unhealthy state and possibly contributing to obesity and related metabolic diseases.24

It’s also well documented that following a course of broad-spectrum antibiotics, it could take weeks, months or even years for your gut microbial community to bounce back — if at all. During this period of imbalance, opportunistic pathogens can take over. While antibiotics are clearly needed in some scenarios, ask your doctor if they’re truly necessary.

Avoid antibacterial soaps and products. Like antibiotics, antibacterial soaps indiscriminately kill both good and bad bacteria, and contribute to growing antibiotic resistance.

Open your windows. Though keeping the outside out has its advantages, it has actually changed the microbiome of your home. Studies25 show that opening a window and increasing natural airflow can improve the diversity and health of the microbes in your home, which in turn benefit the inhabitants.

Eat more plants. This may be one of the single most important dietary strategies for improving the diversity and health of your gut microbiome. In short, your gut microbes thrive on a diversity of fermentable substrates (dietary fiber). But not all fiber is the same (physically or chemically), so consuming a diversity of whole plants will assure a steady flow of substrates for your resident microbes.

Also consider eating more of the whole plant, not just the soft and tasty parts. For example, consume the entire asparagus, not just the tips; consume the trunk of the broccoli, not just the crown; consume all of the greens at the top of the leek, not just the bulb.

By doing so, you will guarantee that the harder-to-digest portions of the plant will extend the metabolic activity of your microbiome deep into your bowels. Also track how many species of plants you eat in a week — shoot for about 30 or more.

Get your hands dirty. More to the point: Start a garden. Getting your hands (and body) dirty not only will help you connect with the natural world, but will also reacquaint your immune system with the wide variety of microorganisms living on plants and in the soil.

As people of the world move from poverty to middle class, they also move from the gritty reality of our ancestral life to the promise of modern development and its triple-washed produce and squeaky-clean surroundings. Reconnecting with ecosystems, through gardening or some other outdoor activity, will improve your internal ecosystem as well.