Lactobacillus acidophilus: A probiotic for more than gut health
Probiotics are becoming widely popular among health-conscious individuals and in preventive medicine. Far from being a passing trend, their importance is recognized by various health authorities. They acknowledge probiotics as beneficial bacteria that co-evolved with the human body and its metabolic processes.
Probiotics play diverse and crucial roles in digestive health. Some may contribute to digesting and absorbing nutrients in the gut. Others help the human body metabolize and get rid of toxic substances. Some bacterial strains may even produce vitamins and compounds that support overall health.
However, there are many probiotic strains, and most people are unfamiliar with their differences. That’s why we’re devoting entire articles to describing exactly what each probiotic does for your health. This time, we’re talking about Lactobacillus acidophilus, one of the most widely available supplements. It is also available in food products, particularly milk, yogurt, miso, and tempeh.
Read on and learn what Lactobacillus acidophilus is and what it offers as a probiotic strain.
What everyone should know about Lactobacillus acidophilus
For simplicity, we’ll refer to Lactobacillus acidophilus as L. acidophilus. This probiotic strain was first isolated from infant feces back in 1900. After that, scientists have found different variations of the same bacteria. They were named with a long list of coded tags such as LA-1, LA-5, and DDS-1. Each has slightly different functions, but they all share most of the metabolic features.
Lactobacilli are gram-positive bacteria characterized by a thick layer of peptidoglycans in the cell wall. This layer protects the cell and maintains its shape. Under the microscope, you would see them as slender rods with a circular end.
These are anaerobic bacteria, which means they do not need oxygen to survive. In fact, they survive better without oxygen in the usual temperature of the human gut (no more than 38ºC). The bacteria are sensitive to high temperatures, so avoid overheating water or milk when preparing these probiotics. In contrast, L. acidophilus is somewhat resistant to acids and bile. Thus, they tend to survive better than others in the stomach’s acidic environment.
All Lactobacillus, including L. acidophilus, can ferment sugar to produce lactic acid. Hence the name Lactobacillus. They are bacilli (rod-shaped bacteria) that produce lactic acid from glucose, fructose, and lactose (1).
Once in your gut, L. acidophilus produces various substances and modulates your gut microbiota. The lactic acid it releases lowers the pH of your gut, making it slightly acidic. This is very good because most harmful bacteria prefer living in a neutral or alkaline environment. By modulating gut acidity, L. acidophilus helps defend against harmful microorganisms (2).
Benefits and health applications of L. acidophilus
Besides influencing gut acidity and modulating gut microflora, L. acidophilus offers numerous health applications. It plays a role in the body’s cholesterol balance, contributing to cardiovascular health. It helps digest foods and counters intolerance. It regulates immune capacity and may even reduce the risk of some types of cancer.
The following sections will cover these properties and how L. acidophilus contributes to various health parameters.
L. acidophilus can regulate blood lipids and prevent heart problems
The first evidence that L. acidophilus can regulate blood lipids comes from studies conducted on African populations in the 1970s. These tribes had very low levels of blood cholesterol compared to the average. Investigators Mann and Shaper found that these African tribes consumed yogurt regularly, and this yogurt was fermented by L. acidophilus.
This finding suggests that L. acidophilus supports healthy cholesterol levels. However, an association is not the same as a certainty, and more studies were required to confirm that such a finding was not incidental. After many years, we had enough data to make health claims. Now it is an undisputed fact that L. acidophilus lowers cholesterol levels and may help prevent atherosclerosis in certain cases (3).
One year after finding the association between blood cholesterol in the African tribes and their feeding habits, a fascinating study proved the same in a controlled environment. A group of babies was fed formula enriched with L. acidophilus, and their cholesterol levels were measured before and after the intervention.
The results were impressive. Serum levels reduced from 147 mg/100 ml to 119 mg/100 ml. Simultaneously, the count of Escherichia coli reduced while L. acidophilus levels increased in fecal samples (4). Further studies showed that if you place L. acidophilus along with cholesterol, the bacteria will reduce the concentration of fatty acids in culture plates. Thus, it was clear that these microorganisms feed from cholesterol, reducing its absorption in the gut (5).
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L. acidophilus influences fat metabolism in the liver
But that’s not the only way L. acidophilus helps the organism handle serum fat levels. A more recent study uncovered an impressive association between this probiotic and fat metabolism in the liver.
After consuming a high-fat meal, the liver starts producing more LDL receptors. These LDL are particles in your blood also known as “bad cholesterol”. With more LDL receptors, the liver and other cells in the body assimilate fats in LDL particles and use them for energy. Then, you’re not only lowering total cholesterol levels but also LDL cholesterol in the blood.
The fact that microbiota in your large bowel can regulate gene expression in a completely different organ highlights the potential of gut microbiota to extend its influence beyond the digestive system (6).
These bacteria not only reduce cholesterol absorption but also promote a faster elimination by the liver. Moreover, some variants of L. acidophilus may even reduce LDL oxidation and suppress inflammation levels.
Doing so may also counter atherosclerosis, a condition in which fatty deposits build up inside blood vessels (7). That’s why, when consuming probiotic foods with L. acidophilus, you protect your gut and contribute to heart health.
L. acidophilus can modulate the type of bacteria that grow in your gut
As mentioned above, L. acidophilus releases a low-grade acid known as lactic acid. It makes the gut environment slightly acidic, which is not a friendly pH for pathogenic bacteria. That is one of the main ways L. acidophilus regulates gut microbiota.
One problem these probiotics solve is known as SIBO, which stands for Small Intestine Bacterial Overgrowth. You can have this problem for many years with persistent gastrointestinal issues. These symptoms may not seem severe enough to seek medical attention, but they are still annoying.
Once you incorporate L. acidophilus into the formula, it reduces bacterial overgrowth and their toxic metabolites. It can be a solution to SIBO and the insidious gastrointestinal symptoms many people have (8).
By consuming probiotic foods or supplements with these bacteria, you also prevent the growth of more dangerous microorganisms such as Salmonella, Staphylococcus, and Shigella. And even if these pathogens colonize your gut, L. acidophilus helps relieve the issue by reducing inflammation.
For example, in Salmonella infections, these Lactobacilli reduce the intensity of the symptoms. They limit the production of receptors that prompt cytokine production. In other words, immune cells stop being overly sensitive, preventing excessive inflammation. The inflammatory response to Salmonella improves, and the symptoms are not as intense (9).
The anti-inflammatory effects of these probiotics may even benefit patients with inflammatory colitis. L. acidophilus has proteins on the cell surface, one of which is known as protein A. This particular surface protein inhibits a type of inflammatory cell called T-cell.
Inflammatory colitis features overactive T-cells in the human gut. When they contact protein A in the L. acidophilus surface, they become deactivated, and colitis symptoms are reduced (10).
That’s not all because probiotics in this group may even reverse the structural damage caused by colitis and inflammation. For all of the above, this probiotic shows promise as a safe option for managing colitis and other forms of inflammatory bowel disease (11).
L. acidophilus digests lactose and helps people with lactose intolerance
Another fact we mentioned above is that L. acidophilus produces lactic acid from various sugars: glucose, fructose, and lactose. These lactobacilli may theoretically improve lactose intolerance in people who experience cramps and diarrhea in response to drinking milk. The bacteria may digest lactose and reduce gastrointestinal complaints after consuming whole dairy.
Lactose intolerance happens when the gut does not produce an enzyme known as lactase. Lactase is the enzyme that breaks down lactose, helping the body digest the sugar. Lactose cannot be broken down when these individuals consume dairy, because there’s not enough of the enzyem. The sugar accumulates and creates an osmotic effect in the gut, resulting in diarrhea and intestinal discomfort.
In these patients, L. acidophilus can provide a supplemental enzymatic activity similar to lactase. The bacteria perform the function of the enzyme the body doesn’t have and reduce the intensity of the symptoms (12).
Many probiotics have a similar effect over lactose, which explains why some people with lactose intolerance can consume yogurt but not milk. However, L. acidophilus is among the probiotics with a higher level of lactase activity. In some cases, patients with lactose intolerance can’t consume yogurt, either. They may not improve their condition with a supplement or probiotic food fermented with L. acidophilus.
Why does it work for some people but not others? The reason can be due to the extent of lactose intolerance and the levels of probiotics we’re consuming. People with more intense symptoms may need a higher concentration of probiotics. Keep in mind that probiotics can alleviate symptoms but may not completely cure the condition. But even if you can’t cure lactose intolerance, a symptomatic reduction is always welcome for these patients.
L. acidophilus has some anticancer potential in the colon and liver
Cancer is a multifactorial disease, meaning it results from various interacting triggers. It is a collection of triggers that may also depend on the environment to grow a tumor. Cancer cells form regularly but are typically destroyed promptly upon detection. Our immune system has different ways to find and tag these cells for destruction before it’s too late.
Studies show that L. acidophilus probiotics enhance the immune response and may help prevent certain types of cancer. For example, these bacteria produce complex substances known as polysaccharides, which interact with the immune system and prevent cancer.
Moreover, by modulating inflammation in the gut, L. acidophilus may also reduce the growth of new blood vessels that provide nutrients to the tumor. The benefits have been shown to target colon and liver cancer, according to studies (13).
L. acidophilus can modulate and improve immune function
Another far-extending effect of probiotics has to do with immunity. The human gut is linked to the largest immune tissue network, known as GALT (gut-associated lymphoid tissue). The surface proteins, antigens, and substances produced by gut microbiota interact with GALT, modulating the behavior of immune cells.
This modulation of immunity in the human body can reduce the risk of infections and improve inflammatory conditions such as enteritis and asthma. The effects extend to areas far away from the intestinal tissue. For instance, in patients with candidiasis, a fungal disease that typically affect the mouth, vagina, and some areas of the skin.
In the presence of L. acidophilus, the immune system produces more mediators called immunoglobulins. They direct our efforts to clear the infection and contribute to reducing the severity of the disease (14).
It is as if probiotics like L. acidophilus can train the human body, and prepare the immune system to respond faster to an infection. But at the same time, the anti-inflammatory effects of probiotics won’t allow for an overactivity of the immune cells.
More health benefits associated with L. acidophilus
Many diseases show improvement when the body achieves a proper immune response and balanced inflammation levels. Thus, the immune modulation of L. acidophilus and its anti-inflammatory effects provide more health benefits that are currently under research.
One has to do with kidney disease, specifically, a type of renal injury triggered by a transient reduction of kidney blood flow. The condition, known as renal ischemia-reperfusion injury, worsens with elevated inflammation and oxidative stress caused by free radical activity.
L. acidophilus increases anti-inflammatory interleukin (IL-4 and IL-10) levels while reducing pro-inflammatory substances (IL-8, tumoral necrosis factor-alpha, among others). All of this results in anti-inflammatory and antioxidant effects that help relieve renal injury in these patients (15).
Similarly, these probiotics may help control the symptoms of chronic inflammatory conditions such as rheumatoid arthritis. Studies suggest that L. acidophilus shows potential as a treatment for inflammatory joint disease.
Its anti-inflammatory and antioxidant effects may reduce the disease’s progression and the intensity of the symptoms. However, there are only animal studies and insufficient data on clinical trials to confirm its application in humans (16).
In probiotic science, sometimes we don’t have all the answers. There are many associations between consuming probiotics and improving health parameters that are not related to each other. For instance, recent studies show that L. acidophilus can help patients after a heart attack.
The probiotic protects the heart muscle from another ischemic attack while improving heart function. However, such an effect is also in the pre-clinical stage, and there is not enough data to confirm its application in a clinical setting (17).
Key takeaways from consuming L. acidophilus
Our article on L. acidophilus shows that probiotic benefits are not limited to gut health. L. acidophilus is an excellent ally against bacterial overgrowth and pathogen colonization in the intestines.
It also helps digest nutrients, especially lactose, while reducing cholesterol absorption and boosting fat metabolism. However, the immune modulation this probiotic achieves has far-extending reach to different organs, such as the liver, the kidneys, and the heart.
Some studies still require more robust data and direct applications in clinical settings. However, it is clear that L. acidophilus is far from being a harmful bacterium. Quite the opposite, as it has a handful of benefits we can seize by simply consuming food and supplements enriched by this bacterial strain.
References:
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