Connie: My dear friends, thank you for joining us on this beautiful Saturday evening. Today, we are happy to have invited our old friend, Dr. Hofstadter. Thank you for being here, Dr. Hofstadter.
Dr. Hofstadter: Thanks for inviting me, Connie. I’m glad to be here.
Connie: In the last program, we discussed using probiotics to treat obesity. Obesity increases the patient’s possibility of suffering from chronic kidney disease and developing end-stage renal disease, and probiotics can reduce the production of some uremic toxins. Obesity changes the intestinal environment by changing the composition of flora, which may be one of the reasons for renal injury. Regulating intestinal flora balance with probiotics may be a more appropriate choice for obese patients to improve renal function. And in today’s episode, we are going to continue to talk about the many benefits of probiotics. Where would you like to start, Dr. Hofstadter?
Dr. Hofstadter: I’d like to start with their cholesterol-lowering benefits. We all know that cholesterol plays an important role in the human body with its variety of functions. The importance of cholesterol is reflected in that it’s not only a component of the cell membrane but also a precursor of many vitamins and hormones. But the elevated levels of low-density lipoprotein cholesterol and high-density lipoprotein cholesterol are the key factors of various cardiovascular diseases. Patients with elevated blood cholesterol levels are three times more likely to have a heart attack than those with normal blood lipids. Cholesterol is synthesized in the human body to maintain a minimum level. Diet will also affect serum cholesterol levels, and the degree of influence varies from person to person.
Connie: Do probiotic products have the potential to reduce serum cholesterol levels?
Dr. Hofstadter: Of course. Probiotics are reported to reduce cholesterol levels through different mechanisms. For example, probiotics promote microbial absorption of cholesterol, uncoupling bile acids, and attaching cholesterol to the bacterial cell wall. Probiotics in the intestine can release the binding of these bile acids, so that total cholesterol in the blood can be reduced. Some animal studies have shown that the more bacteria in the intestine, the more bile acid clearance. Probiotic bacteria degrade bile acids and reduce the reabsorption of bile salts. Due to the reduction of reabsorption, the storage of cholesterol in the liver begins to decrease.
Connie: That makes sense. Are there any experimental results to confirm this mechanism?
Dr. Hofstadter: I believe so. I will give you some examples. A study of animals showed that the excreta of conventional animals had higher cholesterol levels than that of sterile animals. This is due to the presence of microorganisms affecting the level of serum cholesterol in the intestines of conventional animals. In a clinical study, it was observed that yogurt containing Lactobacillus acidophilus starter reduced blood cholesterol and low-fat levels by 4.4 percent and 5.4 percent respectively compared with the control group. More importantly, probiotics may inhibit the synthesis of cholesterol in the liver and its transport to the liver by producing metabolites specifically belonging to short-chain fatty acids.
Connie: As far as I know, some in vitro studies have shown that probiotic cultures can remove cholesterol from the culture medium. Cholesterol removal is due to bile salt hydrolytic enzymes produced by probiotic acid hydrolysis. And not only probiotics can help lower cholesterol. They also have a promising role in cancer treatment. Can you introduce us to the mechanism that probiotics use to fight cancer?
Dr. Hofstadter: It’s mainly that Probiotics help reduce exposure to chemical carcinogens through some mechanisms. For example, probiotics can detoxify swallowed carcinogens and reduce the metabolic process of carcinogen-producing bacteria by changing intestinal conditions. Probiotics can also produce compounds that reduce the expansion of tumor cells, produce metabolites such as butyrate, enhance the ability of cell apoptosis when the cells are supposed to die and activate the immune system to protect the production of cancer cells.
Connie: Is there any relevant research on these mechanisms?
Dr. Hofstadter: Certainly. Several studies involving humans have shown that probiotics may inhibit the occurrence of colon cancer by inactivating mutagenic compounds, producing anti-mutagenic compounds, reducing the assimilation of mutagens in the intestine, inhibiting the transformation of pro-carcinogens into carcinogens, reducing the proliferation of carcinogenic bacteria, and improving immune function.
Connie: That’s impressive. What kinds of probiotics are involved in the treatment of cancer? And in what ways do they improve the condition of cancer patients?
Dr. Hofstadter: So in some epidemiological and population-based studies, researchers showed that lactic acid bacteria or Bifidobacterium fermented dairy products produced by starter cultures can reduce the incidence of breast cancer and colon cancer. Bifidobacterium reduce the pH value of the intestine by producing organic acids, especially lactic acid, and create a bactericidal environment for these intestinal pathogens. Bifidobacterium has anti-tumor properties, I mean, it kills tumor cells through phagocyte activation. According to one hypothesis, lactic acid bacteria combine with mutagens in the intestine to reduce the assimilation of these compounds, so you know, the development of tumors can be delayed or even prevented. And there was another study that showed that Lactobacillus casei Shirota can delay the recurrence of bladder cancer. Lactobacillus casein inhibits tumor growth by stimulating the immune system. It has been reported that the number of T helper cells and NK cells increased in patients with colorectal cancer.
Connie: I’ve seen statistics that colorectal cancer is the main cause of cancer death in the western world. Environmental factors, mainly diet, are associated with about 70 percent of colorectal cancer. What type of probiotics do you recommend for the treatment of colorectal cancer?
Dr. Hofstadter: I will give you some examples and you will see what other researchers are using. In vitro studies on humans and animals showed that fermented milk containing probiotics had a protective effect on colorectal cancer. The genetic toxicity of fecal water in probiotic yogurt prepared with Lactobacillus acidophilus 145 and Bifidobacterium longum 913 as a starter was significantly lower than that in yogurt without probiotics. Although probiotic treatment can also enhance oxidative damage, this may be due to the pro-oxidative activity or activation of some defense systems. In a study in rats, it was observed that the use of products containing Lactobacillus acidophilus resulted in a decrease in the total number of colon cancer cells. Another study in animals was artificially induced colon cancer. Lactobacillus GG treatment reduced the prevalence and many tumors. And besides colorectal cancer, Bifidobacterium longum can also reduce the incidence of breast tumors, liver, colon, and small intestine tumors in rats. The anticancer activities of extracts of Lactobacillus casei, Lactobacillus Swiss, and Lactobacillus acidophilus against mouse sarcoma have been reported.
Connie: That’s exciting. Next, let’s move on to the treatment of irritable bowel syndrome using probiotics. Irritable bowel syndrome is characterized by abdominal pain, abdominal distention, abdominal distention, and diarrhea. These conditions are not easy to treat, so they have a considerable impact on the patient’s life. What factors are associated with the disease?
Dr. Hofstadter: Oh, many different factors, like Food intake, abnormal absorption of nutrients, and psychosomatic diseases, all of which will affect the motor function of the GI tract.
Connie: So how do probiotics affect irritable bowel syndrome in the intestine?
Dr. Hofstadter: How about let me answer this question again with some existing studies. So different clinical trials have shown that eating different kinds of lactic acid bacteria can reduce stomach pain, abdominal distention, flatulence, and constipation. A study shows that S. boulardii can alleviate diarrhea although it cannot effectively alleviate other symptoms of irritable bowel syndrome. Studies on patients with irritable bowel syndrome have shown that when patients are treated with a combination of multiple probiotics, the general symptoms and stomach pain can be relieved over time. Various studies have shown that rhamnose GG has a poor effect on irritable bowel syndrome, while Lactobacillus Plantarum has a significant positive effect on irritable bowel syndrome.
Connie: This is definitely a very useful discovery. Ok, So much for our content today. Thanks, everyone, for listening. I hope you enjoyed our show today. And thanks, Dr. Hofstadter for your great input. We will continue our discussion next week. See you then!
Dr. Hofstadter: Thanks everyone. I hope we will see you next time.