Tag Archive for: microbiome

Artificial Sweeteners and Your Digestive System

/in /by

Before I address the concerns of the study on artificial sweeteners I talked about on Tuesday, be assured that I’m bringing you the facts as I interpret them. If you don’t use artificial sweeteners, I’m not trying to convert you, but I’m not going to let slide inflammatory headlines that only seek to raise fear where none should exist. The problem with the artificial sweeteners study is that it didn’t use a systems approach.

Bench Science

What the researchers did would be considered bench science. It’s basic in its approach: create a medium where the bacteria will grow, throw in various quantities of the artificial sweeteners, and see what happens. That’s a good first step in any type of research to see an impact on an entire organism. The same is true for examining the effect of the artificial sweeteners on the bacteria in the cancer cell medium. They established that chronic exposure to artificial sweeteners cause two probiotics to become pathogenic.

However, that’s where it ends. Trying to explain an increase in the obesity and diabetic epidemics because of how artificial sweeteners may impact a couple of gut bacteria doesn’t make any sense. It’s stretching things way too far with no evidence that what they’re describing happens at all. In effect, they’re trying to explain a health issue by looking at potential causes. Fine, good start—but now there’s a whole lot of animal and human clinical research that has to take place in order to prove whether it’s true, because what happens in a lab is often not what happens in a human.

Bench science has its place for sure, but it has serious limitations. In our headline-a-minute world, everyone is too eager to claim credit for something that hasn’t been proved.

The Digestive System

The human body is made up of various systems; the digestive system is one of them, but it doesn’t begin and end with the epithelial cells of the intestine. Food (including artificial sweetener) starts in the mouth with its salivary glands, goes down the esophagus, enters the stomach with its specialized fluids, travels the 20 to 30 feet of small intestine where more unique fluids do their jobs, and then the 10 to 15 feet of large intestine before it exits the body. The digestive system doesn’t act alone; it requires input from other organs and systems along the way: the pancreas, the liver, and so on. Every one of those could have an impact on the metabolism and elimination of artificial sweeteners and could impact how bacteria behave in the digestive system.

I could write a book on this subject, but let me just point out one thing that should be obvious: they tested two probiotic lines. Two. As of the last count, there are at least 6,500 different microbes that coexist within our digestive system. There are also trillions of them, each with a role to play, and we still don’t know what each and every one does. As I said, it’s complicated.

The Bottom Line

This study illustrates where good research begins: in bench science. There’s a lot more science that has to happen before we become alarmed about whether or not artificial sweeteners directly impact our microbiome, but their approach does raise a question that I’ll talk about next week: a systems approach to Aging with a Vengeance. We look at pain or other conditions as something that stands alone, but in reality, we may need a systems approach to deal with it.

What are you prepared to do today?

        Dr. Chet

Reference: Int. J. Mol. Sci. 2021, 22, 5228. https://doi.org/10.3390/ ijms22105228

Fasting: Another Piece of the Puzzle

/in /by

Fasting is gaining popularity. Actually, periods of complete abstinence from food within a 24-hour cycle is what really seems to be gaining in popularity, but this study doesn’t address intermittent fasting. It examines fasting for a specific period of time before a dietary change—in this case, to the DASH diet. We don’t know if the results would be the same if someone were switching to a ketogenic diet or a paleolithic diet. These are the major results of the study we began examining on Tuesday.

The Results

  • The five-day fast prior to beginning the DASH diet appeared to have positive effects on blood pressure. There was an average drop of eight points in systolic BP and a reduction in the use of medication to lower blood pressure.
  • Subjects adhering to the DASH diet lost weight as well. However, it was not the reduction in weight loss that caused the drop in systolic blood pressure based on their analysis.
  • The immunome, a portion of the total proteome I talked about a few weeks ago, improved. While the exact mechanism is not known, the positive changes in immune proteins appeared to have a positive effect on lowering blood pressure.
  • Researchers also discovered genetic differences between those who responded to the fast and the subsequent DASH diet by lowering their blood pressure and those who did not. The key seems to be in the bacteria that produce short-chain fatty acids. Fasting was identified as a way to increase the bacteria producing those SCFAs.

What Does It Mean?

What are we to conclude? With only 71 total subjects, there’s not a lot of data to generalize to entire populations, but here’s what I think is important.

First, fasting does have a role to play in the health of our microbiome; it also has role to play in our immune function. It’s not completely clear why these changes can occur, but research shows that they do. It may be that eliminating food for a period of time helps the naturally occurring bacteria to function better.

Second, it doesn’t seem to have anything to do with intermittent fasting. It very well may be that complete abstinence from food could get you similar benefits if you were to withhold food for 18 or 20 hours a day and only eat in a very small block of time. But until fasting for a specific amount of days is compared with hourly intermittent fasting, we just don’t have the best answers yet.

The Bottom Line

Fasting, however you define it, appears to have some beneficial effects. If you find a way that fits into your lifestyle, there doesn’t seem to be any reason that you shouldn’t do it unless you have a metabolic disorder and must eat. For example, if you have problems with your blood sugar or take meds that must be accompanied by food, fasting may not be for you.

Here’s my plan: now and then, I’m going to try a reduction to 500 to 800 hundred calories per day for one to three days. That seems to be supported by the most science. It also appears to benefit immune function the most.

Anticipating questions from those doing a ketogenic or paleolithic diet, is the diet after the fast important? Maybe if you select the right foods, such as going vegan during those fasting days, you may get the positive changes in your microbiome. What would happen if you then went on a ketogenic or paleo diet after that? We just don’t know whether the changes would last. This study provided a few pieces of the puzzle, but there’s much we still need to know.

What are you prepared to do today?

        Dr. Chet

Reference: Nat Comm (2021)12:1970. https://doi.org/10.1038/s41467-021-22097-0

How the Quality of Your Diet Changes Your Mycobiome

/in /by

In the experiment I told you about on Tuesday, the researchers established that environment—exposure to light, temperature, and other environmental factors—affects the microbiome, including the fungi or mycobiome. The researchers then tested the changes in the mycobiome (the fungus part of the microbiome) after feeding the mice a highly processed diet compared with mice eating conventional mice chow. They also monitored changes in body composition, triglycerides, and other hormones related to obesity.

After eight weeks on the highly processed diet, there were differences in the quantity of fungi. Some groups of related organisms increased while others decreased. Because not every group has known roles in digestion and metabolism, the researchers examined metabolic changes in response to the dietary change; they found an increase in body fat and triglycerides in the male mice along with concurrent changes in hormones that signified a move toward prediabetes. (For some reason, the female mice in this species are protected from those effects.)

After examining the composition of the highly processed chow, I’d like to have seen one more group of mice in the experimental group. Because the highly processed chow had no fiber, it would have been helpful to see what would happen to the entire microbiome if the amount of fiber was the same in the processed chow as the conventional chow. Maybe it wouldn’t have impacted the fungi at all, or the change could have been significant.

The Bottom Line

What lessons can we learn from this study? We’re not mice after all. I think it means that a highly processed, highly-refined carbohydrate diet may cause undesirable changes in our microbiome, including the fungal levels as well. For example, Candida albicans is a primary fungus in our digestive system, but it can cause all kinds of problems if it gets out of control. Reducing refined carbohydrates has a beneficial impact on keeping that fungus at beneficial levels.

Regardless of your current age, a better diet is part of Aging with a Vengeance. Reducing processed food, especially carbohydrates, can benefit your microbiome and all that it impacts. Time to start now.

What are you prepared to do today?

        Dr. Chet

Reference: Comm Bio (2021).4:281 https://doi.org/10.1038/s42003-021-01820-z

The Fungus Among Us

/in /by

The microbiome is made up of a variety of microbes. I tend to focus on the bacteria because that’s where the bulk of the research exists, but there are more microbes in and on us such as fungi, protozoa, and viruses. A recent paper provided some interesting insight into one category of microbes: the fungi, also called the mycobiome. I loved this research paper; the methodology is extremely complex, but the logic of the questions they lined up and answered was fantastic.

Researchers began with the most basic question: Are the microbiomes, including the fungi, the same when they purchase genetically identical mice from four different animal vendors? It turns out the answer is no. While the core fungi were similar, they each had subtle differences in types of fungal colonies. That means when used in research, although genetically identical, the growing environment was different enough to potentially influence outcomes when using some form of dietary intervention.

What does that mean for human research? Research using dietary changes could be impacted by the microbial differences. The researchers tested that concept, and I’ll talk about that on Saturday.

What are you prepared to do today?

        Dr. Chet

P.S. Members and Insiders: check out the latest Straight Talk on Health covering melatonin and memory, and a dog’s microbiome. Be sure to go to membership log in first.

Reference: Comm Bio (2021).4:281 https://doi.org/10.1038/s42003-021-01820-z

Why You Need Taurine

/in /by

Two years ago, I wrote about an episode of food poisoning that Paula and I both had. It was gut wrenching, literally, but it may have been a good thing. How is that possible? Believe it or not, it might have been a training session for our microbiomes.

Scientists have been examining ways to reduce our dependence on antibiotics, and that includes studying the way the microbiome responds to bacterial infections. They have exposed rodents to specific bacterial pathogens and then studied how the animal’s gut responds. When they later expose the animals to the same or similar pathogenic bacteria, the response is significantly reduced. How?

The second exposure caused an increase in the probiotics that release hydrogen sulfide; this chemical interferes with the pathogenic bacteria’s ability to produce energy, thus reducing the negative effects of the invader. The microbiome “remembered” the invader and responded with the correct defense. They further explored how taurine supplementation would impact the response; because taurine contains a sulfonyl group, it supports the production of hydrogen sulfide. They found taurine was effective to increase production and reduce the impact of the pathogens.

Taurine is found only in animal sources; seafood leads the list. However, the body can make taurine from cysteine; that may help as long as a person, carnivore or vegan, gets all the amino acids. Taurine is also found in energy drinks and assorted sports products. We’re not at the point where a specific quantity of taurine can be recommended for suspected food poisoning, but it’s good to know that our microbiome may be trained against some food-poisoning pathogens.

What are you prepared to do today?

        Dr. Chet

References: Call. 2021. DOI:https://doi.org/10.1016/j.cell.2020.12.011

The Skin Microbiome: Skincare and Cosmetics

/in /by

While the state of the current pandemic has restricted the ability to socialize to any great degree, it may turn out to be beneficial for the skin microbiome. Be honest. If you don’t have to go to work or out into the public, do you still maintain the same personal grooming practices? Do you put on all your makeup? Based on what people say in virtual meetings, the answer is no. Why is that beneficial for the skin microbiome?

The final potential insult to our skin microbiome is from products we willingly use. Most people apply some form of skincare and/or cosmetic products every day, plus deodorant or anti-perspirant, haircare products, moisturizers, and a plethora of make-up products. Here’s the key point: most of these products contain anti-microbials to maintain the safety of the product before use. That means when applied to the skin, they could also impact the microbiome of the skin.

After reading a review article on the state of research on the entire gamut of skincare products, several researchers outlined the type of research that should be done. While encouraging, that means that not much has been done. I couldn’t find any research that directly examined the impact of skin and cosmetic products on the skin microbiome. We just don’t know.

Strategies for Healthy Skin

There are several things we can do to indirectly help our skin.

  • Drink one-half your body weight in ounces of liquid every day.
  • Take 1 to 4 grams of omega-3 fatty acids every day. There are many reasons to take your omegas, but one is to help reduce the production of inflammatory hormones.
  • Take a probiotic with several types of bacteria with a prebiotic every day. They contribute to a healthy immune system and internal microbiome.
  • There are several supplements that may also contribute to the health of the skin including biotin, vitamin C, and collagen. They may not affect the skin’s microbiome, but starting with a healthier surface may be beneficial.
  • Regular exercise increases blood flow to all areas of the body, including the skin. That can deliver nutrients and help remove waste products.

The Bottom Line

Our skin microbiome is part of our first line of defense against microbial invaders. At this point, there’s not enough research to know whether the skincare routines we’ve become accustomed to are beneficial, harmful, or at least neutral. Is that worth stopping all skincare and cosmetic products? Should we stop taking showers? I don’t think we need to do any of those, but if we start paying more attention to the products we use and make better choices in selecting them, that may give us an edge while science catches up with this amazing part of our immune system.

What are you prepared to do today?

        Dr. Chet

Reference: Int J Cosmet Sci. 2020 Apr;42(2):116-126. doi: 10.1111/ics.12594.

The Skin Microbiome: pH

/in /by

The water we shower and bathe in may impact our skin microbiome, but we don’t generally just rinse off with water. We use soaps and shampoos as well. How could they impact the microbiome of the skin? Let’s take a look.

Normal healthy skin has a pH range of 5.4 to 5.9. At that pH, the body maintains a normal microbiome. Researchers examined the pH of shampoos and soaps in about 100 different products. Most soaps were highly alkaline with a pH that averaged between 9 and 10. Shampoos fared much better with most in the 6 to 7 pH range.

Will the exposure to these products damage the skin microbiome? If it does, will it be temporary? After all, the exposure will be limited depending on the length of the shower or bath. We don’t have all the answers on that. The closest I’ve seen to sequential testing was a multi-country study that found that the skin pH was still elevated six hours after washing with soap. The rise was less than a single point; still, the actual impact on the microbiome wasn’t evaluated. There’s still much we don’t know.

We’re still not done with the skin microbiome so we’ll finish this up on Saturday.

What are you prepared to do today?

        Dr. Chet

References:
1. Int Microbiol. 2019 Mar;22(1):1-6. doi: 10.1007/s10123-018-00049-x.
2. Indian J Dermatol. 2014 Sep-Oct; 59(5): 442–444. doi: 10.4103/0019-5154.139861.
3. International J of cosmetic science. 2006 DOI: 10.1111/j.1467-2494.2006.00344

The Skin Microbiome: Birth and Water

/in /by

I began last week’s focus on the skin microbiome based on reading an interview with a scientist who hasn’t taken a shower in over five years (Clean by James Hamblin). We’ve established the basics about skin and the microbes that are supposed to reside in the skin microbiome. This week we’ll cover how the skin microbiome is affected by our environment. What are we doing to our skin that may be impacting our health?

It actually can begin at birth. If we are delivered via the birth canal, we are immersed in vaginal microbes that seed our skin with microbes. In the 1970s, C-sections began to rise from 5% to the current rate of 30%. That means close to one-third of newborns don’t get the initial exposure to skin microbes. Does that result in an increase in skin conditions such as dermatitis? Maybe, but there’s no confirming research to date.

Depending on your water supply, the water may be treated with chlorine and fluoride. While they can kill bacteria to make the water safer, those chemicals may also damage the microbes that live on our skin, hence Hamblin’s avoidance of showers. That impacts the skin microbiome and consequently, our immune system.

What else can impact our skin? I’ll cover more on Thursday.

What are you prepared to do today?

        Dr. Chet

Reference: Int Microbiol. 2019 Mar;22(1):1-6. doi: 10.1007/s10123-018-00049-x.

The Skin Microbes: What They Eat

/in /by

When we talk about the microbiome of the digestive system, it’s well-known what they eat: sugar. That’s also mostly true for the skin’s microbiome, although those microbes eat other substances as well. In today’s Memo, we’ll cover the types of bacteria and where they’re located. Then we’ll look at their diet.

The Microbes of the Skin

It may come as no surprise that the type of bacteria and other microbe depends on the location. That makes sense: what may grow well in moist areas may not grow well in dry areas.

The sebaceous sites on the head and torso are dominated by species of bacteria that like fatty environments. Remember that sebum is primarily a type of fat, so the type of bacteria that will grow in that area has to be able to thrive in that environment. The Propionibacterium species dominates in the oil glands.

The moist and humid sites contain bacteria such as Staphylococcus and Corynebacterium species. They thrive in the bends of the elbow and the feet, as well as other locations.

Bacteria are not the only important microbes in our microbiome; there are plenty of fungi as well, and I know how gross that may seem to some readers, but try to think about how much you like mushrooms. They’re there to do a job: protect us. The genus Malassezia are found at core body and arm sites. The feet are more diverse in fungi species: Malassezia, Aspergillus, Cryptococcus, Rhodotorula, Epicoccum species as well as others. Here’s something that may comfort some of you: bacteria were the most abundant and fungi were the least abundant.

What about viruses? They seem to be specific to the individual without any single virus dominating. Based on the longitudinal studies of the skin microbiome, they remain largely stable for as long as two years, the length of the longest studies. Pretty amazing considering how the seasons change in places like here in Michigan.

What the Skin Microbes Eat

The skin provides a cool and acidic environment for its residents. The primary nutrients are protein and fats. The microbes have adapted to what’s available in the sebaceous glands, the sweat, and the dead skin cells of the stratum corneum.

For example, the anaerobe P. acnes can survive and thrive by using protein enzymes to break down the amino acids found in the dead skin cells of the corneum stratum. Not only that, they have lipases to breakdown the triglycerides in sebum to use fat as a fuel as well as provide the means for the bacteria to adhere to the skin.

The lipids that can be liberated from the oily sebum and the stratum corneum are also used by the fungi for lipids as they cannot manufacture their own lipids. The Staphylococcus spp. have developed several strategies to survive the dry areas of the body. They’re tolerant of the high salt content of the skin and can use the nitrogen group from urea as a nitrogen source. They also produce chemicals that can break down the stratum corneum to extract nutrients from there as well.

As the researchers who wrote the review paper said, “the skin harbors a heterogeneous community of microorganisms that each have distinct adaptations to survive on the skin.”

The Bottom Line

As you can tell from this week’s memos, the skin microbiome is not just a few bacteria that decided to take up residence and are along for the ride; they have adapted to their environment to survive. How are they impacted by the water we bathe in, the soap we use, and the chemicals we use to look and smell better? That’s what I’ll write about next week.

What are you prepared to do today?

        Dr. Chet

Reference: Nature Reviews doi:10.1038/nrmicro.2017.157

The Skin Microbiome: Anatomy

/in /by

The skin microbiome is amazingly complex. Not only do we have all the beneficial bacteria and other microbes, we also have microbes that can be beneficial or damaging depending on how we treat the skin. Let’s begin with location: where are all these microbes located? For that, we need to understand a little bit about the structure of the skin.

The skin is the largest organ of the body and is constructed of two different layers: the outermost or the epidermis and an inner layer called the dermis. The outermost layer called the stratum corneum is composed of dead cells that are chemically crosslinked with each other and with cells below to provide a true barrier. As they’re sloughed off, they’re replaced.

To say “skin is skin” does this organ a disservice. It varies in different locations in the body and provides amazing microenvironments based on UV light exposure, pH, temperature, moisture, and sebum content. What is sebum? That’s the product of sebaceous or oil-producing glands, primarily located on the face, the chest, and the back. The sebum provides a coating that repels water and provides an antibacterial shield to hair and skin.

There are also areas of the body that are moist such as under the arms, between the toes, and in other more private areas. Those areas contain sweat glands which modify the pH of the skin and make it more acidic. That created an unfavorable environment for the growth of some bacteria and other organisms.

That’s the anatomy of the skin. The next question is what type of bacteria and other microbes are found on the skin and exactly what do they eat? We’ll cover that on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference: Nature Reviews doi:10.1038/nrmicro.2017.157