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Category: human microbiome

Published on Leave a comment on Studies Find Fungi In Cancer Tumors

We all know that microbes (fungi, viruses, bacteria) live throughout our bodies - this is the human microbiome or microbiota. What is really interesting is that cancer tumors also have microbiomes (tumor microbiome), and these microbial communities are different than that found in healthy people (without tumors).

For a while it has been known that tumors (e.g., breast cancers) have different bacterial species than healthy tissue - the microbiome is different. Several recent studies find that tumors can also contain fungi, and cancers with certain fungal species have worse outcomes than those without the fungi. The mycobiome is the community of fungi that live in or on humans.

Also, the combination of fungal species are different depending on what kind of cancer that a person has. A group of scientists have put together a list (mycobiome atlas) of the distinctive fungi that are found with 35 different cancer tumors. This is exciting because in the future cancers could potentially be found by the microbial (fungi and bacteria) DNA they shed in the blood.

However, no one knows really why the fungi are in the tumors. For example, are they aiding the cancer development? Or is the cancer allowing the fungi to grow? Are the fungi interacting with the immune system? Or??

Several recent articles discuss this exciting new research.

From NY Times: A New Approach to Spotting Tumors: Look for Their Microbes

Look up an image of a tumor on Google, and you’ll probably end up with a brightly colored cluster of cancer cells on a drab background of healthy tissue. But for Lian Narunsky Haziza, a cancer biologist at the Weizmann Institute of Science in Israel, the picture looks very different. A tumor may also contain millions of microbes, representing dozens of species.

Scientists have long known that our bodies are home to microbes, but have tended to treat tumors as if they were sterile. In recent years, however, researchers have laid that notion to rest, demonstrating that tumors are rife with microbes. ...continue reading "Studies Find Fungi In Cancer Tumors"

Published on Leave a comment on Sugar Substitutes Alter Gut Microbiome

All of us want to have a healthy gut microbiome (the microbial community of viruses, fungi, and bacteria). For health reasons many people try to lower their intake of sugars. However, ingesting artificial or non-nutritive sweeteners such as stevia, sucralose, aspartame, or saccharin may also have an effect on the body.

A recent study in both humans and mice found that these sugar substitutes cause gut microbiome changes and had an effect on a person's glycemic response (blood sugar levels). Saccharin and sucralose significantly impaired glucose tolerance in healthy adults - it impacted their glycemic response even at doses below FDA allowances (average daily intake or ADI).

The non-nutritive sweeteners also had an effect on the oral (mouth) microbiome. Each sweetener had a different and distinct effect on both oral and gut microbiomes. And the effects varied in each person, due to everyone having a different (unique) microbiome.

Earlier studies found negative health effects from sugar substitutes (e.g., higher incidence of diabetes, higher risk of cancer, gut microbiome changes). So be cautious until more is known. One of this study's researchers suggested drinking only water.

From Medical Xpress: Non-nutritive sweeteners affect human microbiomes and can alter glycemic responses

Since the late 1800s non-nutritive sweeteners have promised to deliver all the sweetness of sugar with none of the calories. They have long been believed to have no effect on the human body, but researchers publishing in the journal Cell on August 19 challenge this notion by finding that these sugar substitutes are not inert, and, in fact, some can alter human consumers' microbiomes in a way that can change their blood sugar levels. ...continue reading "Sugar Substitutes Alter Gut Microbiome"

Published on Leave a comment on The Foods We Eat Contain Live Microbes
Credit: Wikipedia

Every month there is more evidence of the importance of the human microbiome or microbiota - the community of microbes that live in and on us. Trillions of microbes! When we eat food, we eat all the microbes that are in the food, and this has effects on the microbes living in the gut (intestines).

How many microbes do we eat daily? An interesting study was published in 2014 that tried to answer this question. The researchers found that the average American adult ingests between 1 million to over 1 billion microbes every day! It depended on food choices.

Another study just published looked at more than 9000 foods in the US health and dietary database (from 74,466 persons). The researchers estimated the number of live microbes present in all the foods. From that they estimated that the intakes of foods with live microbes were pretty low (about 85 grams/day for children and 127 grams/day for adults). Their results were similar to the earlier 2014 study mentioned above.

They found that around 20% of children and 26% of adults consumed foods with high levels of live microorganisms in their diet. Also, American children and adults have steadily increased their consumption of foods with live microbes over an 18 year period of time - but it still didn't meet guidelines.

The researchers found that fruits, vegetables, and fermented dairy foods were the main sources of microbes, as well as 3 important nutrients which Americans generally do not get enough of: calcium, fiber, and potassium. They also mention that fruits and vegetables have more diverse microbes than fermented dairy foods (yogurts have mainly lactic acid bacteria).

Bottom line: Eating a diet rich in fruits, vegetables, and live fermented foods (e.g., yogurt, kefir, fermented pickles, and kimchi) are good ways to increase the number and variety of microbes in your diet. This study did not mention organic foods, but some studies have found more beneficial bacteria in organic produce (e.g., apples).

From Medical Xpress: Quantifying the live microbes on your plate

Many have hypothesized that bacteria and other "friendly" live microorganisms consumed through the diet can play an important role in health. Reduction in dietary microbe consumption has likely contributed to an "impoverished" gut microbiota, which may lead to improper immune system development and an increase in chronic diseases, among other negative health outcomes. ...continue reading "The Foods We Eat Contain Live Microbes"

Published on Leave a comment on Antibiotics Alter Gut Microbes In Young Infants

Many studies show that antibiotics disrupt the gut microbiome (intestinal microbial community of bacteria, viruses, fungi) in adults, but what about infants? A recent study found alterations in the gut microbes of young babies from a single course of antibiotics, with an increase in fungal species. And 6 weeks later the gut microbial community still wasn't back to normal. Yikes.

Antibiotics can be life-saving, but they must be used carefully - only when needed. As research shows, when some microbes are killed off by antibiotics, then other microbes (e.g. fungi such as Candida) that are resistant to the antibiotics increase (multiply) and move into the vacated spaces. There are no empty spaces in the gut.

Babies normally have a variety of fungal species in the gut already at a very young age - and this community of fungi is called the gut mycobiota or mycobiome. The Univ. of Helsinki researchers concluded that normally bacteria control fungi numbers in the gut - there is balance of all sorts of microbes (bacteria, viruses, fungi). But if you kill off bacteria (with antibiotics), then fungi numbers increase - an example of an imbalance in the gut microbial community or dysbiosis.

From Science Daily: A single course of antibiotics affects the gut microbiota of infants

A study recently completed at the University of Helsinki revealed that the fungal microbiota in the gut is more abundant and diverse in children treated with antibiotics compared with the control group even six weeks following the start of the antibiotic course. In light of the findings, a reduction in the number of gut bacteria as a result of antibiotic therapy reduces competition for space and leaves more room for fungi to multiply. ...continue reading "Antibiotics Alter Gut Microbes In Young Infants"

Published on Leave a comment on Some Food Additives May Alter Our Gut Microbes

A recent study gives support to eating a diet with real unprocessed foods and avoiding foods with additives as much as possible. The study found that the commonly used food additive known as xanthan gum (E415 in Europe) can cause disruptions to our gut microbiome.

The gut microbiome or microbiota is the community of microbes living in our intestines, and which are critical to good health. The international team of researchers found that the gut microbes changed when exposed to the additive, so as to be able to digest the xanthan gum.

Xanthan gum is used as a thickener or stabilizer in many foods, including ice cream, sweets, chocolate milk, baked goods, ready-made sauces and dressings. [Note: If present, it is listed in the ingredients on food labels.]

Bottom line: Rather than being harmless and not having any effects, food additives may have effects on or disrupt our gut microbes. Food additive effects may be minimal or can actually cause harm. For example, some emulsifiers (e.g., soy lecithin, carrageenan, polysorbate-80) can promote gut inflammation and alter the gut microbiome in a negative or harmful way

From Medical Xpress: Widely used food additive affects the human gut microbiota

Have you heard about the food additive E415? It is also known as xanthan gum. Most likely, you eat it several times a week. Xanthan gum is used in everyday foods such as baked goods, ice cream and salad dressings. The additive is also widely used as a substitute for gluten in gluten-free foods.  ...continue reading "Some Food Additives May Alter Our Gut Microbes"

Published on Leave a comment on Pancreatic Cancer Has a Distinct Gut Microbial Pattern
Pancreas with cancer (red dot) Credit: Wikipedia

Pancreatic cancer is typically discovered only when it is advanced, very hard to treat, and typically with poor outcomes. Interesting recent research found that the gut microbiome is distinctive in persons with pancreatic cancer, even in the early stages. Perhaps this finding will lead to an easy noninvasive way to screen for pancreatic cancer.

Researchers in Spain and Germany looked at both the community of microbes (microbiome) living in the mouth and the gut (shown in a person's feces). They took samples from healthy persons, individuals with pancreatic cancer, and persons with chronic pancreatitis  and found that the bacteria in the stool were predictive for pancreatic cancer (but not those in the mouth).

The "fecal microbiota signature" or pattern of microbes in those with pancreatic cancer had an increase in some microbes (e.g., Fusobacterium nucleatum) and a decrease in others (e.g., Faecalibacterium prausnitzii) - when compared to healthy individuals.

By the way, Fusobacterium nucleatum is found increased in other cancers, such as colon cancer, and beneficial and anti-inflammatory Faecalibacterium prausnitzii is reduced in a number of diseases. Eating a diet rich in high fiber foods (whole grains, fruits, vegetables, legumes, seeds, nuts) increase the numbers of F. prausnitzi in a person's gut microbial community.

From Medical Xpress: Distinct gut microbial profile may identify pancreatic cancer, irrespective of stage

A specific panel of gut microbes may identify pancreatic cancer, irrespective of how far the disease has progressed, suggests research published online in the journal Gut. ...continue reading "Pancreatic Cancer Has a Distinct Gut Microbial Pattern"

Published on Leave a comment on Adding Prunes to the Diet Has Health Benefits
Prunes

A study has given further support to the view that eating prunes (dried plums) has health benefits. Penn State University researchers reviewed studies and found that eating prunes may help protect against bone loss in postmenopausal women, as well as having anti-inflammatory and antioxidative effects. All good!

A good amount to eat (according to the studies reviewed) is about 100 grams or 10 prunes (dried plums) each day.

But... don't just focus on eating prunes (dried plums) as a healthy food. Eating several servings of a variety of fruits every day (whether fresh, frozen, or dried) has numerous health  benefits and should be part of your regular diet. Fruit is anti-inflammatory, great for the gut microbes, high in fiber, and contains minerals and nutrients. Enjoy!

From Science Daily: Eating prunes may help protect against bone loss in older women

It's already well known that prunes are good for your gut, but new Penn State research suggests they may be good for bone health, too. ...continue reading "Adding Prunes to the Diet Has Health Benefits"

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Published on 1 Comment on Some Emulsifiers Harm the Gut Microbiome

Emulsifiers are in many of the processed foods we buy. They are added to the foods to enhance texture and extend shelf life. Animal and human studies find that some emulsifiers (e.g., soy lecithin, carrageenan, polysorbate-80) can promote gut inflammation and alter the gut microbiome in a negative or harmful way. Recent research adds to this list the common emulsifier carboxymethylcellulose (CMC), also known as cellulose gum.

A small study randomly assigned 16 healthy adults to either an emulsifier-free diet or an identical diet with added 15 g per day of CMC for 11 days. No one knew what diet they were eating, and for those 11 days the participants were inpatient - thus no chance for cheating or altering the diet. Extensive testing (even biopsies on day 1 and 11!) was done before, during, and after the study. The Univ. of Pennsylvania researchers found that CMC resulted in several harmful changes, including a negative effect on the gut microbiome (microbial community of bacteria, viruses, fungi).

Results: The researchers found that CMC increased abdominal discomfort after meals, disturbed the gut microbial community and reduced its diversity (not good!). It resulted in reductions of short-chain fatty acids and free amino acids (thus impacted how nutrients are absorbed). One of the beneficial microbes associated with good health, and that was reduced in number was Faecalibacterium prausnitzii.

Two of the subjects who had CMC in their foods had increased microbial "encroachment into the normally sterile inner mucus layer" of the gut, which is a central feature of chronic inflammation diseases (e.g., IBD, type 2 diabetes). They also had large "alterations in microbiota composition". This means that there is variation in how people respond to the emulsifier CMC, with some people more sensitive than others.

The scary part is that the intestinal changes happened after just 11 days with a daily intake of 15 g of CMC - a dose that is approximately the total emulsifier consumption for a person whose diet is largely highly processed food. Yes, that is many of us eating a Western style diet (e.g., highly processed foods, and low in fiber, fresh fruits, vegetables, and whole grains). The scientists believe that long-term consumption of emulsifiers, because they result in gut microbial disruption and inflammation, are contributing to chronic diseases.

Bottom line: Read the ingredients list on food labels. Try to avoid foods that have ingredients listed that you wouldn't normally have in your kitchen. That means soy lecithin, CMC, cellulose gum, carrageenan, artificial colors. Even "natural flavors" (which are laboratory concoctions) should be avoided as much as possible.

From Medical Xpress: Ubiquitous food additive alters human microbiota and intestinal environment

New clinical research indicates that a widely used food additive, carboxymethylcellulose, alters the intestinal environment of healthy persons, perturbing levels of beneficial bacteria and nutrients. These findings, published in Gastroenterology, demonstrate the need for further study of the long-term impacts of this food additive on health.  ...continue reading "Some Emulsifiers Harm the Gut Microbiome"

Published on Leave a comment on Farts and Good Gut Health

Those who enjoy a little "potty humor" will like the results of a recent nutrition study comparing the results of a Western style diet (high fat, low fiber) to a high fiber Mediterranean diet. The high fiber diet resulted in much larger, softer stools, and an increase in stomach noises and farting. (Yes, they weighed their stools and counted daily farts!) There was no change in the number of stools per day.

In the study 18 healthy men followed both types of diets for two week periods (first one diet, then a break, and then the other diet). The high fiber diet (54.2 grams fiber per day) resulted in numerous beneficial changes, especially nurturing healthy gut bacteria and metabolic improvements. The low fiber Western diet only had an intake of 4.7 g fiber per day. Interestingly, all participants were told to avoid fermented dairy products (e.g. yogurts) during the study.

The high fiber diet resulted in greater numbers of beneficial bacteria in the gut without any major changes in the core microbiome (microbial community). There were also numerous gut microbial metabolic improvements while on this diet. Interestingly, men who already had a more diverse gut microbiota (which is a sign of health) and routinely already ate more fiber rich plants foods, had less farting and stomach noises during the study.

Think of it this way: your diet is what feeds and nurtures the microbes living in your gut. Some microbes are associated with chronic diseases, and some with health - so you want to nurture the health-associated bacteria by eating a diet rich in plant foods (Mediterranean style diet).

By the way, a recent study found that eating fermented foods is a quick way to increase gut microbial diversity and health. It's beneficial to add some fermented foods (e.g. yogurt, kimchi, sauerkraut, kefir) to your regular diet.

From New Scientist: Men fart more when eating a plant-based diet due to good gut bacteria

Plant-based diets cause men to fart more and have larger stools, researchers have found – but that seems to be a good thing, because it means these foods are promoting healthy gut bacteria.  ...continue reading "Farts and Good Gut Health"

Published on Leave a comment on Antibiotics and Colon Cancer

Antibiotics can be life-saving, but there are also unintended consequences. One of them is that they disrupt and alter the gut microbiome (the microbial community of the millions of microbes living in the intestines). A large study found that use of antibiotics is linked to a higher risk of colon cancer 5 to 10 years later.

The researchers thought this was due to the antibiotics having negative effects on the gut microbiome. Antibiotics reduce numbers of beneficial bacteria in the intestines, while allowing bacteria linked to colorectal cancer to increase.

Researchers at Unea Univ. in Sweden compared 40,545 colon cancer cases to 202,720 controls (no cancer), and found that as antibiotic use increased, colon cancer increased in those persons during the next 10 years. It is unknown what happens after 10 years, because that is when the study ended. Interestingly, in women - increased use of antibiotics was linked to a lower incidence of rectal cancer.

The researchers analyzed the results with respect to different classes  of antibiotics, and found the strongest association with the use of quinolones, sulfonamides, and trimethoprims. These antibiotics have an effect on bacterial diversity - specifically allowing anaerobic Fusobacteria and Bacteroidetes species to live and become more abundant. Other studies also support the view that Fusobacteria (e.g., Fusobacterium nucleatum) and Bacteroidetes species contribute to colorectal cancer development.

What to do? To increase beneficial species in the gut and lower levels of inflammation in the body, studies support eating a diet rich in fruits, vegetables, whole grains, nuts, seeds, legumes, and fish - which also results in a high fiber intake (e.g., Mediterranean diet). Also, to quickly improve the diversity of microbes in the gut (a sign of health!) and to lower inflammation in the body, increase your intake of fermented foods.

Fermented foods include: yogurt, buttermilk, sour cream, cheese, kefir, fermented vegetables, kimchi, natto, miso, sauerkraut, traditional pickles, traditional sourdough bread, apple cider vinegar, and kombucha. To quickly improve the gut microbiome, try to eat six 1/2 cup servings each day for a few months.

From Science Daily: Antibiotics linked to increased risk of colon cancer

There is a clear link between taking antibiotics and an increased risk of developing colon cancer within the next five to ten years. This has been confirmed by researchers at Umeå University, Sweden, after a study of 40,000 cancer cases. The impact of antibiotics on the intestinal microbiome is thought to lie behind the increased risk of cancer.  ...continue reading "Antibiotics and Colon Cancer"