How Your Gut Microbiome Influences
Your Mental and Physical Health
January 07, 2016
Story at-a-glance
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Bacteria appear to influence human health and disease in
two key ways. An overabundance of certain bacteria have
been linked to disease, while other microbes are
actively involved in preventing certain diseases
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Foods and chemicals known to produce metabolic
dysfunction (such as processed foods, sugar/fructose,
and artificial sweeteners) also alter the gut
microbiome. This may be a key mechanism by which these
foods promote obesity and chronic disease
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Researchers have linked high-sugar diets to memory – and
learning impairments, courtesy of altered gut bacteria
By Dr. Mercola
Your body houses some 100 trillion bacteria, and about 1
quadrillion viruses (bacteriophages). In essence, we're little more
than walking microbe colonies, seeing how these bacteria outnumber
your cells 10 to 1, and the bacteriophages in turn outnumber
bacteria 10 to 1.
These organisms perform a wide variety of functions, and we've
now come to realize that they need to be properly balanced and
nourished if we want to maintain good physical and mental health.
While the Human Genome Project (HGP) was expected to result in
gene-based therapies to more or less rid us of disease, it actually
revealed that your genetic makeup plays a much smaller role than
anyone imagined.
Your genes, as it turns out, are only responsible for about 10
percent of diseases.1
The remaining 90 percent are induced by environmental factors,
and researchers are now realizing that your microbiome may
be among the most important factors, as genes are turned on and off
depending on which microbes are present!
Emerging science also shows that your microbiome can be rapidly
altered, for better or worse, based on factors such as diet,
lifestyle, and chemical exposures.
This is a double-edged sword, no doubt, considering how many of
our modern conveniences (such as processed foods, antibiotics, and
pesticides) turn out to be extremely detrimental to our gut flora.
On the other hand, your diet is one of the easiest, fastest, and
most effective ways to improve and optimize your microbiome. So the
good news is that you have a great degree of control over your
health destiny.
Human DNA Contains Microbial Genes
Remarkably, some of the most recent research suggests bacteria
may even have played a role in the diversification and alteration of
human DNA, by way of horizontal gene transfer.2
,
3
According to researchers, potentially hundreds of microbial genes
have slipped into our DNA over the course of mankind's history,
including genes that help your immune system defend itself against
infections. It's possible other genes helped mankind adapt to
changing diets and environmental conditions.
It seems not a month goes by without new revelations about how
bacteria influence our lives. Here, I'll review some of the most
recent findings gaining more widespread acknowledgment.
How Gut Bacteria Influence Your Weight
Bacteria appear to influence human health and disease in two key
ways. While an overabundance of certain bacteria have been linked to
various diseases, other microbes appear to be actively involved in
preventing certain disease states.
When they're lacking, you end up losing this protection, which
allows the disease process to set in.
For example, by eradicating four species of bacteria
(Lactobacillus, Allobaculum, Rikenelleceae, and Candidatus
arthromitus), researchers were able to trigger metabolic changes in
lab animals that led to obesity.4
As time goes on, it seems increasingly reasonable to think that
obesity is largely influenced by gut bacteria. This in no way
changes the fact that certain foods will make you pack on the
pounds, the bacteria just play a major role in facilitating that
process.
The foods known to produce metabolic dysfunction and insulin
resistance (such as processed foods,
fructose/sugar, and artificial sweeteners) also decimate
beneficial gut bacteria, and it may well be that this is a key
mechanism by which these foods promote obesity.
Chemicals may also contribute to your weight problem by way of
your gut microbiome.
For example, a study5
published in the July issue of Environmental Health Perspectives
found that persistent organic pollutants (POPs) found in food
altered the gut microbiome in mice, thereby contributing to the
development of obesity and metabolic dysfunction.
Another study6,7
found that one microbe called Akkermansia muciniphila
helps ward off obesity,
diabetes, and heart disease by lowering blood sugar, improving
insulin resistance, and promoting a healthier distribution of body
fat.
A. muciniphila is associated with a fiber-rich diet, and fiber
has long been recognized for its beneficial effects on health and
weight. It's still not known whether A. muciniphila produces these
effects all on its own, or whether it helps promote other beneficial
bacteria, however.
According to the authors:
"Our findings demonstrate the need for further
investigation to ascertain the therapeutic applicability of A.
muciniphila in the treatment of insulin resistance.
A. muciniphila may be identified as a diagnostic or
prognostic tool to predict the potential success of dietary
interventions."
Fiber-Digesting Bacteria Also Influence Your Immune Function
Previous research has also shown that gut microbes specializing
in fermenting soluble fiber play an important role in preventing
inflammatory disorders, as they help calibrate your immune system.8
Specifically, the byproducts of this fermenting activity help
nourish the cells lining your colon, thereby preventing leaky gut —
a condition in which toxins are allowed to migrate from your gut
into your blood stream.
The inflammatory response actually starts in your gut and then
travels to your brain, which subsequently sends signals to the rest
of your body in a complex feedback loop.
So in order to address chronic inflammation and inflammatory
diseases, it's important to nourish your gut flora with the right
foods. Examples include traditionally
fermented foods and raw foods, and especially those high in
fiber.
Sugar, on the other hand, feeds fungi that produce
yeast infections and sinusitis. Researchers have also linked
high-sugar diets to memory – and learning impairments, courtesy of
altered gut bacteria.9,10
According to lead author Dr. Kathy Magnusson:11
"We've known for a while that too much fat and sugar are
not good for you. This work suggests that fat and
sugar are altering your healthy bacterial systems, and that's
one of the reasons those foods aren't good for you. It's not
just the food that could be influencing your brain, but an
interaction between the food and microbial changes."
[Emphasis mine]
Fiber and Fermented Foods Are Key Components of a Healthy Diet
While it's virtually impossible to determine the composition of
an ideal microbiome, seeing how our gut flora is as individual as
our finger print, what we do know is that a healthy diet is key for
optimizing your individual microbiome. We've also come to realize
that fermented foods and foods high in fiber are very important
components of a healthy diet, as these foods help nourish a wide
variety of beneficial bacteria.
Such foods have been part of the human diet since ancient times,
and replacing them with chemically altered and "sterilized"
processed foods has led to many of our current health problems.
Traditional sauerkraut, for example, has been identified as a
heart-healthy superfood. As reported by The Epoch Times:12
"Research in the medical journal Food and Function13
found that unpasteurized sauerkraut contained a
potent probiotic known as wild lactobacillus plantarum FC225, to
which many of sauerkraut's heart-healing abilities could be
attributed. Upon investigation, the scientists conducting the
study found that the probiotic-rich sauerkraut helped in the
following ways:
- Reduced cholesterol levels
- Reduced triglyceride levels
- Significantly increased levels of two powerful
antioxidants known as superoxide disumutase (SOD) and
glutathione
- Decreased the degradation of fats in the body (a
process known as lipid peroxidation)"
New Research Shows How Much Fiber Different Diets Provide
American Gut Project is the largest, open source and crowd
funded microbiome project in the world. Below is a box-and-whisker
plot of the results. Their research14
has collected data from over 5,000 patients who have submitted
samples and dietary questionnaires. They've been able to calculate
the fiber and the median daily fiber intake for various dietary
groups, which is as follows:
- Paleo-Like: 19 g/day
- Omnivore: 19 g/day
- Paleo: 25.1 g/day
- Omnivore, but no red meat: 27.8 g/day
- Vegetarian: 32.8 g/day
- Vegan: 43 g/day
Are You Getting Enough Fiber and Fermented Foods in Your Diet?
Ideally, include a variety of fermented foods and beverages in
your diet, because each food will inoculate your gut with a mix of
different microorganisms. There are many fermented foods you can
easily make at home, including:
- Fermented vegetables, including pureed baby foods
- Chutneys
- Condiments, such as salsa and mayonnaise
- Cultured dairy, such as yogurt, kefir, and sour cream
- Fish, such as mackerel and Swedish gravlax
As for fiber, dietary guidelines call for 20 to 30 grams of fiber
per day. I believe an ideal amount for most adults is likely much
higher, perhaps twice as much. Many whole foods, especially fruits
and vegetables, naturally contain both soluble and insoluble fiber.
This is ideal, as both help feed the microorganisms living in
your gut. So to maximize your health benefits, focus on eating more
vegetables, nuts, and seeds. Following is a small sampling of foods
that contain high levels of soluble and insoluble fiber.
I am a major fan of fiber especially soluble fibers like psyllium as
they not only serve as a prebiotic for your microbiome but are also
metabolized to short chain fatty acids like butyrate, propionic and
acetate that nourish your colonic cells. They are also converted to
ketones that nourish your tissues.
I personally consume nearly 100 grams of fiber a day and about 2
tablespoons of organic psyllium three times a day that provides
about 25 grams of soluble fiber. The other 75 percent of my fiber
comes primarily from vegetables and seeds.
Psyllium seed husk, flax, and chia seeds |
Berries |
Vegetables such as broccoli and Brussels sprouts |
Root vegetables and tubers, including onions, sweet
potatoes, and
jicama |
Almonds |
Peas |
Green beans |
Cauliflower |
Beans |
Swapping Gut Bacteria May Help Reverse Type 2 Diabetes
Type 2 diabetes is another common health problem that can be
traced back to impaired gut flora. Studies have found that the
microbial composition in diabetics differ from non-diabetics. In
particular, diabetics tend to have fewer Firmicutes and more
plentiful amounts of Bacteroidetes and Proteobacteria, compared to
non-diabetics. A positive correlation for the ratios of
Bacteroidetes to Firmicutes and reduced glucose tolerance has also
been found.
A researcher in Amsterdam, Dr. Max Nieuwdorp, has published a
number of studies looking at changes in the microbiome that are
characteristic of type 2 diabetes. In one trial, he was able to
reverse type 2 diabetes in all of the 250 study participants by
doing fecal transplantations on them. Remarkable as it may sound, by
changing the makeup of the gut bacteria, the diabetes was resolved.
Even more interesting, type 1 diabetes (insulin dependent) in
young children also tends to be preceded by a change in gut
bacteria. This makes sense as your gut flora control about 80
percent of your immune response and type 1 diabetes is an autoimmune
disease. The good news is that researchers have found that certain
microbes can actually help prevent type 1 diabetes,
suggesting your gut flora may indeed be an epigenetic factor that
plays a significant role in this condition.
Your Gut Is Your Second Brain
The quality, quantity, and composition of the bacteria in your
gut have enormous influence on your brain. For example, studies15,16
have found that autistic children have distinctly different
microbiome compared to healthy children. Notably, they tend to have
fewer beneficial bacteria such as Bifidobacterium.
Addressing such imbalances is the core component of the
GAPS nutritional program, created by Dr. Natasha
Campbell-McBride, who believes "healing and sealing" the gut is
paramount for those with neurological dysfunction, including autism.
Dr. David Perlmutter also explores the connection between gut health
and degenerative brain disorders such as Alzheimer's in his new
book, "Brain
Maker: The Power of Gut Microbes to Heal and Protect Your Brain for
Life."
This again goes back to the fact that gut microbes help maintain
the integrity of your gut lining. As explained by Dr. Perlmutter,17
many of the factors that affect permeability of the blood-brain
barrier are similar to those that affect the gut, which is why leaky
gut can lead to neurological diseases as easily as it can manifest
as some other form of autoimmune disorder.
The permeability of your gut lining can be measured by looking at
a chemical called lipopolysaccharide (LPS), which is the covering
over certain groups of bacteria in your gut. When you have higher
levels of antibodies against LPS in the bloodstream, it's a marker
of leaky gut. LPS is also in and of itself a powerful instigator of
the inflammatory cascade.
Higher levels of LPS in the blood dramatically increase
inflammation throughout your body, including your brain. Alzheimer's
and Lou Gehrig's disease, for example, are both correlated with
dramatically elevated levels of LPS.
Mood Disorders May Be Rooted in Impaired Microbiome Too
Not only can impairments in your microbiome promote neurological
diseases, it can also have a powerful impact on your general mood.
Depression is increasingly starting to be viewed as a symptom of
poor gut health, and therein may lie the real cure as well ... For
example, in one recent study18
,19,20
researchers found that fermented foods and drinks helped curb social
anxiety disorder in young adults.
Previous trials have also demonstrated that probiotics can help
ease both anxiety and
depression. For example, one study21
found that the probiotic Lactobacillus rhamnosus had a marked effect
on GABA levels — an inhibitory neurotransmitter that is
significantly involved in regulating many physiological and
psychological processes — in certain brain regions and lowered the
stress-induced hormone corticosterone, resulting in reduced anxiety-
and depression-related behavior.
In another study,22
people who took a multi-strain probiotic for at least four weeks
reported a lessening of rumination — recurring, persistent thoughts
about something distressing that has or may happen, which tends to
create anxiety. Another recent study23,24
found that high-glycemic foods (including those high in refined
grains and added sugar) were associated with higher odds of
depression.
While it didn't look at the role of bacteria, the link between
high-sugar diets and alterations in gut bacteria has been
established in other studies, including the one mentioned earlier,
in which these microbial changes led to cognitive impairments such
as learning difficulties and worsened memory.
As discussed in The New York Times,25
researchers are now investigating a number of psychoactive compounds
found in feces, and are experimenting with fecal transplants in
animals to assess its effect on neurodevelopment:
"Anxiety, depression and several pediatric disorders,
including autism and hyperactivity, have been linked with
gastrointestinal abnormalities ... [L]ast September, the
National Institute of Mental Health awarded four grants worth up
to $1 million each to spur new research on the gut microbiome's
role in mental disorders, affirming the legitimacy of a field
that had long struggled to attract serious scientific
credibility ... It seems plausible, if not yet proved,
that we might one day use microbes to diagnose
neurodevelopmental disorders, treat mental illnesses and perhaps
even fix them ...".
Optimizing Your Microbiome Is a Potent Disease Prevention Strategy
I believe optimizing your gut flora may be one of the most
important things you can do for your health, and here you can wield
your personal power to the fullest by making healthy food and
medical choices. Not only can optimizing your gut health help
normalize your weight and ward off diabetes, it's also a critical
component for a well-functioning immune system, which is your
primary defense against virtually all disease.
You will be pleased to know that supporting your microbiome isn't
very complicated. However, you do need to take proactive steps to
implement certain key strategies while actively avoiding other
factors. To optimize your microbiome both inside and out, consider
the following recommendations:
Eat plenty of fermented foods.
Healthy choices include lassi, fermented grass-fed
organic milk such as kefir, natto (fermented soy), and
fermented vegetables.
If you ferment your own, consider using a special starter
culture that has been optimized with bacterial strains that
produce high levels of
vitamin K2.
This is an inexpensive way to optimize your K2, which is
particularly important if you're taking a vitamin D3
supplement. |
Antibiotics, unless
absolutely necessary (and when you do, make sure to reseed
your gut with fermented foods and/or a probiotic
supplement).
And while some researchers are looking into methods that
might help ameliorate the destruction of beneficial bacteria
by antibiotics,26,27
your best bet is likely always going to be reseeding your
gut with probiotics from fermented and cultured foods and/or
a high-quality probiotic supplement. |
Take a probiotic supplement.
Although I'm not a major proponent of taking many
supplements (as I believe the majority of your nutrients
need to come from food), probiotics are an exception if you
don't eat fermented foods on a regular basis |
Conventionally-raised meats
and other animal products, as CAFO animals are routinely fed
low-dose antibiotics, plus
genetically engineered grains loaded with glyphosate,
which is widely known to kill many bacteria. |
Boost your soluble and insoluble
fiber intake, focusing on vegetables, nuts, and
seeds, including sprouted seeds. |
Chlorinated and/or
fluoridated water. Especially in your bathing such
as showers, which are worse than drinking it. |
Get your hands dirty in the
garden. Germ-free living may not be in your best
interest, as the loss of healthy bacteria can have
wide-ranging influence on your mental, emotional, and
physical health.
Exposure to bacteria and viruses can serve as "natural
vaccines" that strengthen your immune system and provide
long-lasting immunity against disease.
Getting your hands dirty in the garden can help reacquaint
your immune system with beneficial
microorganisms on the plants and in the soil.
According to a recent report,28
lack of exposure to the outdoors can in and of itself cause
your microbiome to become "deficient." |
Processed foods.
Excessive sugars, along with otherwise "dead" nutrients,
feed pathogenic bacteria.
Food emulsifiers such as polysorbate 80, lecithin,
carrageenan, polyglycerols, and xanthan gum also appear to
have an adverse effect on your gut flora.29
Unless 100% organic, they may also contain GMO's that tend
to be heavily contaminated with pesticides such as
glyphosate.
Artificial sweeteners have also been found to alter gut
bacteria in adverse ways.30 |
Open your windows. For
the vast majority of human history the outside was always
part of the inside, and at no moment during our day were we
ever really separated from nature.
Today, we spend 90 percent of our lives indoors.
And, although keeping the outside out does have its
advantages it has also changed the microbiome of your home.
Research31
shows that opening a window and increasing natural airflow
can improve the diversity and health of the microbes in your
home, which in turn benefit you. |
Agricultural chemicals,
glyphosate (Roundup) in particular is a known antibiotic
and will actively kill many of your beneficial gut microbes
if you eat and foods contaminated with Roundup |
Wash your dishes by hand instead
of in the dishwasher.
Recent research has shown that
washing your dishes by hand leaves more bacteria on the
dishes than dishwashers do, and that eating off these
less-than-sterile dishes may actually decrease your
risk of allergies by stimulating your immune system. |
Antibacterial soap,
as they too kill off both good and bad bacteria, and
contribute to the development of antibiotic-resistance. |
© Copyright 1997-2016 Dr. Joseph Mercola. All Rights Reserved.
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