Posts Tagged ‘gut bacteria’

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Can Gut Bacteria Make You Fat?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues, Obesity

bacteria

Gut Bacteria, Diet and Obesity

Author: Dr. Stephen Chaney

 

 

Can gut bacteria make you fat? It has been known for some time that the types of bacteria found in the intestines of obese people are different than those found in the intestines of lean individuals. But no one really knew the significance, if any, of that observation. Did obesity favor certain types of intestinal bacteria, or did certain types of intestinal bacteria favor obesity?

Obese individuals are often insulin resistant, and insulin resistance can cause higher sugar levels in the blood, urine and intestine. So it was easy to assume that obesity simply favored the growth of different types of bacteria in the intestine. However, recent studies have suggested that certain types of bacteria in our intestines may actually cause obesity.

Can Gut Bacteria Make You Fat?

For example, one study (Vijay-Kumar et al, Science, 328: 228-231, 2010) compared a strain of mice that are genetically predisposed to obesity with wild type (genetically lean) mice. They first looked at the intestinal bacteria. It turned out that the obese mice and lean mice had the same differences in intestinal bacteria that obese and lean humans have. And just like obese humans the obese mice ate more, displayed insulin resistance, and had elevated levels of triglycerides, cholesterol and blood sugar (They were pre-diabetic).

The investigators then decided to test the hypothesis that the particular bacterial strains found in the intestines of genetically obese mice might be causing their insulin resistance and obesity.

In the first experiment they killed off the intestinal bacteria in the genetically obese mice by putting high dose antibiotics in their food. Depleting the intestinal bacteria created some health problems for the mice, but it completely prevented the insulin resistance, overeating and obesity normally observed with this strain of mice.

In the second experiment they sterilized the intestines of the genetically lean mice and then colonized their intestines with intestinal bacteria from the genetically obese mice. When they did this, the genetically lean mice developed many of the characteristics of the genetically obese mice including insulin resistance, overeating, obesity and hyperglycemia.

insulin resistanceIn short, when their guts became colonized with bacteria from obese mice, the genetically lean mice became overweight and developed diabetes. Based on these experiments and other studies the scientists hypothesized that the wrong kinds of intestinal bacteria can make a significant contribution to insulin resistance, which in turn can lead to overeating and obesity. In short, they concluded that bad gut bacteria may make you fat.

The Battle of The Bacteria

In a second study (Walker et al, Science, 341: 1079-1089, 2013) the intestines of germ free mice were colonized with gut bacteria from lean and obese humans. The results were essentially the same as in the first study. That is, the mice who received gut bacteria from lean humans stayed lean and those who received gut bacteria from obese humans became obese.

But then the investigators asked two really interesting questions:

1) If you mixed the two types of bacteria, which one would win “the battle of the bacteria”?

For this experiment they took mice that had received gut bacteria from lean humans and mice that had received gut bacteria from obese humans and put them in the same cage. It turns out that since mice eat each other’s poop, they pick up each other’s intestinal bacteria. (No, I am not suggesting that you…)

The results of this experiment were (envelop please): The “lean” bacteria won out. They became the predominant bacteria in the intestines of all of the mice in the cage. Furthermore, none of the mice became obese – even the ones that had originally been inoculated with gut bacteria from obese humans.

2) Are the types of bacteria in the intestine influenced by diet?

In the previous experiment the mice were eating standard mouse chow – which is pretty healthy if you are a mouse. So the investigators decided to ask what would happen if they ate foods that were similar to really good and really bad human diets. They devised two types of diets for the mice – one that was high in fresh fruits & vegetable and low in fat (the good diet) and one that was high in fat and low in fresh fruits and vegetables (the bad diet).

On the good diet, the results were the same as in the previous experiment. On the bad diet the “lean” bacteria never grew in the intestines of the mice inoculated with bacteria from obese humans and those mice went on to become obese.

This study confirmed that the wrong kind of gut bacteria can cause obesity, but it also showed that diet can influence the type of bacteria that can grow in the intestine – something I talked about in an earlier issue of “Health Tips From the Professor”  Our Gut Bacteria Are What We Eat.

The Bottom Line

1) Does this mean that you should rush out and buy some probiotics (good bacteria) as part of your weight loss strategy? The simple answer is no. That would be premature. These studies were performed in mice. Although similar results have been reported in humans (for example, Jumpertz et al, Am. J. Clin. Nutr., 94: 58-65, 2011), those studies are very preliminary at present. In addition, genetics and diet obviously played a role in the results. In short, we are a long way from knowing to what extent intestinal bacteria might contribute to obesity in humans.

2) However, there are many very good reasons to make sure that you supply friendly bacteria to your intestinal track on a regular basis. For example, we know that bad bacteria in your intestine can compromise your immune system, convert foods that you eat to cancer causing chemicals, and cause chronic inflammation – which contributes to a number of major diseases.  Can gut bacteria make you fat?  We can’t yet say whether good bugs will help keep you slim, but we do know that they can help keep you healthy.

3) Finally, while we can’t yet say whether probiotic supplements can help you lose weight, it is becoming increasing clear that healthy diets (low fat, high fiber diets with lots of fresh fruits and vegetables) support the type of intestinal bacteria that can make you slim. This is yet one more reason why a healthy diet is so important if you want to stay slim and healthy.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Our Gut Bacteria Are What We Eat

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues

We Grow What We Eat

Author: Dr. Stephen Chaney

BacteriaThe subtitle of this week’s “Health Tips From the Professor” is “We Grow What We Eat”.

No, this is not about each of us starting a backyard garden and literally growing what we eat – although that would probably be a good idea for most of us. I’m actually talking about the bacteria that we “grow” in our intestine.

Most of you probably already know about the concept of “good” and “bad” intestinal bacteria.

Evidence suggests that the “bad” bacteria and yeast in our intestine can cause all sorts of adverse health effects:

  • There is mounting evidence that they can compromise our immune system.
  • There is also evidence that they can create a “leaky gut” (you can think of this as knocking holes in our intestinal wall that allow partially digested foods to enter the circulation where they can trigger inflammation and auto-immune responses).
  • There is some evidence that they can affect brain function and our moods.
  • They appear to convert the foods that we eat into cancer causing chemicals which can be absorbed into the bloodstream.
  • Studies in mice even suggest that they can make us fat.

The list goes on and on…

The “good bacteria” are thought to crowd out the “bad” bacteria and prevent many of the health problems they cause.

In case you’re thinking that it seems a bit far-fetched to think that our intestinal bacteria could affect our health, let me remind you that we have about 100 trillion bacteria in our intestine compared to about 10 trillion cells in our body. They outnumber us 10 to 1.

For years we have thought of “bad” bacteria and yeast as originating from undercooked, spoiled or poorly washed foods that we eat and the “good” bacteria as originating from foods like yogurt and probiotic supplements.

But most of us have not thought that the kinds of foods we choose to eat on a daily basis can affect the kinds of bacteria we “grow” in our intestine – until now. You’ve heard for years that “We are what we eat”. Well it now appears that we also “grow what we eat”. I’m referring to a recent study by G. D. Wu et al (Science, 334: 105-108, 2011).

Our Gut Bacteria Are What We Eat

I’m going to get a bit technical here (Don’t worry. There won’t be a quiz). Scientists refer to the population of bacteria in our intestines as our “microbiome”. Previous studies have shown that people from all over the world tend to have one of two distinct microbiomes (populations of bacteria) in their intestines – Bacteroides or Prevotella. [Again, don’t let the specialized scientific terminology scare you. These are just the names scientists have given to these two distinctive populations of intestinal bacteria].

What this study showed was that people who habitually consumed high-fat/low-fiber diets (diets containing predominantly animal protein and saturated fats) tended to have the Bacteroides bacteria in their intestine, while people who habitually consumed low-fat/high-fiber diets (diets that are primarily plant based and are high in carbohydrate and low in meat and dairy) tended to have the Prevotella bacteria in their intestine. And surprisingly this appears to be independent of sex, weight and nationality.

Is This Important?

The research defining these two distinct microbiomes (populations of intestinal bacteria) and showing that they are influenced by what we eat is very new. At this point in time we know relatively little about the health benefits and risks associated with the Bacteroides and Prevotella microbiomes.

For example:

  • Most of the studies on the health effects of “bad intestinal bacteria” were based on the identification of one or two “bad bacteria” in the gut – not on the hundreds of bacterial species found in the Bacteroides microbiome. So we can’t say for sure that the Bacteriodes microbiome found in people with diets high in animal protein and saturated fats will cause the same health problems as the “bad bacteria”. Nor do we know for sure how important a role the Bacteriodes microbiome plays in the health consequences of consuming that kind of diet.
  • Similarly, many of studies on the health benefits of “good intestinal bacteria” have been based on probiotic supplements containing one or two bacterial species – not the hundreds of bacterial species found in the Prevotella microbiome. So we can’t really say if probiotics or even the Prevotella microbiome will convey the same health benefits seen in populations who consume vegetarian diets.

However, now that do we know that we “grow what we eat” there are numerous studies ongoing to define the benefits and risks associated with each type of bacterial population.

For example, I shared a study with you recently which shows that the intestinal bacteria in people who eat a lot of animal protein convert carnitine (which is also found in meat) to a compound called TMAO, which may increase the risk of heart attacks, and that the conversion of carnitine to TMAO does not occur in people who consume a vegetarian diet ( see “Does Carnitine Increase Heart Disease Risk”)

Stay tuned! I’ll keep you updated as more information becomes available.

The Bottom Line:

Most of the studies I report on are ones that you can act on right away. This one is different. This study introduces a whole new concept – one that raises as many questions as it answers. This makes us ask those “what if” questions.

1)     Previous studies have shown that most people have one of two different kinds of microbiomes (populations of bacteria) in their intestines. This study showed that diets high in animal protein and fat favored one kind of intestinal microbiome, while diets low in fat and high in fiber from fruits & vegetables favored another type of intestinal microbiome.

2)     With a few exceptions we don’t know yet how important a role these intestinal microbiomes play in determining the health consequences of different diets. However, because our intestinal bacteria outnumber the cells in our body by 10:1, it is tempting to ask “What if?”

3)     We also don’t yet know the extent to which probiotics (either from foods or supplements) can overcome the effects of a bad diet on our intestinal microbiome, but it is tempting to ask “What if?”

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Latest Article

Omega-3 Benefits: Lower High Blood Pressure

Posted July 16, 2019 by Dr. Steve Chaney

What Does the FDA Say About Omega-3 Benefit Claims?

Author: Dr. Stephen Chaney

 

 

Among omega-3 benefits is lower high blood pressure.  That claim can be made according to the FDA. 

lower high blood pressureHeart Disease is still the number 1 cause of death in this country. And, while deaths from heart disease have been declining in recent years, deaths due to high blood pressure have been increasing.  That is concerning because:

High blood pressure is a killer! It can kill you by causing heart attacks, strokes, congestive heart failure, kidney failure and much more.

High blood pressure is a serial killer. It doesn’t just kill a few people. It kills lots of people. The American Heart Association estimates that high blood pressure directly or indirectly caused 410,000 deaths in 2014. That is almost 1 person every second and represents a 41% increase from 2000. It’s because high blood pressure is not a rare disease.

  • 32% of Americans have high blood pressure, also called hypertension, (defined as a systolic blood pressure of 140 mm Hg or more or a diastolic blood pressure of 90 mm Hg or more).
  • Another 33% of Americans have prehypertension (systolic blood pressure of 120-139 mm Hg or diastolic blood pressure of 80-89 mm Hg).

That’s over 65% of Americans with abnormal blood pressure!

High blood pressure is a silent killer. That’s because it is a very insidious disease that sneaks up on you when you least expect it. Systolic blood pressure increases 0.6 mm Hg/year for most adults over 50. By age 75 or above 76-80% of American adults will have high blood pressure.  Even worse, many people with high blood pressure have no symptoms, so they don’t even know that their blood pressure is elevated. For them the first symptom of high blood pressure is often sudden death.

Blood pressure medications can harm your quality of life. Blood pressure medications save lives. However, like most drugs, blood pressure medications have a plethora of side effects – including weakness, dizziness, fainting, shortness of breath, chest pain, nausea, diarrhea or constipation, heartburn, depression, heart palpitations, and even memory loss. The many side effects associated with blood pressure medications lead to poor compliance, which is probably why only 46% of patients with high blood pressure are adequately controlled.

You do have natural options. By now you are probably wondering whether there are natural approaches for controlling your blood pressure that are both effective and lack side effects. The answer is a resounding YES! I’ll outline a holistic natural approach for keeping your blood pressure under control in a minute but let me start with the FDAs recent approval of what they call “qualified claims” that omega-3s lower blood pressure.

 

What Does the FDA Say About Omega-3 Benefits?

omega-3 benefitsIn my book “Slaying The Supplement Myths” I talk about the “dark side” of the supplement industry. There are far too many companies who try to dupe the public by making outrageous and unsubstantiated claims about their products.

Only the FDA stands between us and those unscrupulous companies, and they take their role very seriously. That is why it is big news whenever the FDA allows companies to make health claims about their products.

Even then, the FDA is very cautious. They allow what they call “qualified” health claims. Basically, that means they are saying there is enough evidence that the health claim is probably true, but not enough evidence to say it is proven.

Of course, if you understand the scientific method, you realize there will always be some studies on both sides of every issue. That is why the only health claims the FDA allows are qualified health claims.

With that background in mind, let’s look at the qualified health claims the FDA allows for omega-3 benefits.

  • Since 2004 the FDA has allowed the qualified claim “Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease.”
  • A few weeks ago, they added five qualified health claims about omega-3s and blood pressure. The 5 claims are very similar, so I will only list two below for the sake of brevity.
  • “Consuming EPA and DHA combined may reduce blood pressure and reduce the risk of hypertension, a risk factor for CHD (coronary heart disease).”
  • Consuming EPA and DHA combined may reduce the risk of CHD (coronary heart disease) by lowering blood pressure.
  • Of course, they add the usual wording about the evidence being inconsistent and inconclusive.

 

Omega-3 Benefits?

measure omega-3 benefits levelWe’ve known for some time that omega-3 fatty acids help lower blood pressure, but two recent studies were instrumental in convincing the FDA to allow these qualified health claims. These studies have highlighted just how strong the effect of omega-3s on lowering blood pressure is.

The first study was a meta-analysis of 70 randomized, placebo-controlled clinical trials of long chain omega-3 (EPA + DHA) supplementation and blood pressure (Miller et al, American Journal of Hypertension, 27: 885-896, 2014 ).

This study showed:

  • In the group with normal blood pressure at the beginning of the study EPA + DHA supplementation decreased systolic blood pressure by 1.25 mm Hg.
  • Given that systolic blood pressure rises an average of 0.6 mm Hg/year in adults over 50, the authors estimated that omega-3 supplementation alone would delay the onset of age-related high blood pressure by 2 years.
  • In the group with elevated blood pressure not taking medication at the beginning of the study, EPA + DHA supplementation decreased systolic blood pressure by an impressive 4.51 mm Hg and diastolic blood pressure by 3.05 mm Hg.
  • The authors noted that this decrease in systolic blood pressure could “prevent an individual from requiring medication [with all its side effects] to control their hypertension” or decrease the amount of medication required.

However, the doses of omega-3s used in these studies ranged from 1 to over 4 grams/day (mean dose = 3.8 grams/day). That sparked a second study (Minihane et al, Journal of Nutrition, 146: 516-523, 2016) to see whether lower levels of omega-3s might be equally effective. This study was an 8-week double-blind, placebo-controlled study comparing the effects of 0.7 or 1.8 grams of EPA + DHA per day (versus an 8:2 ratio of palm and soybean oil as a placebo) on blood pressure.

This study showed:

  • In the group with normal blood pressure at the beginning of the study, EPA + DHA supplementation caused no significant decrease in blood pressure. This could be due to the smaller number of subjects or the lower doses of EPA + DHA used in this study.
  • In the group with elevated blood pressure not taking medication at the beginning of the study, EPA + DHA supplementation decreased systolic blood pressure by 5 mm Hg and, the effect was essentially identical at 0.7 grams/day and 1.8 grams/day.
  • The authors concluded “Our data suggest that increased EPA + DHA intakes of only 0.7 grams/day may be an effective strategy for blood pressure control.”

 

A Holistic Approach to Lower High Blood Pressure

holistic approach to lower high blood pressureThe FDA’s allowed claims about omega-3s are good news indeed, but that’s not the only natural approach that lowers blood pressure. You have lots of other arrows in your quiver. For example:

  • The DASH diet (A diet that has lots of fresh fruits and vegetables; includes whole grains, low fat dairy, poultry, fish, beans, nuts and oils; and is low in sugar and red meats) reduces systolic blood pressure by 5-6 mm Hg. [Low fat, low carb and Mediterranean diets also lower blood pressure, but not by as much as the DASH diet].
  • Reducing sodium by about 1,150 mg/day reduces systolic blood pressure by 3-4 mm Hg.
  • Reducing excess weight by 5% reduces systolic blood pressure by 3 points.
  • Doing at least 40 minutes of aerobic exercise 3-4 times/week reduces systolic blood pressure by 2-5 mm Hg.
  • Nitrates, whether derived from fresh fruits and vegetables or from supplements probably also reduce blood pressure, but we don’t yet know by how much.

If you’ve been keeping track, you’ve probably figured out that a holistic lifestyle that included at least 0.7 grams/day of long chain omega-3s (EPA + DHA) plus the other omega-3 benefits in the list above could reduce your systolic blood pressure by a whopping 18-22 mm Hg.  What

That’s significant because, the CDC estimates that reducing high systolic blood pressure by only 12-13 mm Hg could reduce your risk of:

  • Stroke by 37%.
  • Coronary heart disease by 21%.
  • Death from cardiovascular disease by 25%.
  • Death from all causes by 13%.

 

A Word of Caution

While holistic approaches have the potential to keep your blood pressure under control without the side effects of medications, it is important not to blindly rely on holistic approaches alone. There are also genetic and environmental risk factors involved in determining blood pressure. You could be doing everything right and still have high blood pressure. Plus, you need to remember that high blood pressure is a silent killer that often doesn’t have any detectable symptoms prior to that first heart attack or stroke.

My recommendations are:

  • Monitor your blood pressure on a regular basis.
  • If your blood pressure starts to become elevated, consult with your doctor about starting with natural approaches to bring your blood pressure back under control. Doctors are fully aware of the side effects of blood pressure medications, and most doctors are happy to encourage you to try natural approaches first.
  • Continue to monitor blood pressure as directed by your doctor. If natural approaches are insufficient to bring your blood pressure under control, they will prescribe the lowest dose of blood pressure medication possible to get your blood pressure where it needs to be.
  • Don’t stop making holistic lifestyle choices to reduce blood pressure just because you are on medication. The more you do to keep your blood pressure under control with a healthy diet and lifestyle, the less medication your doctor will need to use (That means fewer side effects).

 

The Bottom Line

Heart Disease is still the number 1 cause of death in this country. And, while deaths from heart disease have been declining in recent years, deaths due to high blood pressure have been increasing. That is why anything we can do lower blood pressure naturally is important. What does the FDA say about omega-3s and blood pressure?

  • Since 2004 the FDA has allowed the qualified claim “Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease.”
  • A few weeks ago, they added qualified health claims about omega-3s and blood pressure. For example, they now allow the following claims.
  • “Consuming EPA and DHA combined may reduce blood pressure and reduce the risk of hypertension, a risk factor for CHD (coronary heart disease).”
  • Consuming EPA and DHA combined may reduce the risk of CHD (coronary heart disease) by lowering blood pressure.

For more information on the studies that convinced the FDA to allow claims about omega-3s and blood pressure and for a discussion of holistic natural approaches for lowering blood pressure, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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