Exercise May Promote Diversity of Gut Bacteria

Story at-a-glance -

  • Gut health is a foundational key for optimal health and wellbeing; from dictating the function of your immune system and psychological processing, to influencing your weight
  • Researchers have found that athletes, who exercise intensely for prolonged periods and eat a high-protein diet, have greater diversity of gut bacteria, which may have immune boosting effects
  • One particular species of bacteria found in greater amounts in the athletes’ gut has been linked to reduced risk of obesity and systemic inflammation
  • In addition to eating an overall more varied diet, including more fruits and vegetables, than the controls, protein accounted for 22 percent of the athletes’ energy intake, compared to 15-16 percent for controls
  • Previous research has shown that average people (non-athletes) who eat a high-protein diet tend to have far less diversity of gut bacteria compared to those who eat less meat

By Dr. Mercola

Gut health is a foundational key for optimal health and wellbeing; from dictating the function of your immune system and psychological processing, to influencing your weight and a wide variety of other health factors.

Beneficial bacteria in your gut control the growth of disease-causing bacteria by competing for nutrition and attachment sites in your colon. This is of immense importance, as pathogenic bacteria and other less beneficial microbes can wreak havoc on your health if they gain the upper hand.

For all of these reasons, and more, I strongly recommend a diet rich in whole, unprocessed foods along with cultured or fermented foods. Interestingly, however, recent research also suggests that exercise may have an influence on your gut flora.

Exercise May Promote Bacterial Diversification

As recently reported by news outlets such as Philly.com,1 The New York Times,2 and Time Magazine,3 Irish researchers have found that exercise—especially in combination with a protein-rich diet—increases the amount and diversity of gut bacteria, which may have immune boosting effects.4

Compared to controls, athletes (in this case rugby players) were found to have a "higher diversity of gut micro-organisms... which in turn positively correlated with protein consumption and creatine kinase," the authors note.

One particular species of bacteria called Akkermansiaceae, found in greater amounts in the athletes' gut, has been linked to reduced risk of obesity and systemic inflammation.

The rugby players were chosen specifically because athletes tend to adhere to a more extreme diet than the average person, and they also exercise more intensely—in this case, they trained several hours a day.

This is not necessarily healthy and likely is not for most. Nevertheless, that is what they studied. The researchers wanted to explore the degree to which exercise and diet in combination might affect the gut microbiota.

The controls, meanwhile, consisted of two groups: men with a normal body mass index (BMI) who engaged in occasional light exercise, and sedentary men who were overweight or obese. In conclusion, the researchers stated that:5

"The results provide evidence for a beneficial impact of exercise on gut microbiota diversity but also indicate that the relationship is complex and is related to accompanying dietary extremes."

The Link Between Your Diet and Gut Microbiota

As you would expect, there were significant differences between the diets of the test and control groups. The athletes not only ate a more varied diet than the controls, protein (in the form of meat and protein supplements) accounted for 22 percent of the athletes' total energy intake—five to six percent higher than the non-athletes.

Not surprisingly, non-athletes ate less fruits and vegetables, and consumed more snack foods. According to the authors:

"Our findings indicate that exercise is another important factor in the relationship between the microbiota, host immunity and host metabolism, with diet playing an important role."

The results have given rise to criticism, as the study cannot prove that exercise necessarily had anything to do with the proliferation of gut bacteria, considering the fact that the athletes' diet was so different from the non-athletes. Diet, we already know, is a critical factor that influences the microbial balance in your gut.

We know that the bacterial imbalance in your gut can be made worse by processed foods, for example—which the controls indulged in to a far greater degree than the athletes. Like processed foods, sugar of all kinds also promotes the growth of disease-causing yeasts and fungi.

Fermented foods, on the other hand, act as natural fertilizers—providing nutrients and promoting growth of healthy bacteria in your digestive tract. As an added boon, fermented foods are also very good chelators, meaning they can help rid your body of toxins such as pesticides.

With regards to protein, I don't believe it is healthy to have a high-protein intake—UNLESS you're a professional athlete who works out for hours on end each day.

So, I'd caution you to come to the conclusion that this study shows high-protein intake to result in improved gut flora and decreased risk of obesity and inflammation!

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Your Diet Dictates Gut Bacteria

In fact, it's worth noting some other research when discussing the role of protein in gut health. Earlier this year, Science News6 ran an article about how local diets dictate the bacterial balance found in residents. For example, despite living on opposite ends of the earth, people in Malawi and the Guahibos of Venezuela have similar microbial makeup, courtesy of the similarities between their native diets.

"Americans, on the other hand, have a distinctive microbiome with about 25 percent less diversity than indigenous Venezuelans'," the article states.

One of the primary differences between the diets is meat consumption. Malawian and Guahibo diets are high in corn and cassava, with an occasional piece of meat. Americans, on the other hand, are far more carnivorous, and also eat far more bread, lettuce and tomatoes, potatoes, pasta, milk, and dairy products. The microbial makeup of the three groups reveals these dietary differences.

Needless to say, altering your diet has a direct impact on the microbial community residing in your gut—for better or worse—but in the case of protein, this particular study suggested that higher protein intake was associated with less diverse gut bacteria. Of course, here the subjects were NOT athletes who worked out several hours a day, and who knows, perhaps intense exercise is the key that makes a high-protein diet beneficial?

Unless You're an Athlete, Be Mindful of Eating Too Much Protein

Granted, your body needs protein. It's a main component of your body, including muscles, bones, and many hormones. As you age, consuming adequate amounts of high-quality protein is especially important, as your ability to process protein declines with age, raising your protein requirements.

That said, you do need to be careful to not consume too much. The average American consumes anywhere from three to five times as much protein as they need for optimal health.

I believe it is the rare person who really needs more than one-half gram of protein per pound of lean body mass. Those that are aggressively exercising or competing and pregnant women should have about 25 percent more, but most people rarely need more than 40-70 grams of protein a day.

To determine your lean body mass, find out your percent body fat and subtract from 100. This means that if you have 20 percent body fat, you have 80 percent lean body mass. Just multiply that by your current weight to get your lean body mass in pounds or kilos.

The rationale behind limiting your protein is this: when you consume protein in levels higher than recommended above, you tend to activate the mTOR (mammalian target of rapamycin) pathway, which can help you get large muscles but may also increase your risk of cancer.

There is research suggesting that the "mTOR gene" is a significant regulator of the aging process, and suppressing this gene may be linked to longer life. Generally speaking, as far as eating for optimal health goes, most people are simply consuming a combination of too muchlow-quality protein and carbohydrates, and not enough healthy fat.

Translating Ideal Protein Requirements Into Foods

Unfortunately, many are still confused about these protein requirements, so let me try to give you some examples to clarify them further. Substantial amounts of protein can be found in: meat, fish, eggs, dairy products, legumes, and nuts. To determine whether you're getting too much protein, simply calculate your lean body mass as described above, then write down everything you're eating for a few days, and calculate the amount of daily protein from all sources. Again, you're aiming for one-half gram of protein per pound of lean body mass, which would place most people in the range of 40 to 70 grams of protein per day. If you're currently averaging a lot more than that, adjust downward accordingly. You could use the chart below or simply Google the food you want to know and you will quickly find the grams of protein in the food.

Red meat, pork, poultry, and seafood average 6-9 grams of protein per ounce.

An ideal amount for most people would be a 3-ounce serving of meat or seafood (not 9- or 12-ounce steaks!), which will provide about 18-27 grams of protein
Eggs contain about 6-8 grams of protein per egg. So an omelet made from two eggs would give you about 12-16 grams of protein.

If you add cheese, you need to calculate that protein in as well (check the label of your cheese)
Seeds and nuts contain on average 4-8 grams of protein per quarter cup Cooked beans average about 7-8 grams per half cup
Cooked grains average 5-7 grams per cup Most vegetables contain about 1-2 grams of protein per ounce

Optimize Your Gut Health Through Diet and Exercise

Two things are clear:

  1. Sufficient amounts of friendly bacteria are fundamental to your good health. It's impossible to be optimally healthy if your gut's bacterial balance is out of whack. Two primary aids in optimizing your gut health are: a primarily organic, whole food diet, fermented foods, and intense exercise.
  2. Your lifestyle – such as a diet full of processed foods, lack of exercise, medications, the antibacterial cleansers you use, and other factors outside your control – are working together to compromise the number of lifesaving friendly bacteria in your digestive system.

Maintaining a good balance of gut bacteria through diet is one of the most important things you can do to increase your chances of remaining healthy and vital for a lifetime. Remember, a gut-healthy diet is one that is rich in whole, unprocessed, unsweetened foods, along with traditionally fermented or cultured foods. And, 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 is an exception if you don't eat fermented foods on a regular basis.

A strong case can be made for eating organic to protect your gut flora as agricultural chemicals take a heavy toll on beneficial microbes—both in the soil in which the food is grown, and in your body. Glyphosate (Roundup), used in particularly hefty amounts on genetically engineered crops, appears to be among the worst of the most widely used chemicals in food production. As for general lifestyle advice, you'll also want to avoid well-known culprits that kill beneficial bacteria, such as:

  • Antibiotics (also note that most store-bought beef typically comes from cattle raised with antibiotics. To avoid getting a low dose of antibiotics in every piece of meat you eat, make sure your meat is grass-fed and finished)
  • Chlorinated water
  • Antibacterial soap
  • Pollution