Category Archives: gut

A New Source of Protein for the Athletic and the Sedentary?

A New Source of Protein?

This is an odd and interesting bit of research.  It relates to reaborption of nitrogen . . . and presents the possibility that more protein is conserved than previously thought.  First dietary nitrogen 101: Nitrogen is a major component of amino acids.  Amino acids are needed to form proteins.  We can synthesize some amino acids ourselves, but others need to be obtained through diet.  Dietary protein provides nitrogen and amino acids from plant or animal sources which are resynthesized into human proteins.  Unused nitrogen is converted into Ammonia and Urea and excreted.

Can nitrogen be reabsorbed from the intestines?

WODMasters Eye Pood Kettle Bell
Even if you don’t have the right microbial stuff, you can still look awesome and powerful with the right shirt

The answer is a shocking “maybe.”  A new nutritional study (published ahead of print in the Journal of Nutrition) has found that nitrogen appears to be reabsorbed.  This makes little sense at first glance.  Until we consider the vast populations of microorganisms that reside in the gut.  Until recently, they were all thought of as “germs” that needed to be quashed.   That has changed.  We are learning more and more about how important they are for our health and even our survival.

The study is titled:

Nonprotein Nitrogen Is Absorbed from the Large Intestine and Increases Nitrogen Balance in Growing Pigs Fed a Valine-Limiting Diet.

Valine is an essential Amino Acid, so these animals were fed a protein-deficient diet.   Then researchers administered urea or casein into the cecum of pigs.  Let’s consider this research a step toward greater understanding of how nitrogen may be recycled in living animals.  Not a new way to increase protein for strength.  (Although who knows.  It might work.) The urea was synthesized using Nitrogen-15.  Dietary nitrogen is Nitrogen 14.  Using nitrogen-15 lets the team know where the cecum-delivered nitrogen ended up.


Researchers found that more than 80% of the cecum delivered nitrogen was absorbed.  Some of it was excreted in urine, but some was retained. This is a shocker.  I know.   Humans cannot synthesize protein using nitrogen.  So WTF?  The researchers propose that urea traveled through the bloodstream and into to the small intestine.   Bacteria (some of which can make amino acids using urea or plain nitrogen) in the small intestine then used the extra urea to make amino acids.  Amino acids produced by bacteria could then be absorbed the host (animals).


More research would need to be done to confirm that this happens.  But it is very interesting.  Humans vary in the types of bacteria they host.  Bacterial populations vary according to diet, environment, chance (?) and who knows what else.  Do people get extra protein from bacteria?  Does this happen under normal circumstances (i.e. not piped in through the back end.)?  One thing is sure: there is a lot to learn.

Columbus DA, Lapierre H, Htoo JK, & de Lange CF (2014). Nonprotein Nitrogen Is Absorbed from the Large Intestine and Increases Nitrogen Balance in Growing Pigs Fed a Valine-Limiting Diet. The Journal of nutrition PMID: 24647394

Exercise and Weight and Gut Microbiota

Exercise and Weight.

Crossfit womens shirt model at Crossfit Seven in Fort Worth
Our crossfit women prefer to lift in WODMASTERS shirts. Designed to protect the sternum from bar abrasions while looking cool and beautiful.

Exercise and weight are closely related. We all know that exercise burns calories and helps maintain body weight. Exercise has a lot of other health benefits. And maintaining a healthy body weight is important too. But ever wonder how gut microbes, exercise and weight interact? If you are like most people you will be thinking about such things as you wander the grocery store aisles, forgetting why you are there in the first place. Or you may wonder about how physical activity changes gene expression. Or how inactivity changes gene expression. You may wonder, as you pass the yogurt section, “what is with this probiotic stuff?” We’ll talk about probiotics another time.

Exercise weight and bacteria.

Exercise and weight are inter-related. But it looks like there is another player involved. (At least one and probably many.) It looks like exercise has influence over the bacteria that live in your digestive tract. Most of us have been taught that bacteria are bad. But they are not all bad. We need some species to help us digest food, access vitamins, stay healthy and defend us against evil germs. New research shows that the kinds of bacteria in the digestive tract differ depending on level of physical activity.  The study was of mice. Mice may have been chosen for the project because it is more agreeable to pick up their poop and analyze it.  You can scoop them into a flour sifter to remove the litter.  And because you can easily control their diets. And keep them in cages with few complaints.

The researchers wanted to know how exercise, obesity, diabetes and gut microbes interact. The mice were placed in a cage with an exercise wheel. OR placed in a cage with an exercise wheel that didn’t work. After five weeks of exercising or not exercising animals were dosed with a common environmental contaminant. The chemical (PCBs) are known to impair glucose handling. They may also increase risk of diabetes. And a lot of other health problems. After dosing doots were collected. Little rodent poops are often called “doots” by the research community.

Mice who exercised had different kinds of bacteria in their doots. Bacteria from the digestive tracts of sedentary mice had a dramatic loss of proteobacteria and a hugely dramatic loss of Erysipelotrichaceae. The guts of exercising mice had many different kinds of bacteria.

What does this mean for us humans?

This research fits a piece into a larger puzzle. How are exercise and weight and bacteria related? People who are overweight have different gut bacteria profiles. The profiles change when a person loses weight. There are still many other puzzle pieces to fit And many that are missing. But it looks more and more that we need to move to keep our bodies running the way they should. And that things may go badly if we don’t.

Choi JJ, Eum SY, Rampersaud E, Daunert S, Abreu MT, & Toborek M (2013). Exercise Attenuates PCB-Induced Changes in the Mouse Gut Microbiome. Environmental health perspectives, 121 (6), 725-30 PMID: 23632211

CrossFit and Paleo: Why cutting gluten out of your diet may set you up for trouble later: the microbial explaination

CrossFit, Paleo and Gluten

Many CrossFit enthusiasts follow the “paleo diet”.  This diet claims, among other things, that gluten is bad for you.  Is gluten “bad” or are some people not able to tolerate it?  Is toleration genetic or aquired?  So far it looks like exposure to gluten during infancy plays a key role in determining whether or not someone will become gluten intolerant.

The human gut maintains large bacterial populations. In fact they outnumber you by about 10 to 1 on a cell to cell level (as in for each of your cells, there are ten bacteria). Each of us is a walking bus. We are designed to be this way. Our bacterial passengers have always been here. Our good health requires passengers who are not hijakers, jerks or even dead weight. The good ones help us digest food, keep us from getting horrible gas and other forms of intestinal distress, may protect us from obesity, defend against pathogens and degrade harmful substances.

Gut Bacteria and health

The dominant bacterial family present in infants, if they are breast fed, are Bifidobacteriaceae. Bottlefed infants also harbor Bifida sp., but not as much. If a breastfed infant is supplemented with formula he or she will experience a rapid loss of bifida sp. Bifida sp. provide many benefits to their human hosts including protection against pathogens, prevention of diarrhea, maturation of the immune system and reduced risk of developing allergies. Breastfed infants may be better able to handle exposures to environmental chemicals too (Shellor et al. 2012).

The bacteria in your gut will also be dependent on what you eat. A change in diet, for example elimination of gluten by a person who does not have celiac disease, may cause a decline in bacterial populations that help digest gluten (Nistal et al. 2012).

A person eating gluten after a period of abstinence may not be able to digest gluten as well if they eat it again, at least not until bacterial populations re-balance. This may lead some people to get gas, cramps etc. and conclude that they have celiac disease, or that gluten is harmful in itself. It has been brought up by some that the intestinal distress suffered by people following a Paleo-type diet who start eating wheat again is all in their heads (some chat board or other). It probably isn’t. But it’s probably not because gluten is inherently bad either.

Shelor, C., Kirk, A., Dasgupta, P., Kroll, M., Campbell, C., & Choudhary, P. (2012). Breastfed Infants Metabolize Perchlorate Environmental Science & Technology, 46 (9), 5151-5159 DOI: 10.1021/es2042806

Nistal, E., Caminero, A., Herrán, A., Arias, L., Vivas, S., de Morales, J., Calleja, S., de Miera, L., Arroyo, P., & Casqueiro, J. (2012). Differences of small intestinal bacteria populations in adults and children with/without celiac disease: Effect of age, gluten diet, and disease Inflammatory Bowel Diseases, 18 (4), 649-656 DOI: 10.1002/ibd.21830