Monday, April 19, 2010

Tale of Two Rats – How Fiber Can Make You Beautiful and Healthy

Not an epic novel, my story concerns two rats – a fat rat and a thin rat. Some bored scientists analyze their fecal content and discover they are distinctly different. The gut flora in the fat rat has more of a bacteria called firmicutes (think F for fat) and the thin rat has more bacteriodes (think B for beautiful). Said scientists decide to amuse themselves by performing a fecal transplant. The unsuspecting thin rat gets the fecal content of the fat rat. It’s a tragic story. With no change in diet, the thin rat whose gut flora is now dominated by firmicutes gets fat.

Another two rats, another story. Two thin rats and each has more bacteriodes in the gut flora. The sadistic scientists put one of the healthy rats on a high fructose diet. Predictably, thin rat develops a new gut ecology with dominant firmicutes … and gets fat.

Final story. Some kind hearted scientists observe that bacteriodes are able to produce a short-chain fatty acid called butyric acid which seems to improve the gut ecology with many benefits. Being better scientists than cooks, rather than feed the rats some tasty food naturally high in fiber, they add 5% sodium butyrate to their laboratory rat chow. The rats that are supplemented with sodium butyrate do not get fat like their buddies on the same highly fattening diet. Check out the graph below:

Actually, the last story has a really happy ending. Not only do these rats not get fat, their post prandial blood glucose levels are much better with the butyrate and their insulin resistance improves as measured by HOMA-IR.

Moral of the story? Nope, I am not recommending fecal transplants for all my chubby T2 friends and I am not suggesting you use sodium butyrate as a condiment in all your favorite foods. Let me tell you how the same healthy gut environment can be achieved in the human species.

The way bacteriodes are supposed to work in people is that they ferment fiber to produce butyrate. Nope, I am not talking about your raisin bran cereal. The sugar in it will feed the evil firmicutes and hasten your demise while the insoluble fiber from the wheat bran going through your gut like sawdust will likely providing more irritation than health. But isn’t fiber supposed to help diabetics? As it turns it, only soluble fiber is the diabetic’s friend.

Soluble fibers from rich sources like low carb veggies, flax meal, chia seeds and supplements like pectin, beta-glucan, FOS, inulin, etc. are the healthy nutrients that the good bacteria love. The bacteriodes will thrive on this stuff and you will look and feel great.

While you are are savoring your broccoli and enjoying a flax meal muffin, don’t forget the bad guys. Do not feed the firmicutes! NO FRUCTOSE! If you dare consume any unhealthy quantities of sugar, HFCS or fruit juices (and any quantity is unhealthy) please contact me immediately to learn how you can schedule that fecal transplant.

OK, most of my readers already know that I am no doctor or scientist … and certainly not a pillar of virture. Seems I succumbed to temptation only this morning when my wife offered me a piece of nice dark chocolate. Should perfection elude you, too, please refer to my earlier posting and eat lots of low carb, probiotic yogurt daily. Having more probiotic bacteria in the neighborhood will help keep out the bad guys.

Breaking News -- According to an article in ScienceNews, my Venti-sized Americano coffee may have as much as 2 grams of that soluble fiber that is so beloved by bacteroides. Discussion continues at the Da Mu Zhi Guangchang Starbucks.


  1. Denny, this is interesting.

    Which veggies have the most insoluble fibres?

    I know that most veggies have the other type of fibre - the really tangible fibrous fibre which unfortunately is not soluble and sometimes irritates my bowels (mainly the leafy varieties like Swiss Chard, spinach etc.) to cause loose motion. Does coconut have a good amount of soluble fibre? Coconut does not irritate my bowels at all. We add coconut (ground into paste form) and dal (lentils) when making curries out of leafy vegetables. This reduces the bowel irritation that the leafy vegetables sometimes cause.


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  3. Rad,

    It is soluble fiber not insoluble fiber which improves the gut ecology and generates the health benefits mentioned in this post.

    Veggies with lots of soluble fiber include the leafy green veggies you mentioned plus broccoli, cauliflower, cabbage, brussel sprouts, green beans, carrots, sweet potatoes and others.

    Fruit also has soluble fiber with prunes and mangoes being the highest followed by berries, citrus fruit, pears and apples. The problem with fruit is the fructose. Fructose feeds the firmicutes, the bad bacteria in the gut and also creates too many advanced glycation end-products (AGEs).

    Whole grains and nuts have some soluble fiber, but far more insoluble fiber. Barley and oat bran have the most soluble fiber. Of course, diabetics need to be careful about all the carbs in these starchy foods.

    Legumes generally have a higher proportion of soluble fiber than grains with the lentils you mentioned being about the highest. Again, I have problems with all the carb.

    I get most of my dietary soluble fiber from flaxseed meal (14% soluble fiber & 12% insoluble) and chia seed which is about the same as flax. Psyllium seed husk is the soluble fiber superstar with 71% soluble fiber. These seed sources are all relatively low carb.

    Besides psyllium, I recommend pectin, inulin and FOS as soluble fiber supplements.

    As for coconut, I think it is mostly insoluble fiber plus relatively healthy fat. The medium chain triglycerides in coconut oil are good for the gut. Defatted coconut flour contains 60.9% total dietary fiber, 56.8% insoluble and 3.8% soluble.