The health of the gut determines the health of the body, including depression.

The health of the gut determines the health of the body.  This is a well-known fact.  There are roughly 100 trillion cells inside our bodies, yet the there about 10x as many cells of bacteria living on our bodies.  This mass of bacteria lives in harmony with us (most of the time) and helps make sure our immune system is functioning and we are able to digest our food.   Without these bacteria in our gut and on our skin, we wouldn’t survive long.
That is all good news but what happens when these bacteria become imbalanced?  What are the implications to our health when we have an overgrowth of bacteria in the gut?  As we will see, when the small intestine is overwhelmed with bacteria (diagnosed as Small Intestine Bacterial Overgrowth – SIBO) it can have major impacts on our methylation cycle…it can make methylation problems much worse!
As a quick reminder, those of us with MTHFR, PEMT, MTR, MTRR, etc. have defects in how well we recycle homocysteine and how well we convert folic acid into folate.  Many of you are aware of Dr. Lynch and his concept that folic acid is a toxin for those with MTHFR.  While there is still some debate about this issue, Dr. Lynch is right on when he points out that having too much folic acid can impair the methylation cycle.  Here is how it works:

1) Folic acid comes from fortified food AND from gut bacteria.  Yes, you heard that right…folic acid is a NATURAL by product of the metabolism of bacteria that live in our intestines, mainly the colon.  Every person on earth gets some folic acid into their bodies from the action of our gut bacteria.

We get in trouble when the bacteria in our colon grows and moves into the small intestine.  Normally only a small amount of bacteria is found in the small intestine, but when the digestive system becomes imbalanced the population of bacteria in the small intestine can increase, creating a condition of SIBO.

2) Folic acid and folate both enter the cell through the same receptor.  If there is an excess of folic acid, it is harder for the folate to get into the cell.  The more folic acid you have inside your blood stream, the less often folate will get to the receptor.  In other words, there is competition between folic acid and folate, and when folic acid is elevated, it wins the competition to enter the cell.

3) In a person WITHOUT MTHFR issues, this poses zero problems since folic acid is rapidly converted to folate in their methylation cycle.  For the rest of us however excess folic acid makes it harder for us to create methyl donors.  Since MTHFR is often slowed down along with MTR, MTRR, BHMT and other SNPs, having high doses of folic acid may slow down the methylation cycle.  This is why folic acid in high amounts can be a problem.

There is new research that shows that the bacteria involved with SIBO actually poop out large amounts of folic acid (yes the dreaded folic acid!) and we absorb that folic acid into our bodies.  Many individuals with MTHFR C677T/A1298C, MTR, BHMT, etc. may have symptoms of under- or overmethylation due solely to the excess folic acid from improper gut bacteria and digestion.  An imbalance of the gut bacteria, namely in the small intestine, is a major reason WHY an individual has elevated unmetatoblized folic acid.  If we are going to balance methylation pathways, we need to control how much folic acid gets into the system. – we have to control the gut!
In other words, until the gut infection is properly taken care of, the methylation cycle is at the mercy of what is happening in the gut.  The same is true of important vitamins like choline, B12, vitamin D, protein, etc…the gut imbalance makes it very difficult to absorb these vitamins.  Side effects from vitamins are most commonly due to an untreated gut problem.
When someone has SIBO, or an overgrowth of “non-pathogenic” (aka normal species of gut flora) bacteria in the small intestine, the bacterial infection can produce EXCESS AMOUNTS OF FOLIC ACID!  Too many bacteria in your gut, can lead to way too much folic acid being released and absorbed.  This can lead to high blood levels of folic acid, which as Dr. Lynch and other researchers have shown, can impair the methylation cycle in people with MTHFR and other genes.  What I have just discovered is that one important and often-overlooked source of this increased, UNMETABOLIZED Folic Acid is a raging Gut Infection!
This gut infection, aka SIBO, is an infection made up of non-infectious bacteria.  Meaning, its not an infection the traditional sense, its an overgrowth of something that should normally be there, only exists in way too high of a quantity.  This is a problem since the bacteria down there can produce folic acid while at the same time causing all kinds of other digestive issues.  more at
http://www.beyondmthfr.com/mthfr-and-sibo/