What is methylmalonic acid and how does it relate to vitamin B12?

What is Methylmalonic AcidMethylmalonic acid (MMA) is a popular vitamin B12 test.

But what actually is MMA and where does it come from? In the human body, MMA is a breakdown product or byproduct of protein, carbohydrate, and cholesterol metabolism. In other words, when a variety of proteins, fatty acids, and cholesterol are used to create energy, one of the byproducts is methylmalonic acid.

The specifics of this energy producing pathway are described as follows: In the creation of energy, the amino acids valine, isoleucine, methionine, threonine, odd-chain fatty acids, and cholesterol all go through a variety of metabolic processes to be converted into a substance called propionyl CoA. Propionyl Co-A is then converted into methylmalonyl CoA. When we are in good human bioactive B12 status, methylmalonyl CoA is then converted into succinyl CoA by an enzymatic reaction in which vitamin B12 is a co-factor. In other words, vitamin B12 is essential for the conversion of methylmalonyl CoA into succinyl CoA.


Succinyl CoA is an intermediate in the Kreb’s Cycle (also known as the TCA cycle), which is involved in energy production. We now see how vitamin B12 plays a role in energy production in our body.

What happens when someone becomes B12 deficient? The pathway that converts methylmalonyl CoA into succinyl CoA becomes de-emphasized and the amount of methylmalonyl CoA starts to increase. As this amount increases, methylmalonyl CoA is converted into methylmalonic acid. Methylmalonic acid does not have any specific function in the body, so it is eliminated from the body by the urinary tract. When one is deficient in vitamin B12, their blood and urine generally have elevated levels of methylmalonic acid.


Vitamin B12 is very important for this pathway and many other reactions throughout the body. The bottom line is that it is a good idea to know our vitamin B12 status, which we can achieve through reliable B12 testing.

We cover the importance of vitamin B12, reliable testing, and reliable sources in our book, The Raw Food Nutrition Handbook, An Essential Guide to Understanding Raw Food Diets. If you are interested in our lab testing and nutrition consulting services, please visit www.rawfoodconsulting.com.

This video explains how and why methylmalonic acid can be created in the human body:

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