First and foremost, diabetes should ALWAYS be managed principally with diet. However, in the short term, until the changes are fully implemented, there are supplements that can be powerful players in improving your health.
The standard ones like fish oil and chromium are the first supplements that come to mind. The B vitamins are not the supplements that come to mind first, but maybe they should.
B12, B6, folic acid and betaine are considered “methylation factors” because they are required by the body to undergo a process called methylation. Methylation is an absolutely essential process for hundreds of reactions in the body that include turning genes on or off, protecting against DNA damage, healthy dilation of blood vessels and formation of neurotransmitters.
The conversion of folic acid (or rather, the activation of folacin, which is the form found in our foods) to its active form, 5-methyltetrahydrofolate (5-MTF) is done by an enzyme called methyltetrahydrofolate reductase, or MTHFR. This enzyme, MTHFR, is linked to a wide variation of genetic uniquenesses called SNPs (single nucleotide polymorphisms). This means that, in different people, this enzyme may run faster or slower because of these differences. Because this pathway is very important for the healthy growth of a developing infant in the womb, a prenatal vitamin containing folic acid is now recommended for all women of child bearing age.
In general, because the methylation cycle is involved in some many aspects of physiology, it may be difficult to pin down exactly why this particular study saw such dramatic benefits with folic acid supplementation. Regardless, the use of 5 mg (this is a high dosage–most supplemental forms of folic acid contain up to 800 mcg, or .8 mg) for 2 months. An 8% drop in HbA1c levels and a 20% improvement in insulin action were seen. These are pretty strong changes given how simple, safe and inexpensive this level of supplementation is.
The only thing I would add is that, although they did not do this in the study, make sure you combine folic acid supplementation with B12 as they play in the same circles and deficiency of one can be masked by supplementation of the other. This would become more important with long term supplementation.