Yesterday on an email list I’m on, someone mentioned d-chiro-inositol (DCI) (part of the B-vitamin group), which I’d never heard of before, but which plays a part in carbohydrate metabolism as some sort of helper to insulin. It turns out insulin resistant/Type 2 diabetic people in general, & women with polycystic ovarian syndrome (PCOS) in particular (which affects about 10% of all women, including me), have been found to have deficient levels of DCI in their bodies.
It’s theorized that this is due to an impairment in whatever it takes for the closely related myo-inositol to be changed into d-chiro-inositol in the body. Furthermore, studies have shown that women with PCOS & Type 2 diabetics who are given supplements of DCI have improvements in insulin sensitivity, blood sugar levels, blood insulin levels, etc. — as well as improvement of the additional symptoms (high androgen levels, irregular to nonexistent menstrual periods, infertility) that tend to accompany PCOS. On an anecdotal level, there are a number of women at the forums at Soulcysters.com (a major PCOS support site) who report having successfully regulated their menstrual cycles & achieving pregnancy (as well as other improvements) through supplementation with DCI. The word “miracle” tends to show up. (Well, I guess miracles do happen when deficiencies are addressed. That’s how sailors must’ve felt when they learned all they had to keep from getting scurvy was to eat citrus fruits.)
Here’s some relevant studies. All of these have full-text available online:
- Ostlund, et al.D-chiro-inositol metabolism in diabetes mellitus. Proceedings of the National Academy of Sciences 90 (1993), 9988-9992.
- Nester, et al. Ovulatory and metabolic effects of d-chiro-inositol in the polycystic ovary syndrome. New England Journal of Medicine 340 (1999): 1314-1320.
This is a really central study related to PCOS. Obese PCOS-affected women on doses of 1200mg/day showed marked improvements on a bunch of different things when compared with controls on placebo.
- Larner, Joseph. D-chiro-inositol – its functional role in insulin action and its deficit in insulin resistance. International Journal of Experimental Diabetes Research 3(1) (2002): 47-60.
Larner has apparently been involved in the investigation of d-chiro-inositol in carbohydrate metabolism in mice for a couple of decades, per his 2005 press release from UVa.
- Shashkin, et al. Fasting decreases the content of d-chiroinositol in human skeletal muscle. International Journal of Experimental Diabetes Research 3(3) (2002): 163-169.
I’m wondering from this if DCI is one of the substances mentioned in Lyle McDonald’s The Ketogenic Diet that gets downregulated during fasting & ketogenic diets. [Later: I asked Lyle, who answered that “arguably the primary effector for the fasting issue is PDH downregulation“ — PDH is pyruvate dehydrogenase.]
Unfortunately there are few sources of DCI supplements, & they tend to be expensive (e.g., Chiral Balance). Apparently the mega-pharmaceutical companies haven’t found it worth their while to bring their own versions to market. Less expensive supplements called simply inositol or myo-inositol seem to be helpful for some people, but since the problem insulin resistant people seem to have is in changing myo-inositol to DCI, it’s really DCI that needs to be supplemented. Another supplement that might work, though, is d-pinitol (aka D-chiro (+)-o-methyl inositol), which is available under the trade name Inizitol (New Zealand company, but there are distributors in the U.S. & Canada); this is also recommended as a possible supplement for PCOS by Richard Bernstein in Dr. Bernstein’s Diabetes Solution. Apparently d-pinitol is also used a lot by athletes and affects whole-body creatine retention. More info on d-pinitol & DCI from a PCOS-suppement supplier here.
The food source with the highest level of DCI is buckwheat (which is actually a rhubarb relative, not a grain), especially in buckwheat bran (farinetta) (available in quantity from Minndak.com). Apparently some other legumes (e.g., garbanzo beans) also contain small quantities of DCI. People at Soulcysters, who have become quite expert at creating recipes containing these foods, have also mentioned carob syrup & soy lecithin — I think those are supposed to be sources of pinitol. Carob syrup is something of a problem since it’s got a lot of sugar.
… Since I’m insulin resistant & have PCOS, I probably have this deficiency in d-chiro-inositol, so I am likely going to get some of this stuff no matter how expensive & experiment with it when I get back from my trip.