… you’ve probably never heard of it before, but if you struggle with PCOS, anxiety, panic attacks, high blood sugar, high blood pressure, fertility problems, or depression…
…then you’ll be glad you read this article.
Inositol is actually a collection of similar compounds (stereoisomers) of which the most prominent form is myo-inositol. Inositol is a sugar alcohol. While formerly considered a member of the vitamin B complex (vitamin B8), it is actually a pseudovitamin because it is produced by the body from glucose and therefore is not an essential nutrient (these cannot be made by the body and must be obtained from the diet).
Inositol is involved in a number of biological processes:
- insulin signal transduction
- intracellular calcium concentration control
- breakdown of fats
- gene expression
- cytoskeleton assembly
- nerve guidance
- cell membrane potential maintenance
There is limited human evidence for intentional inositol deficiency, but there does not appear to be a disease state associated with depletion of the molecule nor does dietary deprivation cause any adverse health effects in the short term (long term not studied). This is unlike the essential nutrients, such as a deficiency of vitamin C which leads to scurvy.
In almost all instances where insulin resistance is present there is an increased urinary excretion of inositol metabolites. Because of this, it is thought that those who are insulin resistant are in a state of relative inositol deficiency due to an increased excretion rate.
Depression and Mood
Inositol concentrations in depressed persons may be lower than normal. Relative to placebo, inositol appears to be somewhat effective in reducing depressive symptoms in unmedicated persons. Benefits stop upon discontinuation.
High doses of inositol may be able to reduce depressive symptoms in persons with bulimia and binge eating disorders and result in fewer bulimic symptoms.
In persons who do not respond to selective serotonin reuptake inhibitor (SSRI) medications it does not appear that inositol provides any further benefits.
Lithium is a bipolar medication that works via depleting inositol in in the brain, and side-effects of lithium therapy are thought to be related to excessive inositol depletion. Low dose inositol supplementation that cannot easily get into the brain due to poor transportation is able to effectively reduce side-effects in other body areas.
Anxiety and Panic Disorders
There does appear to be some anxiety reducing properties associated with high dose myo-inositol. Supplementation was shown to be as effective as fluvoxamine, a SSRI medication, in reducing anxiety symptoms associated with panic.
While there seems to be benefit to panic attacks association with long-term inositol use, it has failed to show benefit in persons with post-traumatic stress disorder (PTSD).
Scyllo-inositol, one of the stereoisomers of inositol, is found in the brain and seems to accumulate in the brain with aging. Myo-inositol also increases during aging. Scyllo-inositol can prevent aggregation of Αβ42 fibrils and because of this is thought to be therapeutic against Alzheimer’s disease, however clinical trials have shown that symptoms of Alzheimer’s were not significantly reduced.
Polycystic Ovarian Syndrome (PCOS)
PCOS is a condition affecting an estimated 10% of females. It is associated with abnormalities in glucose metabolism (elevated fasting blood glucose, insulin resistance) and androgen metabolism (excess testosterone) which results in difficulties losing fat and impaired fertility. Insulin sensitizing medications are usually the first line of treatment in PCOS.
When looking at studies assessing biomarkers of androgen and glucose metabolism, supplementation with myo-inositol appears to have a therapeutic benefit at modest dosages over the long-term (12+ weeks).
In vitro fertilization (IVF) as well as overall pregnancy rates in women with PCOS improve with myo-inositol supplementation and appears to alleviate symptoms of oligomenorrhea (disrupted periods) or amenorrhea (absent periods).
Pro-fertility effects of myo-inositol supplementation in women appear to be additive or synergistic with supplemental melatonin to increase the amount of mature oocytes (ovarian egg cells).
Inositol (myo-) is a secondary messenger of insulin signalling. There are two classes of signalling molecules derived from inositol, the P-IPGs and the A-IPGs, and they tend to be antagonistic to each other and generally regulate body functions. The state of insulin resistance seems to be associated with an increase in A-IPG relative to P-IPG. Supplementation with inositol is thought to normalize this ratio.
Activation of insulin receptors cause glucose uptake by mobilizing GLUT4 vesicles. When an insulin receptor is activated, the resulting signalling process uses inositol derivatives. Oral ingestion of myo-insositol appears to induce GLUT4 translocation rapidly when used with or without additional orally ingested glucose.
In women with insulin resistance (such as in PCOS, type 2 diabetes, gestational diabetes, or metabolic syndrome), supplemental myo-inositol appears to be effective in improving insulin sensitivity.
Insulin sensitivity describes how sensitive the body is to the effects of insulin. Someone who is insulin sensitive will require smaller amounts of insulin to lower blood sugar levels than someone who has low sensitivity (insulin resistance).
Myo-inositol is thought to be beneficial for diabetic neuropathy (degradation of peripheral neurons that results in impaired sensory capacities).
HOW TO TAKE
For the treatment of polycystic ovarian syndrome (PCOS), myo-inositol taken in the range of 200-4,000mg once daily before breakfast has been tested and deemed effective. In studies, the higher dose seems to be used more often and is more effective.
Neurological benefits tend to require higher doses. While antidepressant effects have been noted at doses as low as 6g at times, the standard dose is between 14-18g per day.
If using a soft gel formulation rather than the more widely available powdered myo-inositol, only 30% of the same dose is required. This would mean that a 14-18g powdered dose for psychopharmacological effects would be reduced to 4.2-5.4g of myo-inositol soft gels.
In general, supplementation of myo-inositol is well tolerated up to doses of about 12g, above which mild gastrointestinal side-effects may occur in an estimated 5% of people. Several human studies have been conducted in pregnant women in which 4,000mg daily inositol dosages were used from near conception to delivery with no clinically relevant adverse effects.
Inositols are pseudovitamins found in most foods and especially whole grains, cantaloupe, and citrus fruits.
Myo-inositol shows promise as a supplement for restoring insulin sensitivity in instances of insulin resistance (such as in PCOS and type 2 diabetes), promoting fertility in females, and for reducing anxiety.
It is generally considered a safe supplement with associated side effects being mostly mild gastrointestinal distress at high doses. High doses (12-18g) are required for neurological benefits while lower doses (2-4g) are sufficient for insulin sensitization and fertility. Evidence appears to be stronger in female subjects with little or no benefit shown in male subjects.
Disclaimer: I am not a physician. Please consult your doctor before taking any new supplements.