What Is Inositol?
Inositol, sometimes called vitamin B8, is a sugar alcohol and structural isomer of glucose found in the cell membranes of all living organisms. It is involved in the production of membrane phospholipids, as well as being involved in the system which allows neurotransmitters to "talk" to cells and affect what happens inside them.
How Does It Work?
Inositol is used in the production of inositol triphosphate and diacylglycerol, both of which are molecules involved in the system that allows communication between neurotransmitters and the interior of cells. It is believed that a decrease in inositol could lead to a shortage of these two molecules, causing mood-regulating neurotransmitters - such as serotonin, dopamine and norepinephrine - not to be able to properly communicate with the interior of brain cells. Supplementation with inositol could help depression by improving the functioning of this messenger system.
Is Inositol an Effective Treatment for Depression?
Thus far, inositol has mainly been investigated as an add-on to mood stabilizers and antidepressants for the treatment of the depressive symptoms of bipolar disorder. Findings suggest that it may be at least somewhat helpful for these patients.
It is not known whether inositol could also help unipolar depression. Although two studies conducted using unipolar patients had negative results, their sample sizes were too small to draw any definitive conclusions.
Is Inositol Safe and Well-Tolerated?
Inositol is well-tolerated and appears to be quite safe. Side effects may include: mild decreases in plasma glucose, flatulence (gas), nausea, sleepiness, insomnia, dizziness and headache.
There have been some case reports of inositol-induced mania in bipolar patients.
To date, there have been no reports of toxicity or drug-drug interactions with inositol.
Pregnancy and Breastfeeding?
Inositol supplementation is not recommended for pregnant women due to the fact that there is a risk of inducing uterine contractions. It is not known if it is safe for breastfeeding women.
How Can I Get More Inositol in My Diet?
Fruits and vegetables that are especially rich in inositol include: cabbage, beans, legumes, seeds, nuts, cantaloupe, bananas, raisins, oranges and other citrus fruits. It is also found in wheat, cereal, oat flakes, wheat bran, wheat germ, brown rice, brewer's yeast and unrefined molasses.
Inositol is also found in organ meats, such as brain, heart and liver.
How Do I Use Inositol Supplements?
The recommended doses for inositol generally fall in the range of 6 to 20g per day, with 12g being the more usual dose. It is taken in divided doses, two to four times a day.
Due to the potential risk of cycling, patients with bipolar disorder should consult with their physician before supplementing with inositol.
What is Myo-Inositol and Can I Use This Instead of Inositol?
There are actually nine different isomers of inositol, but myo-inositol is the most common form, comprising the major part of inositol found in the human body. Because of this, the terms inositol and myo-inositol are often used interachangeably and you may see inositol supplements labeled with either term.
What Is IP-6 and Can I Use This Instead of Inositol?
IP-6, also known as myo-inositol hexaphosphate or phytic acid, is a form of inositol found in cereals and legumes. It is related to myo-inositol, yet chemically distinct from it. It has mainly been investigated in the treatment of cancer, kidney stones and heart attack prevention. Although it might potentially be helpful for depression, it has not yet been studied for this application. If you are planning to supplement with inositol, do not purchase this form.Source:
Iovieno, Nadia, Elizabeth D. Dalton, Maurizio Fava and David Michoulon. "Second-tier natural antidepressants: Review and critique." Journal of Affective Disorders. 130 (2011): 343-357.
"Myoinositol." Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica, 2011. Accessed: Aug. 28 2011.