Health Benefits of Inositol

Natural compound may help boost mood and metabolism

plate of cantaloupe
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Inositol is a substance found naturally in cantaloupe, citrus fruit, and many fiber-rich foods (such as beans, brown rice, corn, sesame seeds, and wheat bran). It is also widely sold in supplement form and used as a form of complementary therapy to treat a wide range of medical conditions, including metabolic and mood disorders.

Inositol is often referred to as vitamin B8, but it is actually not a vitamin. Inositol is, in fact, a type of sugar that not only influences the insulin response but a number of hormones associated with mood and cognition. Inositol also exerts antioxidant properties that temper the damaging effects of free radicals in the brain, circulatory system, and other body tissues.

D-chiro-inositol, inositol hexaphosphate (often referred to as "IP6") and the compound myo-inositol are the most widely used inositol supplements. They are generally considered safe if taken appropriately.

Health Benefits

Proponents believe that inositol supplements can be beneficial in treating a wide range of health conditions. Some therapeutic approaches are better supported by research than others. Among the conditions for which inositol may be useful are:

In addition, inositol is believed by some to slow the progression of Alzheimer's disease and prevent certain cancers. Some people also use inositol to promote hair growth or overcome insomnia.

Although research is sorely lacking, there is some evidence that inositol may offer some tangible benefits:

Mood and Anxiety Disorders

Inositol is believed to improve depression, anxiety, and other mental disorders by stimulating the production of the "feel-good" hormones serotonin and dopamine. The hypothesis is largely supported by research in which myo-inositol concentrations in blood is suggested a reliable marker for clinical depression.

In application, the benefits have mostly been seen in people with panic disorder (PD) in whom depression is common. A small study published in the Journal of Clinical Psychopharmacology in 2001 investigated the effect of myo-inositol on 20 people with PD.

After being provided a daily 18-gram dose of myo-inositol for four weeks, the participants were given a daily 150-mg dose of Luvox (fluvoxamine)—a commonly prescribed psychiatric drug—for the four weeks. When compared to a matched set of individuals not given myo-inositol, those who did had an average of 2.4 fewer panic attacks per week.

A number of other studies have investigated the use of inositol with selective serotonin reuptake inhibitors (SSRIs) used to treat a variety of depressive and anxiety disorders. The results have thus far been inconclusive.

While a double-blind study in 1995 suggested that a daily 12-gram dose of inositol improved depression scores compared to people provided a placebo, the results have not been replicated elsewhere.

In addition to panic disorder, inositol may be useful in treating obsessive-compulsive disorder (OCD), attention deficit-hyperactivity disorder (ADHD), and post-traumatic stress disorder (PTSD) given its effect on serotonin and dopamine levels.

Metabolic Disorders

There are scientists who believe that inositol can correct may metabolic disorders that contribute to the development of high blood pressure, diabetes, and metabolic syndrome.

A 2016 pilot study published in the International Journal of Endocrinology reported that people with type 2 diabetes given myo-inositol and d-chiro-inositol daily along with their anti-diabetes drugs had a significant drop in their fasting blood glucose (192.6 mg/dL down to 160.9 mg/dL) and A1C (8.6% down to 7.7%) after three months.

Another small study published in the journal Menopause suggested that myo-inositol may aid in the treatment of metabolic syndrome in postmenopausal women. According to the research, women assigned to six months of myo-inositol supplements experienced significantly greater improvements in blood pressure and cholesterol levels than women provided a placebo.

When treated with myo-inositol, women with metabolic syndrome experienced an 11 percent drop in diastolic blood pressure, a 20 percent drop in triglycerides, and a 22 percent increase in "good" high-density lipoprotein (HDL) cholesterol.

All of these values translate to an improvement of metabolic syndrome as well as a decreased risk of cardiovascular disease.

Polycystic Ovary Syndrome (PCOS)

D-chiro-inositol may help manage PCOS, according to a small study published in Endocrine Practice. For this study, 20 women with PCOS were given either a placebo or 6 grams of D-chiro-inositol once daily for six to eight weeks.

The results revealed that D-chiro-inositol helped treat several abnormalities associated with PCOS, including high blood pressure and elevated levels of blood fats. In addition, elevated testosterone levels (consistent with PCOS-related hormone imbalances) decreased by 73 percent compared to 0 percent for those given a placebo.

Generally speaking, a normalization of hormonal balances translates to an improvement of PCOS symptoms.

Other Benefits

While not standard medical practice, the intravenous use of myo-inositol can significantly reduce the risk of death in infants with acute respiratory distress syndrome (ARDS), according to a collaborative study published in Pediatric Research.

Inositol has also been found to reduce psoriasis symptoms in people taking lithium, a drug commonly prescribed to treat bipolar disorder, depression, schizophrenia, and eating disorders. Depending on the usage, lithium-induced psoriasis can affect anywhere from 3 percent to 45 percent of users.

Possible Side Effects

Inositol is generally considered safe in adults. Side effects, if any, tend to be mild and may include nausea, stomach pain, tiredness, headache, and dizziness. Most side effects occur with doses greater than 12 g per day.

The metabolic effects of inositol may not be appropriate for everyone. Even in people with diabetes, the prolonged use or overuse of inositol may lead to hypoglycemia (low blood sugar).

There is also concern that the stimulation of serotonin may not be appropriate for people with bipolar disorder. It is possible that inositol so may inadvertently spur a manic or hypomanic episode.

There is also some concern that high doses of inositol hexaphosphate may reduce the body's ability to absorb zinc, calcium, iron, and other essential minerals, triggering a nutritional deficiency even if you're eating a balanced diet.

As a dietary supplement, inositol products are not tested for safety, and their effect on pregnant women, nursing mothers, and children has not been established. As such, it is best to speak with your doctor before trying this or any other natural remedy.

Dosage and Preparation

Inositol supplements are usually provided in a tablet or capsule formation. There is no standardized dosing schedule, but manufacturers will recommend different doses for different conditions.

They can range from 2 gram twice daily to treat metabolic syndrome and PCOS. Lithium-related psoriasis may require up to 6 grams once daily, while some doctors will prescribe up to 12 grams daily to treat extreme anxiety, including panic attacks.

For infants with ARDS, an intravenous dose of 80 to160 milligrams per kilogram (mg/kg) has been used.

What to Look For

Widely available for purchase online, inositol supplements can also be found in natural foods stores and those specializing in dietary supplements. To ensure quality and safety, always look for products tested and approved by an independent certifying body like the U.S. Pharmacopeia (USP), NSF International, or ConsumerLab.

If you decide to take an inositol supplement, speak with your doctor to ensure that it's appropriate based on your health and medical history.

Other Questions

Due to the lack of quality research, it is too soon to consider inositol supplements as an effective, standalone treatment for any health condition. With that being said, inositol is generally well tolerated if taken in moderation.

Alternatively, stock up on foods rich in inositol, most of which offer the fiber and nutrients needed for good, long-term health. This includes fruits, beans, grains, and nuts. Cantaloupe, oats, bran, and citrus fruits (other than lemons) are especially rich in myo-inositol.

Cooking or freezing fruits and vegetables reduces their inositol content. There is very little inositol in milk or yogurt. 

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