Inositol benefits a number of health conditions. In this article, we share information about what inositol is, how it works, and how it may benefit your health.
What is inositol?
Before diving into inositol benefits let’s answer the question, “what is inositol”? Inositol is a B-vitamin-like nutrient the occurs naturally in whole grains, beans, nuts, and fruits. The human body also makes inositol and it is available as a dietary supplement.
There are nine types of inositol occurring in nature. Two forms, myo-inositol and D-chiro-inositol, have specific functions in our cells. Over the last several years, research has found that a certain ratio of these two forms seems to work better than either form alone. That ratio is 40 to 1, meaning forty parts myo-inositol to one part D-chiro-inositol.
The recommended dose of myo-inositol for most people is 2,000 mg, and the recommended dose of D-chiro-inositol is 50 mg, taken twice a day (total daily dose of 4,000 mg of myo-inositol plus 100 mg of D-chiro-inositol). It takes at least three months of consistent use to see inositol benefits.
How does inositol work?
Inositol works by helping the body use insulin. Insulin is a hormone made by the pancreas and released into the bloodstream. Insulin allows our cells to take in glucose (sugar) and produce energy.
When you eat, your body breaks down glucose in your bloodstream. Increasing glucose in your blood tells your pancreas to make insulin. For insulin to work, it has to bind to the insulin receptor on the surface of the cell. Think of a lock (the insulin receptor) and a key (insulin).
When insulin binds to its receptor, it “unlocks” and releases secondary messengers. These secondary messengers tell the cell it is time to take in glucose from the blood.
Inositols function as secondary messengers. This means that inositols help with insulin signaling. In other words, they help the cell take in glucose from the blood.
People who have insulin resistance do not properly release secondary messengers (like inositol). Glucose does not get into the cell efficiently. Therefore, glucose in the blood remains high, which tells the pancreas to make more insulin. The over-production of insulin results in both high insulin levels and high blood sugar.
You often see insulin resistance in certain conditions such as polycystic ovarian syndrome (PCOS), gestational diabetes (diabetes during pregnancy), metabolic syndrome, and type 2 diabetes.
Taking an inositol supplement can help with insulin signaling, resulting in less insulin resistance, and lower blood sugar and insulin levels.
How Inositol Benefits Insulin Resistance
Here’s how inositol benefits conditions where insulin resistance may be a factor.
1. Inositol and PCOS (Polycystic Ovarian Syndrome)
PCOS is an endocrine disorder. Women with PCOS tend to have high androgen (male hormones such as testosterone) levels. As Lisa Johnston, MS, RD mentions, many women with PCOS have insulin resistance. Some women have small cysts on their ovaries. Symptoms of PCOS include irregular menstrual periods, excess facial hair, thinning of hair on the scalp, weight gain, darkening of the skin in certain areas, and skin tags.
Lifestyle strategies for dealing with PCOS include eating foods with a low glycemic load, exercise, and taking certain supplements such as inositol powder. As explained by Angela Grassi, Registered Dietitian and PCOS expert, inositol is an important supplement for women with PCOS.
Inositol decreases testosterone levels and promotes regular menstruation and ovulation in women with PCOS. Studies have also shown that inositol reduces triglyceride levels, increases HDL (“good”) cholesterol, and decreases blood pressure. Although it isn’t proven, many women note that taking inositol helps reduce carbohydrate/sugar cravings and may even aid in weight loss.
Myo-inositol and D-chiro-inositol are sometimes out of balance in women with PCOS. Recent studies have found that there is too much D-chiro-inositol and not enough myo-inositol in the ovary. In other tissues, the opposite is true- there is too much myo-inositol and not enough D-chiro-inositol.
Taking a 40 to 1 combination inositol powder supplement helps correct this imbalance.
2. Inositol and Gestational Diabetes
Pregnant women who develop high blood sugar levels during pregnancy have gestational diabetes. You are at an increased risk for gestational diabetes if you:
- have a family history (parent or sibling with type 2 diabetes) or personal history (prediabetes or slightly high blood sugar),
- have PCOS,
- are obese,
- have excessive weight gain during pregnancy,
- are of older maternal age,
- have had gestational diabetes during a previous pregnancy, or
- have given birth to a baby over 9 pounds.
Women typically change their diet when diagnosed with gestational diabetes. A doctor may also prescribe medication when needed to control blood sugar levels. Gestational diabetes can lead to problems for mother and baby if blood sugar levels are not controlled.
Studies show that inositol reduces the risk of gestational diabetes. In a recent study, overweight pregnant women who took inositol powder throughout pregnancy had a 67% lower risk of gestational diabetes than those who took placebo powder. Other studies have shown that inositol reduced the risk of gestational diabetes in women with PCOS, and in women with a family history of type 2 diabetes.
3. Inositol and Metabolic Syndrome
Metabolic syndrome is a combination of factors that increase the risk of diseases such as heart disease, diabetes, and stroke. These risk factors are high blood pressure, high blood sugar, high triglycerides, low HDL (“good”) cholesterol, and large waist size. When someone has three of these risk factors, they are diagnosed with metabolic syndrome.
Studies show that inositol improves the risk factors of metabolic syndrome. One study demonstrated that inositol lowered blood pressure, blood sugar, triglycerides, and total cholesterol, and increased HDL cholesterol, in postmenopausal women with metabolic syndrome.
4. Inositol and Type 2 Diabetes
It makes sense that inositol benefits people with type 2 diabetes because of its effects on insulin signaling. Until recently, no research had been done with inositol and diabetes. The first inositol study in people with type 2 diabetes was published in 2016. This study showed that those who took myo-inositol and D-chiro-inositol in the 40 to 1 ratio in addition to their diabetes medication, had lower blood sugar levels after three months. Although this study was small, it produced promising results.
How Inositol Benefits Other Health Conditions
In addition to health conditions related to insulin resistance, inositol benefits a number of other health conditions.
5. Inositol and Female Fertility
Inositol’s benefit for fertility is evident in women with PCOS. Many studies show that inositol normalizes menstrual cycles and helps restore ovulation. Other studies have found that inositol improves egg and embryo quality, and increases pregnancy rates in women with PCOS going through in vitro fertilization (IVF).
For women with PCOS, inositol may even work better than the commonly used diabetes drug Metformin to restore ovulation and improve pregnancy rates.
Inositol may also have fertility benefits for women who do not have PCOS. Studies indicate that inositol is helpful for women going through IVF, improving the response to ovarian-stimulating drugs used during this fertility treatment.
So, if you have PCOS, are of older maternal age and trying to improve egg quality, or you have responded poorly to previous fertility treatments, taking inositol may help you conceive.
6. Inositol and Mental Health
Inositol functions as a secondary messenger for serotonin and dopamine, neurotransmitters that send signals back and forth between the brain and other systems in the body. Low levels of inositol in the body may disrupt this signaling, possibly resulting in mood disorders and impaired mental health.
More research needs to be done to understand exactly how inositol benefits mental health. There is some evidence that people with obsessive-compulsive disorder may improve when taking a myo-inositol supplement. Myo-inositol also shows promise for individuals who suffer from panic attacks. People with depression may also benefit from myo-inositol, although studies have found that inositol does not make antidepressant medications work better.
These mental health studies have used much higher doses of myo-inositol than used for the other conditions described in this article. For example, depression studies used 12 grams per day, and panic disorder studies used 12-18 grams per day. Studies indicate that taking up to 12 grams per day, in divided doses, is safe. However, be sure to consult your physician before taking high doses of inositol.
While inositol benefits a number of health conditions, it is always a good idea to consult your healthcare provider before starting any new health practice or dietary supplement.
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