Vitamin B8 (Inositol)

What is Vitamin B8 (Inositol)?

Vitamin B8, also commonly known as Inositol is a carbocyclic sugar. Although it had been classified as a vitamin in the past, eventually inositol’s status as a vitamin was dropped since the body naturally produces around a few grams daily from glucose by intestinal bacteria and is now considered a pseudo vitamin and a component of the B complex group of vitamins. Despite this it is required for various important bodily functions. Like many of the B vitamins inositol is water soluble.

The name ‘Inositol’ has been adopted from the Greek word “inos” which means “muscle” due to being first discovered in muscle tissue in 1850 by the German physician Johannes Joseph Scherer.

Inositol is similar to choline and can be found body tissue with higher concentrations found in the brain, heart, liver, skeletal muscles and eye lens.

Some of the main functions include balancing hormones, regulating gene expression, maintaining healthy cell membrane, regulates glucose and is involved in metabolism of fats and cholesterol.

There are nine isomers in the Inositol family, all of which are near identical compounds with one difference between each compound with the active form being Myo-Inositol. If the body is lacking in any one of the compound, the available compound will simply convert to the missing compound.

In the body the two compounds of inositol, Myo inositol and D-chiro-inositol can be found in the body in a ratio of 40:1.

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Health benefits of Vitamin B8 (Inositol)

Improves insulin sensitivity

Inositol has been used to treat metabolic syndrome in postmenopausal women, gestational diabetes and insulin sensitivity in women with PCOS. Many studies are showing the potential benefit of insotiols ability to improve insulin sensitivity. [2] [3] [4] [5]

Promotes brain health

Inositol is involved in the function of nerves, muscles and promotes brain health. A deficiency of inositol in the body can lead to cognitive malfunction. Inositol works with choline which when combine form lecithin, an essential component for cell membranes which protect cells from oxidation and protect the myelin sheath. This is important for regulating nerve transmissions and has shown to have a positive impact in diabetics with nerve pain and numbness.

Many studies are showing potential benefits of inositol on mental health conditions such as anxiety, schizophrenia, Alzheimer’s disease, obsessive compulsive disorder (OCD) and attention deficit-hyperactivity disorder ADHD. Reports of inositol use reveal an increased levels of energy and improved memory, mental alertness and concentration. It has also shown to be helpful with treating anxiety. [6] [7]

Used for treating depression

Inositol can help regulate mood through its involvement in the manufacturing of serotonin, melatonin, dopamine, norepinephrine, acetylcholine and GABA. These neurotransmitters require inositol for transmitting messages between the brain cells. A deficiency of inositol has been linked to various mental health problems which includes depression, anxiety and panic attacks where many of the neurotransmitters are out of balance. [8] [9] [10] [11] [12]

Improves sleep

Inositol helps improve serotonin levels which can play a part in regulating the wake and sleep cycle needed to maintain a healthy circadian rhythm. Insomnia is also linked to low levels of serotonin, which inositol in combination with other sedative nutrients such as L-theanine or 5-HTP may alleviate. These nutrients help with the production of hormones serotonin and melatonin, for regulating the wake sleep cycle. [13]

Important for fat and cholesterol metabolism

Inositol is similar to choline in that they both function as lipotropic agents and act as fat emulsifiers helping to break down fats, although this function of choline may be more potent. It has the beneficial effect of removing fats from the liver and lower blood cholesterol but increases HDL (good) cholesterol levels. It is also involved in the transportation of fats and helps prevent build-up in various organs such as the brain and heart. It also helps to regulate intracellular calcium and prevents a build-up of plaque in the arteries (arteriosclerosis). This improves blood pressure and maintains healthy blood circulation.

Deficiency of inositol has been linked to high cholesterol, fatty liver disease and arteriosclerosis. Proper metabolism of fat and cholesterol also maintains healthy liver function. [14]

Maintains healthy skin and hair

Inositol is needed for hair growth and maintaining healthy skin.

Deficiency of inositol has been linked to various skin conditions, such as dermatitis, eczema, and psoriasis. It has also been linked to hair loss. Inositol has been used to treat many of these skin conditions with positive results.

Improves PCOS and infertility in women

Studies suggest numerous benefits of inositol for women suffering from polycystic ovary syndrome (PCOS) and infertility. Many of the studies have shown an improvement in symptoms of PCOS including infertility. Some of the positive effects of inositol on women with PCOS include:

Weight loss
Lowers testosterone levels
Improves insulin sensitivity
Increases SHBG (sex hormone binding globulin)
Decreases luteinizing hormone
Increases progesterone
Controls estrogen levels
Reduces hirutism
Improves fertility (restoring ovulation, improve egg quality)
Improves pregnancy rate (may prevent miscarriages)
Improve insulin sensitivity

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Agonist / Synergist

Vitamins: C, E, Folic acid, B vitamins, Choline

Inositol and choline function in a very similar way. When paired together it can help to synthesize acetylcholine and other neurotransmitters to improve cognitive function.

Antagonists / Inhibitors

Caffeine (tea, coffee, cocoa), antibiotics, sulfur drugs, estrogen, phytates, birth control pill, alcohol, processed foods

Food sources of Vitamin B8 (Inositol)

Food sources high in Inositol include chickpeas, whole grains, brown rice, wild rice, wheat germ, pulses (lentils), offal (organ meats such as beef liver), egg yolk, oranges, peanuts, peas, cauliflower, cantaloupe melon, lecithin, seeds, nuts, green leafy vegetables, yeast and soy flour.

Inositol can be found in many foods in the form of phytic acid which may bind with minerals reducing absorption. This can be counteracted by soaking, cooking or sprouting grains, seeds, nuts and legumes.

Intestinal bacteria can help manufacture inositol.

Recommended Dietary Allowance

The amounts recommended for vitamins and minerals are different for each country which can be found on the government website of host country. The nutritional data for each country are based on scientific research which are presented by the scientific academies in each country to help advise governmental departments for food and human nutrition.

Below is a list of some of the countries and the EU for which nutritional guidelines are available found on corresponding official government website (including the national academy of science website for the USA).

Vitamin B8 (Inositol) Supplementation

Inositol as a supplement is available in capsules and powder forms. It can also be found in many b complex multivitamins which are also likely to contain choline, another key nutrient that works synergistically with inositol.

The natural form of vitamin B8 most commonly used is myo-inositol. Powdered form of myo inositol can be mixed in water which will taste sweet but tolerable. Another form of inositol is D-chiro-inositol. Some supplements contain both Myo inositol and D-chiro-inositol forms of inositol.

Inositol can also be found in lecithin supplements which is also a good source of other nutrients such as phosphatides and choline.

It is recommended to take inositol in the morning or afternoon with food.

Deficiency symptoms of Vitamin B8 (Inositol)

Deficiency of inositol is rare as it is available in a variety of foods and the body naturally synthesizes inositol sufficient amount.

Although rarely reported symptom of inositol deficiency include:

Mental disorders
- Anxiety
- Mood swings
- Irritability
- Agoraphobia
- Bulimia
- Depression (Unipolar / Bipolar)
- Hyper-excitability
- Obsessive compulsive disorder (OCD)
- Memory loss
Insomnia
Stress
Oxidative cell damage
Polycystic ovary syndrome (PCOS)
Diabetes
Peripheral neuropathy
Insulin resistance
Hair loss (alopecia)
Dermatitis
Eczema
Skin eruptions
Eye abnormalities
Constipation
Hyperlipidemia
High cholesterol level
Low HDL cholesterol
Fatty livers (Liver disease)
Low bile production
Plaque build-up in arteries (arteriosclerosis)
Cardiovascular disease
Low blood pressure

The following health conditions have been linked to a deficiency of inositol:

Diabetes
Multiple sclerosis
Cardiovascular disease
Polycystic ovary syndrome (PCOS)

Antibiotics, excessive consumption of coffee and tea can lead to a deficiency.

Toxicity symptoms of Vitamin B8 (Inositol)

Toxic levels of inositol may result from prolonged high intake of inositol through supplements. The following are symptoms for toxic levels of inositol:

Nausea
Vomiting
Diarrhea
Dizziness
High blood pressure
Liver disease
Kidney disease
Increased magnesium requirements
May increase potassium requirements
Cardiovascular disease
Skin rash (Appears as acne)

Precautions and warnings

Research on the safety of taking inositol in high doses is limited. It is always important to check with your doctor if you are pregnant, on any medications or have any health conditions before supplementing. Inositol may interact with other medications.