Inositol is one of those supplements that’s still unknown to most people, but that doesn’t detract from its goodness, as the impact it has on our health simply can’t be underestimated.
It can be described as a carbohydrate with a cyclical structure that’s ubiquitous within the human body, and present in most cells too. It’s also known as Vitamin B8.
- 1 What is Inositol and what’s it for?
- 2 What are its health properties?
- 3 What is its role as a second messenger mechanism?
- 4 Natural sources of Inositol
- 5 Inositol Deficiency, should you be concerned?
- 6 How and when should you take B8?
- 7 In what formats can you find this supplement?
- 8 Does it have any side effects?
- 9 Any contraindications?
What is Inositol and what’s it for?
Within the rich repertoire of nutrients that make up what are known as essential, inositol shares its carbohydrate nature with that of B group vitamins and, in particular, is linked to vitamin B8.
The food most rich in this substance is breast milk – irrefutable proof that the newborn has an innate need for a regular supply of it.
Considered a substance with nutritional activity, various biological effects are attributed to it once it enters the bloodstream, after its absorption by the intestinal tract.
However, unlike the other vitamins, it isn’t essential in adults, given the body’s ability to synthesise it from the glucose molecule.
It has 9 possible presentations, which only differ in the arrangement of some of its atoms. More specifically, we can point to the arrangements of the hydrogen and OH groups around the carbon atoms that make up their ring structure.
Out of all of them, myoinositol stands out as the one that makes up the vast majority. Furthermore, it is closely related to the mammalian nervous system (which includes humans) as well as to a number of other locations.
As for the rest of the isometric isomers (to use their technical name), there are only four that occur spontaneously in nature, the rest being the product of laboratory synthesis. These are: D-inositol, L-inositol, myoinositol and scyloinositol or scyclitol.
What are its health properties?
One of the most important features of inositol metabolism is that the human body has been “programmed” to synthesise inositol. The main tissues in which it is synthesised are the central nervous system, the intestinal mucosa, the kidney and the liver.
Let’s review of the main properties of inositol:
Participates in the organisation of tissues
The existence of inositol is fundamental for the transmission of the nervous impulse and for the synthesis of neurotransmitters.
An extensive catalogue of pathological processes related to the nervous system start from this property, which can be prevented with adequate inositol ingestion and internal synthesis.
Take note of the pathologies you can prevent with a sufficient supply of inositol!
- Bipolar disorder
- Obsessive compulsive disorder
- Agoraphobia, or the fear of open spaces, and claustrophobia, or fear of closed spaces
- Attention deficit hyperactivity disorder (ADHD)
- Anorexia and bulimia
- Quality of sleep, maintenance of a good mood, states of anxiety and stress
Inositol levels in the cerebrospinal fluid (the one that bathes the central nervous system) of individuals suffering from depression (as well as the others also mentioned) have been found to be markedly low. It would seem that it is the dependence between inositol and the synthesis of the neurotransmitter serotonin that’s the factor in triggering depression.
Reduces cholesterol and fat accumulation
It distributes fat throughout the body, eliminating it from places where it accumulates. This helps free the liver from fat accumulation, providing a detox effect.
Performs a lipotropic function in the liver
It plays a key role in the mobilisation of fats, in conjunction with choline. It prevents lipid deposits in the liver and, on the contrary, promotes transport to the tissue cells in need of it.
It intervenes in the stimulation of the smooth muscles of the gastrointestinal tract
It helps to regulate peristalsis and intestinal motility and, accordingly, to cope with constipation.
By virtue of its vitamin status, it’s a necessary partner in the enzymatic activity of a multitude of chemical reactions in metabolism:
- Eyesight, hair and skin.
- Optimal digestion and good condition of the digestive system.
- Regulation in the formation of bone marrow cells essential for blood circulation and the immune system.
What is its role as a second messenger mechanism?
The molecular structure of inositol is designed to move easily between the exterior and interior of cells, being a determining substance in vital functions.
Based on the above, it adopts a mechanism called “second messenger”, the essence of which lies in the intracellular response of the inositol molecule to the presence of a specific hormone. The result? The setting in motion of a chain of biochemical reactions that bring about a precise physiological effect.
In order to organise and structure the cells into tissues and organs, it’s essential to establish a subtle communication network which controls the phenomena of cellular multiplication and coordination of all the activities carried out by the cells.
If we look at the working scheme of any of the multiple communication systems that intervene in the body, the starting signal is always given by a first signal called the “first messenger”, which can be a hormone, a growth factor, or a “releasing” factor from the hypothalamus (a vital gland inserted in the brain), among others.
The first messenger is released to the extracellular medium and mobilised by specific stimuli called tactismsuntil it comes into chemical contact, in the plasma membrane of the cell, with a highly specific membrane receptor that identifies it.
This is the starting point for a series of biochemical phenomena responsible for the vital function of each case, both at the level of the membrane and of the organs contained in the cytoplasm of the cell.
Myoinositol and diacylglycerol
Among the aforementioned receptors, there’s one that deserves special mention and that uses what are known as G proteins, linked to nitrogenous bases called guanines (of which DNA is composed).
Their functions include controlling the release of two new intracellular messengers, the “second messengers”, namely myoinositol and diacylglycerol, which occupy the last link in the communication chain immediately prior to the manifestation of the physiological effect.
What effect does this have
One of the methods it uses involves the regulation of the mineral calcium contained inside cells, when inositol triphosphate is projected onto an organelle in the cell’s cytoplasm, called the endoplasmic reticulum. Well, within this reticulum it facilitates the release of calcium reserves. These reserves, in turn, and in a kind of “domino effect”, activate that of neurotransmitters.
On the other hand, inositol acts as a regulator of osmosis (an innate permeability of the cell lining), which facilitates the movement of water and dissolved elements across the membrane.
The next interesting example of the remarkable changes that inositol promotes in the body is the response to insulin release from the islets of Langerghans in the pancreas, a physiological channel in which its behaviour is that of an insulin sensitising agent.
On top of this, subjects suffering from type 2 diabetes have been shown to see changes in the amount of inositol eliminated through the urine.
What role does it play in the Metabolic Syndrome?
Closely linked to changes in insulin resistance is the so-called metabolic syndrome, in which inositol also plays a key role in preventing some of the disorders that comprise it, such as hyperlipidaemia (high blood fats) or obesity.
But, to what extent is the abundance of inositol necessary in the central nervous system? Well, to the extent that numerous studies that have analysed in detail the role of inositol in different syndromes have resulted in a finding as conclusive that a prolonged deficit in cellular inositol is capable of triggering the appearance of neurological disorders of a certain entity, among which are Alzheimer’s disease and amyloid pathology.
Natural sources of Inositol
Luckily, and for the purpose of enjoying the benefits of inositol, you may be interested to know that there’s a current trend for foods to contain the myoinositol isomer in greater or lesser amounts.
Broadly speaking, we could say that the foods that contain the most inositol are whole grain cereals and citrus fruits (lemon being an exception), with dairy and meat products at the end of the list.
- Raisin (4.70)
- Cantaloupe melon (3.55)
- Orange (3.07)
- Mandarin (1.49)
- Kiwi (1.36)
- Cherry (1.27)
- Nectarine (1.18)
- Mango (1)
- Pear (0.73)
- Peach (0.53)
- Apricot (0.52)
- Watermelon (0.46)
- Avocado (0.46)
- Pineapple (0.33)
- Apple (0.24)
- Swede or Kohlrabi (2.52)
- Aubergine (0.84)
- Brussels sprouts (0.81)
- Cabbage (0.70)
- Asparagus (0.68)
- Spinach (0.66)
- Artichoke (0.6), particularly artichoke hearts
- Pepper (0.57)
- Tomato (0.54)
- Onion (0.27)
- Lettuce (0.16)
- Cucumber (0.15)
- Carrots (0.12)
- Mushrooms (0.09)
- Wheat bran (2.74)
- Whole wheat (1.42) and integral wheat (0.47)
- Oatmeal (0.40)
- Pasta (0.31)
- Brown rice (0.30) and white rice (0.17)
- White bread (0.25)
Meat and its derivatives:
- Beef liver (0.64)
- Minced meat (0.37)
- Egg yolk (0.34)
- Sirloin (0.30)
- Chicken breast (0.30)
- Pork chop (0.42)
Fish and seafood:
- Oysters (0.25)
- Tuna (0.15)
- Sardines (0.12)
- Clams (0.03)
- Whole milk (0.04)
- Yoghurt (0.1)
- White (2.83), red (2.49) and green (1.93) beans
Inositol Deficiency, should you be concerned?
Well, probably. Unfortunately, an inositol deficiency should be of concern to you. It’s capable of greatly worsening your quality of life, and may also be at the origin of many important long-term health disorders.
These are the main problems an inositol deficiency can cause:
- Eye diseases, as the eyes are one of the body’s organs with the highest concentration of inositol. For this reason, a vitamin B8 deficiency could be the cause of night blindness and photophobia (a condition that makes it extremely difficult to bear direct light).
- It intensifies neurological problems in diabetes patients, causing what’s known as diabetic neuropathy.
- It can lead to a relaxation of the smooth muscle fibres of the intestinal wall, responsible for the maintenance of peristalsis, becoming a predisposing factor for constipation.
- Male infertility, because inside the testicles, vitamin B8 contributes to the production of sperm.
- Other nervous system problems. As a vitamin, one of its functions is to act in the enzymatic mechanisms regulating the balance between copper and zinc in neurons. As you might expect, its deficiency causes the breakdown of that equilibrium in which copper is the predominant factor. Such a circumstance could lead to a good number of nervous system problems, such as anxiety, phobias or insomnia.
How and when should you take B8?
The first thing to know in this regard is that a balanced diet ensures the daily requirement of this nutrient is met.
Under the criteria of most specialists, we need around a gram of inositol a day.
Although in principle you should have no problem meeting your daily vitamin B8 requirements if you eat well, the truth is that, in the end, reality dictates, and your lifestyle might not allow you to eat as healthily as you’d like.
Another factor that could also lead to inositol deficiency is having a condition that raises the required levels of dietary supplements.
You need to take Inositol supplements if …
- You follow a poor diet, with hardly any fresh food and an abundance of highly processed foods and additives
- You smoke or are addicted to alcohol or drugs
- You suffer from a disease of the organs in which inositol is synthesised, especially the mucosa of the stomach, liver, kidney and central nervous system
- You suffer from overexertion, anxiety or stress
- You consume too many drinks with caffeine or other stimulants (such as coffee, tea, or cola)
- You’re receiving antibiotics, which are known to hinder its absorption at the intestinal level. There are other drugs that reduce the capacity of inositol because they neutralise vitamins in general, among which contraceptives stand out
- You emit excessive amounts of urine as a result of a diuretic-based medication or by ingesting a lot of water
Check out the recommended daily dose here
- In more aggressive therapeutic approaches, such as with depression, sometimes up to 12 grams a day are needed, which is normally well tolerated
- For the treatment of the aforementioned psychiatric disorders, the prescribed dose is between 10-12 grams per day, for which a water-soluble powder presentation is usually best
If you’re going to start supplementing with inositol, it’s best to start with moderate doses and gradually assess how you feel before increasing them, which should be done gradually.
Don’t make the mistake of taking more than necessary, as this could lead to the typical side effects of inositol supplementation (diarrhoea, nausea and gastrointestinal discomfort).
When to take vitamin B8
If you are looking for a greater buffer against the insulin resistance typical of polycystic ovarian syndrome () experts recommend taking the dose of inositol in a single dose before breakfast.
In what formats can you find this supplement?
Inositol is available in different formats
- In soft capsules or gels, the bioavailability of myoinositol is higher. In contrast to hard capsules, gels are a good alternative if supplementing for the purpose of alleviating mental disorders.
In fact, we’re referring to the option of transforming the 12 g per day required to produce psychopharmacological effects into 4 g of myoinositol.
- As a white or crystalline powder, all you need to do is dissolve it through vigorous mixing in a glass of water or fruit juice.
Two other inositol isomers are also commonly incorporated in supplements, designed to address specific health conditions. These are:
Women who suffer from the aforementioned Polycystic Ovarian Syndrome (PCOS), can opt for two substances: myoinositol and D-chiro inositol.
Some women base their treatment on myoinositol alone at 4 grams per day (it seems that powder may be more advisable than capsules).
If you’re going to go for capsules, you can do so in a mixture with metformin, a drug used primarily for antidiabetic purposes. You can also opt for a combination of myoinositol and D-chiro inositol. This combination, according to the experts, seems to significantly improve both the clinical and metabolic profile of patients.
The synergy of myo and D-chiro inositol is a key factor in the normalisation of hormonal imbalances that occur in the reproductive area, as well as in ovulation and menstrual cycles.
It also significantly reduces the levels of circulating androgens (such as testosterone), responsible for the appearance of excess body hair and acne. It’s also related to polycystic ovary syndrome.
Does it have any side effects?
Taken following the recommended doses, inositol is a safe substance. However, to take an extreme example, a dose of 10 g per kg of body weight of this vitamin could have fatal consequences.
Therefore, with the exception of such deviations, everything indicates that we’re dealing with a well-tolerated substance and that the therapeutic doses contain a wide margin of safety.
This is why the reported side effects associated with the more conventional doses are quite mild and almost entirely confined to digestive discomfort such as diarrhoea, nausea and flatulence.
Although there aren’t too many, there are still a few contraindications in relation to taking vitamin B8.
The following people shouldn’t take inositol…
- Children with hyperactivity disorders
- People suffering from bipolar disorder
Are you pregnant? Then you should check with you doctor about taking inositol, as a state of insulin resistance develops during pregnancy, often leading to gestational type 2 diabetes.
During this period, the aim is to reduce the uptake of circulating glucose in the blood so that the foetus receives the sustained supply of this sugar required for its development.
The treatment of type 2 gestational diabetes requires the use of a hypoglycaemic drug that isn’t toxic to the mother and foetus and that maintains stable blood glucose levels. Well, myoinositol may be that treatment.
So, now you know a bit more about inositol. All that remains is for you to assess the extent to which it can benefit you and decide to try its benefits.
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