The Missing B1 Link: Low Energy and Poor Focus

Vitamin B1 (thiamine) is one of the key vitamins on which the body’s ability to properly produce energy depends.

Its role is not limited to individual functions. Thiamine is involved in fundamental metabolic processes, without which cells cannot function properly. Tissues with high energy demand — the nervous system, brain, and heart — are the most sensitive to its deficiency. Therefore, vitamin B1 deficiency rarely presents in isolation and usually affects multiple systems at once.

A lack of thiamine can present in a way that is mistaken for other conditions. It may resemble infectious processes or detoxification disturbances, as vitamin B1 is critical for the energy supply of these systems.

Such disturbances often appear nonspecific, which is why they are not always linked to thiamine deficiency.

History of Discovery

In the late 19th and early 20th centuries, beriberi was widespread across many regions of Asia and reached epidemic proportions, particularly among soldiers, sailors, and prisoners. In some groups, the incidence was so high that the disease was perceived as an unavoidable part of life under those conditions.

This was a severe condition involving the nervous system and the heart, with patients gradually developing weakness, sensory disturbances, and difficulty walking, while severe cases progressed to pronounced edema and heart failure.

At the same time, the disease did not occur in the context of starvation, but in individuals with adequate nutrition, which long made its nature unclear and misled researchers.

It was later observed that beriberi developed more frequently in populations consuming polished rice and much less often in those eating whole grain, pointing to a link not with the quantity of food, but with its processing.

A key contribution to understanding this process was made by Christiaan Eijkman, a Dutch physician and researcher. His observations showed that chickens fed polished rice lost mobility and developed symptoms resembling beriberi, whereas reintroducing unpolished rice led to recovery.

Initially, the cause was thought to be related to a toxin, but it later became clear that the issue was the absence of a necessary component in the outer layer of the grain.

Despite accumulating evidence, beriberi was long considered an infectious disease, which delayed understanding of its true nature. Only later did it become clear that it was a dietary deficiency.

Within the development of the vitamin concept, including the work of Casimir Funk, this factor was identified and later named thiamine. In 1929, Christiaan Eijkman was awarded the Nobel Prize in Physiology or Medicine for establishing the link between nutrition and the development of this disease.

The Role of Vitamin B1 in the Body

Vitamin B1 is essential for the proper processing of carbohydrates and the production of energy within the cell. After eating, carbohydrates enter the body and go through several transformation steps before they can be used to generate energy. Vitamin B1 participates in key stages of metabolism and enables the conversion of these substances into forms that can be used for energy production.

If thiamine is insufficient, some of these reactions slow down or become blocked. As a result, carbohydrates are not fully utilized, and energy is produced less efficiently, even with normal nutrition.

Under these conditions, some intermediate metabolic products begin to accumulate. One of them is lactate.

Lactate is a substance that forms when carbohydrates are not fully processed. Normally, it may be produced temporarily and then utilized. However, in vitamin B1 deficiency, its levels can increase due to impaired further use of these products in energy metabolism.

The accumulation of lactate is associated with changes in metabolic balance and may be accompanied by fatigue, reduced tolerance to physical activity, and overall decreased well-being.

Vitamin B1 is also involved in processes related to cell protection against damage. Through its role in the pentose phosphate pathway, it contributes to the production of substances that help neutralize metabolic byproducts and maintain cellular balance.

At the organ level, its role is most evident in tissues that require constant and stable energy production.

• In the nervous system, vitamin B1 is necessary for normal function of nerve fibers and signal transmission. Its deficiency may lead to sensory disturbances and weakness;
• In the brain, it supports processes related to memory, attention, and other cognitive functions. Energy deficiency in these structures quickly affects their performance;
• The heart also depends on stable energy metabolism. With vitamin B1 deficiency, its function may be impaired, leading to reduced exercise tolerance and other symptoms.

Nutrients That Work with Vitamin B1

Vitamin B1 does not function in isolation but as part of enzyme systems that require other cofactors and nutrients to operate properly.

• Magnesium - an essential cofactor for thiamine activation. Without it, the vitamin cannot convert into its active form (thiamine pyrophosphate), and its effectiveness is significantly reduced;
• B vitamins - participate in the same metabolic pathways. In particular, B2 and B3 are involved in electron transport in energy-producing reactions, while B6 is linked to neurotransmitter metabolism;
• Alpha-lipoic acid - participates in reactions that work in conjunction with thiamine and are involved in mitochondrial metabolism;
• Protein - required for the synthesis of enzymes in which vitamin B1 participates. When protein intake is insufficient, the efficiency of these processes declines.

When these cofactors are deficient, vitamin B1 may still be present in the body but unable to support normal metabolic processes.

Vitamin B1 Deficiency: Causes, Mechanisms, and Key Features

Vitamin B1 deficiency can occur not only due to insufficient intake. In most cases, it results from a combination of factors: the vitamin may be consumed in inadequate amounts, poorly absorbed, used more rapidly, or not properly utilized at the cellular level.

It is important to distinguish between two conditions:

• Insufficient intake of the vitamin;
• Impaired utilization, where the vitamin is present but cannot be converted into its active form or effectively participate in metabolic processes.

The body’s requirement for thiamine is directly related to carbohydrate intake. The higher the intake, the greater the demand on thiamine-dependent processes. Under these conditions, a relative deficiency may develop — when the vitamin is present but insufficient for current metabolic needs.

Dietary patterns also play a role, particularly diets high in refined foods, which are naturally low in vitamin B1.

• Alcohol - impairs absorption, disrupts utilization, and increases excretion of the vitamin;
• Gut health - inflammation or damage to the intestinal lining reduces thiamine absorption;
• Increased demand - stress, infections, and other conditions raise the body’s need for the vitamin;
• Impaired activation - in the absence of adequate cofactors, the vitamin cannot convert into its active form.

At the cellular level, this leads to reduced efficiency of energy production and accumulation of intermediate metabolic products, reflecting a disruption in metabolic balance.

A key feature of vitamin B1 deficiency is that it often goes unrecognized. Its manifestations are non-specific, and standard laboratory tests do not always reflect not only the level of the vitamin, but also its ability to function within the cell.

What Can Worsen the Condition in B1 Deficiency

When vitamin B1 deficiency is already present, the condition may worsen under the influence of factors that increase the body’s demand for energy or further impair the function of the vitamin.

• Infections — activate the immune system and increase energy demands, intensifying deficiency symptoms;
• Stress — increases metabolic load and raises the need for energy;
• Physical activity — significantly increases energy expenditure and may worsen symptoms;
• High carbohydrate load — increases the number of reactions involving vitamin B1 and may worsen symptoms after meals;

Under these conditions, vitamin B1 deficiency becomes more pronounced and progresses more rapidly.

Symptoms of Deficiency

The manifestations of vitamin B1 deficiency develop gradually and intensify as energy production declines.

General condition:

• Fatigue and low energy;
• Reduced concentration;
• Irritability;

Cognitive functions:

• Impaired memory;
• Difficulty with learning and processing information;
• A sense of “brain fog”;

Nervous system:

• Numbness and tingling;
• Weakness;
• Reduced sensitivity;
• Impaired coordination and gait;

Cardiovascular system:

• Rapid heartbeat;
• Shortness of breath;
• Reduced exercise tolerance;
• In more severe cases — edema;

Gastrointestinal symptoms:

• Loss of appetite;
• Gastrointestinal discomfort.

As the deficiency progresses, symptoms become more pronounced and begin to overlap, affecting multiple systems simultaneously.

Severe consequences

With pronounced or prolonged vitamin B1 deficiency, conditions develop that are associated with profound disruption of energy metabolism and tissue damage.

• “Dry” beriberi - involvement of the nervous system with development of polyneuropathy, weakness, sensory disturbances, and progressive loss of muscle function;
• “Wet” beriberi - involvement of the cardiovascular system with development of heart failure, edema, tachycardia, and hemodynamic disturbances;
• Wernicke encephalopathy - an acute form of central nervous system involvement with impaired coordination, altered consciousness, and oculomotor dysfunction;
• Korsakoff syndrome - a chronic condition with marked impairment of memory and other cognitive functions.

With prolonged deficiency, persistent cognitive impairment may develop, including reduced memory and other brain-related functions.

In some cases, the damage may become irreversible, especially with delayed recognition and lack of timely intervention.

Diagnosis and Testing

Assessing vitamin B1 levels has limitations, as standard laboratory markers do not always reflect its true status in the body.

• Blood thiamine — shows only the current concentration and does not reflect how effectively the vitamin is used inside cells;
• Functional methods — assessment of the activity of thiamine-dependent enzymes is more informative but is used infrequently and is not always available;
• Lactate — an indirect marker of impaired energy metabolism, may be elevated in deficiency but is not specific.

Therefore, diagnosis is often based not only on laboratory tests but also on the clinical picture, the combination of symptoms, and the presence of risk factors.

Forms of Vitamin B1

Vitamin B1 is available in several supplemental forms that differ in absorption and tissue penetration.

Thiamine hydrochloride:

• The most commonly used form;
• Water-soluble;
• Absorption is limited, especially at higher doses;

Thiamine mononitrate:

• A more stable form;
• Commonly used in supplements and fortified foods;
• Similar in effect to hydrochloride;

Benfotiamine:

• A fat-soluble form;
• Better penetration into cells;
• Provides higher levels in tissues;
• More commonly used for symptoms involving the nervous system;

Sulbutiamine:

• A fat-soluble form;
• Penetrates the brain more easily;
• Used when effects on cognitive function are desired;

Cocarboxylase (thiamine pyrophosphate):

• The active form of vitamin B1;
• Does not require conversion in the body;
• More commonly used in injectable forms;
• Primarily used in Eastern Europe and post-Soviet countries;
• May be used in cases of significant deficiency when activation is impaired.

Injections and Intravenous Administration (IV)

Injectable forms of vitamin B1 are used in situations where a rapid increase in vitamin levels is required or when oral absorption is impaired.

Intramuscular and intravenous administration (IV) allow bypassing the gastrointestinal tract and ensure direct delivery of the vitamin into the bloodstream. This is especially important in cases of severe deficiency, neurological symptoms, and conditions associated with impaired absorption.

Intravenous administration (IV) provides the fastest increase in vitamin concentration and is used in severe conditions, including suspected Wernicke syndrome.

Injectable forms of vitamin B1 have been used for a long time, and substantial clinical experience has been accumulated. It is known that high doses may cause reactions, which are associated with the rapid entry of the vitamin into the bloodstream and its interaction with proteins.

For this reason, vitamin B1 is usually not administered as a single large dose. Instead, a series of administrations is typically used, allowing levels to be increased more gradually and safely.

Conclusion

Vitamin B1 is a key element that determines how effectively the body can use carbohydrates to produce energy.

In deficiency, the issue is not a lack of nutrition, but the inability of the body to properly use the energy that is already available. This primarily affects the brain, nervous system, and heart.

Due to nonspecific symptoms and limitations of laboratory diagnostics, vitamin B1 deficiency often goes unnoticed, even in the presence of significant clinical manifestations.

As a result, the condition may progress, affecting multiple systems simultaneously, despite the absence of an obvious cause.