In the practice where I work, two dietary supplements containing B vitamins are the most popular. I give them to almost everyone who tells me that they drink alcohol regularly, or to those who I suspect of doing so. And anyone who has just stopped drinking still gets them. Why am I so pedantic? The following situation recently occurred during my office hours. An elderly gentleman complains of increasing difficulty walking. He can hardly keep his balance, reports numbness in his hands and feet. He is particularly afraid of falling in the dark and when climbing stairs. When I ask him if he drinks alcohol, he replies: ‘Yes, but not much. Two or three glasses of red wine in the evening. Rarely more.’ ‘Every evening?’ ‘Yes, more or less.’ ‘And for how long?’ ‘For years, it's just how it is. But that's not so bad, is it?’ The neurological examination confirms my suspicions. The man is suffering from polyneuropathy. This disease causes nerve damage, usually in the hands and feet. The most common causes are diabetes or regular alcohol consumption. The disease usually develops gradually over a long period of time. Those affected complain of paraesthesia in their hands and feet, weakness and pain, as well as balance disorders. In the advanced stages, the disease can have a massive impact on quality of life. This is not an isolated case. Incidentally, the man's liver values were in the green range. His doctor never mentioned his alcohol consumption. I explain to the astonished man that the red wine is probably the cause of his complaints. But how does it come about?

Alcohol is a nutrient robber

Alcohol is a nutrient robber. In addition to the known risks such as liver damage and an increased risk of numerous diseases, regular alcohol consumption also has a profound effect on the nutrient supply of the human body. In particular, the supply of B vitamins and essential minerals is affected. In the following, I would like to explain why I use the term ‘nutrient robber’ in the context of alcohol and what consequences a deficiency caused by it can have, especially for the nervous system and mental health.

Alcohol has a negative influence on the absorption and metabolism of numerous nutrients. Alcohol breakdown puts a great deal of strain on the liver and requires a large number of micronutrients. Furthermore, alcohol consumption leads to increased excretion of nutrients via the kidneys, which hinders their utilisation in the stomach and intestines. In particular, the B vitamins (B1, B6, B12 and folic acid), magnesium, zinc and potassium are affected.

The influence on B vitamins and minerals

B vitamins are essential for the functioning of our nervous system, energy metabolism and blood formation. A deficiency can lead to fatigue, poor concentration and irritability. In particular, vitamins B1 (thiamine), B6 (pyridoxine) and B12 (cobalamin) are crucial for the functionality of the nervous system.

Vitamin B1 (thiamine)

A thiamine deficiency is a frequently observed consequence of chronic alcohol consumption. Thiamine plays a central role in energy metabolism and is essential for the functioning of the nervous system. A deficiency can lead to a variety of neurological symptoms, including coordination problems, muscle weakness and memory disorders. An especially severe form of thiamine deficiency is Wernicke-Korsakoff syndrome, which is associated with severe memory loss and confusion.

Vitamin B6 (pyridoxine)

Vitamin B6 is involved in the synthesis of neurotransmitters (messenger substances), including serotonin and dopamine, which play an important role in mood and well-being. A vitamin B6 deficiency can lead to irritability, depression and weakness. Consuming alcohol reduces the absorption and utilisation of vitamin B6 in the body.

Vitamin B12 and folic acid

A vitamin B12 (cobalamin) deficiency can lead to nerve damage characterised by numbness, tingling in the limbs and muscle weakness. Folic acid (vitamin B9) is important for cell growth and DNA formation. A folic acid deficiency increases the risk of cardiovascular disease and depression and weakens the immune system. In addition, vitamin B12 and folic acid are essential for blood formation. A vitamin B12 and/or folic acid deficiency can cause anaemia, which causes tiredness and weakness.

Minerals

Magnesium, zinc and potassium are essential for numerous biochemical processes. Magnesium, for example, is involved in the transmission of stimuli and muscle contraction, while zinc is essential for cell division and the functioning of our immune system. Consuming alcoholic beverages can affect the storage and excretion of these minerals, which in turn can cause muscle cramps, a weakened immune system and a deterioration in mental performance.

How much is too much?

The amount of alcohol above which a harmful effect can be expected depends on various factors. These include gender, body weight and genetic disposition. The FOPH states that a maximum daily alcohol intake of around 20 g for men and 10 g for women is a guideline for low-risk consumption, with at least two alcohol-free days per week. However, studies show that even these amounts over long periods of time can contribute to nutrient deficiencies and the resulting health damage.

A study by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) shows that regular consumption of one to two standard drinks per day over several years significantly increases the risk of a deficiency in B vitamins and minerals. There is a particularly strong correlation between alcohol consumption and a deficiency in vitamin B1, B6 and magnesium, which has a negative effect on the nervous system.

Effects on the peripheral and central nervous system

The nervous system is particularly sensitive to the consequences of a nutrient deficiency caused by alcohol consumption. In particular, the peripheral nervous system, which connects the brain to the body, suffers from vitamin deficiency. Symptoms such as tingling, numbness or pain in the extremities may occur. This condition is known as peripheral neuropathy. In addition to alcohol, there are other triggers such as diabetes or certain medications. However, it is often a consequence of alcohol consumption.

The central nervous system (CNS) is also affected. Regular alcohol consumption can lead to a reduction in brain volume, which can exacerbate memory problems and cognitive impairment. The combination of reduced brain mass and a lack of nutrients such as vitamin B1 increases the risk of neurodegenerative diseases.

Depression and mood swings

Studies show that a deficiency of B vitamins and minerals increases the risk of depression and mood swings. For example, vitamin B6 and folic acid are known to be involved in the formation of serotonin and dopamine – neurotransmitters that are crucial for emotional well-being and mood regulation. A deficiency can therefore trigger or intensify depressive symptoms.

Vitamin B12 deficiency is also associated with mood swings and depression. One study showed that individuals with vitamin B12 deficiency suffer from anxiety and depression more often (Tiemeier et. al. 2002). This is especially true for individuals who consume alcohol regularly and thus have an increased risk of vitamin B12 deficiency.

Prevention and treatment of alcohol-related nutrient deficiencies

The long-term consequences of alcohol-related nutrient deficiencies can be severe and affect not only the nervous system but also mental health and general physical performance. To avoid these risks, it is advisable to keep alcohol consumption to a minimum, avoid drinking regularly and ensure you have a balanced diet that is rich in B vitamins and minerals . For those who drink alcohol regularly, I recommend taking a dietary supplement with a vitamin B complex.