Sana Hospital Group 19 May 2021

In continuation of our series on Neurological Diseases, here is the next segment on Neurological Diseases caused by Malnutrition.

 This segment covers:

  • Beri-Beri
  • Wernicke Encephalopathy
  • Korsakoff’s Syndrome
  • Pellagra
  • Neuropathy by Nutrient Deficiency

Neurological Diseases Caused Specifically by Malnutrition

The entire body requires adequate nutrients to maintain functions at the cellular level. Malnutrition, therefore, increases the risk of acquiring any disease, and particularly with regard to the nervous system. As of 2008, nearly 800 million people worldwide were found to not have enough to eat[1]. Many more individuals are affected by pre-existing health conditions and medications that hamper nutrient absorption, resulting in malnutrition[2].

A few of the most well-known neurological conditions associated with malnutrition are discussed, followed by generalized neuropathies caused by nutritional deficiencies. B vitamins are common culprits as they are required for many chemical reactions at the cellular level, especially those pertaining to energy production and cellular respiration.

NOTE: All deficiencies discussed in this section are severe and are not to be confused with temporary or mild states of nutritional deficiency (e.g. symptoms of short-term fasting or mild dehydration).


Beri-Beri was the first nutritional deficiency syndrome diagnosed in patients. It is caused by severe thiamine (vitamin B1) deficiency. Initial symptoms include fatigue, muscle cramps and irritability.

There are two types of Beri-Beri: wet and dry.[3]

In wet Beri-Beri, cardiovascular symptoms are evident, including:

  • Shortness of breath during physical activity or upon waking
  • Arrhythmia
  • Increased heart rate
  • Swelling of the lower legs

Dry Beri-Beri affects the nervous system more and includes the following symptoms:

  • Pain
  • Confusion and speech difficulties
  • Reduced cognition
  • Less muscle function, especially in the lower legs
  • Involuntary eye movements
  • Numbness or tingling in the extremities
  • Nausea and vomiting
  • Paralysis

In some cases, Beri-Beri can cause Wernicke Encephalopathy, Korsakoff’s Syndrome or a combination (Wernicke- Korsakoff Syndrome).

Wernicke Encephalopathy

Wernicke Encephalopathy refers to a health condition brought about by severe thiamine deficiency which is often a result of malnutrition, infection, alcoholism or liver disease. The condition results in lesions in the thalamus, including the hypothalamus, as well as the midbrain and cerebellum. [4] Wernicke Encephalopathy is generally brought on suddenly and often reversible if treatment is not delayed for a prolonged period of time. If left untreated, Wernicke encephalopathy may develop into Korsakoff’s syndrome.

Symptoms include:

  • Ataxia, especially cerebellar ataxia
  • Muscle movement and coordination difficulties
  • Reduced cognition
  • Involuntary eye movements and muscle spasms
  • Hyperthermia (very high body temperature)
  • Disorientation and sensory confusion
  • Hypotension

Severe manifestations may result in an inability to walk, decreased levels of consciousness, coma and death.

Korsakoff’s Syndrome

Korsakoff’s Syndrome is a neurological condition similar to dementia in which the patient suffers damage to multiple areas of the brain that coordinate memory and recall.

It is often conflated with Wernicke Encephalopathy as it falls on the same spectrum of thiamine deficiency disorders; however, it is a chronic syndrome that is generally regarded as irreversible and tends to affect different brain areas. Brain areas affected include the thalamus, corpus callosum, midbrain and brain stem, the cerebellum and the mammalian portions of the cortex such as the hippocampus and limbic regions. The entire cerebral cortex shows less energy metabolism which may contribute significantly to cognition.[5]

Symptoms include:

  • Dementia and cognitive impairments
  • Severe forgetfulness or amnesia
  • Confusion
  • Disorientation
  • Sleeping difficulties
  • Any symptoms of Wernicke Encephalopathy


Pellagra is not a neuropathy, per se, but may result in dementia if left untreated. It is a clinical syndrome ascribed to severe Vitamin B3 (niacin) deficiency. Aside from dementia, it results in dry skin that is inflamed (dermatitis) and very light sensitive. Diarrhea and ulcers or sores in the mouth are also common symptoms.

Other symptoms include:

  • Apathy
  • Inability to focus
  • Irritability
  • Depression

Severe manifestations can cause a coma.

Most patients with niacin deficiency develop neuropathies when deficient in other nutrients.

Neuropathy by Nutrient Deficiency

Aside from the well-studied deficiency syndromes described above, the following deficiencies can result in neurological symptoms as well:

  • Cobalamin (Vitamin B12) deficiency commonly results in many neurological conditions such as myeloneuropathy or subacute combined degeneration. It is required for myelin sheath formation and severe deficiency can result in demyelination as well as eventual neurologic disability. Peripheral nerves are commonly affected, which results in peripheral pain, numbness, tingling and other neurological symptoms. The ocular nerve is also a common site that B12 deficiency affects, resulting in visual issues and eye movement problems.[6]
  • Copper deficiency causes a very similar set of symptoms to Cobalamin deficiency and the two are often co-arising. Other symptoms that may be present in a severely copper deficient person are bladder dysfunction, hyper reflexes, and ataxia. Zinc in excess may cause a copper deficiency.[7]
  • Pyroxidine (Vitamin B6) deficiency is a lot rarer than toxicity and both can cause neuropathy. In infants, it may cause seizures. In adults, it causes pain, burning, numbness and tingling in the feet that spreads over time to the hands. Reduced sensation and reflexivity, ataxia and mild weakness are also common symptoms.
  • Vitamin E deficiency is not very common, but may cause ataxia (loss of movement and coordination), lowered reflex responsiveness, bad posturing and reduced sensory perceptions. Muscle weakness and involuntary movements especially eye movements may be present. Degeneration and eventual loss of myelinated axons may result, leading to neurologic disabilities. It may take 5-10 years for vitamin E deficiency to manifest clinical symptoms as it is found abundantly in body fat.
  • Magnesium deficiency is a very common deficiency, with severe forms contributing towards stroke, seizures, migraine[8], and potential dementia.[9]
  • Vitamin A deficiency can affect the neurologic functioning of the eyes and result in night blindness.
  • Folate (Vitamin B9) deficiency may contribute towards stroke, dementia, visual disturbances, depression and reduced cognition. B9 is required for optimal B12 metabolism and may contribute towards B12 deficiency as well as the resultant neuropathy.[10]

Risk Factors

Risk factors for malnutrition or nutritional deficiencies include[11]:

  • Non-nutritious or extremely restrictive diets
  • Chemical exposure
  • Acute toxicity, such as alcohol poisoning or heavy metal toxicity
  • Metabolic diseases and eating disorders
  • Certain pharmaceutical drugs that block nutrient absorption
  • Bariatric surgery
  • Muscle wasting syndromes, such as seen in AIDS and cancer
  • Anemia
  • Aging and age-related changes with nutrient absorption
  • Diarrhea, vomiting or constipation
  • Being unable to swallow properly[12]

Pre-existing malnutrition that creates or contributes towards a neurological condition may cause difficulties in nutrient absorption, thus further exacerbating the issue.

Treatment Options

It can be exceedingly difficult to treat nutritional deficiencies, particularly since it is far more common that multiple deficiencies contribute towards a state of disease. In cases where an underlying condition is diagnosable and treatable, treating the condition may reverse the deficiency without much need for nutritional intervention.

If a severe nutritional deficiency can be diagnosed as causing a health condition, increasing dietary nutrition is recommended and nutritional supplementation may be prescribed. In the case of alcoholism, rehabilitation may be required to reverse the condition. If the condition is very severe, nutrients may need to be infused in a saline drip or injection for the patient. For example, thiamine infusions are a common treatment for severe Beri-Beri.

B vitamins and magnesium are commonly prescribed to patients with neurological conditions that are associated with deficiencies in each nutrient. In many cases, dosages are not currently well understood for nutritional deficiency disorders and more research is still required to perfect treatment protocols.

About the Author:

Sana Hospital Group is one of the largest independent healthcare providers in Germany. With over 50 world-class hospitals and more than 2 million patients yearly, Sana operates leading facilities, among them university hospitals, tertiary care centers, and specialized hospitals to deliver a broad portfolio of top-tier medical care. Whether it is preventive health care, an acute or chronic illness, a planned procedure, or a long-term diagnosis - more than 600 chief physicians, 4,500 medical professionals, and 11,000 nursing staff provide excellent treatment options, world-class medicine, and the best possible medical care.


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