Describe the 3 types of Beriberi

1. Describe the 3 types of Beriberi.
2. Explain the relationship between B1 and membrane and nerve conduction?

Beriberi is a chronic condition of thiamine deficiency, for which there are 2 main types: Wet Beriberi and Dry Beriberi. The Wet form is so names are it affects the cardiovascular system and causes swelling of legs along with shortness of breath and tachycardia. The Dry form impacts the nervous system and causes a neuropathy due to damage of the peripheral nerves. A lesser known 3rd form is Acute beriberi seen mostly in infants and results in cardiomegaly, arrhythmia, lactic acidosis, and failure to thrive. (1)

Major clinical signs of beriberi include (3):

• Hyporeflexia
• Hypesthesia (a diminished capacity for physical sensation, especially of the skin.)
• Edema
• Lowered diastolic blood pressure
• Tenderness of calf muscles when grasped

Thiamine “is an incredibly active molecule” and play prominent roles in many aspects of cellular metabolism which is vital to many forms of life (3). One key factor is thiamine’s pyrophosphate ester, thiamine diphosphate (TPP) which is a cofactor for enzymatic reactions that cleave alpha-keto acids:

“TTP activates decarboxylation of pyruvate in the pyruvate dehydrogenase complex. This complex is a group of enzymes and cofactors that form acetyl CoA that condenses with oxaloacetate to form citrate, the first component of the citric acid cycle. Since pyruvate is derived from glucose via the Embden–Meyerhof pathway, it should be emphasized that the energy drive from oxidation of glucose is highly dependent upon TPP. It is also a cofactor in the decarboxylating component of alpha-ketoglutarate dehydrogenase, an important link in the citric acid cycle.”

One key point is that a diet high in simple carbohydrates (glucose) “automatically” requires an increased need for thiamine! (3). Therefore, it follows that a modern diet high in “sugar” but low in nutrient dense foods may cause berierbi symptoms. In this article "It is very likely that many of the poorly understood symptomatology seen today that responds to nutrient therapy is caused by a mixture of marginal classic nutritional diseases, including beriberi, pellagra and scurvy. In our experience it is certainly true that symptoms arising from autonomic dysfunction are usually reversible by nutritional therapy." (3)

As far as the nerves and membranes: thiamine is important for the nerve action potential allowing for proper conductance of nerve signals, especially at the synapse where it is also involved in production of acetylcholine (the neurotransmitter that mediates nerve transmission across the synapse) (2). Also, thiamine appears to be involved in nerve tissue repair (2).

Sources:

1/ Hammond, N., Wang, Y., Dimachkie, M.M., Barohn, R.J., 2013. Nutritional Neuropathies. Neurologic Clinics 31, 477–489. https://doi.org/10.1016/j.ncl.2013.02.002 (Links to an external site.)Links to an external site.

2/ Manzetti, S., Zhang, J., van der Spoel, D., 2014. Thiamin Function, Metabolism, Uptake, and Transport. Biochemistry 53, 821–835. https://doi.org/10.1021/bi401618y (Links to an external site.)Links to an external site.

3/ Lonsdale, D., 2006. A review of the biochemistry, metabolism and clinical benefits of thiamin(e) and its derivatives. Evid Based Complement Alternat Med 3, 49–59. https://doi.org/10.1093/ecam/nek009 (Links to an external site.)Links to an external site.

Edited by Mason Gasper on Dec 5 at 6:07pm