Which of the following is a sign of thiamine deficiency?

Thiamine deficiency, also known as vitamin B1 deficiency, is primarily associated with specific neurological and cardiovascular symptoms. One of the most well-recognized signs of thiamine deficiency is peripheral neuropathy, which manifests as weakness, numbness, and pain in the extremities due to nerve damage. This occurs because thiamine plays a crucial role in energy metabolism, particularly in nerve tissues, and its deficiency can lead to impaired nerve function.

Other conditions related to thiamine deficiency include Wernicke's encephalopathy and beriberi, both of which have significant neurological implications. In the case of peripheral neuropathy, patients may experience difficulty with coordination and movement, alongside other sensory issues, highlighting the impact of thiamine on the nervous system.

Gray-brown spots on the teeth and thyroid enlargement are not classic signs of thiamine deficiency. The former is more associated with dental issues, potentially linked to metabolic or nutritional deficiencies, while thyroid enlargement typically relates to iodine deficiency or other thyroid-related disorders. Therefore, the choice identifying peripheral neuropathy effectively represents a clear indicator of thiamine deficiency.