Vitamins are the organic compounds required in the diet in small amounts to perform specific biological functions for normal maintenance of optimum growth and health of the organism. Vitamins are classified into two groups depending on their solubility in water or fat. Vitamins which are soluble in fat and oils but insoluble in water are fat-soluble vitamins. Fat-soluble vitamins are vitamins A, D, E and K. Fat-soluble vitamins are stored in the liver and adipose tissues. Vitamins of B group and vitamin C are soluble in water and are known as water-soluble vitamins. Water-soluble vitamins must be supplied regularly in the diet because they are readily excreted in urine and cannot be stored (except vitamin B₁₂) in our body. Plants can synthesize all vitamins whereas only a few vitamins like vitamin K, vitamin A from carotene, and some members of the vitamin B complex are synthesized in the human body. Vitamins catalyze biological reactions in very low concentrations. Multiple deficiencies caused by a lack of more than one vitamin are called avitaminosis.

Which of the following vitamins is responsible for causing beriberi?

Vitamin B₁

The correct answer is option 2. Vitamin \(B_1\).

Beriberi is caused by a deficiency in vitamin \(B_1\), also known as thiamine. Thiamine is an essential nutrient that plays a critical role in carbohydrate metabolism and the function of the nervous system, muscles, and heart.

There are two main types of beriberi:

1. Dry beriberi: This form primarily affects the nervous system and can lead to symptoms such as:

Nerve degeneration

Muscle weakness and wasting

Difficulty walking

Loss of reflexes in the knees and feet

2. Wet beriberi: This form primarily affects the cardiovascular system and can lead to symptoms such as:

Swelling of the lower legs

Increased heart rate

Shortness of breath

Congestive heart failure

Thiamine deficiency can occur due to poor diet, malabsorption, chronic alcoholism, or certain medical conditions that impair thiamine uptake or utilization. Ensuring an adequate intake of thiamine-rich foods, such as whole grains, legumes, nuts, and seeds, can help prevent beriberi. In cases where dietary intake is insufficient, thiamine supplements may be necessary.