1.5.4.b. Vitamin B1 (Thiamin)

Thiamin

What is the preferred spelling of vitamin B₁?

Anti-beriberi vitamin, aneurin, antineuritic vitamin, and “morale” vitamin

What are the other names for thiamin listed in the text?

Milligrams (mg) or micrograms (µg)

In what units is thiamin measured?

Thiamin pyrophosphate (TPP)

What is the major coenzyme form of thiamin?

Thiamin diphosphate (TDP)

What is another name for thiamin pyrophosphate?

Carbohydrate

Thiamin is primarily required for the metabolism of which macronutrient?

Acts as a coenzyme in carbohydrate metabolism

What major metabolic role does thiamin perform through TPP?

Transketolation reactions

Thiamin diphosphate participates in what type of reaction mentioned in the text?

Appetite, muscle tone, and normal nerve function

Besides metabolism, what general functions does thiamin help maintain?

Gastrointestinal tract

Thiamin is particularly important for maintaining muscle tone in which system?

Yes

Is thiamin stable to dry heat?

Alkalis and sulfites

Which substances readily destroy thiamin?

Acidic medium

What type of environment favors thiamin absorption?

Proximal duodenum

Where is most dietary thiamin absorbed?

It is less alkaline than the lower small intestine

Why is the proximal duodenum favorable for thiamin absorption according to the text?

Liver, brain, heart, and muscles

In which tissues is thiamin concentrated?

No — stores last only a few days

Does the body store large amounts of thiamin?

Excreted in the urine

What happens to excess thiamin?

Carbohydrate

A high intake of which macronutrient increases the need for thiamin?

Fat and protein

Which macronutrients are described as having a thiamin-sparing effect?

Loss of appetite, weakness, gastrointestinal disturbances, poor reflexes, and numbness

What are the early signs of thiamin deficiency?

Constipation, indigestion, and gastric atony

Which gastrointestinal problems may appear early in thiamin deficiency?

Poor reflexes and numbness of the extremities

What neurologic changes may occur early in thiamin deficiency?

They are retarded

What happens to growth and development in thiamin-deficient infants and children?

Polyneuritis

What neurologic condition occurs in later stages of thiamin deficiency?

Beriberi

What classic disease results from severe thiamin deficiency?

Nervous, cardiovascular, and gastrointestinal systems

Which body systems are mainly affected in beriberi?

Wet beriberi and dry beriberi

What are the two major forms of beriberi?

Edema

What is the hallmark feature of wet beriberi?

Lower extremities

Where is edema especially evident in wet beriberi?

Abdominal cavity and chest

In severe wet beriberi, where else may fluid accumulate?

Enlarged heart

What major cardiac change may occur in wet beriberi?

Difficulty breathing

What respiratory symptom may occur in severe wet beriberi?

Dry beriberi has little or no edema

What is the hallmark difference between dry and wet beriberi?

Paresthesia or “pins and needles”

What sensory symptom is characteristic of dry beriberi?

It gradually decreases

What happens to peripheral nerve sensation in dry beriberi?

Weakness may progress to paralysis

What happens to muscle strength as dry beriberi progresses?

They are reduced

What happens to the reflexes of the legs, ankles, and knees in dry beriberi?

Foot drop and wrist drop

What characteristic motor deficits may occur in severe dry beriberi?

They become tender and atrophied

What happens to the muscles in advanced dry beriberi?

2–5 months old

In what age group does infantile beriberi commonly occur according to the text?

Beriberi

Infantile beriberi may occur when an infant is breastfed by a mother with what condition?

Aphonia or loss of voice

What voice-related symptom may occur in infantile beriberi?

Whining cry

What characteristic cry may be heard in infantile beriberi?

Cyanosis

What skin discoloration may occur in infantile beriberi?

Difficulty breathing

What respiratory problem may occur in infantile beriberi?

Wernicke-Korsakoff syndrome

What thiamin-deficiency syndrome is strongly associated with chronic alcoholism?

Memory loss, mental deterioration, and abnormal perception

What cognitive problems characterize Wernicke-Korsakoff syndrome in the text?

Loss of eye control

What ocular neurologic abnormality may occur in Wernicke-Korsakoff syndrome?

No — no known thiamin toxicity is reported in the text

Is thiamin toxicity commonly recognized in humans?

0.7–1.4 mg/1,000 kcal

Approximately how much thiamin is recommended per 1,000 kcal according to the text?

0.5 mg/1,000 kcal

What minimum thiamin need per 1,000 kcal is cited in the text?

Energy intake, sex, body weight, muscular activity, and diet composition

What factors influence thiamin requirements?

Pregnancy and lactation

Which physiologic states increase thiamin requirements?

Hyperthyroidism

Which metabolic condition increases thiamin requirements?

Fever and infections

Which illnesses can increase thiamin requirements?

Alcoholism

Which substance-use condition substantially increases the risk of thiamin deficiency?

1.2 mg/day

What is the Philippine RNI for thiamin in adult men?

1.1 mg/day

What is the Philippine RNI for thiamin in adult women?

1.4 mg/day

What is the Philippine RNI for thiamin during pregnancy?

1.5 mg/day

What is the Philippine RNI for thiamin during breastfeeding?

Lean pork

What is one of the outstanding food sources of thiamin?

Pork liver

Which pork organ is especially rich in thiamin?

Glandular organs

Which other pork foods are outstanding sources of thiamin?

Shellfish

What seafood group is listed among good thiamin sources?

Unpolished rice and whole grains

Which cereal foods are good natural sources of thiamin?

Munggo, kadyos, and soybean

Which legumes are specifically mentioned as good thiamin sources?

Dried yeast, rice bran, and wheat germ

Which concentrated natural sources of thiamin are listed in the text?

Processing removes thiamin, so enrichment restores it

Why are rice and wheat flour commonly enriched with thiamin?

Thiamin (vitamin B₁)

Which B vitamin forms the coenzyme TPP?

Niacin

Which vitamin forms the coenzymes NAD and NADP?

Riboflavin

Which vitamin forms the coenzymes FMN and FAD?

Pantothenic acid

Which vitamin forms CoA?

Vitamin B₆

Which vitamin forms the coenzyme PLP?

Folate

Which vitamin forms the coenzyme THF?

Vitamin B₁₂ (cobalamin)

Which vitamin is represented as B₁₂ in metabolic pathways?

Biotin

Which B vitamin functions as a coenzyme in carboxylation reactions and is shown in fat metabolism?

TPP

Which B-vitamin coenzyme is directly associated with pyruvate metabolism in the figure?

NAD, FAD, and FMN

Which B-vitamin-derived coenzymes are central to electron transport and energy production?