Vitamins: Vitamin B1 - Thiamine

Question 1

Vitamin B1 – Thiamine
What is the active form?
What is conversion dependant on and impaired by?

Answer 1

Vitamin B1 (Thiamine) functions in the body as the active form ‘thiamine pyrophosphate’ (TPP); conversion to this enzyme is dependent upon magnesium, and impaired by alcohol.

Question 2

How long is B1 stored in the body?

Answer 2

 Bodily stores of B1 last for approximately one month

Question 3

How does Food prep affect B1?

Answer 3

 B1 content is very easily reduced by processing including milling, chopping, canning, adding sulphites (e.g. dried fruit), baking soda.
 Boiling or freezing reduces B1 content by 50%
 Toasting bread reduces B1 by 30%

Question 4

Food sources

Answer 4

Fresh, raw sources are best
 Yeast extract
 Peas
 Oranges
 Nuts (E.g. Macadamia)
 Pulses
 Sunflower seeds
 Whole grains
 Meat
 Fish

Question 5

Energy (ATP) Production: function and therapeutic uses

Answer 5

 Functions:
o Crucial for carbohydrate, as well as fat and protein metabolism
o Needed to the formation of Acetyl-CoA (key for ATP production)

 Therapeutic uses:
o Fatigue
o Supporting energy production in increased need (e.g. pregnancy, heart failure)
o Fertility

Question 6

Nervous system functioning: function and therapeutic uses

Answer 6

 Functions:
o Acetyl-CoA is an important precursor of acetylcholine =
o The amino acids that are metabolized by thiamine can be used to create neurotransmitters e.g. GABA

 Therapeutic uses:
o Cognitive decline and memory loss
o Alzheimer’s
o Low mood
o Parkinson
o Nerve repair

Question 7

Dietary requirements- which food causes extra requirement for B1?
How much B1 is recommended?

Answer 7

 The more carbohydrate you eat, the more B1 you need (i.e. to create ATP from it). An average of 0.4 - 0.5 mg/1000 kcal is recommended

Question 8

What is absorption Impaired by?

Answer 8

Absorption is impaired by:
 Alcohol
 Tea (Tannins)
 Coffee
 The oral contraceptive pill (OCP)
 Stress
 Antacids

Question 9

Deficiency (Beriberi)

Answer 9

 Beriberi is the primary deficiency disease. Most forms are rare in the west. A white rice diet is thiamine depleted (these are at risk)
 Alcoholics are particularly prone to deficiency – ‘cerebral beriberi’ (Wernicke-Korsakoff syndrome) is most common western cause

Question 10

Subclinical deficiency symptoms

Answer 10

Symptoms of subclinical deficiency:
 Depression
 Irritability
 Fatigue
 Memory loss
 Muscle weakness and cramps
 GIT disturbance
Be aware that elderly people are frequently more depleted of thiamine and can benefit from it

Question 11

Toxicity

Answer 11

Only seen in supplementation (i.e. 5 g daily), but is rare

Question 12

Synergistic

Answer 12

Like the antioxidants, B vitamins generally work synergistically and are often found together in nature.

Question 13

B1 thiamine functions

Answer 13

Energy (ATP) production
Nervous system functioning