Vitamin B1, also known as thiamin, is
essential for the transmission of certain types of nerve signals between the
brain and the spinal cord. It is also crucial for the workings of particular
types of enzymes that make energy available in the body. Body stores are
relatively small and so regular intakes are vital.
Vitamin C and citric acid, found in oranges and other citrus fruits, may
help to prevent thiamin destruction, while B vitamins tend to work together
to enhance one another's absorption.
Long-term intakes of antacids reduce B1 levels in the body, as do high
intakes of alcohol. Caffeic acids in coffee, tannic acids in tea, and
sulphur dioxide used in the drying of fruit adversely affects vitamin B1
absorption and destroy thiamin. Eating sushi regularly may reduce absorption
as raw fish contains thiamin-breaking enzymes.
The adult RDA for thiamin (1.4mg a day) is
equivalent to one bowl of fortified breakfast cereal.
Large single doses of thiamin are poorly absorbed by the body, so it is best
to have 100 per cent of the RDA on a regular basis. No long- or short-term
effects have been established in adults taking up to 100mg supplements a
day. Optimum nutritionists recommend 3.5-9.2mg per day to maintain health,
and 25-100mg a day for therapeutic use.
Taking vitamin B1 supplements together with vitamins B2 and B6 appears to
help B1 to work more effectively in the body.
Intakes greater than 50mg per kilogram of body-weight, or 3g per day have
been shown to be toxic. Such levels have led to symptoms such as a rapid
pulse, inability to sleep, general weakness, headaches, and irritability.
Too much thiamin may lead to the loss of other B vitamins from the body.
Full-blown thiamin deficiency, known as
beriberi, is unusual in western countries. Alcoholism is a main cause of
thiamin deficiency but a stressful life, physically active people, and those
over 55 may benefit from taking supplements. B1 deficiency may trigger these
Thiamin is necessary for the glucose in the blood to produce a substance
called acetylcholine, which transmits messages between nerves and is
crucial for the memory and for concentration levels. It has been suggested
that eating a breakfast that includes both carbohydrate, which increases
blood glucose levels, and thiamin, which facilitates acetylcholine
production, may lead to improved memory functioning in the morning ahead.
cravings A mild deficiency of thiamin may lead to sugar cravings,
which could be improved through a modest intake of the supplement.
New studies have shown that thiamin supplements might be helpful for
preventing and slowing Alzheimer's disease - essentially a disease of
ageing - which is characterized by forgetfulness.
Doctors may prescribe thiamin supplements to treat a range of disorders of
the nervous system, such as the disease multiple sclerosis, Bell's palsy,
RDA for adults
Top sources of Vitamin B1 mg/100g of food