Vitamin B1 is a water-soluble vitamin also referred to as thiamine. It is part of the B complex group and essential for normal metabolism, cardiovascular and nervous system health.
Why you may need vitamin B1
Cataracts – a high dietary intake of thiamine is associated with a reduced risk of cataracts.
Mouth ulcers – low blood levels have been found in people with recurrent mouth ulcers.
Insect repellent – vitamin B1 is a popular natural insect repellent. Many people report benefits but no actual research can confirm this handy use.
How much do you need?
Recommended Daily Intake (RDI)
Adults (over 19 years): 1.1mg (women)m 1.2mg (men) daily
Pregnancy: 1.4mg daily
Breastfeeding: 1.4mg daily
Children 9-13 years: 0.9mg daily
Children 14-18 years: 1.1mg (girls), 1.2mg (boys) daily
Symptoms of deficiency
A deficiency or abundance of a single B vitamin may cause problems in the metabolism of other B group vitamins. Dermatitis, swollen cracked bright red lips (especially the corners) and inflamed tongue are common for general B vitamin deficiency.
Beriberi is a condition directly linked to vitamin B1 deficiency. It was first observed in Asia when they developed a custom of polishing rice (removing the rice hulls, rich in vitamin B1). Since this was the main part of their diet, beriberi spread very fast. Initially medical researchers thought that beriberi was caused by a pathogen but soon realised that diets lacking in vitamin B1 was the cause.
There are two major types of beriberi: wet beriberi and dry beriberi (Wernicke-Korsakoff syndrome). Dry beriberi mainly affects the nervous system and includes the following symptoms: pain, numbness, tingling, peripheral neuropathy, muscle wasting, and paralysis of the lower extremities, brain damage and death. Wet beriberi mainly affects the cardiovascular system with the following symptoms: swelling, increased heart rate, enlarged heart, lung congestion, cough and congestive heart failure.
Many of our foods are enriched with vitamin B1 to help achieve adequate intake of vitamin B1. Beriberi is mainly seen in alcoholics because excessive alcohol can reduce the absorption of vitamin B1. They develop Wernicke-Korsakoff syndrome, which affects language, memory, cognition and walking.
The best dietary sources of vitamin B1 include: brewer’s yeast, pork chops, sunflower seeds, wheat germ, green peas, green beans, oysters and oatmeal.
Other reasons why you may need more
There are some conditions that increase the demand for vitamin B1 – these include malabsorption conditions such as alcoholism, cirrhosis, and gastrointestinal (GI) diseases such as coeliac disease. In addition, a rare condition known as genetic beriberi affects the absorption of vitamin B1.
Stress and smoking will also increase your demand of vitamin B1.
Vitamin B1 is required for carbohydrate metabolism, so if you find yourself eating a carbohydrate rich diet, keep in mind that vitamin B1 requirements are increased. Coffee, tea and raw fish (sushi / sashimi) can interfere with the absorption of vitamin B1. Raw fish and shellfish contain ‘thiaminase enzymes’ which destroy vitamin B1. Lucky for fish lovers the enzymes are destroyed by cooking.
Vitamin B1 is unstable above pH 7 (alkaline). Sodium bicarbonate, which has an alkaline pH is sometimes added to green vegetables to retain the rich bright green colour. This can destroy any vitamin B1 present. It is also destroyed by heat and in processed foods. You are safe with freezing – it does not affect vitamin B1.
- Orally, thiamine is usually well tolerated.
- Always consult your healthcare professional during pregnancy and while breastfeeding.