Vitamin B1 - Thiamine
Vitamin B1 is a water soluble vitamin found in many foods including yeast, cereal grains, beans, nuts, and meat. It is often used in combination with other B vitamins. It's often found in many vitamin B complex products and multivitamins.
The body needs vitamin B1 to convert carbohydrates into glucose, the main source of energy in the body. As vitamin B1 is an essential co-factor in carbohydrate metabolism, low levels are thought to have an impact on glucose control in the body.
People take B1 for maintaining brain health, enhancing learning abilities, increasing energy, combating stress, preventing memory loss and Alzheimer's disease. Deficiency in B1 is very serious. Beriberi is a disease caused by a vitamin B1 deficiency (Wet beriberi affects the heart and circulatory system. In extreme cases, wet beriberi can cause heart failure. Dry beriberi damages the nerves and can lead to decreased muscle strength and eventually, muscle paralysis).
The RDA for vitamin B1 is 1.2mg for men and 1.1mg for women.
Diabetes and vitamin B1
B1 levels are lower in diabetics in part because the elevated blood sugar causes increased B1 excretion by the kidney many times higher than normal (type 1 diabetics 25x, type 2 diabetics x16). This leads to an acute deficiency of B1. If you are pre-diabetic, as many people are, you will experience elevated excretion of B1. This can lead to kidney failure and heart disease. Benfotiamine is a synthetic fat soluble version of vitamin B1 that is very beneficial with diabetics or people who suffer from Peripheral Nerve Function (tingling fingers etc). These symptoms are referred to as paresthesia of the fingers. Peripheral neuropathy is damage to the nerves of the extremities that often results in numbness or tingling. Diabetes is one of the major causes of peripheral neuropathy. Alcohol abuse is another cause of peripheral neuropathy. Dr Mercola does a super B complex supplement with benfotiamine.
Low vitamin B1 + diabetes + high blood sugar = disaster
Vitamin B1 deficiency can occur as a result of:
- Inadequate intake.
- Increased requirements due to fever.
- Increased requirements due to pregnancy or breast feeding).
- Excessive renal loss.
- Consumption of anti-B1 factors (tea, coffee, raw shellfish).
- Gastrointestinal diseases that cause B1 malabsorption.
Vitamin B1 supplementation
Supplementation is very safe, even at high doses. This may compensate for poor absorption or a high rate of excretion.
- B1 supplements are typically in large dose quantities.
- B complex supplements contain all the B vitamins. Typically in large dose quantities.
- Multi-vitamins: centrum for men contains 4.6mg.
- Benfotiamine is a synthetic fat soluble version of vitamin B1. It is though to be very beneficial with diabetics or people who suffer from Peripheral Nerve Function (tingling fingers etc). Dr Mercola does a super B complex supplement with benfotiamine.
Vitamin B1 Testing
About 80% of the approximately 25–30mg of thiamin in the adult human body is in the form of thiamin diphosphate (TDP). TDP serves as an essential cofactor for five enzymes involved in glucose, amino acid, and lipid metabolism. Levels of B1 in the blood are not reliable indicators of B1 status. Vitamin B1 status is often measured indirectly via the activity of the transketolase enzyme, which depends on TDP. The result, is known as the “TDP effect”. Another commonly used measure of B1 status is urine excretion, which provides data on dietary intakes but not tissue stores. For adults, excretion of less than 100 mcg/day thiamin in urine suggests insufficient thiamin intake, and less than 40 mcg/day indicates an extremely low intake.
How much vitamin B1 do I need?
The RDA for vitamin B1 is 1.2mg for men and 1.1mg for women. But in reality, way more is needed due to excretion issues. However, vitamin B1's main use is in the metabolism of glucose and this RDA is based on calorific intake. So if you are very active (or just eat and drink a lot!) you will require more B1. The other issue with the RDA is that of excretion, with diabetics urinating out many times the normal amount.
Vitamin B1 Foods
Nutritional yeast (1tbsp): 5.0mg
Sunflower seeds (1/2 cup): 2mg
Marmite (1tsp): 0.5mg (New Zealand marmite has double)
Macademia nuts (50g): 0.6mg
Fortified cereal: 1.5mg
White enriched rice (1/2 cup): 1.4mg
Bacon (3 rashers): 0.5mcg
Pork (100g): 0.5-1.2mg
Trout (100g): 0.5mg
Black beans (½ cup): 0.4mg
Lentils (100g): 90mg
Beef liver (100g): 0.4mg
Asparagus (½ cup): 0.15mg
Sources: ncbi.nlm.nih.gov, hal.archives-ouvertes.fr