Thiamin (B1)

This vitamin is needed for several bodily processes - one of its main jobs is to help your body to turn the carbohydrate in your food into energy. It’s a water-soluble vitamin and should be eaten every day.

Where can I get it?

Unrefined (unprocessed) carbohydrate foods are usually good sources of thiamin – wholegrain cereals, for example, and wholemeal flour. Breakfast cereals lose thiamin during processing but are often fortified so they’re actually a good source.

Beans, seeds and nuts are rich in thiamin, as are yeast and yeast extracts (like Marmite). You can find it in pork (but not other meats, except liver*), dairy products like milk and cheese, fruit and vegetables.

*Pregnant women should avoid eating liver because it contains high amounts of vitamin A.

How much should I eat?

Like all water-soluble vitamins, thiamin can’t be stored so any that’s eaten and not needed will usually leave the body in the wee. However, extremely high intakes over an extended period can be toxic but this is unusual (over 3g a day).

It’s recommended that you consume around 1mg a day (one milligram = one thousandth of a gram). You can easily get this by eating Marmite on two slices of wholemeal toast with a glass of orange juice.

What does it do?

The body has to get energy from food in order to function. Some systems can use energy created from fat or protein, but the nervous system needs energy from the carbohydrates in food.

Thiamin helps convert carbohydrate into energy, so a lack of thiamin means a lack of energy. The nervous system then has nothing to power it and this has very serious consequences.

Although it’s rare in this country, thiamin deficiency is a big problem in countries where there isn’t enough food, and it’s sometimes seen here in people with alcoholism. Effects of a lack of thiamin in the diet (called ‘beriberi’) can range from fatigue, breathlessness and weakness, to mood changes and even paralysis.