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Vitamin B1, also called thiamine or thiamin, is an essential vitamin or micronutrient needed by the body for healthy cell growth and function – more on this below. As discussed in our Vitamins Explained article, certain micronutrients like B1 cannot be made by the body and so it’s essential for healthy body function to get it in the right amounts through our diet or supplementation.
Vitamin B1 is a water-soluble vitamin, meaning that it can dissolve in water and is not stored in the body (a small amount can be stored in the liver for a short period). This is why it’s important to have regular intake of vitamin B1. It’s very rare to have a B1 deficiency because it is found naturally in common foods that we eat, is added to fortified foods, and can also be found in many supplements.
There’s a lot to get through here, so if you’d rather spend six minutes watching a valuable explainer, check out this video. If not, keep reading!
Functions of Vitamin B1
Vitamin B1 plays an important role in cell function and turning nutrients into energy because it is a cofactor for five important enzymes in the body. A cofactor is a substance that is needed by an enzyme in order for it to work (think of a key in order to start an engine). Without B1, these five enzymes can’t do their jobs in glucose, amino acid, and lipid metabolism.
The enzymes for which B1 – which is needed in its thiamine pyrophosphate (TPP) form – is a cofactor for include transketolase, pyruvate dehydrogenase (PDH), and 2-oxoglutarate dehydrogenase (OGDH), which are all important for metabolizing carbohydrates.
Transketolase is necessary for making up the sugars deoxyribose and ribose, which you may be familiar with in the “D” and “R” in DNA and RNA. PDH and OGDH are essential parts of the powerhouse of every cell, the mitochondria. These are needed for adenosine triphosphate or ATP, which is the energy-carrying molecule found in all living organisms.
PDH is also needed in the central nervous system for the production of acetylcholine, which is a neurotransmitter, and for the synthesis of the myelin sheath – an insulating later around nerve cells.
The inability of the body to do any of these functions means it won’t be able to turn food into fuel. It also won’t be able to keep the nervous system, brain, muscles, heart tissue, and gastrointestinal system healthy and functioning properly.
Recommended Amounts of Vitamin B1
Research suggests that the optimum daily amount of B1 for men over the age of 19 is 1.2 mg. For women of the same age group, 1.1 mg is sufficient unless she is pregnant or breastfeeding, in which case B1 intake should increase slightly to 1.4 mg per day.
Children of different ages also require different amounts of B1. From birth to 13 years old, both boys and girls should receive the same daily amount of B1. From 14 years old, boys require slightly more than girls in their daily diet. According to the National Institute of Health, here are the amounts different age groups of children should receive:
- Birth to 6 months – 0.2 mg per day
- 7 to 12 months – 0.3 mg per day
- 1 to 3 years – 0.5 mg per day
- 4 to 8 years – 0.6 mg per day
- 9 to 13 years – 0.9 mg per day
- 14 to 18 years – 1.2 mg per day for boys and 1.0 mg per day for girls
If you’re wondering what these amounts look like in the form of food, one cup of cooked brown rice contains 13% (or around 0.15 mg) of your daily thiamine intake, while one cup of cooked brown lentils provides 28% (or 0.33 mg) of your recommended intake.
If you’re a meat-eater, you can get 96% of your daily recommended amount in one cup of cured ham, or 28% from 100 g of salmon, for example.
It’s unrealistic to try and get 100% of your daily recommended intake from one source alone – it will quickly lead to monotony and boredom. So the key is to find delicious combinations of different ingredients to create a tasty and nutritious dish and to use your three meals a day plus snacks as a way to reach your intake goals. Check out our suggested recipes and modifications below to get sufficient vitamin B1 each day without the need for supplements or fortified foods.
Signs and Symptoms of Vitamin B1 Deficiency
Deficiency of vitamin B1 has been known to us for centuries, but it was only in the late 1800s that we started to figure out the connection between disease caused by B1 deficiency and diet.
In 1884, a Japanese scientist found a link between sailors who ate a nutrient-poor diet of plain white rice for months at a time while at sea with increased occurrence of disease. The rate of disease and even death almost completely disappeared when the sailors were given a more nutritious diet of vegetables, meat, beans, and whole grains upon their return.
Dutch scientists also confirmed this link when feeding chickens polished versus whole rice for feed. Chickens eating only white rice developed paralysis in their legs, while those on whole rice did not.
Because B1 is a water-soluble vitamin, it doesn’t get stored in the body. As such, a deficiency can begin to set in in as little as 14 days after no B1 intake. As mentioned earlier in this article, because of modern food technology, it’s quite difficult to develop a B1 deficiency, although risk factors for developing a deficiency can include alcoholism, dialysis, abusing diuretics, or chronic diarrhea associated with gastrointestinal diseases like celiac disease. Where mild B1 deficiency exists, people may experience weight loss, confusion or mild memory loss, muscle weakness, tingling or mild numbness in the fingers and toes, and a weakened immune system.
So what are the diseases and symptoms associated with a deficiency? The common name for a severe, chronic Thiamine/B1 deficiency is called beriberi. It comes in two forms, namely wet beriberi, which affects the cardiovascular system, and dry beriberi, which affects the nervous system.
Wet beriberi will manifest as a rapid heartbeat, swollen legs, and shortness of breath. These are all linked to the heart’s ability to pump blood around the body.
In dry beriberi, manifestations of deficiency include numbness in the extremities like hands and feet, mental confusion, pain, and difficulty moving one’s limbs. This is typical of a nervous system that is not functioning properly. Three brain diseases associated with dry beriberi are Wernicke’s encephalopathy, Korsakoff syndrome, and Wernicke-Korsakoff syndrome which come about as a result of alcohol abuse.
B1 deficiency can also affect the digestive system and is called gastrointestinal beriberi, which is associated with nausea, vomiting, abdominal pain, and a build-up of lactic acid in the bloodstream known as lactic acidosis.
Signs and Symptoms of Vitamin B1 Toxicity
Because vitamin B1 is water-soluble, it’s highly unlikely to get too much. The body will only take up as much as it needs and the rest is filtered by the kidneys and excreted in the urine. For this reason, there’s no established Tolerable Upper Intake Level (UL) for how much B1 you could ingest as there’s little science showing negative results from taking too much., Although anecdotal reports suggest mild nausea can occur. The only real symptom would be a lighter wallet as you’re wasting your money!
Medical Uses for B1
Thiamine can be used in a medical setting as part of treatment for pellagra, which is can be a fatal deficiency of niacin or vitamin B3. Pellagra causes damaging inflammation to the brain and nerves and is accompanied by the three Ds symptoms: Dementia, diarrhea, and dermatitis. B1 can also be used to help treat the symptoms of peripheral neuritis (inflammation) or neuropathy (degeneration), which manifest with numbness or tingling in the fingers and toes. Other nerve disturbances can result in impaired vision, hearing, and balance.
For individuals with gastrointestinal diseases such as celiac or ulcerative colitis, or eating disorders like anorexia or bulimia, doctors may include B1 supplementation or injections in the treatment plan.
B1 is also a useful treatment in rare congenital disorders like maple syrup urine disease, congenital lactic acidosis, and congenital neurometabolic disorder, Leigh syndrome.
Because of its role in healthy nerve functioning, B1 can be supplemented for athletes needing improved performance. Individuals with weakened immune systems such as HIV/AIDS patients would also benefit from increased doses of B1. Other reasons for increased B1 can include eye problems like cataracts or glaucoma, brain damage, heart and kidney disease, or motion sickness.
B1 supplementation should be carefully evaluated in people undergoing chemotherapy with Fluorouracil for the treatment of tumor cancers or colorectal cancer. Patients receiving loop diuretics like Furosemide to treat edema and hypertension should also take care with B1 supplementation. This is because these medications can block the active form of thiamin.
Food Sources for Vitamin B1
It’s worth noting upfront that vitamin B1 is destroyed by high heat and long cooking times. It can also leech out of food and into the water, so bear that in mind when soaking grains or throwing away cooking water.
Fortunately, vitamin B1 can be found naturally in a number of common and affordable foods. The most common sources are whole grains (cereals that have not been heavily processed), like wheat, rice, barley, maize, rye, and oats, to name some examples.
Because it’s common for these grains to be processed – think of white rice instead of brown and white bread instead of whole grain – much of the thiamine-containing elements like the outer husk and endosperm are removed. This means that manufacturers might choose to fortify the processed product by adding synthetic B1 back into the food.
Legumes (food plants that produce a pod with seeds inside them) like beans, peas, chickpeas, lentils, and soybeans are also excellent sources of thiamine, as well as in some meat and fish.
Here’s a table of 10 common food sources for thiamine and their quantities. We’ve kept things simple at the amount of thiamine per 100g so that you can work out quantities based on your age and sex, which we discussed above:
10 Vegan and Vegetarian Options for Vitamin B1
| Food Source for Vitamin B1 | Milligrams of Vitamin B1 per 100 g |
| Macadamia nuts | 1.2 mg per hundred grams |
| Cooked soybeans | 0.3 mg per hundred grams |
| Pistachio nuts | 0.9 mg per hundred grams |
| Chia seeds | 0.6 mg per hundred grams |
| Soy milk | 0.2 mg per hundred grams |
| Garden peas | 0.3 mg per hundred grams |
| Wholewheat pasta | 0.2 mg per hundred grams |
| Cooked brown lentils | 0.2 mg per hundred grams |
| Black beans | 0.2 mg per hundred grams |
| Brown rice | 0.2 mg per hundred grams |
A note here that flax seeds are a vitamin B1 powerhouse containing 1.6 mg of thiamine per hundred grams. However, we can all agree that it’s unrealistic to consume even close to 100 g of this on a given day. The same applies to other seeds such as sunflower seeds at 1.5mg per 100g, hemp seeds at 1.3 mg per hundred grams, and tahini at 1.2 mg per 100 grams.
Seeds and nuts in general are very healthy food choices, but they also tend to be calorific, and when eaten in quantity can result in weight gain.
10 Gluten-Free Options for Vitamin B1
Barring the wholegrain pasta above, all of those listed are also gluten-free. Here’s some more though.
| Food Source for Vitamin B1 | Milligrams of Vitamin B1 per 100 g |
| Sun-dried tomatoes | 0.5 mg per hundred grams |
| Firm tofu | 0.2 mg per hundred grams |
| Buckwheat | 0.1 mg per hundred grams |
| Cornmeal | 0.1 mg per hundred grams |
| Kidney beans | 0.2 mg per hundred grams |
| Chickpeas (fava beans) | 0.1 mg per hundred grams |
| Black-eyed peas | 0.2 mg per hundred grams |
| Melon | 0.2 mg per hundred grams |
| Currants | 0.2 mg per hundred grams |
| Grapes | 0.1 mg per hundred grams |
10 Meat and Dairy Options for Vitamin B1
| Food Source for Vitamin B1 | Milligrams of Vitamin B1 per 100 g |
| Lean pork chops | 0.7 mg per hundred grams |
| Salami | 0.9 mg per hundred grams (be aware that salami is high in salt and saturated fats that can have adverse consequences for heart health) |
| Salmon | 0.3 mg per hundred grams |
| Duck | 0.3 mg per hundred grams |
| Ostrich | 0.2 mg per hundred grams |
| Beef Liver | 0.2 mg per hundred grams |
| Whey Powder | 0.6 mg per hundred grams |
| Feta Cheese | 0.2 mg per hundred grams |
| Hard-Boiled Eggs | 0.1 mg per hundred grams |
| Brie Cheese | 0.1 mg per hundred grams |
It’s worth noting that plant-based foods are far better sources of vitamin B1 than meat and dairy products. It’s not only healthier in general to eat more plant-based foods, but also better for the planet and your pocket.
Recipes High in Vitamin B1
If you want to explore food sources further, we highly recommend visiting My Food Data’s Nutrient Ranking Tool where some of this data is gathered from to discover more B1-containing foods to include in your daily diet.
If you want to increase your intake of vitamin B1 through a more varied and balanced diet, we’ve compiled a list of delicious, easy, and affordable recipes that are suitable for a wide range of dietary choices, such as vegetarians, vegans, and gluten intolerance.
We especially love the recipe builder from My Food Data, which helps you build recipes to meet your nutrition goals.
Afghan Red Lentil Soup. This is another fab vegan or vegetarian meal that comes with a bumper serving of vitamin B1 at 3.4 mg per serving. It’s delicious, plant-based, and easy on the pocket.
Pork Chops Saltimbocca with Sauteed Spinach. For our meat-lovers, there’s this yummy recipe that delivers 2.7 mg of thiamin per serving. It’s hearty and meaty, with all the attributes of a comforting home-cooked meal.
BLT Sandwich. You know it’s a good day when nutrition goals include the classic bacon, lettuce, and tomato sandwich! The combination of pork and break sees this tasty treat provide you with 1.6 mg of vitamin B1 per serving.
Recommended Supplements
Coming soon!