Vitamin B1 (thiamine) is vital for the functioning of the nervous system, brain, and breaking down carbohydrates and sugar. Our bodies aren’t able to store thiamine very well, so you need to get most of your intake from food.
Vitamin B1 deficiency can result in serious and life-threatening conditions such as beriberi and Wernicke-Korsakoff syndrome. It is rarely seen in the developed countries, except in cases of alcoholism and after bariatric (weight loss) surgery.
Instead, thiamine deficiency tends to be more common in countries where unpolished white rice (that hasn’t been artificially enriched) is a major part of the diet.
Causes of Vitamin B1 Deficiency
Causes of vitamin B1 deficiency include:
- low dietary intake
- acute alcohol consumption and alcoholism
- poor absorption (especially after bariatric surgery)
- pregnancy and breastfeeding (especially in women who suffer from severe morning sickness)
Here are some of the key symptoms and signs of vitamin B1 deficiency:
1. Loss of Appetite and Weight Loss
Thiamine deficiency causes anorexia by inhibiting hypothalamus activity. The hypothalamus is responsible for signaling to our body that we are full. When you are deficient in vitamin B1, the hypothalamus keeps telling your body that it’s full. This can result in a loss of appetite.
At the same time, vitamin B1 deficiency increases the amount of energy that your body uses even when you are resting and it lowers the uptake of glucose.
All of this together means that thiamine deficiency can lead to weight loss, as well as a lack of hunger/loss of appetite.
2. Nausea and Vomiting
Thiamine is essential for normal pituitary function. When you are deficient in vitamin B1, your pituitary gland produces lower hormones levels, which can result in nausea and vomiting.
This is especially obvious in pregnant women. Being thiamine deficient can cause preeclampsia, and one of the main symptoms of this life-threatening disorder is nausea and vomiting.
3. Tiredness and Weakness
Vitamin B1 is important for the normal functioning of the muscles and the peripheral nervous system (PNS). The PNS helps connect the nerves in the brain and the spinal cord to the rest of the body.
Vitamin B1 deficiency can result in muscle weakness in the arms and legs, as well as muscle pain and tiredness. It also causes shortness of breath on exertion. Both of these can result in a feeling of tiredness, weakness, and fatigue.
On the other side of this, thiamine supplements can help to prevent exercise-induced fatigue.
4. Vision Problems
Vitamin B1 deficiency can cause nystagmus. Nystagmus is involuntary rapid eye movement, either vertically or horizontally. It’s also referred to as the “dancing eyes” syndrome. This movement of the eyes is obvious to other people and can result in blurred vision for the person suffering from it.
This happens because the nerves in the visual cortex rely on vitamin B1 to function properly.
5. Anxiety and Depression
One of the more surprising symptoms of thiamine deficiency is anxiety and depression. Vitamin B1 helps the nerves in the brain to function properly and it also lowers homocysteine levels. High homocysteine levels are associated with increased levels of anxiety and depression. If you are deficient in vitamin B1 it can lead those homocysteine levels to rise, resulting in anxiety and depression.
Low thiamine levels are found in psychiatric patients, especially those with severe depression, and giving people yeast spreads that are high in B1 improves the symptoms of anxiety and stress.
6. Swelling in the Hands and Feet
This symptom might not seem that severe. However, in the case of vitamin B1 deficiency, it can be the result of heart failure, which is considered a medical emergency. This is also known as wet beriberi and is a result of vitamin B1 deficiency causing the heart to work too hard, leading to its failure.
If you have swelling of the hands and feet (oedema), breathlessness, and fatigue that are persistent or getting worse, you should seek medical attention. If these symptoms are sudden and severe, you should call 999.
7. Chest pain
This is another symptom of thiamine deficiency resulting in wet beriberi and heart failure. Beriberi is one of the most common nutritional disorders.
Three out of 5 of people with wet beriberi will have chest pain.
8. Poor Reflexes
Thiamine is essential for the central nervous system (CNS) to function. When you are deficient in thiamine, this can lead your nerves to not fire as they should. One symptom of this is a reduced reflex in the tendons, for example, when a knee-jerk test is performed.
These CNS problems that result from vitamin B1 deficiency are also known as dry beriberi.
9. Numbness in the Arms and Legs
This is another symptom of vitamin B1 deficiency leading to problems with the central nervous system (CNS). The numbness is symmetrical (it is not seen on one side only), occurs without tingling, and is in a “stocking and gloves” pattern. This means that the numbness occurs in the areas where stockings and gloves would normally be worn.
10. Problems Moving the Arms and Legs
Dry beriberi can eventually result in muscle wastage in the arms and legs, and this can lead to difficulties with movement and walking. The damage from this can be long-term, with reports of it taking six months to recover with thiamine supplements.
11. Brain Damage
Wernicke-Korsakoff syndrome is a disease caused by deficiency of vitamin B1. It is a form of dry beriberi that can result in permanent brain damage.
It is known as Wernicke’s encephalopathy when the symptoms first appear but can result in Korsakoff syndrome if left untreated for too long. The symptoms of Wernicke’s encephalopathy can include all of the ones listed above, such as stomach issues, vision problems, mental issues, dizziness, unsteadiness, and confusion.
If Wernicke’s encephalopathy is left untreated for too long, it can lead to Korsakoff syndrome. This is permanent brain damage that results in dementia. The main symptom of this condition is memory loss. However, personality changes, difficulty acquiring new information and inventing events to fill memory gaps can also occur.
12. Vitamin B1 Deficiency Symptoms in Infants
Breastfed infants can suffer from thiamine deficiency is their mother is deficient in it. It is a very serious condition in infants that requires immediate treatment. Symptoms include hoarseness, weight loss, vomiting and diarrhea, pale skin, irritability, swollen hands and feet, and a rapid heart rate.
The Best Food Sources of Vitamin B1
Your body only stores vitamin B1 for one month, so you need a constant source of it in your diet. The recommended daily intake of thiamine is 1.2 mg for men and 1.1 mg for women.
Many foods are a good source of thiamine. Making sure that your diet is rich in these should ensure that you never have to worry about vitamin B1 deficiency.
Here are the top 6 foods for thiamine intake:
- rice, white, long-grain, enriched, parboiled – 117% DV (daily value)
- breakfast cereals, fortified with 100% of the DV for thiamine – 100% DV
- egg noodles, enriched, cooked – 42% DV
- porkchop, bone-in, broiled – 33% DV
- trout, cooked, dry heat – 33% DV
- black beans, boiled – 33% DV
Some foods can destroy your body’s stores of thiamine. It’s important to make sure that you don’t consume them excessively:
- tea and coffee
- raw fish
Cooking foods results in some of the thiamine being destroyed. It can also dissolve into cooking and be lost when the water is thrown out. Thiamine can also be taken in supplement form.
What to Take Away
Vitamin B1 deficiency is relatively rare in the Western world and is most common in people with alcoholism and those recovering from weight loss surgery. Most of these thiamine deficiency symptoms can be easily treated if diagnosed early enough.
Our bodies don’t store vitamin B1 for very long so you will need a constant intake of it in your diet. Foods such as fortified cereals, pork, eggs, fish and black beans are great sources of thiamine. You might also consider taking a vitamin B complex supplement to ensure you’re meeting your RDA for all B vitamins.
READ ALSO: Vitamin B1 Dosage: Always Stick to Your RDA