Is It Safe To Take Vitamin B1 During Pregnancy?

Vitamin B1, also known as thiamine, has been the first B-type vitamin discovered, being isolated in the 1920s. Studies have shown that this vitamin has essential roles in the human metabolism that contribute in a remarkable way in maintaining health.

Is It Safe To Take Vitamin B1 During Pregnancy

Group B vitamins have been grouped together due to their similar properties as well as because of their presence in the same food sources. Due to the close connection between the vitamins of this group, deficiency of a vitamin will lead to improper use of the others.


Thiamine is deposited in very small amounts in the human body, and the reserves can be totally emptied in 2 weeks.

This vitamin, which is usually measured in mg (μg), needs to be taken together with magnesium and folic acid, to be used in an effective way.

The main function of this vitamin is taking part in the metabolism of sugars in fat or energy. Vitamin B1 contributes to physical and muscle strength, as well as the central nervous system.

We need this vitamin when:

  • We experience muscle sensitivity.
  • We lose our appetite.
  • We are depressed or irritated.
  • We feel a sense of numbness, especially in our legs.

Therapeutic Use

  • Deafness.
  • Diarrhea.
  • Cardiovascular illnesses.
  • Apathy.

Food Sources of Thiamine

Peas (1cup) 0.386 mg
Asparagus (1 cup) 0.19 mg
Brussels sprouts (1 cup) 0.122 mg
Sesame seeds (1 tablespoons) 0.142 mg
Sunflower seeds (1/4 cup) 0. 17 mg
Fistic (1 oz) 0.247 mg
Hering (1 filet) 0.105 mg
Crimini mushrooms (1 cup) 0.086 mg
Flaxseeds (1 tablespoon) 0.115 mg
Spinach 0.265 mg
Green salad (2 cups) 0.11 mg
Boiled spinach (1 cup) 0.17 mg
Sprinkled broccoli (1 cup) 0.09 mg
Pineapple (1 cup) 0.14 mg
Canned chicken (1cup) 0.26 mg
Cooked lentils (1 cup) 0.33 mg
Carrots (1 cup) 0.12 mg
Cooked cabbage (1 cup) 0.09 mg

Does Vitamin B1 Loss Its Properties during Cooking?

This vitamin is very instable and easy damageable to heat, acidity (pH), as well as other chemical substances. Both sulfites and nitrites can inactivate vitamin B1. For instance, the thiamine from cereals losses around 50% of its properties during processing or cooking.

Long-term refrigeration (e.g. 1 year) may lead to important losses of vitamin B1. Green beans lose more than 90% of the original content of this vitamin after refrigeration.

Vitamin B1 Deficiency

A thiamine deficiency occurs especially when excessive consumption of alcohol, sweets or husked rice takes place, as well as in the case of infectious diseases or excessive tiredness.

Related: Can You Take Vitamin D While Pregnant?

Deficiency of vitamin B1 leads to:

  • Cardiac disorders.
  • Reduced immunity.
  • Cerebral affections.
  • Neuralgia.
  • Anorexia.
  • Anxiety.
  • Decrease in muscle tone.
  • Asthenia.
  • Mental confusion.
  • Visual disturbances.
  • Depression.
  • Diminishing memory.
  • Gastritis.
  • Liver failure.
    Lack of motor coordination.
  • Polyneuropathy.
  • Severe psychiatric disorders.

A severe vitamin B1 deficiency leads to Beriberi disease, very common in developing countries, where rice is the main source of food. Being a rare illness in industrialized countries, it isn`t encountered in other than people with an unbalanced diet, such as elderly or alcoholic people. This disease shows first symptoms of weight loss and fatigue, but it can then evolve in 2 different forms:

  • Dry beriberi, which generally affects muscles or nerves, shows signs of burning senses of the calves, a muscular atrophy or numbness. In more severe situations, the patient can`t walk or even stand up.
  • Wet beriberi, which mostly translates in a heart failure: the heart doesn`t get to play its normal role of a pump, the veins become congested and edema starts occurring on the calves, and on occasion on the body or the face. If treatment isn`t followed, a fast evolution of heart failure and heart rhythm disturbances can even lead to death.

Overdose of Vitamin B1

Although any excess of water-soluble vitamins are excreted in the urine, administering a 100 times higher dose than the one recommended may lead to:

  • Headache.
  • Irritability.
  • Insomnia.
  • Accelerated heart rate.
  • Respiratory system damage.
  • General weakness.

In extreme cases, such an overdose might be fatal.

Is It Safe to Take Vitamin B1 during Pregnancy?

Generally speaking, thiamine is perfectly safe for expecting mothers or breastfeeding women. Actually, these women need even higher amounts of vitamin B1 than normal.

You should first check what the doctor has to say before start taking any drugs or supplements. If you may be pregnant, visit your doctor`s office in order to find out how much of this vitamin you have to take on a daily basis, and if these supplements will help you or not.

What Does Thiamine Do for Pregnancy?

Vitamin B1 will enable both the pregnant woman and baby to convert carbs into energy. It aids the heart, muscles and nervous system to function in a normal manner and is crucial for the brain development of the baby.

How Much Vitamin B1 Pregnant Women Need?

Expecting mothers and women who are breastfeeding require 1.4 mg each day, while non-pregnant women only 1.1 mg a day.

Research & Studies

According to an article posted on ncbi.nlm.nih.gov, the status of vitamin B1 of 60 expecting mothers and 20 non-pregnant women has been assessed. Only 49 pregnant women were tested for the status of biochemical vitamin B1 in the last trimester of pregnancy and 25 of them after giving birth. Thirty percent of the women who weren`t pregnant as well as 28% to 39% of expecting mothers (in either the second, third trimester of pregnancy or postnatal phase) had a status of thiamin deficiency with the TPP effect greater than 20%. None of the pregnant women had any deficiency in all the 3 periods. Follow up of the expecting mothers in the second and third trimester of pregnancy as well as after birth revealed that the vitamin B1 deficiency wasn`t really established at the onset of pregnancy and wasn`t aggravated with the evolution of pregnancy either. The intake of vitamin B1 was more than 2/3 of the recommended dose in all the expecting mothers and didn`t revealed any relation regarding the biochemical indices.

Interaction with Drugs

It isn`t known if vitamin B1 interacts with any drugs! Before taking it, ask a health professional if it`s ok to take it in case you are already taking medications. – Visit this page!

Interaction with Foods

Betel nuts are known to change vitamin B1 chemically, so it does not work well. Chewing of betel nuts on a long term might contribute to deficiency of thiamine.

Horsetail contains a chemical substance which may destroy vitamin B1 in the stomach, maybe even causing vitamin B1 deficiency. The Canadian government asks that any products that contain this plant be certified free of this particular chemical. If you are at risk for vitamin B1 deficiency, you should avoid using horsetail.

Image courtesy of momjunction.com

Show Comments


  1. RalphLep June 4, 2022
  2. IverDarm June 6, 2022
  3. ChesterDyesy June 6, 2022
  4. Stromvar June 8, 2022
  5. Dyrwyk June 27, 2022
  6. Camille Hite January 22, 2023
  7. Davidopera January 22, 2023
  8. Orbaog February 7, 2023

Leave a Reply