You've probably eaten some vitamin B1 today already. But did you know that vitamin B1 can help prevent certain eye diseases?

Vitamin B1, also called thiamine, is essential for healthy vision. It helps keep diseases like cataracts, diabetic retinopathy, uveitis, and dry eyes at bay.

Vitamin B1 and vision benefits go hand in hand. In this post, we'll review them and also talk about vitamin B1 food sources, daily recommended dosage, and deficiency symptoms.

Read on to find out more.

How Was Vitamin B1 Discovered?

As the name suggests, vitamin B1 was the first B vitamin discovered. Its discovery began with the search for microbes. During the late 1800s, beriberi, a disease causing nerve damage, was linked to germs.

It was the Japanese surgeon Takaki Kanehiro who, in 1884, rejected the beriberi germ theory. Instead, he showed that beriberi occurred due to a diet lacking certain nutrients. But he incorrectly assumed that this was because of a high protein intake.

In 1897, Dutch military doctor Christiaan Eijkman observed that fowls fed white (polished) rice developed paralysis. On the other hand, fowls fed brown rice did not. He attributed this to the high levels of starch in white rice.

Later in 1901, Eijkman’s successor Gerrit Grijns correctly linked the consumption of white rice with beriberi. He concluded that the outer layers of brown rice contain an essential nutrient that is removed when the rice is polished.

In 1910, the compound was first isolated from rice bran by Umetaro Suzuki, a Japanese agricultural chemist. It was synthesized by Robert Williams in 1936. Williams named it thiamine, that is, “thio/sulfur-containing amine.”

What Is Vitamin B1 (Thiamin)?

Vitamin B1 is one of the eight vital B vitamins. It helps your body use carbs as energy and plays a key role in the growth and function of your body cells.

Like all the other B complex vitamins, vitamin B1 is water-soluble. It’s carried to different parts of your body through the bloodstream. Your body does not store it. Any excess is eliminated in urine.

closeup of vitamin B supplement bottle with a few vitamins spilled on the table and black bottle back in the background

You can get your daily dose of vitamin B1 through both plant and animal-based foods. You can also consume it as a supplement.

Vitamin B1 Eye Health Benefits

Vitamin B1 is one of the essential vitamins for eye health. Without enough of this vitamin, you have a higher risk of cataracts, diabetic retinopathy, uveitis, and dry eye disease.

So, why is vitamin B1 good for eyes?

May Slow Cataracts Development

Cataracts can cloud your eye’s lens, turning your vision foggy and unclear. Cataracts are generally age-related, developing mostly in older people. But in certain cases, young people and babies can also get cataracts.

Vitamin B1 intake, along with other nutrients, can reduce your risk of developing nuclear cataracts, shows an Australian study. The research involved a group of 2,900 men and women aged 49 and older.

It found that individuals with a high vitamin B1 intake were 40% less likely to develop cataracts than those with low vitamin B1. This suggests a clear link between vitamin B1 and reduced risk of cataracts.

May Prevent Diabetic Retinopathy

Diabetic retinopathy is an eye-related disease that occurs as a complication of diabetes. It damages the blood vessels in the retina, leading to vision loss and even blindness.

A study published in Nature Medicine showed that diabetic rats, when treated with high doses of thiamine, had lowered or no diabetic complications.

Vitamin B1 is recommended for patients in the early stages of diabetic retinopathy. So, include whole grains, meat, and fish in your diet if you’re at risk of developing diabetic retinopathy.

May Prevent and Treat Uveitis

Uveitis is an inflammation of the middle layer of your eyes. It accounts for about 10 to 15% of blindness cases in the US. The warning signs, like eye redness, pain, and poor vision, get worse quickly.

According to a 2009 study, vitamin B1 holds great promise in the prevention and treatment of uveitis. During the study, lab rats were first injected with bacterial toxins that produced a uveitis-like reaction.

The rats were then fed benfotiamine, a form of vitamin B1. They did not show any signs of an inflammatory disorder. Benfotiamine helped suppress the production of inflammatory proteins that cause uveitis.

May Relieve Dry Eye Symptoms

A new study suggests that the use of vitamin B1 and vitamin B12 can relieve eye dryness, pain, and light sensitivity. In the study, 76 patients were divided into four groups.

Patients in group 1 were treated with artificial tears while patients in group 2 were treated with corticosteroid eye drops. Group 3 was given oral vitamins B1 and B12. Finally, group 4 had the same treatment as group 3, along with corticosteroid eye drops.

After two months, groups 3 and 4 showed improvements in dry eye symptoms, like dryness, grittiness, and burning sensations. Additionally, group 4 patients experienced positive differences in blurred vision and eye pain.

The study concluded that thiamine use can repair the nerve layer of the cornea. This helped alleviate symptoms of dryness, burning, and sensitivity to light.

Foods High in Vitamin B1

Most plant and animal-based foods are a good source of thiamine. But for a boost, include the following vitamin B1 sources in your daily diet.

different types of beans and lentils in sacks
  • Yeast
  • Tofu
  • Whole grains and cereals including brown rice
  • Beans, lentils, and pulses
  • Vegetables like cauliflower, beans, peas, potatoes, squash, spinach, and kale
  • Fruits, including oranges, pineapple, grapes, and figs
  • Fortified breakfast cereals containing muesli, oatmeal, and granola
  • Nuts and seeds like pecan, pistachio, and sunflower seeds
  • Eggs and dairy foods
  • Animal-based products like beef, pork, poultry, and organ meats
  • Mackerel, salmon, tuna, and mussels are the best source of thiamin for seafood lovers

Fact: Thiamine has low heat resistance, so cooking will reduce the vitamin B1 content of foods. It’s best to have your fruits and veggies raw.

Vitamin B1 Deficiency Symptoms

Symptoms of vitamin B1 deficiency were first recorded in ancient Chinese medicine texts. But the symptoms were only connected with diet in the late 19th century.

Vitamin B1 deficiency is rare in the western world. But it may still occur because of poor diet, decreased absorption, and alcohol abuse.

Since vitamin B1 is not stored in your body, symptoms of deficiency manifest quickly. Watch out for these mild to moderate thiamine deficiency symptoms.

  • Blurry vision caused by swelling of the optic nerve
  • Weight loss
  • Loss of appetite and fatigue
  • Poor sleep and irritability
  • Weakened muscles
  • Lowered immune function
  • Confusion and memory loss
  • Tingling sensation in arms and legs
  • Nausea and vomiting

In severe cases, vitamin B1 deficiency may lead to:

  • Beriberi, a disease that causes nerve inflammation
  • Brain-related abnormalities
  • Accelerated heartbeat and low blood pressure

Vitamin B1 Toxicity

Toxicity is unlikely with any food source of vitamin B1. If you have an elevated vitamin B1 due to high intake, don’t panic. Only a limited amount of thiamine in the body will be absorbed. The rest will be flushed out via urine.

That said, excessive intake of thiamine (50 mg/day or more) may still have adverse effects. So, better consume it with caution.

What Is the Daily Recommended Vitamin B1 Intake?

The National Institutes of Health recommend the following daily intake of vitamin B1 for various age groups.

  • 0 to 6 months: 0.2 mg
  • 7 to 12 months: 0.3 mg
  • 1 to 3 years: 0.5 mg
  • 4 to 8 years: 0.6 mg
  • 9 to 13 years: 0.9 mg
  • 14 to 18 years: 1 mg for females and 1.2 mg for males
  • 19+ years: 1.1 mg for females and 1.2 mg for males
  • Pregnant or breastfeeding individuals: 1.4 mg

Should You Take a Vitamin B1 Supplement?

The best way to get vitamin B1 is naturally through your food. It’s significantly less expensive than buying supplements.

Plus, supplements of vitamin B1 for eyes are generally not necessary since your diet can take care of most of your needs. But people with certain conditions, like HIV, cancer, and diabetes, may need oral supplementation.

closeup of woman's hand with ring finger holding a few white capsules

Make sure to check with your healthcare provider before taking vitamin B1 supplements. Also, discuss with your doctor other medications, as thiamine may interact with them and cause side effects.

If you're not at risk of vitamin B1 deficiency, consider taking instead a full-spectrum vision supplement such as SightC. Packed with antioxidants and phytonutrients from plants, SightC is all-natural and sugar-free.

It brings together goji berries, turmeric, dwarf lilyturf, Cherokee rose, and other plants in a synergistic formula inspired by decades of clinical experience in treating patients with eye disease.

Learn more about SightC.


Thiamine is vitamin B1 and is found in many food sources. Deficiency is commonly associated with heart and brain diseases. But a diet low in vitamin B1 can also be harmful to your eyes.

That’s because vitamin B1 helps prevent cataracts, diabetic retinopathy, and uveitis. It also alleviates eye dryness, burning sensations, and sensitivity to light.

The best source of vitamin B1 is plant and animal-based food. Make sure to also add fresh fruits, eggs, nuts, and seeds to your diet for good eye health.

These are enough to give you the essential dose of vitamin B1 needed per day.

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