By Roberta H. Anding, MS, Baylor College of Medicine and Texas Children’s Hospital

Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily

Professor Anding’s guide to B vitamins begins with —delicate vitamins with a strong purpose.

Functions of Thiamine

Thiamine and riboflavin are essential for helping your body run. Overall, deficiency in these vitamins is rare in modern Western society, but it is becoming increasingly common due to poor lifestyle choices.

Thiamine, or vitamin B₁, deficiency disease was first described in Chinese writings over 4,000 years ago. In 1885, though, a physician of the Japanese Naval Medical Services cured sailors of a disease called “beriberi” by adding meat and milk to their diets. Beriberi means “I can’t; I can’t” in Sinhalese. 

This relates to the overall purpose of vitamin B, which is providing lubrication to the “engine” of our bodies. If we do not have enough “lubrication,” the “engine” cannot go.

Thiamine is part of a coenzyme that breaks down carbohydrate and powers protein synthesis. It helps in the production or the synthesis of neurotransmitters.

Thiamine as a B vitamin is delicate. Heat destroys the vitamin. 

“Adding baking soda to vegetables, which my grandmother used to do all the time to preserve their green color, destroys thiamine,” Professor Anding said. “Thiamine actually likes an acidic environment … likes the acidic environment of your stomach.”

Thiamine Deficiency

Thiamine deficiency can occur in as little as 10 days. Body systems with high energy needs deteriorate first. This is because your central nervous system is a major energy consumer. 

Symptoms of thiamine deficiency include a sensation of pins and needles, particularly in the hands and feet. Be careful with self-diagnosis, though, because other diseases and conditions, such as neuropathy developed as a complication of diabetes, can cause that tingling sensation. 

Beriberi, or significant thiamine deficiency, falls into two categories. Wet beriberi refers to cardiac damage and fluid retention, similar to what you would see in congestive heart failure. Dry beriberi, on the other hand, doesn’t have the fluid accumulation, but it damages the nervous system.

Thiamine deficiency is rare in developed countries, as we have fortified foods and a wide variety of food sources. It’s not rare among alcoholics, though. 

Approximately 25% of alcoholics show signs and symptoms of thiamine deficiencies. Often, when paramedics find an unconscious, unknown person, or a homeless alcoholic on the side of the road, they automatically assume that the person has thiamin deficiency. 

When it comes to excess, thiamine is a B vitamin that doesn’t have a known toxicity. It is truly a water-soluble vitamin where you excrete the excess.

Riboflavin Roles

Another member of the vitamin B family, riboflavin, is also known as vitamin B₂. It was originally thought to be part of the thiamine molecule. 

Originally, scientists believed that B vitamins were one compound, so they confused riboflavin and thiamine. Excess riboflavin is excreted in your urine; so if you take a multivitamin and get a greenish-yellow color in your urine, that’s the excess riboflavin being excreted.

The main purpose of riboflavin is lubrication. It extracts energy from carbohydrate, protein, and fat. However, some newer studies, including one in the journal Headache, suggest that a higher dose of riboflavin may help prevent migraine headaches, and this actually was reviewed. 

“We certainly see a lot of our children at Texas Children’s who have chronic migraines now being prescribed really large doses of riboflavin,” Professor Anding said. “But the key word here is ‘prescribed’ large doses of riboflavin.”

Like thiamine, riboflavin is not a very stable B vitamin. It can be destroyed by ultraviolet light. 

Milk is a primary and significant source of riboflavin, and the milk should be stored in opaque containers. This is because as milk is transported to the grocery store, if it’s exposed to UV light, the riboflavin in the milk can be destroyed. 

“One of the things is that we’re now seeing—almost a retro trend—putting milk in glass bottles,” Professor Anding said. “It’s really a bad idea. It should be in paper cartons or in the white opaque containers.”

Riboflavin Deficiency and Toxicity

As with thiamine, riboflavin deficiency can occur in chronic alcoholics. Symptoms include an inflamed tongue and cracks and fissures at the corners of the mouth called “glossitis” and “angular stomatitis.” The lips can become inflamed and split, which is called cheilosis. 

“Where I see this in a nonalcoholic population is in teenage girls,” Professor Anding said. “They don’t drink milk. They’re drinking diet soft drinks, and you can see these cracks and fissures at the corners of the mouth, what appears to be dry lips. That’s actually cheilosis.”

Riboflavin deficiency can also make deficiencies in other B vitamins such as vitamin B₆ worse. Those who skip breakfast are eliminating an opportunity for fortified foods and milk, often ending up with a riboflavin deficiency.

Unlike with other vitamins, you don’t have to worry about going too far in the other direction when consuming riboflavin to avoid deficiency, especially if you’re getting it from natural food sources and not supplements. Riboflavin is nontoxic, so no upper limit has been set. 

Stay tuned for tomorrow, where you’ll learn about niacin, or vitamin B₃.

This article was edited by Kate Findley, Writer for The Great Courses Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for The Great Courses Daily.