Are you struggling with hair loss? It could be a vitamin deficiency.

Throughout the worst of the pandemic, doctors reported an uptick in stress-related hair loss. COVID-19 brought about death and illness, shuddered schools and businesses, and put people's lives on pause. The resulting emotional stress had significant repercussions, among them unprecedented hair loss for many people.

While stress is certainly one contributing factor to the loss or thinning of one's hair, it's far from the only one. Preventable vitamin deficiencies cause hair loss as well.

Hair loss is a common disorder defined as an interruption in the body’s cycle of hair production. It can happen to anyone, but is more common in men. Male or female pattern baldness is thought to affect some 50 million men and 30 million women in the United States, though some research shows that as many as 50% of all men are afflicted with the disorder by age 50.

What else causes hair loss?

Hair loss, also called alopecia, has many causes including aging, hormones, genetics, intense physical or emotional stress, hairstyles, drugs and chronic illness – though heredity is the most common contributing factor. And while male or female pattern baldness can be managed with medication or surgery, other causes of hair loss can be prevented, in part, with proper nutrition and maintenance.

"Much like mental fitness, hair health is partly the result of overall diet and lifestyle choices," says Dr. Uma Naidoo, director of nutritional and lifestyle psychiatry at Massachusetts General Hospital and the author of “This is Your Brain on Food."

Which vitamin deficiencies cause hair loss?

Indeed, multiple vitamin and mineral deficiencies have been associated with hair loss and even premature graying. "While hair loss and its causes and treatments are complex, we can look at what’s possible from the viewpoint of nutrients," says Naidoo.

The most important vitamins and minerals "noted to promote long, strong, thick hair," she says, include the following:

  • B vitamins, particularly B12, because "they help encourage healthy blood flow to the scalp and an abundance of red blood cells which support the hair follicle and cell rejuvenation for hair growth," Naidoo says.

  • Iron because it helps the body produce hemoglobin which carries oxygen to one's scalp cells for improved skin cell repair and a healthy scalp.

  • Vitamin D, because some research suggests that symptoms of a common form of alopecia may be more severe in people with low levels of vitamin D.

  • Vitamin E, because it acts as a powerful antioxidant, "and has been shown to reduce inflammation in the scalp which may interfere with hair growth," Naidoo explains.

  • Omega 3 Fatty Acids, because they reduce follicle inflammation and promote scalp circulation. "They have also been shown to both increase hair density and reduce hair loss," Naidoo says.

  • Zinc, because "zinc deficiency has largely been associated with conditions resulting in hair loss such as alopecia so maintaining healthy zinc levels may reduce the risk of hair thinning," Naidoo says.

How much B12 should I take for hair loss?

Though all such vitamins and minerals are helpful in maintaining a healthy head of hair, vitamin B12 deficiency is one frequently marketed by some organizations as causing hair loss. Though such research is mixed, maintaining enough B12 in one's diet is essential for growth and development, high function of one's central nervous system, and healthy red blood cell formation.

And while most people consume adequate amounts of vitamin B12 from a healthy diet, the recommended daily amount of the vitamin is 2.4 micrograms for adults, and more for groups at risk for vitamin B12 deficiencies such as the elderly, vegetarians and people with gastrointestinal problems.

Maintaining adequate amounts of B12 and all of the vitamins and minerals associated with healthy hair growth production can be done by including vitamin- and mineral-rich foods in one's diet, and possible supplementation through safe pills or multivitamins. "When we choose wholesome, nutrient-dense foods like veggies, berries, clean proteins and healthy fats, and tend to our physical beings through exercise and self-care," Naidoo says, "we naturally feel better both emotionally and physically."

Interested in learning more about vitamins? Read this next:

What does vitamin D do?  Plus who actually needs to be taking this popular supplement.

Are you getting enough vitamin C per day?  And why it matters.

This article originally appeared on USA TODAY: Which vitamin deficiency causes hair loss? All about B12, Vitamin D