Vitamin D is an important nutrient that is essential to our health. It boosts immunity, keeps bones strong and skin healthy, stimulates cell growth, and helps create new hair follicles. You absorb vitamin D through sun exposure primarily, but you can take dietary supplements and eat certain foods to up your intake of the nutrient.

A number of symptoms, such as hair loss, can occur when your body lacks the recommended amount of vitamin D. Vitamin D deficiency has been linked to alopecia, also known as spot baldness, and a number of other health conditions. These include bone softening, low bone density, osteoarthritis, heart disease, and cancer.

Recommended doses of vitamin D

It’s recommended that you get at least 600 IU (international units) — or 15 micrograms (mcg) — of vitamin D a day starting at the age of 1. Babies younger than 1 should receive 400 IU of vitamin D. For people over the age of 70, the suggested intake jumps to 800 IU (or 20 mcg). If you’re concerned about your vitamin D intake, ask your doctor about checking your vitamin D levels. When you get the recommended daily amount of vitamin D, you’re able to maintain hair growth, bone health, and normal calcium breakdown.

Research shows that a lack of vitamin D in your body can lead to hair loss. One role vitamin D plays is stimulating new and old hair follicles. When there isn’t enough vitamin D in your system, new hair growth can be stunted.

Vitamin D deficiency has been linked to alopecia, the autoimmune condition that causes bald patches on the scalp and other areas of the body. Both men and women can experience alopecia. Another study found that women 18 to 45 years old who experienced alopecia or other types of hair loss had low levels of vitamin D.

Reasons for insufficient vitamin D levels include spending more time indoors, wearing a lot of sunscreen, and not eating foods packed with the nutrient.

Vitamin D supplements

Multivitamins typically include only 400 IU of vitamin D, which is below the recommended daily allowance. You should also receive some vitamin D in your diet. Your doctor can check blood levels of vitamin D and decide the dose of supplementation. If levels are very low, high prescription doses might be recommended by your doctor. Make sure to take the supplement during mealtime so your body can absorb the fat-soluble vitamin properly. Breast-fed babies receive their nutrients through their mother’s milk. If a breast-feeding mother doesn’t have an adequate amount of vitamin D in her diet, her baby will likely need a vitamin D supplement.

Sun exposure

Most people get the bulk of their vitamin D from basking in the sun. Not spending enough time in the sun or using too much sunblock limits your exposure, which can lead to a deficit of vitamin D. If you can, take a 15-minute tour of your neighborhood on a sunny day. There is a fine balance between protecting our skin from sun exposure and absorbing vitamin D. If you can’t stay in the sun for long, try to spend some extra time near a window where sunlight is shining through.

Foods with vitamin D

Eating a healthy diet of foods naturally containing or fortified with vitamin D can improve your levels. Some foods are naturally rich with the nutrient. Salmon, mackerel and other fatty fish, fish liver oils, and animal fats are great sources. In fact, one tablespoon of cod liver oil provides 340 percent of your daily vitamin D value. But you can also eat food products fortified with vitamin D, such as certain cereals, milk, and orange juice. Vegan and vegetarian diets, though, tend to lack enough vitamin D, so supplements may be needed if you follow that lifestyle.

Studies shows that vitamin D receptors, rather than the nutrient itself, can help produce new hair follicles and restore hair growth. A 2014 study published in Molecular Endocrinology found that hair regrew in mice two weeks after introducing vitamin D receptors in the VDR null rodents. But scientific research is scarce on how long it will take for hair to grow back — and if there is a significant amount of hair regrowth — after upping your vitamin D intake and improving your levels. Anecdotal evidence, though, suggests hair may stop shedding and regenerate in as little as two months after treatment.

A lack of vitamin D can lead to a number of symptoms, including hair loss. You can start to boost your nutrient levels by spending an extra hour in the sun or by taking vitamin D supplements, which you can buy at your local supermarket or pharmacy for $10 or less. But make sure to consult your doctor first about your best treatment options for hair loss caused by vitamin D deficiency.