7 low vitamin D symptoms and deficiency signs you need to know

Editor: John Ajayi, B.Sc, MBA
Medical review: Moyo Adeyemi, M.B., B.S., FRCPC
Science Editor: Sunday O. Ajayi, Ph.D
A bottle of vitamin D supplements
Vitamin D builds strong bones and strengthens the immune system. Pic credit: stevepb/Pixabay

Low vitamin D symptoms are common among people living in high latitude regions of the world.

If you live at latitudes above 37 degrees north, you are at a higher risk of vitamin D deficiency than people living in places closer to the equator.

Vitamin D is called the “sunshine vitamin” because the skin can only make it when exposed to a part of solar radiation known as ultraviolet B (UVB) radiation.

Solar radiation is richer in UVB in the summer months, especially when the sun is directly overhead during the hours around midday. Sunshine is even richer in UVB at high altitudes and places near the equator.

The discovery of vitamin D, a nutritional factor in cod liver oil that prevents rickets in children, was one of the most important early 20th century breakthroughs in medical research.

The skin does not directly make the sunshine vitamin. It naturally contains a precursor molecule called 7-dehydrocholesterol. The precursor is converted to vitamin D3 (cholecalciferol) in the presence of UVB. Cholecalciferol is then converted to the biologically active form called calcitriol in the liver and kidneys.

We need only about 10-15 minutes of exposure of our arms and legs to sunshine a few times a week to make all the vitamin D we need. However, people living in high latitude regions usually can’t get even a few minutes of the right intensity and quality of sunshine to replenish their vitamin D stores during the long winter months.

7 little-known low Vitamin D symptoms you shouldn’t ignore

Depression is one of the many symptoms of low vitamin D. Pic credit: rebcenter-moscow/Pixabay

The better-known vitamin D deficiency symptoms result from the fact that deficiency reduces intestinal absorption of dietary calcium the body requires from bone mineralization. Deficiency of the sunshine vitamin results in impaired bone mineralization and growth in young children.

However, there are several lesser-known telltale signs and symptoms of low vitamin D you need to know.

Check out the following unusual low vitamin D symptoms.

1. Excessive sweating

Excessive sweating (known as hyperhidrosis) not related to heat or physical exercise is one of the several low vitamin D symptoms that people often miss.

Excessive sweating is one of the earliest signs and symptoms of deficiency of the sunshine vitamin.

In infants, the sign often manifests as sweating in the head region. This explains why physicians often ask mothers to look out for “sweaty heads” in their infants as an early warning sign of deficiency.

2. Hair loss

Hair loss is sometimes a symptom of nutritional deficiencies. Recent studies suggest that vitamin D levels could play a role in certain types of hair loss (alopecia), including alopecia areata and telogen effluvium, a pattern of hair loss that sometimes occurs in women.

“The majority of studies revealed decreased serum 25-hydroxyvitamin D levels in patients with different types of non-scarring alopecia, which could suggest its potential role in the pathogenesis of hair loss,” Gerkowicz and colleagues concluded in their study. “Supplementation could be a therapeutic option for patients with alopecia areata, female pattern hair loss, or telogen effluvium.”

Iron deficiency could also play a role in hair loss, including alopecia areata, telogen effluvium, and androgenetic alopecia.

3. Anxiety and Depression

Studies have linked vitamin D deficiency with increased levels of anxiety and depression. The studies suggest that supplementation could alleviate the symptoms of depression, especially in elderly patients.

“It appears to be a relation between serum levels of 25(OH)D and symptoms of depression,” according to Jorde and colleagues. “Supplementation with high doses of vitamin D seems to ameliorate these symptoms [of depression] indicating a possible causal relationship.”

4. Decreased sexual function and erectile dysfunction

Vitamin D deficiency has also been linked with poor sexual function in men. Studies also suggest that supplementation can boost testosterone levels and sexual function.

“Vitamin D is important for the wellness of male sexual function, and vitamin D administration improves sexual function,” Tirabassi and colleagues concluded.

Another study concluded that men suffering from severe erectile dysfunction (ED) had lower levels of the sunshine vitamin than men with milder ED symptoms.

“This meta-analysis suggests an association between vitamin D deficiency and the presence of severe forms of ED, independent of testicular function,” Crafa and colleagues concluded.

5. Fatigue and excessive daytime sleepiness

Due to its involvement in the regulation of immune function, low Vitamin D compromises the body’s immunity resulting in fatigue and weakness.

Studies have found a link between excessive daytime sleepiness (EDS) and low vitamin levels.

According to McCarty and colleagues, “The results suggested the novel possibility that Vit D deficiency-related disease has a yet-to-be-identified mechanistic role in the presentation of sleepiness, sleep disorders, or both.”

6. Pains and aches

There is evidence that vitamin D deficiency causes muscular and skeletal pains and aches. Patients with deficiency of the sunshine vitamin often present with back pain, generalized bone pain, and body aches.

Vitamin D deficiency may worsen back, neck pain, and muscle spasm (Cai, 2019).

Studies indicate that supplementation alleviates the troublesome symptoms of aches and pain in patients confirmed to have low blood levels of the vitamin.

Another recent study found that supplementation improved muscle strength and boosted athletic performance in people with low vitamin levels.

7. Ear diseases and tinnitus

Several studies have found a link between ear, nose, and throat (E.N.T.) diseases (including hearing loss) and vitamin D deficiency (Brookes, 1983; Ghazavi et al., 2020).

Bigman (2022) reported that vitamin D deficiency was associated with hearing loss in older adults.

A study found a high incidence of deficiency among E.N.T. patients and that supplementation yielded “promising” results in many cases. The researchers recommended “empirical supplementation in patients not responding to conventional treatment.”

A 2021 study also found a link between tinnitus (ringing in the ears) and low vitamin levels.

“Our findings suggest that a large proportion of tinnitus patients suffers from vitamin D deficiency and that levels correlates with tinnitus impact,” the researchers concluded. “We recommend a vitamin D assessment for all tinnitus patients.”

What does vitamin D do?

Woman with low vitamin D symptoms
Low vitamin D symptoms afflict millions of people. Pic credit: Mojpe/Pixabay

If you’ve been asking what is vitamin D good for, here is what you need to know.

1. Good for Strong bones

Low vitamin D levels lead to the weakening and softening of developing bones in children and a condition called rickets characterized by slow growth and bow legs (genu varum).

The bowing of the legs in young children is caused by the pressure of the bodyweight on the weakened leg bones.

In adults and growing adolescents, deficiency could lead to osteomalacia, characterized by dental problems, weak, brittle and deformed bones susceptible to fracture. A condition called tetanic hypocalcemia also afflicts infants with low vitamin levels. Tetanic hypocalcemia causes involuntary muscle contractions that lead to cramps and spasms in patients.

A 2020 study concluded that the “use of vitamin D supplement, especially vitamin D3, could reduce the incidence of fall. Only vitamin D with calcium supplement showed benefit in fracture reduction.”

2. Reduces inflammation

The sunshine vitamin reduces inflammation. It is involved glucose metabolism and regulation of vital processes such as cell growth and neuromuscular function.

3. Boosts immunity and protects from various diseases

The sunshine vitamin plays an important role in maintaining the immune system.

It is involved in the processes of the immune cells, such as B and T cells. It modulates immune response and deficiency is associated with increased susceptibility to infections.

Supplementation reduces the risk of acute respiratory tract infections.

4. Prostate and breast cancer

Vitamin D supplementation protects against certain types of cancer, including colon cancer, prostate cancer in men, and breast cancer in women.

A study found a link between low Vitamin D and aggressive prostate cancer in men.

Deficiency of the vitamin is also associated with an increased risk of various health problems, such as cardiovascular diseases, hypertension, diabetes, and multiple sclerosis.

5. Dementia and Schizophrenia

Some studies have reported a link between low vitamin D and dementia, including Alzheimer’s disease. Severe deficiency was found to be strongly linked with hearing loss and dementia in older adults (Geng et al., 2022;. Kang et al., 2021; Szeto et al., 2021).

Other studies found that people with schizophrenia had a higher incidence of deficiency.

Emotional and mental health issues may also be associated with iron and vitamin B12 deficiencies.

6. Multiple sclerosis

Vitamin D deficiency is one of the nutritional factors that may increase the risk of developing multiple sclerosis. Some studies indicate that MS patients low in the sunshine vitamin may experience more frequent and severe relapses.

What causes low Vitamin D symptoms?

Low vitamin D is common among people living in the northern hemisphere. Pic credit: unknownuserpanama/Pixabay

People living in higher latitude regions suffer a higher risk of low vitamin D symptoms. The risk is further compounded by diets lacking in the vitamin. Young children and the elderly who have little exposure to sunshine are also at greater risk than the rest of the population.

Frail elderly people who live in care homes are also susceptible to deficiency.

Rickets used to be very common among young children in the U.S. and Canada. Today, the condition is rare due to the widespread consumption of dairy products, breakfast cereals fortified with the vitamin, and supplements.

Dark-skinned people and immigrants from tropical countries living in higher latitude regions of North America and Europe are also particularly susceptible to deficiency of the sunshine vitamin.

The skin pigment melanin acts as a broadband UV absorber. Thus black Africans and other people with dark skins do not make as much of the vitamin when exposed to the same amount of sunshine as lighter-skinned people.

Doctors often advise dark-skinned people living in the northern hemisphere to increase their supplementation.

However, deficiency is relatively rare among dark-skinned people living in sunny tropical countries. Health conditions caused by vitamin D deficiency — such as rickets — found among young children in these countries are due to diets with low calcium and phosphorus levels.

People who have trouble absorbing fat due to health conditions, such as Crohn’s disease, celiac disease, and ulcerative colitis, are also at higher risk of deficiency and need to take extra amounts. Vitamin D is a fat-soluble nutrient absorbed along with dietary fat, so those who have difficulty absorbing fat will also have trouble absorbing it.

Patients who have also undergone gastric bypass surgery are more likely to suffer deficiency.

How to get vitamin D

You can get enough of the vitamin by ensuring you get plenty of sunshine. However, if you aren’t getting enough exposure to solar radiation, you can also get vitamin D3 by purchasing high potency supplements.

In addition to sunshine and supplements, you can get vitamin D by eating foods rich in the nutrient. You can prevent deficiency symptoms by eating these foods:

  • Cod liver oil
  • Oily fish, such as salmon, sardines, herring, swordfish, and mackerel
  • Liver
  • Egg yolk
  • Fortified dairy products, including milk, yogurts, and cheese
  • Fortified breakfast cereals and some fruit juices

How much Vitamin D should I take?

Nutritionists have established a Vitamin D recommended daily allowance (RDA) of at least 400 IU (10 mcg) for children less than a year old, 600 IU for people up to 70 years (15 mcg), and 800 IU for people older than 70 years (20 mcg).

Experts advise pregnant and breastfeeding women to take 600 IU daily.

These amounts are considered sufficient to maintain optimum calcium metabolism and bone health.

Older people need more because they are less able to manufacture the vitamin on exposure to sunlight. They also absorb less of the vitamin through the gut.

Can you overdose on vitamin D?

Getting too much vitamin D can make you sick. People usually get too much of the vitamin from supplements. However, you can’t get too much from sunshine because your skin will simply stop producing more when your body has had enough.

Individuals with excessively high levels of vitamin D can experience symptoms, such as nausea and vomiting, weakness, mental confusion, loss of appetite, frequent urination, thirst, dehydration, and kidney stones.

Excessive levels can lead to serious health complications, such as irregular heartbeat, kidney failure, and death.

How much vitamin D is too much?

According to the National Institute of Health (NIH), experts recommend the following upper daily limits of vitamin D intake:

  • Birth to 6 months — 1000 IU or 25 mcg
  • Infants 7–12 months — 1500 IU or 38 mcg
  • Children 1–3 years — 2,500 IU or 63 mcg
  • Children 4–8 years — 3,000 IU or 75 mcg
  • Children 9–18 years — 4000 IU or 100 mcg
  • Adults 19 years and older — 4,000 IU or 100 mcg
  • Pregnant and breastfeeding teens and women — 4,000 IU or 100 mcg

A note to our readers

We recommend that you talk to your healthcare provider if you believe you may have symptoms of vitamin D deficiency. While this article is based on peer-reviewed studies published by reputable academic journals, information from authoritative government agencies and societies, it meant only for informational purposes. It is not intended to take the place of professional medical advice and healthcare service.

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