Signs of vitamin D deficiency and (7 Benefits of vitamin D)

Benefits of vitamin D and signs and symptoms of vitamin D deficiency

 Signs of vitamin D deficiency can be subtle and eventually, may lead to many health problems. Unfortunately, signs of vitamin D deficiency are rising globally with up to 1 billion people estimated to have suboptimal levels, research finds.  These suboptimal levels lead to an increase in osteoporosis, bone fractures, and falls especially in the elderly.

Many studies also show a link between vitamin D deficiency and diseases like prostate, colon, and breast cancer. Deficiency is also linked to heart disease, diabetes,  depression, autoimmune diseases, and neurologic conditions such as multiple sclerosis, Alzheimer’s, and Parkinson’s diseases.

Vitamin D is a fat-soluble vitamin that is produced,d in the skin when the skin is exposed to the sun’s UVB light. Unlike other vitamins, vitamin D is a prohormone or a precursor to a hormone. And the fact that there are vitamin D receptors in almost every cell shows its diverse role in many bodily functions.  


Functions of Vitamin D

The NIH fact sheet on vitamin D outlines some of the main functions of vitamin D including:

  • Promoting the absorption of calcium, and phosphorous in the gut
  • Maintains adequate serum calcium levels which help in bone mineralization and keeping bones strong. Without Vitamin, D bones would be brittle and misshapen.
  • Vitamin D’s role in calcium absorption also keeps muscles from involuntary contraction, therefore preventing muscle spasms and cramps.
  • Reduces inflammation
  • Modulates cell growth
  • Immune function
  • Neuromuscular function
  • Modulates gene-encoding proteins
  • Glucose metabolism.

Deficiency in vitamin D has long been known to put one at risk of osteoporosis, osteopenia(soft bone), and rickets in babies with severe deficiency. 

,Signs of vitamin D deficiency




What are the benefits of vitamin D?


#1 Strong bones

vitamin d deficiency signs


Vitamin D regulates calcium and phosphorus in the blood. It stimulates the absorption of calcium from the gut and prevents the kidneys from excreting it. Without optimal vitamin, D secondary hyperparathyroidism happens.

This leads to taking the calcium out of the bones to boost circulating calcium in the blood. The result is weak bones causing rickets in children, osteoporosis, and osteomalacia in adults. 

So vitamin D keeps that from happening by maintaining gut absorption of calcium phosphorous and magnesium to maintain strong bones. 


#2 Improves immune function.

Vitamin D is involved in the function of the immune system and the inflammatory response. Studies have shown that vitamin D may be protective against the flu virus and helps fight and prevent other respiratory illnesses. 

But since not all study’s findings were the same, further research is warranted. 


#3 Reduce the risk of developing diabetes

Vitamin D helps prevent insulin insensitivity and improves the function of beta cells in the pancreas to produce insulin per research.  

According to studies, vitamin D deficiency seems to impair glucose-mediated insulin secretion from the pancreatic beta cells. And vitamin D supplementation seems to restore beta cell function.


#4 Prevention of cancer growth and severity

Per this 2006 study published in the American Journal of Public Health, people living in sunnier areas or those with more sunlight exposure tended to have a lower risk of colon, breast, and prostate cancers. 

Studies found there were fewer incidents of death from colon cancer in areas with more sunny days and more colon cancer deaths in areas that were less sunny. 

Vitamin D may also prevent cancer development and growth according to National Cancer Institute.

Several studies are cited indicating that vitamin D may play a role in stopping cancer development growth and proliferation.

Other studies however are inconclusive, but it doesn’t hurt to make sure that your levels are optimal. 



#5 prevents depression and anxiety

A study in the Journal of Internal Medicine found that for people suffering from depression and anxiety who were low on vitamin D, supplementing improved symptoms.

It is important though to note that you need to see your doctor for evaluation and recommendation.

And also not all cases of depression or anxiety are due to vitamin D deficiency.

Vitamin D deficiency is also a common occurrence in people suffering from fibromyalgia who also tended to have anxiety and depression. In this case, the research found that supplementing with vitamin D also improved these mood problems. 

Related: 10 Habits that make depression worse 


#6 oral health

Vitamin D as we know is crucial in bone health. That also means strong teeth and prevention of tooth decay. Per a 2011 study published in The Tennessee Dental Association, vitamin D helps fight inflammation, and having enough vitamin D may help prevent inflammation in the mouth and gums, as well as promote the production of microbial peptides, further enhancing oral health. 


#7 Healthy pregnancy

Having optimal levels of vitamin D may help with a healthy pregnancy. Studies have found a deficiency in pregnancy can increase the chances of preeclampsia and preterm birth.

And there is also a possibility that low levels of vitamin D as associated with gestational diabetes and infections during pregnancy. 



what is considered low vitamin D?

It appears that experts are not quite in agreement with what the cut-off number for deficiency is.

Some say less than 20 nanograms per milliliter, others less than 30, recommending optimal levels between 30 to 40.

Some doctors feel that deficiency is exaggerated and recommend an optimal level of 12.5 according to an article in Havard health.

  And this 2010 study further talks of a wide optimal range with differences of opinion from experts, but cites a blood level of less than 20 ng per milliliter to be a deficiency and less than 30 to be an insufficiency. 


Who is more at risk of vitamin D deficiency? 

It is difficult to get enough vitamin D from natural foods alone and many people just don’t spend enough time in the sun. 

For these groups without supplementation deficiency easily occurs.

Others can get by getting some sunlight and eating fortified foods but for many, that is not enough. 


The following are the groups most at risk of a vitamin D deficiency. 

Older adults 

As we age the skin loses more of its ability to absorb and synthesize vitamin D.

Also, older adults are less likely to spend much time outdoors in the sun. And too, older adults are likely to be consuming less vitamin D foods. All these factors put older adults at a higher risk for vitamin D deficiency. It is a good idea to have your doctor check your levels to see if supplementation is needed. 


People with dark skin

The larger amount of melanin causing dark skin also leads to the dark skin’s inability to produce as much vitamin D.

Studies show that black people have lower blood levels of vitamin D than white people do.

However, it is not known if this has an effect given that studies find more white people have more bone fractures and weaker bones compared to black people (source). But if you are melanated, have your vitamin D levels checked. 


People with certain chronic conditions. 

Per an article in NIH, certain medical conditions make it hard to absorb fat. And since vitamin D is a fat-soluble vitamin, meaning its transport requires fat molecules, people suffering from these conditions may not get enough vitamin D. These conditions include, liver disease, Kidney disease, cystic fibrosis, celiac disease, Crohn’s, and ulcerative colitis.

   Also, sources say, these people may not also consume certain foods such as milk which is fortified with vitamin D. As such they need a vitamin D supplement. 



Among smokers, levels of vitamin D deficiency appear higher. The reason is associated with the likelihood that smoking may affect the gene that activates the production of vitamin D-3.  



Some medications may reduce how well vitamin D and other nutrients are absorbed and or synthesized. Such drugs include cholesterol-lowering medications,  steroids like prednisone, laxatives, seizure drugs like phenobarbital and Dilantin, some weight-loss drugs, and Rifampin for tuberculosis. 


People who are obese or have undergone a gastric bypass

Obese people or those with a BMI of more than 30 have lower blood vitamin D levels than nonobese people studies find. 

And while fat doesn’t stop the absorption of vitamin D, it does sequester most of the vitamin D. For that reason obese people need more supplementation of vitamin D. 

People who have had a gastric bypass tend to have a vitamin D deficiency as well because the part of the small intestines where vitamin D is absorbed has been bypassed. 

As such expert medical groups in this area have guidelines on supplementing and monitoring vitamin D levels in cases of bariatric surgery per the Official Journal of the American Society of Bariatric Surgery. 



Be sure to consult your doctor before supplementing. While experts are not sure if supplementing during pregnancy is a good idea, the need for more vitamin D may be increased during pregnancy. 


Breastfed infants

Breastfed babies may have a vitamin D deficiency because breast milk doesn’t have enough vitamin D and also depends on the mother’s vitamin D status.  So if she is not consuming enough vitamin D the infant can be deficient as well. 

A mother would need to be consuming at least 2000iu  or 50mcg of vitamin D3  to provide enough to the baby.

  And it is not advised to keep babies in direct exposure to UV light. Intact the American Academy of Pediatrics advises keeping babies younger than six months away from direct sunlight.

 But if they have to be out in the sun dress them in protective layers. It is recommended to give babies 10mcg of vitamin D for breastfed and partially breastfed babies until they are weaned and are consuming at least 1000 ml a day of vitamin D-fortified formula or milk. Check your pediatrician for recommendations.



Other  risk factors  of vitamin D deficiency

Where you live

Living far from the equator where it is cold and the sun doesn’t shine for many months of the year such as in Alaska, Siberia, and areas in  Northern Canada puts one at risk of a vitamin D deficiency.  

 Heavily polluted areas can also put one at risk of deficiency.  Pollution blocks UVB high which is what is needed for the skin to be able to synthesize vitamin D. 


What happens when your vitamin D is low? 

Low vitamin D levels can have serious consequences on health due to vitamin Ds many roles in metabolism, cell growth, immune health, and anti-inflammation effects. When vitamin D is low, the following signs and symptoms of deficiency occur. 


Signs and symptoms of Vitamin D deficiency

signs of vitamin D deficiency

1 Neurological disease and vitamin D deficiency

Multiple Sclerosis

According to studies, there is a strong correlation between vitamin D deficiency and the development of MS. In fact, studies found that the occurrence of MS increased as latitude increased away from the equator and decreased sun exposure. 

It is now known that  MS occurrence is multifactorial, and one of the strongest environmental influences was found to be a vitamin D deficiency. Researchers also found that supplementing with vitamin D decreased symptoms of MS. 


Parkinson disease

Some studies have found that low vitamin D blood levels were found in those with Parkinson’s’ disease.

And it was also evident that the worse the case of PD  the lower the serum D levels were.

In one study low D levels were seen to be a predictor of the development of PD, but further studies seem to refute that. However, supplementation with vitamin D appears to improve PD symptoms and progression. 



2  ache and pains 

signs of vitamin D deficiency

Vitamin D deficiency can cause muscle and bone pain. 

Since vitamin D is needed for calcium absorption, and calcium is required for the strengthening and building of strong muscles, a deficiency can cause the weakening of both muscles and bones. This often causes pain such as back pain and generalized muscle aches.


3 Chronic and frequent infections

Various studies show that a vitamin D deficiency may be implicated in the presence of various infections including bacterial, viral, and even fungal

infections.  Vitamin D works with the innate immune system and with the epithelial cells in many organs including the cells in the gut, the lungs, and the oral cavity.

And according to research, vitamin D can help in healing infections and immune diseases including tuberculosis, psoriasis, Crohn’s, and more.  Research has also found that vitamin D deficiency may lead to more respiratory infections like the flu.


4 Depression

Studies have found an association between depression and other mental health illnesses and depression. 

And this 2008  randomized controlled study found that supplementing with vitamin D improved depression. And there are many more studies that have found supplementing with vitamin D helps improve depression and anxiety. 


5 Hair loss

While stress is associated with hair loss, especially in women, sometimes nutritional deficiency is implicated.  Studies have shown that some conditions such as alopecia areata are significant when vitamin D is low. 


6 Bone loss 

signs of vitamin D deficiency

Vitamin D  is important in bone metabolism and the absorption of calcium from food which is required for building strong bones.

Vitamin D and mineral deficiency are common, especially in postmenopausal and menopausal women a 2015 study published in the Journal of Midlife finds found. Bone density issues tend to result in more fractures in women in menopause and post-menopause. It is important to discuss your vitamin D needs with your doctor to ensure optimal vitamin D levels. 


7 Feeling run down and fatigued

signs of vitamin D deficiency

Unfortunately, chronic exhaustion is common these days due to lives excess such as working too much, doing too much, staying up too late, and more.  Sometimes there are other causes of fatigue that can easily be missed such as a deficiency in vitamin D. 

A case study on a 28-year-old woman who complained of headaches and excessive daytime sleepiness found that chronic fatigue may have been due to vitamin D deficiency.

The researchers followed the woman with excessive daytime sleepiness, fatigue, dizziness, and headaches for 4 months and after supplementing with 50000 IU of vitamin D, her symptoms resolved.

 There is other research also that shows a vitamin D deficiency may cause vertigo, or make it worse, and supplementation seems to decrease symptoms. 

If you are feeling tired all the time, you need to check whether you have a  vitamin D deficiency as one sign of a deficiency is chronic fatigue.  The research found that taking vitamin D supplements improved feelings of fatigue. 


8 weight gain

signs of vitamin D deficiency

 Researchers are not quite sure if vitamin D deficiency causes weight gain. But a 2016 study found that vitamin D may lead to less fat storage. A BMI of greater than 30 is associated with a lower vitamin D level. Vitamin D  deficiency is also associated with weight gain. 

 Fat cells sequester vitamin D and so it is not released into the circulation. Also, overweight people require higher doses of vitamin D to get to optimal levels. Other studies propose that the low vitamin D level in obesity is related to diet habits, and lack of outdoor activities, and sun exposure in this group. 


 9 Vitamin D deficiency and Slow wound healing 

Vitamin D  also plays a role in generating new tissue and slow wound healing may be due to a vitamin D deficiency.

Vitamin D regulates growth factors needed for wound healing and wounds take longer to heal when vitamin D is low. Other studies have found that people with ulcers were more likely to have a vitamin D deficiency. 



10 Infertility

It a possibility, that deficiency in vitamin D may increase infertility incidents.

Researchers found that among women treated with IVF those with less than 20 ng of vitamin D had a harder time conceiving.

However, since there is no researcher showing results after supplementing, it is not quite clear if there is a link.



vitamin D deficiency treatment guidelines 2019

Given the differences in recommendations, and various considerations and levels needed depending on one’s health, it is always best to speak with your doctor before supplementing with vitamin D, or any other supplement.

However, according to Mayo Clinic, the Institute of Medicine recommends 600 IUs for young adults and 800 for adults older than 70.

The Endocrine Society recommends 1500 to 2000ius daily.

Mayo Clinic’s recommendation is 1000-2000 one advises this dose should be adequate to maintain optimal blood levels of vitamin D.

But always be sure to speak to your doctor first.


What are the best vitamin D food sources?

Unfortunately, there are not many foods that naturally contain vitamin D. Fortifications of certain foods help. It is important to get the vitamin D you need from various sources including these food sources:
  • Cod liver oil
  • salmon
  • eggs
  • mushrooms
  • tuna fish
  • fortified foods like cereal, milk, orange juice
  • beef liver


It is important to know your vitamin D level as a deficiency is common. And given the importance of vitamin D in the body, it is therefore important to ensure your levels are optimal. 
Although there are more vitamin D benefits that are not yet conclusive, it is still better to avoid deficiency. 
So eat more food sources of vitamin D, and check with your doctor to see if supplementing is required.  Better yet spend more time outside and get vitamin D from the sun whenever possible.
Of course, this requires one to be careful about too much sun exposure and sunburn or cancer.  Let me know your comments. How are your vitamin D levels? Have you had yours tested? 



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  1. I enjoyed this article so much!
    I got such an education with the information you shared.
    Finally something real without crazy typos and half-baked theories.
    Thank you!

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