Find out how getting out in the sun can help your body produce Vitamin D – a vital micronutrient that can not only promote health but can also prevent chronic diseases.

It’s no secret that vitamin D can promote bone health. While you can get this essential nutrient by exposing yourself to sunlight, you can also boost your vitamin D intake with a few foods and supplements.

Checkout how much you actually know about vitamin D! Look at the health benefits of vitamin D, what happens if you do not get enough vitamin D and learn how to boost your vitamin D intake.

What is Vitamin D? What is the function of Vitamin D in the body?

Vitamin D, widely referred to as the “Sunshine vitamin,” is shrouded in mystery. This nutrient has been linked to everything from bone health to improved immunity. 

It’s a fat-soluble vitamin produced in the body when ultraviolet (UV) rays from sunlight strike the skin. Vitamin D helps absorb and balance the levels of calcium in our body, reduce our risk of fractures, and also helps regulate our mood [1].

Vitamin D is obtained in three ways: through the skin, through the diet, and through supplementation. But the amount of vitamin D you get from exposing your bare skin to the sun depends on:

  • The color of your skin– Melanin is the pigment that gives skin its color, and dark-skinned people have more of it than lighter-skinned people. More melanin reduces your ability to synthesize vitamin D from sunlight [2].
  • Latitude– People on the equator receive more sunlight than on poles.
  • Season and time of the day– UV rays are hindered when the sun’s rays penetrate the Earth’s atmosphere at a steep angle which happens during the early and late periods of the day, as well as the majority of the days during the winters.

In most situations, approximately 30 minutes of skin exposure (without sunscreen) of the arms and face to sunlight can provide all the daily vitamin D needs of the body.

Did You know? – Window glasses absorb almost all UV B rays. Thus catching the sun rays in an office or while traveling in a car won’t help you get vitamin D.

Continue reading to know more facts about the benefits of Vitamin D, its food sources, the amounts required in the body, and its available supplements.

Forms of Vitamin D

The two major forms of Vitamin D are:

  1. Ergocalciferol (Vitamin D2) – derived from plants.
  2. Cholecalciferol (Vitamin D3)- derived from animal products and produced in the skin when exposed to sunshine.

Health Benefits of Vitamin D

A few health benefits of vitamin D are

1) Benefits of Vitamin D For Hair

If you don’t have enough vitamin D in your system, new hair growth can be inhibited. Vitamin D aids in the stimulation of both new and old hair follicles and helps hair retain its thickness, and current hair may not fall out prematurely as a result of new follicles. [3].

Alopecia, a condition that affects both men and women, is an autoimmune condition that causes bald patches on the scalp and other parts of the body. It has been linked to a lack of vitamin D [4].

2) Benefits of Vitamin D For Nails

Vitamin D is metabolized in the skin by keratinocytes. Keratin, a protein found in hair, nails, and skin, is processed by these skin cells. Vitamin D keeps your nails healthy and prevents them from peeling and chipping, which can be caused by nutritional shortages. It also helps regulate calcium levels in the body, which is important for strong nails [5].

3) Benefits of Vitamin D For Bones

Vitamin D plays a significant role in regulating calcium, maintaining phosphorus levels in the blood, and maintaining a healthy mineralized skeleton. These factors are vital for keeping bones healthy.[6].

It is required in the intestines to stimulate and absorb calcium and reclaim calcium that the kidneys would otherwise excrete.

Vitamin D deficiency can cause rickets in children and osteoporosis & osteomalacia in adults.

4) Benefits of Vitamin D For babies

Infants are born with minimal vitamin D levels and rely on breast milk, sunlight, or supplementation for vitamin D.

Newborns are susceptible to vitamin D deficiency since the vitamin D content of breast milk is dependent on maternal vitamin D status and is often low. Sun exposure may be restricted for infants living at higher latitudes. Vitamin D helps them build strong bones and teeth, and deficiency of vitamin D in infants can lead to bone malformation (rickets), seizures, and difficulty breathing [7]. 

5) Benefits of Vitamin D For pregnancy

Vitamin D and calcium are essential for the development of the baby’s bones, teeth, kidneys, heart, and nervous system throughout the pregnancy. 

Prenatal vitamin D supplementation improves maternal vitamin D status and may lower the risk of pre-eclampsia (a potential pregnancy complication characterized by high blood pressure), low birth weight, and premature birth [8,9].

6) Aids in weight loss

Vitamin D can raise your body’s levels of the hormone “leptin,” which stimulates the sensation of satiety, giving you the feeling that you’ve had enough to eat and therefore reducing appetite. 

It may also inhibit fat cell storage, thereby reducing fat accumulation [10,11].

7) Reduces effects of flu

Vitamin D supplementation is associated with decreased risk of infection and upper respiratory diseases. It also helps boost our immune function to fight infectious diseases [12].

8) Can reduce the risk of COVID 19

Vitamin D deficiency can be an easily modifiable risk factor of acute respiratory infections [13]. 

Vitamin D supplementation might not reduce the incidence of covid 19 [13]. But adequate vitamin D is important for improving immunity, providing resistance to viral infections and also for reducing inflammation. Vitamin D supplementation in those with a marked deficiency can help reduce the severity of Covid 19 [14,15].

9) May prevent cardiovascular disease

Vitamin D may protect heart health too! Quite a few observational studies reported the link between vitamin D deficiency and the risk of developing hypertension, atherosclerosis (buildup of plaque in the walls of arteries) and heart failure [16].

Vitamin D levels are inversely related to cardiovascular risk and cardiovascular disease. While it isn’t clear if vitamin D supplementation can decrease the risk of cardiovascular disease, having enough vitamin D in your body can help maintain heart health [17].

10) Vitamin D can reduce the incidence of kidney disease

One of the most common characteristics in chronic kidney disease (CKD) is abnormal mineral and vitamin D metabolism. 

Vitamin D deficiency in CKD can also cause hyperparathyroidism, skeletal abnormalities like osteomalacia (softening and weakening of bones), mixed uremic osteodystrophy (abnormal changes in growth and formation of bone) etc [18,19]. 

Treatment with vitamin D supplementation can be helpful in such conditions [20].

Recommended Daily Intake of Vitamin D

In most situations, approximately 30 minutes of skin exposure of the arms and face to sunlight can provide all the daily Vitamin D needs of the body.

Adequate Intake for Vitamin D is [21]:

Age Group Adequate Intake
Infant, 0-12 months 400 IU (10 mcg)
Children, 1-13 years 600 IU (15 mcg)
Adolescent, 14-18 years 600 IU (15 mcg)
Adults, 19-50 years 600 IU (15 mcg)
Pregnant and Lactating women 600 IU (15 mcg)
Elderly,> 70 years 800 IU (20 mcg)

Vitamin D Rich Foods

Only a few foods contain vitamin D naturally- fish liver oils, egg yolk, etc. Others like milk and fat/oil are fortified to meet the adequate intake [22].

Food Sources Amount of Vitamin D/100g
Cod Liver Oil 10,000 IU
Sockeye Salmon 526 IU
Egg Yolk 218 IU
Milk, 3.25% fat 51 IU
Cheese, Cheddar 24 IU
Beef, rib steak 19 IU

Because fruits and vegetables do not contain vitamin D, sunlight and fortified foods are the best sources for people who cannot obtain it from the sources mentioned above.

Some mushrooms on the market have been treated with UV light to increase their vitamin D2 levels. Furthermore, the FDA has approved UV-treated mushroom powder as a food additive for use as a source of vitamin D2 in food products [21].

Also Read: Vitamins in Milk: Health Benefits of Milk You Need to Know

Vitamin D Deficiency

Deficiency is commonly seen in people: 

  • Living in dark, overcrowded slums.
  • People dressed in traditional clothing that covers the majority of their skin.
  • Places where winters are prolonged, and the sun is very mild.
  • Communities with a lot of poverty.
  • People who spend most of their time indoors.

Worldwide, it is estimated that 1 billion people suffer from vitamin D deficiency or insufficiency; it is prevalent among the elderly [23].

A lack of calcium and vitamin D in the diet, poor absorption, or a metabolic need for higher amounts can all lead to deficiency. People who can’t tolerate or don’t consume milk, eggs, or fish, such as those who are lactose intolerant or who follow a vegan diet, are also more likely to develop a deficiency.

Symptoms of deficiency include-

  • Fatigue.
  • Bone and back pain.
  • Impaired wound healing
  • Bone loss
  • Hair loss
  • Depression.

Prolonged deficiency can lead to [21]:

  • RicketsA softening and weakening of bones in children.
  • Osteoporosis– Osteoporosis is defined as “porous bone.” It is a condition in which the bones become brittle and weak.
  • Osteomalacia– It is a disorder characterized by decreased mineralization, which causes the bone to break down faster than it can re-form. It is a condition that affects adults.

Other factors that can reduce Vitamin D absorption include:

1) Where you live

The closer you live to the equator, the easier it is for your body to synthesize vitamin D from sunlight all year. For example, if you live in a northern latitude, such as Anchorage or Alaska, your body will produce less vitamin D during the winter than someone who lives in Miami because Florida receives more UVB rays, which are required to produce vitamin D [24].

2) The amount of skin you expose

You may be at risk of vitamin D deficiency if you wear clothing that covers the majority of your skin. Cloudy weather can also be a problem because it allows fewer UVB rays to reach your skin.

3) The color of your skin

People with darker skin may also have difficulty synthesizing vitamin D from sunlight. Melanin, a pigment found in darker skin, reduces your body’s ability to produce vitamin D in response to sunlight exposure. This essentially means that people with pale skin produce vitamin D faster than people with darker skin.

This essentially means that people with pale skin produce vitamin D faster than people with darker skin, who may require ten times the amount of sun exposure as a lighter-skinned person in order to produce the same amount of vitamin D.

4) The time of year and day

UVB rays are blocked when the sun’s rays enter the Earth’s atmosphere at a steep angle. This occurs during the early and late parts of the day, and for the majority of the day during the winter. So, if you want to boost your vitamin D levels, expose your skin to the sun closer to midday for maximum production.  

5) Season

Vitamin D levels are lowest during the winter months in general. In the summer, the angle of the sun rays  hitting the atmosphere is optimized for vitamin D production because more UVB reaches places far from the equator.

Toxicity of Vitamin D

Most people in the world depend on natural exposure to sunlight to meet their need for this vitamin. There is no risk of toxicity, even if there is prolonged exposure to the sun. This is because the vitamin precursor in the skin is degraded on long exposure and can not be converted to the active vitamin form.

However, prolonged exposure to sunlight regularly can prematurely wrinkle the skin and increase the risk of sunburn and cancer.

Since food sources contain very low amounts of Vitamin D, toxicity mostly results from excess intake of supplements. 

Excess vitamin D raises calcium concentration in the blood (hypercalcemia) and also causes hypercalciuria (excess calcium in the urine). It could be secondary—that is, a side effect of another condition that causes high calcium levels in the bloodstream. Symptoms of deficiency include:

  • Irritability
  • Nausea
  • Vomiting
  • Constipation
  • Weight loss
  • Irregular heartbeat
  • Anorexia
  • Excessive thirst

Severe toxicity results in-Calcification of soft tissues- due to the precipitation of excess blood calcium in soft tissues such as the heart, blood vessels, bronchi, kidney tubules, etc [21,25].

Vitamin D Supplements

There are two types of vitamin D supplements available: D2 and D3.

Vitamin D supplements are available in a variety of forms, including chewable tablets, liquids, and sprays.

Their personal preferences and medical needs determine the type of supplement that a person takes. A liquid or spray, for example, may be more convenient to use than a pill.

What to look for in a supplement

Drug Interactions

Vitamin D has the potential to interact with the following medicines [26]: 

  • Cholesterol-lowering drugs.
  • Laxatives
  • Steroids 
  • Seizure-control drugs (such as phenytoin). 

Before starting a supplement, always tell your doctor about any medications you’re taking, as well as any vitamin D supplements or other vitamins, herbs, or alternative health products you’re using.

FAQs

Q: Does vitamin D deficiency cause hair loss?

A: Vitamin D stimulates new and old hair follicles and a deficiency can lead to hair loss

Q: Best time to take vitamin D?

A: For maximum absorption, the best time to take vitamin D and other fat-soluble vitamins is after you’ve eaten foods that contain fat.

Q: Best time to get vitamin D from the sun?

A: Between 10 a.m. and 3 p.m. is the best time to acquire the most vitamin D from the sun. The UVB rays are particularly strong at this time, and it is also stated that the body is more efficient in producing vitamin D at this time.

Q: How exactly does the sun provide us with vitamin D?

A: When exposed to sunlight, the skin absorbs UV radiation and 7 DHC (7-dehydrocholesterol) is converted into vitamin D3.

Q: Is it okay to take vitamin D every day?

A: It is okay to take vitamin D everyday if your doctor/dietitian tells you to. However, taking more than 4,000 IU (100 mcg) per day especially for long periods of time can cause toxicity.

Wrapping Up

Vitamin D is an essential nutrient, and your vitamin D levels should be fine if you go outside every day and get enough sun exposure. However, the only way to know for sure is to have your blood tested. 

There are numerous health benefits of vitamin D, including the prevention of cardiovascular disease and type 2 diabetes.

Before starting any supplement, it’s usually a good idea to consult with a doctor or a nutritionist.

References

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  2. Slominski, Andrzej, and Arnold E Postlethwaite. “Skin under the sun: when melanin pigment meets vitamin D.” Endocrinology vol. 156,1 (2015)   
  3. Amor, Karrie T et al. “Does D matter? The role of vitamin D in hair disorders and hair follicle cycling.” Dermatology online journal vol. 16,2 3. (2010) 
  4. Lin, Xiran et al. “Vitamin D and alopecia areata: possible roles in pathogenesis and potential implications for therapy.” American journal of translational research vol. 11,9. (2019):  5285-5300 
  5. Almessiere, M A et al. “Qualitative and quantitative analysis of human nails to find correlation between nutrients and vitamin D deficiency using LIBS and ICP-AES.” Talanta vol. 185 (2018): 61-70.
  6. Laird, Eamon et al. “Vitamin D and bone health: potential mechanisms.” Nutrients vol. 2,7 (2010),
  7. Centers for Disease Control and Prevention, Vitamin D, (2021)
  8. Wagner, Carol L et al. “The role of vitamin D in pregnancy and lactation: emerging concepts.” Women’s health (London, England) vol. 8,3 (2012) 
  9. Mithal, Ambrish, and Sanjay Kalra. “Vitamin D supplementation in pregnancy.” Indian journal of endocrinology and metabolism vol. 18,5 (2014)
  10. Gangloff, Anne et al. “Relationships between circulating 25(OH) vitamin D, leptin levels and visceral adipose tissue volume: results from a 1-year lifestyle intervention program in men with visceral obesity.” International journal of obesity (2005) vol. 44,2 (2020)
  11. Chang, Eugene, and Yangha Kim. “Vitamin D decreases adipocyte lipid storage and increases NAD-SIRT1 pathway in 3T3-L1 adipocytes.” Nutrition (Burbank, Los Angeles County, Calif.) vol. 32,6 (2016) 
  12. Gunville, Cameron F et al. “The role of vitamin D in prevention and treatment of infection.” Inflammation & allergy drug targets vol. 12,4 (2013) 
  13. Zemb, Patrick et al. “Vitamin D deficiency and the COVID-19 pandemic.” Journal of global antimicrobial resistance vol. 22 (2020): 133-134. 
  14. Alexander, Jan et al. “Early Nutritional Interventions with Zinc, Selenium and Vitamin D for Raising Anti-Viral Resistance Against Progressive COVID-19.” Nutrients vol. 12,8 (2020) 2358 
  15. Xu, Yi et al. “The importance of vitamin d metabolism as a potential prophylactic, immunoregulatory and neuroprotective treatment for COVID-19.” Journal of translational medicine vol. 18,1 (2020) 322. 
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  17. Skaaby, Tea et al. “Vitamin D, Cardiovascular Disease and Risk Factors.” Advances in experimental medicine and biology vol. 996 (2017): 221-230. 
  18. Chau, Yahn-Yir, and Juhi Kumar. “Vitamin D in chronic kidney disease.” Indian journal of pediatrics vol. 79,8 (2012): 1062-8. 
  19. Zand, Ladan, and Rajiv Kumar. “The Use of Vitamin D Metabolites and Analogues in the Treatment of Chronic Kidney Disease.” Endocrinology and metabolism clinics of North America vol. 46,4 (2017): 983-1007. 
  20. Bover, Jordi et al. “Vitamin D, vitamin D receptor and the importance of its activation in patients with chronic kidney disease.” Nefrologia : publicacion oficial de la Sociedad Espanola Nefrologia vol. 35,1 (2015): 28-41. 
  21. “Vitamin D fact sheet for health professionals” National Institutes of Health, (2021)
  22. Food Data Central, USDA (2021)
  23. Sahota, Opinder. “Understanding vitamin D deficiency.” Age and ageing vol. 43,5 (2014)
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  26. Robien, Kim et al. “Drug-vitamin D interactions: a systematic review of the literature.” Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition vol. 28,2 (2013)