search
Health Insiders
Vitamin D – Learn the Unbiased Truth (Information, Benefits, Effects, and Important Facts)

Vitamin D – Learn the Unbiased Truth (Information, Benefits, Effects, and Important Facts)

A Scientific Review of Vitamin D- Learn how much you need, good sources, benefits, and health effects here.

vitamin d

Vitamin D has a range of benefits, it is one of the most common nutrient deficiencies in the world. Image via Shutterstock


Throughout childhood, you may have been told to go outside and get some Vitamin D without knowing what this even meant.

As an adult, you are likely familiar with a relationship between Vitamin D and healthy bones but is that all to Vitamin D?

This article will go over the “ins and outs” of Vitamin D along with the many researched benefits.

What is Vitamin D?

Vitamin D is a fat-soluble vitamin that is obtainable from either dietary intake or produced by your skin when exposed to the sun.

Unlike any other vitamin, Vitamin D acts as a hormone, or messenger, in the body. It helps to coordinate and control other activities throughout our body.

Though before Vitamin D can do anything, it must be converted to its active form.

Types of Vitamin D

While there are several forms of Vitamin D, the two major types are:

  • cholecalciferol, vitamin D3
  • ergocalciferol, vitamin D2

These two types of Vitamin D can be easily retrieved in your diet.

Vitamin D3 is found in animal-based foods like liver, egg yolk, butter, and fish oils. Vitamin D2 is found in plant-based foods like mushrooms and fortified foods. Vitamin D3 is also the type of Vitamin D that your skin will make when exposed to the sun.

Both Vitamin D2 and Vitamin D3 are considered inactive forms of Vitamin D. The liver metabolizes D2 and D3into a different form called calcifediol.

Studies show that Vitamin D3 is more effective at raising calcifediol levels than D2 [1],[2].

Calcifediol is further hydroxylated into its final form of active Vitamin D in the kidneys called calcitriol.

This final step allows Vitamin D to now act as a hormone and complete important roles in our bone health.

Important Roles of Vitamin D

The most well-known role of Vitamin D is role it plays in benefits of bone health. Vitamin D increases calcium absorption in the gut which enables normal mineralization of the bone.

This plays a part in controlling osteoblasts and osteoclasts which helps with bone growth and remodeling.

Besides keeping our bones healthy, other roles of Vitamin D involve cell growth, neuromuscular and immune function, and reduction of inflammation.

These functions help your muscles to move and carry messages to your body through nerves.

Benefits

While a lot of factors play into developing diseases or disease progression, here are some potential benefits of sufficient Vitamin D:

1) Supports healthy bones

Vitamin D prevents rickets in children and osteomalacia in adults. With the help of calcium, Vitamin D can also prevent osteoporosis in older adults.

2) Reduces cancer risk and cancer progression

Studies have shown that a lack of Vitamin D and the sun can increase the risk of cancer.

A study published in the National Institutes of Health found that certain cancers were lower among people living in southern latitudes where southern exposure was high compared to those in northern latitudes [3].

In a study with mice, Vitamin D supplementation decreased cancer cell growth, stimulated cancer cell death, and reduce tumor blood vessels [4].

3) Reduces cognitive decline in older individuals

A study published in JAMA Neurology found Vitamin D prevents cognitive decline. The study recruited 382 participants with an average age of 75.5 years.

Vitamin D levels and cognitive tests were assessed every year for 5 years. Participants with lower Vitamin D levels showed a greater decline in cognitive ability [5].

4) Decreases risk for hypertension

Vitamin D increases an enzyme called renin which regulates the amount of blood and fluid in the veins along with controlling artery restriction.

These roles of renin help control blood pressure and prevent hypertension when correctly regulated.

5) Protects against diabetes

Scientists analyzed 21 studies which together had 76,220 participants. There was a significant association between lack of sunshine and/or Vitamin D supplements with type 2 diabetes risk [6].

6) Supports healthy pregnancies

Inadequate Vitamin D intake during pregnancy has been associated with preeclampsia, gestational diabetes, and cesarean section.

These issues can increase the risk of low birth weight, hypocalcemia, rickets, asthma, and type 1 diabetes.

7) Boost immunity

With Vitamin D’s role in immunity and inflammation, supplementing it can reduce the chances of getting the flu.

8) Combats depression

Studies have found symptoms of Seasonal Affective Disorder, a mood disorder featuring depressive symptoms during seasons with less sunlight, maybe due to changing levels of Vitamin D3.

This may affect serotonin levels which contributes to well-being and happiness [7].

Vitamin D excess

Excessive intake of Vitamin D can lead to a Vitamin D toxicity. Symptoms of Vitamin D toxicity can include anorexia, weight loss, heart arrhythmias, and polyuria.

Potentially, the most serious issue is elevated blood calcium leading to calcification in blood vessels and organs.

Long-term effects of calcification may damage the heart, blood vessels, and kidneys.

Excessive Vitamin D was from sun exposure won’t likely happen as your skin only absorbs the amount needed. The majority of Vitamin D toxicities develop from Vitamin D supplementation.

Tolerable Upper Intake Levels (ULs) of Vitamin D are 4000 IU daily for ages 9 and above. For children ages 8 and below, levels range from 1000-3000 IU.

Recommended Guidelines of Vitamin D

Studies have shown different recommendations for Vitamin D intake. Recommendations maybe different for individuals based on the amount of sunlight received.

According to the US Institute of Medicine, 400-800 IU or 10-20 micrograms is adequate for 97.5% of adult individuals. One study found a daily intake of 1120-1680 IU was needed to obtain sufficient Vitamin D blood levels [8].

Another study suggested that overweight or obese individuals may require higher amounts of Vitamin D [9].

A daily Vitamin D intake of 1000-4000 IU, or 25-100 micrograms, should be enough to ensure sufficient Vitamin D levels. For individuals 18 and younger, the recommended dietary allowance (RDA) is 400-800 IU daily.

Vitamin D Sources

Only a few foods contain Vitamin D naturally. In certain areas of the world, foods come fortified with Vitamin D.

Fish liver oils and flesh of fatty fish like salmon, tuna, and mackerel contain the best sources of Vitamin D. Smaller amounts of Vitamin D are found in beef liver, cheese, egg yolks, and some mushrooms.

In the United States, most milk is voluntarily fortified with 100 IU/cup. Some brands of ready-to-eat breakfast cereals, orange juice, margarine, and yogurt are also fortified with Vitamin D.

Bottom line

It comes in many different forms but is not as plentiful in food as other vitamins.

Vitamin D supplementation may be recommended for certain individuals, especially those who do not receive direct sunlight often.

You should speak with your medical provider about Vitamin D before you begin supplementation.

Feedback:

References

1. Am J Clin Nutr. 2012 Jun;95(6):1357-64. doi: 10.3945/ajcn.111.031070. Epub 2012 May 2. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. https://www.ncbi.nlm.nih.gov/pubmed/22552031
2. Bone. 2013 Oct;56(2):271-5. doi: 10.1016/j.bone.2013.06.012. Epub 2013 Jun 20. Calculated free and bioavailable vitamin D metabolite concentrations in vitamin D-deficient hip fracture patients after supplementation with cholecalciferol and ergocalciferol. https://www.ncbi.nlm.nih.gov/pubmed/23792937
3. Vitamin D and Cancer Prevention - National Cancer Institute https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/vitamin-d-fact-sheet#r7
4. Vitamin D Benefits (& How To Get Enough) https://www.algaecal.com/algaecal-ingredients/vitamin-d/benefits/
5. Link Found Between Vitamin D Deficiency and Dementia https://www.alzheimers.net/8-27-14-vitamin-d-and-dementia/
6. Diabetes Care. 2013 May;36(5):1422-8. doi: 10.2337/dc12-0962. Blood 25-hydroxy vitamin D levels and incident type 2 diabetes: a meta-analysis of prospective studies. https://www.ncbi.nlm.nih.gov/pubmed/23613602
7. Psychological Consequences of Vitamin D Deficiency | Psychology Today https://www.psychologytoday.com/us/blog/the-breakthrough-depression-solution/201111/psychological-consequences-vitamin-d-deficiency
8. Am J Clin Nutr. 2008 Jun;87(6):1952-8. Vitamin D intake to attain a desired serum 25-hydroxyvitamin D concentration. https://www.ncbi.nlm.nih.gov/pubmed/18541590
9. PLoS One. 2014 Nov 5;9(11):e111265. doi: 10.1371/journal.pone.0111265. eCollection 2014. The importance of body weight for the dose response relationship of oral vitamin D supplementation and serum 25-hydroxyvitamin D in healthy volunteers. https://www.ncbi.nlm.nih.gov/pubmed/25372709
10. Vitamin D — Health Professional Fact Sheet https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
11. J Pharmacol Pharmacother. 2012 Apr-Jun; 3(2): 118–126. doi: 10.4103/0976-500X.95506. PMCID: PMC3356951. PMID: 22629085. Vitamin D: The “sunshine” vitamin https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356951/
Author
instagram

Samantha Carter, MS, RD, LD

Samantha is a clinical registered dietitian nutritionist in Houston, Texas. Samantha has worked in many clinical areas of nutrition inc...

READ THIS NEXT

View All
X

How helpful was it?

icon This article changed my life! icon This article was informative. icon I have a medical question. icon Ask a Question
X

How helpful was it?

icon This article changed my life! Change
Your Rating
Note: Health Insiders isn't a healthcare provider. We can't respond to health questions or give you medical advice.
Your Privacy is important to us.
X

How helpful was it?

icon This article was informative. Change
Your Rating
Note: Health Insiders isn't a healthcare provider. We can't respond to health questions or give you medical advice.
Your Privacy is important to us.
X
icon I have a medical question. Change

We’re unable to offer personal health advice, but we’ve partnered with JustAnswer who offers on-demand doctors to answer your medical questions 24/7. Talk online now with a doctor and get fast 1-on-1 answers from the comfort of your couch.

just answer logo
ASK A DOCTOR NOW

If you’re facing a medical emergency, call your local emergency services immediately, or visit the nearest emergency room or urgent care center.

X

How can we improve it?

icon This article contains incorrect information. icon This article doesn’t have the information I’m looking for. icon I have a medical question. icon Ask a Question
X

How can we improve it?

icon This article contains incorrect information. Change
Your Rating
Note: Health Insiders isn't a healthcare provider. We can't respond to health questions or give you medical advice.
Your Privacy is important to us.
X

How can we improve it?

icon This article doesn’t have the information I’m looking for. Change
Your Rating
Note: Health Insiders isn't a healthcare provider. We can't respond to health questions or give you medical advice.
Your Privacy is important to us.
X
icon I have a medical question. Change

We’re unable to offer personal health advice, but we’ve partnered with JustAnswer who offers on-demand doctors to answer your medical questions 24/7. Talk online now with a doctor and get fast 1-on-1 answers from the comfort of your couch.

just answer logo
ASK A DOCTOR NOW

If you’re facing a medical emergency, call your local emergency services immediately, or visit the nearest emergency room or urgent care center.

x

Have a Question? Please Tell Us What We Are Missing Here!

Find answers in product info, Q&As, reviews
Submit Your Privacy is important to us.
X

Healthinsiders.com is intended to be used for educational and information purposes only. All Health Insiders content is medically reviewed and fact-checked by a board of medical experts to ensure accuracy.

In keeping with our strict quality guidelines, we only cite academic research institutions, medical authorities, or peer-reviewed studies in our content. You will be able to find links to these sources by clicking the numbers in parentheses (1, 2, etc.) that appear throughout our content.

Medical Disclaimer: This product/supplement review is not intended to provide diagnosis, treatment, or medical advice. Please consult with a physician or other healthcare professional regarding any medical or health-related diagnosis or treatment options.

Health Insiders does not assume liability for any actions undertaken after visiting these pages and does not assume liability if one misuses supplements. Healthinsiders.com and its Editors do not ensure that unforeseen side effects will not occur even at the proper dosages, and thereby does not assume liability for any side effects from supplements or practices hosted under the domain of Healthinsiders.com.

We invite you to contact us regarding any inaccuracies, information that is out of date, or any otherwise dubious content that you find on our sites via our feedback form.