Introduction

The human body relies on a variety of hormones, vitamins, and nutrients to maintain balance and proper cell function. Among the 13 essential vitamins, there are water-soluble (B1, B2, B3, B5, B6, B7, B9, B12, C) and fat-soluble (A, D, E, K) types. Vitamin D, also known as the Sunshine vitamin or Calciferol, is important for overall health and can be obtained through diet and sun exposure. This blog focuses on the benefits of vitamin D and some of its fruit sources.^1-3

Role of Vitamin D in Our Body Functions

Calcium and phosphate are two minerals present in major quantities in teeth, bones, and muscles. The amount of calcium and phosphate available in the body is regulated by Vitamin D. Bodies that are deficient in Vitamin D are more prone to bone fractures and delayed recovery, osteomalacia, rickets, and brittle teeth. ² 

• Vitamin D helps in the absorption of calcium and phosphate as calcium and phosphate are vital for bone formation, healthy teeth, and preventing tetany (involuntary muscle contraction). ⁴
• In both children and adults, vitamin D plays an important role as its optimum serum concentration in the body prevents rickets, osteomalacia, and osteoporosis. 
• Vitamin D plays an important role in hormone function in several ways:
  • Firstly, vitamin D helps regulate the production of parathyroid hormone (PTH), which is important for maintaining calcium and phosphorus levels in the body. When calcium levels are low, PTH stimulates the release of calcium from bones into the bloodstream, which helps maintain normal calcium levels in the blood. Vitamin D helps increase the absorption of calcium from the intestines and helps the kidneys retain calcium, which can help reduce the amount of PTH that needs to be produced.
  • Secondly, vitamin D is involved in the regulation of insulin secretion and glucose metabolism. Studies have shown that low vitamin D levels are associated with an increased risk of type 2 diabetes and that vitamin D supplementation can improve insulin sensitivity and glucose tolerance.
  • Thirdly, vitamin D plays a role in the production and regulation of sex hormones, such as oestrogen and testosterone. Vitamin D receptors have been found in several reproductive organs, including the testes, ovaries, and uterus, suggesting that vitamin D may play a role in the regulation of sex hormone production.
• Studies have found that people with low vitamin D levels are more likely to experience symptoms of depression and anxiety than those with normal levels. In addition, vitamin D supplementation has been shown to improve mood in people with depression.
• One theory is that vitamin D may help regulate the production of serotonin, a neurotransmitter that plays a key role in mood regulation. Low levels of serotonin have been linked to depression, and studies have shown that vitamin D supplementation can increase serotonin levels in the brain.
• Another theory is that vitamin D may have anti-inflammatory properties that help reduce inflammation in the brain, which is believed to be a contributing factor in depression.¹¹

As we all know that our body cannot produce vitamin D, we must consume foods that are rich in vitamin D because sun exposure may not suffice. Vitamin D is essential in calcium absorption, muscle regulation, and some other functions. Some studies show that mushrooms may give a good boost of vitamin D. According to some research, 100g servings of vitamin D might be able to provide 50 to 100% of the daily requirement of vitamin D.

Dr. Siddharth Gupta, MD

Also Read: Vitamin D3 Benefits: A Research-Based Approach to Optimal Health

Recommended dietary allowances for vitamin D

The Food and Nutrition Board (FNB) committee has set Recommended Dietary Allowances (RDAs) for vitamin D, that indicate its needed daily intake to support proper bone health and normal calcium metabolism in individuals without any health conditions. 

• The RDAs for vitamin D are provided in two units of measurement: micrograms (mcg) and international units (IU). It is important to note that 1 mcg of vitamin D is equivalent to 40 IU.⁴

Our body needs vitamin D for multiple bodily functions that include maintaining bone health, regulation of muscle function, upliftment of mood, etc. According to some studies, vitamin D might also guard against various forms of cancer, cardiovascular diseases, depression, etc.

Dr. Rajeev Singh, BAMS

Also Read: What is Monk Fruit: Discovering the Health Benefits and Potential Uses

What are the best sources of Vitamin D?

The best sources of this vitamin are fatty fish (salmon, mackerel), cod liver oil, fortified cereals, oranges, milk, and dairy products.¹   However, there are some fruits (vitamin D fruits), cereals, and vegetables which have some percentage of vitamin D.  

Some of the other rich sources of vitamin D: 

• Only a few natural food sources contain vitamin D, with fatty fish like trout, salmon, tuna, and mackerel, as well as fish liver oils, being the preferred choices. 
• Interestingly, a study revealed that when considering the vitamin D content of chicken, turkey, and eggs, the total vitamin D content can be 2 to 18 times higher compared to the vitamin alone, varying depending on the specific food.⁴

Also read: Boost Your Mood: Methods To How To Increase Serotonin Levels

Research facts

• Approximately one billion individuals worldwide are affected by a deficiency of vitamin D.⁷
• As per a study on an updated overview of the global status of vitamin D levels. It reveals that low vitamin D status is a widespread issue across all age groups, even in countries with year-round sun exposure. The problem is particularly prominent in the Middle East, especially among girls and women.³
• Several factors contribute to this highly prevalent vitamin D deficiency, including reduced vitamin D production in individuals with darker skin or ageing, limited sun exposure due to clothing choices, and inadequate vitamin D intake combined with high rates of obesity worldwide.³

FAQ’s

Conclusion

Diet and exposure to the sun are simultaneously required to maintain decent levels of vitamin D. As mentioned above, there are a few fruits (vitamin D fruits) and vegetables whose daily intake can aid in maintaining stronger bones, teeth, and immunity. Sun exposure is very essential for vitamin D to get absorbed, therefore, 10 to 15 minutes of sunshine exposure thrice a week is sufficient to maintain optimum vitamin D levels for our body.¹ 

Disclaimer: The information included on this site is for educational purposes only and is not intended to be a substitute for medical treatment by a healthcare professional. Because of unique individual needs, the reader should consult their physician to determine the appropriateness of the information for the reader’s situation.

References

1. Vitamins: MedlinePlus Medical Encyclopedia [Internet]. Available from: https://medlineplus.gov/ency/article/002399.htm

2. Vitamin D – NHS [Internet]. [cited 2023 May 2]. Available from: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/

3.        Palacios C, Gonzalez L. Is vitamin D deficiency a major global public health problem? J Steroid Biochem Mol Biol [Internet]. 2014 [cited 2023 May 2];144PA(PART A):138. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4018438/

4.       Vitamin D – Health Professional Fact Sheet [Internet]. [cited 2023 May 2]. Available from: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/ 

5.         Cell Cycle [Internet]. [cited 2023 May 3].  Available from: https://www.genome.gov/genetics-glossary/Cell-Cycle 

6.         Vitamin D | The Nutrition Source | Harvard T.H. Chan School of Public Health [Internet]. [cited 2023 May 2]. Available from: https://www.hsph.harvard.edu/nutritionsource/vitamin-d/

7.        Vitamin D Deficiency: Causes, Symptoms & Treatment [Internet]. [cited 2023 May 2]. Available from: https://my.clevelandclinic.org/health/diseases/15050-vitamin-d-vitamin-d-deficiency  

8.      Risk of Incident Kidney Stones. J Urol [Internet]. 2017 Feb 1 [cited 2023 May 2];197(2):405. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5241241/ 

9.     Vitamin D Toxicity: What It Is, Causes, Symptoms & Treatment [Internet]. Available from: https://my.clevelandclinic.org/health/diseases/24750-vitamin-d-toxicity-hypervitaminosis-d

10.    Vitamin D Deficiency and Oral Health: A Comprehensive Review – PMC [Internet]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7285165/

11.  The parathyroid glands and vitamin D – endocrinology – NCBI bookshelf [Internet]. The parathyroid glands and vitamin D. 2001 [cited 2023 May 19]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK24/