Why You Should Take Vitamin D Supplement

Updated on December 31, 2017
Beth Eaglescliffe profile image

Science graduate and business advisor, health educator and author, Beth writes articles on a wide variety of subjects.

Sunshine is top source of Vitamin D, but oranges can also help.
Sunshine is top source of Vitamin D, but oranges can also help. | Source

The Main Source of Vitamin D is Natural Sunlight

Do you …

  • Use a high SPF sun barrier cream
  • Work long hours in an office environment
  • Cover up your arms, legs, face for religious or cultural reasons
  • Stay out of direct sunlight because of sensitive skin
  • Have a restricted diet that excludes fish, red meat or eggs
  • Stay indoors all the time through frailty or ill health (e.g. live in a care home or other institution)

If any of these apply to you, you may need to take Vitamin D tablets. You are not getting enough exposure to natural sunlight.

Between 1988 and 1994, 45 percent of 18,883 people had 30 nanograms per milliliter or more of vitamin D; a decade later, just 23 percent of 13,369 of those surveyed had at least that amount. The slide was particularly striking among African Americans: just 3 percent of 3,149 blacks sampled in 2004 were found to have the recommended levels compared with 12 percent of 5,362 sampled two decades ago.

— Scientific American 2009

The Importance of Vitamin D

Consult Your Doctor

This article is for general information only. For health advice you should consult a medical doctor or nurse practitioner.

Why There's a Need for Vitamin D Supplements

A well-balanced diet and active lifestyle should give you all the vitamins and nutrients your body needs. This assumes that you spend some of your day out-of-doors in the fresh air and sunshine. There's normally no need for a healthy adult to take any vitamin supplements unless you are advised to do so by a medical doctor or nurse practitioner.

The one exception to this is Vitamin D. Research studies show that a large percentage of people who live in less sunny climates are deficient in this vitamin. (The non-profit Vitamin D Council lists relevant studies on its website.) If you decide to take a vitamin d supplement there is no proven difference in effect between swallowing a cheap generic tablet and a more expensive branded one.

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Vitamin D promotes calcium absorption in the gut … . It is needed for bone growth … Without sufficient vitamin D, bones can become thin, brittle, or misshapen. Vitamin D sufficiency prevents rickets in children and osteomalacia in adults. Together with calcium, vitamin D also helps protect older adults from osteoporosis.

— US National Institute of Health

Signs and Symptoms of Vitamin D Deficiency

Vitamin D is essential for good body health. It helps control the amount of calcium and phosphate in your body. These nutrients help you maintain healthy bones, teeth and muscles. For most people the only sign they may have low vitamin D levels are vague symptoms such as intermittent bone pain or muscle tenderness.

There are virtually no obvious external signs you are lacking vitamin D. It’s difficult to know you don’t have enough unless it is a severe deficiency. There are blood tests available that reveal your levels of vitamin D, but these can be expensive and the test may not be offered routinely to patients.

In extreme cases, bone diseases such as rickets can result from vitamin D deficiency. This was a common disease in Victorian times when people lived in crowded slum conditions with poor diets and little access to fresh air and sunshine. However in the later part of the 20th century and into 21st century rickets has become rare in developed countries.

10 Warning Signs of Serious Lack of Vitamin D

Good Sources of Vitamin D

The main (and free) source of vitamin D is sunlight. It’s not enough to sit in a sunny room. The window glass blocks the UVB (ultra violet-B) rays. These are the ones that you need to produce vitamin D. You need to get outdoors and feel the sunshine on your skin to benefit from its health giving properties. During summer months, most people will get enough sunlight on their skin without having to think too much about it. However, during the winter months, or if you are someone who does not get much sun in the summer (see the opening paragraph above) then you should consider taking vitamin D supplement.

The main source of Vitamin D is sunshine, but there is some in these foods.
Oily fish (such as salmon, sardines, herring and mackerel)
Red meat
Egg yolks
Fortified foods (many fat spreads, some milks and some breakfast cereals)

How Much Sunlight Do You Need?

There's no simple answer to this question. A key factor is the color of your skin. The darker your skin, the more melatonin pigment is present. This pigment interferes with the amount of UVB penetrating the skin. Thus you need to spend longer in the sun to manufacture enough of this vital vitamin.

Using sun block with a high SPF also blocks the UVB rays that are needed to produce vitamin D. There is a dilemma here. You need to protect your skin against burning and potentially skin cancer, while at the same time allow enough sunlight onto your skin to achieve overall bone and muscle health.

Sardines are a good source of Vitamin D.
Sardines are a good source of Vitamin D. | Source

Because vitamin D is found only in a small number of foods, it might be difficult to get enough from foods that naturally contain vitamin D and/or fortified foods alone. So everyone, including pregnant and breastfeeding women, should consider taking a daily supplement containing 10mcg of vitamin D.

— www.nhs.uk
Dairy (milk, cheese, cream and butter) adds sunshine to your diet.
Dairy (milk, cheese, cream and butter) adds sunshine to your diet. | Source

Recommended Daily Dose

There's no universally agreed daily dose of vitamin D supplement.

The US National Institutes of Health recommends an adult dose of 15 mcg (600 IU) per day.

The UK National Health Service recommends a slightly lower adult dose of 10mcg (400IU) per day.

Both health bodies advise against taking more than 100mcg (4,000 IU) of vitamin D a day, as it can be harmful. If you take too much vitamin D over a long period it could cause hypercalcaemia (high levels of calcium in the blood). This condition affects the bones, kidneys and heart.


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  • Kristen Howe profile image

    Kristen Howe 15 months ago from Northeast Ohio

    Great hub, Beth. This is so insightful and useful to know about Vitamin D. I take multi-vitamins for my leukopenia, and Vitamin D is one of the Vitamins I use with two gummy tablets.

  • MsDora profile image

    Dora Weithers 15 months ago from The Caribbean

    Many people are not aware of the importance of Vitamin D. On year I was so deficient that my dosage had to be prescribed. Thank you for underscoring these important facts that we need to know.