Vitamin D revealed

Vitamin D is actually a vitamin and a hormone because it can be聽manufactured聽in the body. This vitamin/hormone is聽produced from cholesterol聽when聽our skin聽comes into direct contact with聽electromagnetic radiation, transmitted from the sun. Sunlight interacts with cholesterol to form cholecalciferol which is then聽transformed into 25-hydroxycholecalciferol in the liver, another form of vitamin D. The liver then sends this form of vitamin D to the kidneys for conversion into its most active state, 125-dihydroxycholecalciferol, commonly聽referred to聽as vitamin D3.聽

Many people think of vitamin D as the bone and immune health vitamin however, it聽is responsible for many more functions in the body which we will discuss today.

Vitamin D receptors聽can be found in nearly every type of human cell聽in the body, confirming its importance for whole-body health.聽


Optimal vitamin D levels

Deficiency in vitamin D has been linked with聽numerous diseases which is why establishing optimal levels is so important to ensure you stay well. Vitamin D status may be a聽more significant determinant of disease risk than we think.

But before you decide to start supplementing, it is recommended to聽test your levels聽in order to establish whether deficiency is an issue for you or not聽and to determine聽your dosage.

The聽National Institute of Health, adequate levels fall around聽20 ng/ml, though optimal ranges aim for much higher聽from 50 to 70 ng/ml聽(1).

Vitamin D levels can be tested聽via聽bloodwork聽blood by asking your medical provider for a聽25-Hydroxy聽Vitamin D test.聽


Symptoms of low vitamin D

A deficiency in vitamin D聽can show up聽quite聽commonly, especially in countries that are far away from the equator. A聽 Canadian 2013 study showed Inadequate levels of vitamin D affected聽about 32% of Canadians while10% were deficient (2).聽Up聽to one-third of Canadians are said to reach below the聽recommended levels of vitamin D.

Vitamin D requirements usually increase during the winter months when sunlight exposure is limited.

Signs and symptoms associated with low vitamin D status include:

  • mood imbalances such as anxiety and depression
  • fatigue
  • bone pain and bone loss
  • muscle weakness and cramps
  • compromised immunity and falling sick often
  • slow聽wound healing
  • hair loss

Research also suggests that vitamin D聽therapy could also help to prevent and treat certain conditions聽such as diabetes, cardiovascular disease, glucose intolerance, and autoimmune conditions.聽


Causes of low vitamin D聽

  • Low dietary intake
  • Impaired digestive absorption聽such聽as fat malabsorption or gastric bypass surgery
  • Excessive alcohol consumption
  • Tobacco smoking聽
  • Limited聽access聽to direct sunlight聽
  • Decrease in cutaneous vitamin D synthesis
  • Impaired conversion from the kidneys聽

Additional factors that can be linked to low vitamin D include obesity, impaired absorption in cases such as celiac and聽Crohn's disease, darker colored skin tones,聽 and kidney and liver diseases.聽

Due to the importance of vitamin D for bone health, a deficiency is particularly聽problematic in elderly populations聽and can聽increase the risk of bone loss and osteoporosis.聽


How much vitamin D should聽I supplement?

Though we always suggest testing to verify your personal levels,聽requirements will vary with age as well. These are the recommendations from the聽National Istntitue of Health:聽

  • 0-6 months: 1000 IU
  • 7-12 months: 1,500 IU
  • 1-3 years: 2,500 IU
  • 4-8 years: 3,000 IU
  • 9-18 years: 4,000 IU
  • 19+ years: 4,000 IU

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When should I take vitamin D?聽聽

As a fat-soluble vitamin, it is recommended to take vitamin D along with a meal that contains fat in order to聽improve the absorption rate

Morning is聽most likely the best time to take聽vitamin D as it聽could potentially affect聽sleep聽if taken later at night. This also helps to support聽our natural circadian rhythm.聽

Supplementing with vitamin D has the potential to interact with various medications so be sure to verify with your health care practitioner聽to avoid any potential interactions.聽

Supplementing with vitamin D

Vitamin D supplementation is available in various forms such as capsule, powder, liquid, and intravenously.聽

The 2聽primary forms of vitamin D are vitamin D2聽(ergocalciferol) and vitamin D3 (cholecalciferol).

Vitamin D2 is聽found in plant sources聽whilst vitamin D3聽can be聽found in animal products, the same聽type produced by our skin with exposure to sunlight.

Evidence聽favors聽vitamin D3 as being the more bioavailable and bioactive form as聽experts believe it to be the more potent form of the vitamin聽(3).

This is why we recommend聽choosing聽vitamin D3 when you are looking for a supplement. Cod liver oil is another food supplement source of聽vitamin D, shown to be the richest source of vitamin D found in foods.聽


What helps the absorption of vitamin D?

It is聽not enough to simply take a vitamin D supplement, you must be absorbing it! Improving the absorption of vitamin D and its聽beneficial effects in the body will be determined by various factors.

As mentioned before, vitamin D is a fat-soluble vitamin therefore either taking the vitamin聽alongside聽dietary fat聽or聽choosing a supplement that already provides a fat such as coconut or olive oil will help to improve the absorption. It is usually recommended to take your vitamins with food to improve the assimilation of the nutrients.聽

The effectiveness and benefits of vitamin D are also linked to adequate intake of other nutrients such as magnesium as聽this mineral聽helps to activate vitamin D in the body聽(3).聽

Vitamin K2 is also recommended alongside vitamin D as vitamin K2聽helps to enhance the effects of vitamin D and ensure it goes exactly where it is needed in the body instead of coagulating in the arteries.

In order to ensure healthy bones, vitamin D works best with adequate calcium, phosphorus, magnesium, and vitamin K2 intake. This is why most bone supporting formulas include these vitamins and minerals together as they work more effectively synergistically than isolated.聽


Restoring聽vitamin D levels

Your personal vitamin D status will determine your course of action to restore your vitamin D levels. If you do find out you are deficient, you聽will require higher levels of vitamin D for a certain period of time, usually several weeks. We recommend working with your health care provider to ensure you are doing this properly and to avoid any side effects.


Vitamin D rich foods

Vitamin D is聽found in relatively low quantities in just a few foods, most of them being animal-based which is why vegans and vegetarians聽are recommended to supplement.聽

Animal sources of vitamin D include egg yolks, dairy, butter, liver, and oily fish such as mackerel, sardines, and wild salmon.聽

Many foods are also enriched in vitamin D such as plant-based milks, orange juice, and cereal.


Vitamin D foods for vegetarians

  • mushrooms
  • dairy milk
  • fortified vegan milks
  • eggs
  • cheese

    Our favorite vitamin聽D supplements


      Side effects of vitamin D supplementation

      Though fairly rare, vitamin D toxicity is also possible. This is mainly caused by excess intake in the form of supplementation, especially over longer periods of time.

      Less severe symptoms of vitamin D聽toxicity include excessive thirst, diarrhea, nausea, weakness, nausea, vomiting, stomach pain, weight loss, constipation, and headaches.聽

      More serious聽signs and symptoms聽of vitamin D toxicity may include:

      • polyuria (increased urinary frequency)
      • heart arrhythmias
      • hypercalcemia (calcium buildup in the blood)
      • kidney failure聽
      • bone loss聽

      You may also聽notice increased blood and urine levels聽of calcium and phosphorus, as well as the calcification of soft tissues.聽

      We recommend working closely with your health care practitioner if you are聽supplementing with聽a high dose of vitamin D and to聽verify your levels regularly.

      聽

      Can you聽receive the benefits of聽vitamin D through a window?

      Humans can manufacture vitamin D through exposure to direct sunlight but does this work through a window? Ultraviolet rays, needed for vitamin D production, are blocked by glass windows therefore you would need to actually get outside to receive the benefits of vitamin D (4).聽

      Can you聽receive the benefits of聽vitamin D from a tanning bed?

      Tanning beds may聽provide an effective source of vitamin D, and this would be especially useful during the winter months.聽Tanning beds聽have been shown to increase serum vitamin D levels D without burning, especially useful for those with compromised digestive absorption聽(5). However, tanning beds still represent a risk for health as they are linked with skin cancer, therefore supplementation is generally preferred.
      聽

      Can聽you get vitamin D from the sun?

      Yes, sunshine is the most effective way to聽obtain vitamin D naturally.

      However, there聽are many factors that can alter the聽synthesis of vitamin D from sunlight聽which include season, time of day, location, cloud coverage, and skin pigmentation. Your ability to create vitamin D from the sun聽may also be inhibited by smog, clouds, clothing, glass windows, sunscreens, and darker skin tones.

      Sun exposure for about 15-20 minutes聽three聽times a week between the Spring and Fall months is usually sufficient to reach adequate levels however the effects will vary from person to person.

      聽
      Benefits of vitamin D

      • Does vitamin D help hair growth?
        Vitamin D is an important mineral for hair health as it helps to stimulate hair growth. Deficiency can lead to hair loss and is linked with alopecia聽areata, an autoimmune condition that triggers hair to fall out in patches. If you are dealing with hair loss it may be worthwhile to verify your vitamin D levels.
      • Does vitamin D improve immune function?
        Commonly recommended聽to support the immune system during the聽cold and flu season, vitamin D can help to regulate the innate and adaptive immune responses and improve the clearance of foreign agents that put the body out of balance (6). In addition, vitamin D聽can聽help to stimulate certain proteins that are naturally antimicrobial聽and can attack pathogens. Research聽has linked聽low vitamin D levels with an increased聽vulnerability to illness and disease such as infections and autoimmunity (7).聽
        • Does vitamin D help with depression?
          Vitamin D can significantly impact mood and mental health as low levels聽have been linked to depression and seasonal affective disorder (8)(9). Vitamin D receptors have been found in聽various areas of the brain and lowered levels of this hormone can affect neurotransmitter production such as serotonin, our feel-good hormone. Sufficient vitamin D levels help to聽protect brain cells and reduce inflammation (10). Though depression is more complex than just a vitamin D deficiency it is a natural treatment that can help to improve symptoms聽of low mood.
        • Vitamin D and sleep
          Inadequate blood levels聽of vitamin D have been linked to poor quality sleep and sleep disorders in humans (11)(12). A study found聽that participants suffering from insomnia who were supplementing with vitamin D聽were able to improve sleep quality and聽increase sleep duration聽(13).
          Vitamin D does play a role in the production of serotonin, a hormone needed for optimal melatonin synthesis, which promotes sleep.聽
          Supplementing in the morning may be a good idea because vitamin D is inversely related to melatonin, meaning if you take it at night it could keep you up! This also makes sense from an evolutionary standpoint as we get vitamin D from the sun which rises in the morning.聽
        • Does vitamin D help with anxiety?
          Vitamin D聽affects the brain in various ways such as reducing inflammatory markers which can help to reduce anxiety and improve mental health disorders聽(14). Vitamin D is an important nutrient for brain health and needed for proper neuroendocrine functioning.
          Low levels of serum vitamin D have been associated with聽neurological conditions such as Parkinson's disease, Multiple Sclerosis, Alzheimer's disease, and Autism聽(15). The rates of anxiety are actually increased in those聽experiencing聽low vitamin D聽which is why regular screening and supplementation may be a worthwhile treatment聽(16).聽

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        About Author

        Laurence Annez

        Laurence AnnezLaurence Annez is a Certified Nutritional Practitioner and Health Coach,聽specializing in PCOS and women's hormones. She also holds a degree in Creative Writing and has extensive experience writing on health and wellness topics.聽Laurence's聽mission is to inspire and motivate individuals to take control of their own health and reach their ultimate health goals.