Should I be taking vitamin D?

Should I be taking vitamin D?

Margie GanderJul 19, '19

Low vitamin D levels have been called "the silent epidemic" with an estimated 1 billion people worldwide having inadequate levels of vitamin D. Measuring and tracking healthy levels of vitamin D is one of easiest biohacks for optimal health. 

What is vitamin D?

What you may not know is that vitamin D is actually a prohormone – and not a vitamin!  Understanding this hormone and the role it plays in the body will help you make informed health decisions. Nearly every cell in your body has a VDR (vitamin D receptor) which is encoded by your VDR gene. Because of this, I view medium to high misspellings in this gene as having a potentially global impact on that person's health. In fact, because of its presence in nearly all cells, it forms part of your cellular defence system.

Your body makes vitamin D in a chemical reaction that occurs when sunlight hits the skin. This reaction produces cholecalciferol and the liver converts it to calcidiol. The kidneys then convert the substance to calcitriol, which is the active form of the hormone in the body. Calcitriol (1,25-dihydroxyvitamin D3) is the biologically most active form of vitamin D and what we use to measure vitamin D levels. 

Vitamin D and bone health

Vitamin D helps the body absorb calcium so that blood calcium levels are at the ideal point. This helps enable the mineralisation of bone that is required for strong, healthy bones. Testing levels become really important as you get older in order to prevent osteoporosis. 

Vitamin D and weight management

There are many factors that can influence weight gain and weight loss resistance. When looking at your overall 'diet' genotype, it is important to consider your genetic variation for in the VDR gene together with your current levels. I coach many people in my practice who are wanting to lose weight, particularly belly fat. Determining what their VDR genetic variation is together with their current vitamin D levels, is one of the key factors that we look at as part of their weight loss plan. 

A US-based study found that women with lower levels of this vitamin were “prone” to weight gain, compared to women with higher levels. Measuring the weight and vitamin D level of more than 4,000 women aged over 65, they found that women with inadequate levels of this vitamin gained more weight. This research has indicated that there are several effects of vitamin D storage on adipose tissue and its role in regulating fatty acid and glucose metabolism.

Vitamin D and immunity

A vitamin D deficiency can result in immune dysfunction with people being prone to infections and illness. As the vitamin D receptor is expressed on immune cells (B cells, T cells, and antigen-presenting cells), vitamin D can modulate innate and adaptive immune responses. Deficiency in vitamin D is associated with increased autoimmunity as well as increased susceptibility to infection. The immune system defends the body from foreign, invading organisms, promoting protective immunity while maintaining tolerance to self. The implications of vitamin D deficiency on the immune system have become clearer in recent years and in the context of vitamin D deficiency, there appears to be an increased susceptibility to infection and a diathesis, in a genetically susceptible host to autoimmunity. 

Vitamin D and mood

Researchers have found that vitamin D helps regulate adrenaline, noradrenaline (also called norepinephrine), and dopamine production in the brain; as well as helping to protect from serotonin depletion. For this reason, low vitamin D levels increase an individual's risk of depression significantly.  

Vitamin and cancer protection

There is mounting evidence that that function of vitamin D is to help regulate cellular growth and thus inhibit tumor growth. When I was diagnosed with estrogen-positive ovarian cancer at 36, my vitamin D levels were at 12ng/ml! This is considered vitamin D deficient.

Vitamin D and the thyroid

There are vitamin D receptors (VDR) are present in the pituitary gland; which is the gland responsible for stimulating thyroid-stimulating hormone (TSH). Presence of vitamin D is needed to promote the balance of thyroid hormones and prevent autoimmune thyroid disorders such as Hashimoto’s thyroiditis.

Vitamin D and hormone balancing

As vitamin D is thought of as a precursor hormone or a prohormone, low levels are associated with insufficient production of sex hormones including; testosterone, progesterone, and estrogen. Vitamin D is also useful in maintaining estrogen balance. If you suffer from estrogen dominance or elevated estrogen in relationship to progesterone; optimal vitamin D levels have been shown to have estrogen lowering effects and limit common symptoms such as weight gain, insulin resistance, PCOS and irregular menstrual cycles. 

Vitamin D and hair 

Vitamin D stimulates hair follicles, so a deficiency may lead to hair loss. There is some evidence that having a vitamin D deficiency does cause hair loss and other hair problems. If you looking to grow your hair quickly, supplementing with vitamin D may just help you get that long, think ponytail! Research shows that people with alopecia areata have much lower levels of vitamin D than people who do not have alopecia. 

How to test

Before adding in a vitamin D supplement, it is important that you know what your genetic variation is for the VDR gene and what your current vitamin D levels. 

You can test your VDR gene in the DNA HEALTH test



As more is understood about the many roles vitamin D plays in so many processes in the body; patients are noticing the value of obtaining optimal rather than “average” levels of Vitamin D.

We are talking about the blood level of 25-hydroxyvitamin D, which is usually measured in nanograms per milliliter. Most laboratory tests and physicians recommend a blood level of 20-30 ng/ml to avoid being Vitamin D deficient. This set range is based on the average person and does not consider levels needed for optimal health but instead is simply a range to prevent deficiency. One would need far more than 20-30 ng/ml (likely 60-75ng/ml ) to prevent inflammatory diseases, cancer, and other chronic diseases. 

You should find this table useful, in benchmarking your current vitamin D levels:

Level Indication  Test
Below 20ng/ml Deficient Vitamin D Profile
Between 20 - 40ng/ml Average
Vitamin D Profile
Between 70 -80 ng/ml Optimal   
Vitamin D Profile

Vitamin D promoting foods and supplements

As part of our 'food first' philosophy, you can increase your vitamin D by eating foods rich in vitamin D.

However, if you have a medium to high impact variation in the VDR gene or have very low blood levels of vitamin D, then I would recommend supplementing with a bioactive vitamin D3 supplement. One of the main reasons for this is that when eating foods high in vitamin D, your body still needs to convert that vitamin D into the bioavailable D3, so it is 'easier' for your body to utilize it on a cellular level. If you are a poor converter genetically, then you still may not be getting sufficient vitamin D3. In this case, supplementing with bioavailable vitamin D3 is essential. Vitamin D3 supplements are measured in international units and supplement doses range from 1000IU to 5000IU. The dosage will depend on your unique profile. 

If you would like help in chartering your own path to optimal wellness, why not book a Functional Medicine Coaching session where we will help you make better choices from your DNA up!




Written by:
Marguerite Doig-Gander
BA (Speech, Hearing & Lang Therapy) Hons | FMCHC | ReCODE Coach | HMX Genomics & Biochemistry (candidate)

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