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Optimize Your Vitamin D Levels for Disease Prevention

Optimize Your Vitamin D Levels for Disease Prevention

By Andrea Bartels CNP NNCP RNT
Registered Nutritional Therapist

11 Oct 2022

Optimize Your Vitamin D Levels for Disease Prevention

Low blood levels of vitamin D are associated with higher incidence of certain cancers, respiratory diseases, auto-immune disorders, cardiovascular disease, osteoporosis and mental illnesses. Are you getting enough to help reduce YOUR risk? Let’s look at a summary of the research and then outline how to find out your ideal dosing.

Illnesses Associated with Low Vitamin D Status

Depression and Seasonal Affective Disorder (SAD):   It is no coincidence that Seasonal Affective Disorder (SAD)—a type of depression that occurs in the colder, darker months of the year—is associated with lower vitamin D levels in sufferers. According to the Canadian Mental Health Association, some degree of SAD is experienced by about 18% of Canadians, with the occurrence being four times higher in women than in men. That’s nearly one-fifth of the population, so chances are high that you know someone who experiences it. 

A systematic review and meta-analysis published in 2013 found that among 14 studies involving a total of over 31,000 adults, “lower [serum] vitamin D levels were found in people with depression compared to controls”. The fact that there are vitamin D receptors in parts of the brain that are influential to depression may be important in understanding why.  In addition, the well-known feel-good neurotransmitter, serotonin is known to interact with vitamin D in a positive manner (Anglin 2013).

Breast Cancer: This is the most frequently diagnosed cancer in Canadian women.  In a pooled analysis of two randomized trials and a prospective cohort, there was an 82 percent lower incidence of breast cancer in American women with serum vitamin D concentrations over 150 nmol/L compared to those with 50 nmol/L (McDonnell 2018, Hossain 2019).

Colorectal Cancer: Since it is the third most common cancer in men and the 2nd most common in women worldwide, the relationship between colorectal cancer and vitamin D status has been widely studied over the past 42 years. Collecting data from 17 countries, the meta-analysis of 31 such studies revealed a 25 percent lower incidence in individuals with the highest blood levels compared to those with the lowest blood levels, among those that were case-control studies (Boughanem 2021, Lappe 2008).

Multiple Sclerosis: Health geographers, who study spatial patterns of disease across the globe, were among the first to note that the highest prevalence of this auto-immune disease was in countries located further from the equator. From there, hypotheses bloomed about the minimal direct sun exposure, and studies have been taking place over the past 30 years that have quite consistently revealed that higher blood levels of vitamin D are associated with reduced risk of developing this disease of the central nervous system. Not only that, but participants with higher levels experienced reduced disease activity, including a reduction in signs and symptoms compared to those with low levels of the nutrient. Another impressive study even showed a reduced incidence of MS in the children born to women who were supplementing before and during their pregnancies (Sintzel 2017).



Pneumonia:  As a lung infection, pneumonia can occur by itself or as a complication of COVID-19, strep throat or the common cold.  A meta-analysis performed in 2018 that included 8 observational studies and over twenty thousand subjects found that patients with vitamin D levels lower than 20 ng/ml (50 nmol/L) experienced a significantly increased risk of community-acquired pneumonia (CAP).  Multiple studies have concluded that low vitamin D status is linked to increased risk of pneumonia, more severe disease and a worse outcome (Slow 2018, Zhou 2019).

Osteoporosis: This degenerative bone disease heightens fracture risk and is expected to rise in incidence as more members of the population become seniors. In large-scale epidemiological studies, serum vitamin D levels are associated with bone mineral density in both sexes. Although calcium intake are also strongly associated with fracture risk, vitamin D is crucial to the delivery of calcium to the bones (Ebeling 2014, Sunyecz 2008).

Cardiovascular disease: As the top killer of Canadians, coronary artery disease needs preventative care—not just management or acute-care. One meta-analysis that included 34 observational studies and a total of more than 180,000 participants concluded that higher baseline serum vitamin D levels were associated with lower number of cardiovascular ‘events’ (heart attack, heart failure and stroke) as well as lower mortality from these events. In fact, the occurrence of cardiovascular events in the participants was 10 percent lower for each 25 nmol/L increase in serum vitamin D (Zhang 2017).


How Much To Take and How to Monitor Your Levels

Certainly, the amount of vitamin D you need is individual, and depends on whether you are looking to prevent disease in the first place, or, to help manage a diagnosed illness.  Testing for vitamin D status by measuring 25-OH-Cholecalciferol in the blood is a good way to check if you’re absorbing it, and, will determine what level of supplementation is needed.

Here are our guidelines for assessing your needs:

First, obtain a set of multiple requisition forms from your primary health care provider—one for each of the several blood draws you will obtain over the coming year. 

Then, take 2,000 i.u. of vitamin D3 daily, being consistent in taking it each day.

After 3 weeks, go get your vitamin D levels checked. If it is below the optimal range of 75 – 100 nmol/liter it makes sense to increase the dosage you take each day.

After 3 weeks more on the new dosage your levels can be checked once again. If you are now in the optimal range, stick with the dose; if not, increasing your intake should increase blood levels. 

This cycle can be repeated until the desired range is reached.  It is especially important to test near the beginning of ‘flu season’, and again in early winter, to see if increased indoor time is reducing your levels. 

Quality and Stability of Supplementation Matters

PureLab Vitamins offers only high-quality, stable, dry-form vitamin D to suit different needs. Our Vitamin D 1000 with 1000 IU per capsule offers great flexibility with dosing, while our new Vitamin D 2500 offers 2500 IU’s per capsule—providing 2 and a half times the dosage most commonly available in natural health products. This enables replenishment with fewer capsules per day for those who are in need of repleting their previously-deficient levels, or by those requiring higher dosages prescribed by their health care practitioner.   

Pure Lab Vegan Vitamin D 1000 is not only encapsulated in a vegetable capsule; the vitamin D inside is 100 percent vegan vitamin D-3.

Finally, knowing your levels to start and follow ups are just one part of your protection plan. Be consistent with your dosing throughout the year in order to maintain your blood levels of vitamin D to gain the maximum benefit possible from taking it.


Note: In the interest of brevity, throughout this article, “serum vitamin D” refers to the active form of vitamin D that is found in the blood. Technically, active form vitamin D is known as 25-hydroxy-cholecalciferol, or 25 (OH) D. Care has also been taken herein to ensure that vitamin D measurements in blood are expressed uniformly in nmol/L. 



Anglin RE, Samaan Z, Walter SD, McDonald SD. Vitamin D deficiency and depression in adults: systematic review and meta-analysis. Br J Psychiatry. 2013;202:100-107.

Boughanem H, Canudas S, Hernandez-Alonso P, Becerra-Tomás N, Babio N, Salas-Salvadó J, Macias-Gonzalez M. Vitamin D Intake and the Risk of Colorectal Cancer: An Updated Meta-Analysis and Systematic Review of Case-Control and Prospective Cohort Studies. Cancers (Basel). 2021 Jun 4;13(11):2814. 

Ebeling PR. Vitamin D and bone health: Epidemiologic studies. Bonekey Rep. 2014 Mar 5;3:511. 

Heath AK, Kim IY, Hodge AM, English DR, Muller DC. Vitamin D Status and Mortality: A Systematic Review of Observational Studies. Int J Environ Res Public Health. 2019;16(3):383. Published 2019 Jan 29.

Hossain S, Beydoun MA, Beydoun HA, Chen X, Zonderman AB, Wood RJ. Vitamin D and breast cancer: A systematic review and meta-analysis of observational studies. Clin Nutr ESPEN. 2019 Apr;30:170-184.(author’s manuscript). Epub 2019 Jan 9.

Lappe JM, Travers-Gustafson D, Davies KM, Recker RR, Heaney RP. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial [published correction appears in Am J Clin Nutr. 2008 Mar;87(3):794]. Am J Clin Nutr. 2007;85(6):1586-1591.

McDonnell SL, Baggerly CA, French CB, et al. Breast cancer risk markedly lower with serum 25-hydroxyvitamin D concentrations ≥60 vs <20 ng/ml (150 vs 50 nmol/L): Pooled analysis of two randomized trials and a prospective cohort. PLoS One. 2018;13(6):e0199265. Published 2018 Jun 15.

Sintzel MB, Rametta M, Reder AT. Vitamin D and Multiple Sclerosis: A Comprehensive Review. Neurol Ther. 2018 Jun;7(1):59-85. Epub 2017 Dec 14.

Slow, S., Epton, M., Storer, M. et al. Effect of adjunctive single high-dose vitamin D3 on outcome of community-acquired pneumonia in hospitalised adults: The VIDCAPS randomised controlled trial. Sci Rep 8, 13829 (2018). 

Sunyecz JA. The use of calcium and vitamin D in the management of osteoporosis. Ther Clin Risk Manag. 2008 Aug;4(4):827-36.

Zhang R, Li B, Gao X, et al. Serum 25-hydroxyvitamin D and the risk of cardiovascular disease: dose-response meta-analysis of prospective studiesAm J Clin Nutr. 2017;105(4):810-819.

Zhou, Yun-Fang MMa; Luo, Bang-An MMb,; Qin, Lu-Lu MD, PhDc,The association between vitamin D deficiency and community-acquired pneumonia: A meta-analysis of observational studies. Medicine: September 2019 - Volume 98 - Issue 38

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