Essential Vitamin D & Supplementation

Supplementation in context

A single supplement will never be a magic bullet for our health as the human body requires a synergy of multiple nutriments (50 Essential bioavailable nutrients). These nutrients are required  in individually quantities determined by our genetics and our lifestyle conditions.  Supplements should always play a secondary supportive role in optimising health. A wholefoods diet, regular exercise, appropriate rest & optimal sleep should be our main focuses. Certain supplements are recommended for probable modern day nutrient deficiencies (a blood test will testify this) and increased nutrient demands when training. Typical modern lifestyles of high stress, high environmental pollution and processed nutrient deprived foods increase our needs for supplementation. Supplements are not compensators for an enduring poor diet.

Vitamin D Intro:

With the rise of indoor sedentariness and out-dated medical/media sun bathing scar mongering, vitamin D deficiency is now an unrecognised epidemic – the most common deficiency worldwide.

Vitamin D is an essential nutrient required by the body. It enables numerous vital functions like our skeletal structures, our blood pressure, immunity, mood and brain function etc. It’s really a pro-hormone (a chemical signaller that controls/regulates bodily functions). Being Fat soluble it can be stored in body fat, the liver as well as skeletal muscle and drawn upon in periods of low UV. UV light activates vitamin D production in our skin.

Vitamin D Benefits:

  • Vitamin D is really a pro-hormone, a precursor to our steroid hormones
  • 2000 genes are regulated by vitamin D and 160 recognised metabolic pathways are affected by it
  • Improves cardiovascular disease, since it is involved in regulating blood pressure, cholesterol levels, and inflammation
  • Protect us from cancer especially breast, colon, and prostate cancers. Vitamin D enhances the self-destruction of mutated cells, slowing down the production and spread of cancer cells, blocks excess estrogen, helps the differentiation of cells (cancer cells are not differentiated) & prevents the formation of new blood vessels from pre-existing ones (this can help stop the progress of benign tumours into cancerous ones)
  • Increases calcium absorption. A deficiency in vitamin D will dictate calcium absorption no matter how much calcium is in your diet! Calcium deficiency increases bone thinning, weakening, fractures, osteoporosis and teeth cavities especially in the elderly.
  • Vitamin D has an effect on other important vitamins and minerals that contribute to mineralised bone density, including vitamin K and phosphorus.
  • At optimal levels vitamin D can increase magnesium absorption. Excess vitamin D will increase magnesium excretion, contributing to magnesium deficiency.
  • Protects against the development of autoimmune conditions (multiple sclerosis, rheumatoid arthritis, irritable bowel syndrome and other digestive disorders) by improving cell replication
  • Prevents prolonged or excessive inflammatory responses

Vitamin D deficiency:

  • Is linked to an increased risk for mental health disorders including depression, seasonal depression (SAD), insomnia, anxiety, developing schizophrenia, and severe mood problems during PMS
  • Poor performance on standardized exams, may have poor decision making skills, and have difficulty with tasks that require focus and attention.
  • Low vitamin D interferes with proper testosterone and estrogen production, leading to imbalances
  • Decreased immunity and increase susceptibility to infections
  • Reduces calcium absorption
  • Increases parathyroid hormone which increases calcium release stored in bones increasing the likelihood of fractures
  • Causes hypercalcemia – excess calcium in the blood. This can bring about calcium deposits in the blood vessels and other organs (e.g. kidney stones). Blood-calcium levels also influences nerve impulses, muscular contractions, insulin secretio n, immune system regulation, the growth and maturation of all cells and inhibits cancer growth
  • Increases blood-cholesterol levels
  • Decreases serotonin production and increases melatonin production. Serotonin controls mood, sleep, body temperature, digestion, sex drive and supresses’ neurohormone melatonin. Excess melatonin causes sleepiness, decreases brain activity and slows all physiological processes (metabolism)

Diseases related to lack of vitamin D:

Breast cancer, colon cancer, diabetes, high blood pressure, cardiovascular disease, multiple sclerosis, Ovarian Cancer, osteomalacia (weak bones), osteoporosis, Prostate cancer, psoriasis, Season affective disorder (SAD), Tooth decay and Tuberculosis

Common deficiency symptoms:

Are vague, such as tiredness or general aches, pains and frequent infections. More severe symptoms are pain in your bones and difficulty getting around.


The only way to know if you are deficient is to have a blood test – the most accurate test being the 25-hydroxoyvitamin D test or 25(OH) D test. Test before and during supplementation.

Vitamin D blood Levels should be 25(OH)D as a minimum, preferably 40-60(OH)D and no more than 150(OH)D.

50+equals a good level of Vitamin D.
30-50means that you will want to be supplementing Vitamin D, working on spending more time in the sun and adding in Vitamin D rich foods to your diet.
<30means that you are very deficient and you will definitely want to take immediate action to bring your levels up

People At high Risk:

Pregnant and lactating womenDarker skinOn low fat diets
Taking steroidsOn Weight loss medicationsThose who spend long periods of time indoors
Liver and kidney disease can lead to a vitamin D deficiency

‘Wearing protective clothing year round is the strongest indicator of a vitamin D deficiency.’  Dr R Hobday

Vitamin D and nutrition

It is impossible to meet our daily recommended dose of vitamin D through diet alone. Only about 100IU’s (2.5 mcg) of our vitamin D needs are met by a conventional western diet. Oily fish contains around 500 – 1000IU’s per 3.5 lbs (1.6kg) you’d need 5-7 servings a day! Products ‘fortified’ with low bioavailable vitamin D2 are not reliable sources.

 Vitamin D-rich Foods:

Oily fishCod liver oilLiverButter
Egg yolkCreamCheeseUV exposed mushrooms

Vitamin D Supplementation:

If you get the right amount of sun at the right times of the year there’s no need to supplement vitamin D (like our ancestors).

Reasons to Supplement:

  • As a winter insurance strategy
  • if your vitamin D levels are low
  • If you spend a lot of time indoors or works night shifts etc.

The government’s recommendation of 400IU/day vitamin D is not sufficient to prevent Vitamin D deficiency – this dose assumes year round sunlight exposure. However for cancer prevention and optimal bone health at least triple is needed.

Practical Supplement Guidelines:

Age Range/YearsPreferred Dose/DayUpper/Limit Day
0-1400 – 1000 IU2000 IU
1-18600 – 1000IU4000 IU
18 +*1500 – 2000IU10,000 IU
Pregnant Women8000 IU10,000 IU
*If overweight or obese increase dose to 2 to 3 times more.

If your supplement is in water-soluble form consume in small frequent doses e.g. 2-3 x day.  If in fat-soluble form, take as a single dose ideally first thing in the morning with a fatty meal.

Vitamin D3 Vs D2

Man-made Vitamin D is made one of two ways: Vitamin D2 is created by irradiating yeast and other moulds, a vegetarian source, or by irradiating animal oils and cholesterol creating vitamin D3. The cholesterol in our skin converts into vitamin D3 (cholecalciferol). Animal-derived vitamin D3 is thought to be more beneficial, absorbing up to 500 times faster than D2 and estimated to be 4X more effective in humans.

Here are the vitamin D3 supplements I recommend form local independent health food shop Greens