Simple Way To Optimize Your Immunity

Evolution created effective mechanisms for the survival of our species, including our inner biological timing system (circadian rhythms) that generates restorative sleep and many natural defence mechanisms including the immunomodulatory effects of molecules like melatonin, sirtuins, glutathione and vitamin D.

Importance of Vitamin D

Especially the steroid hormone vitamin D has potent immunomodulatory and anti-inflammatory properties which reduce the damaging effects of the cell stress response in case of infection, disease or injury.

Vitamin D is an ancient hormonal molecule, and it is photosynthesized in all forms of life, including phytoplankton, mammals and of course, humans. In humans, evolution has decided on the cholesterol-derived synthesis of vitamin D.

Since humans evolved for millions of years under the natural light frequencies of the sun we synthesize most vitamin D in the skin upon exposure to sunlight, which is then metabolized in the liver and kidney to the metabolically active form called 1α,25-dihydroxy vitamin D. The binding of vitamin D3 to the vitamin D receptor (VDR) through the body, regulates hundreds genes expression that involved in biological functions. 

Vitamin D Foods

You can obtain small amounts of vitamin D from foods including fatty fish, cod liver and mushrooms, but the primary source is a stepwise process that starts in your skin following exposure to ultraviolet light. Our natural light environment, especially during the summer months is essential for the delivery and storage of vitamin D.

Vitamin D Supplementation And Immunity

In the case of infection with COVID 19 or other viral diseases with no current curative treatment, vitamin D is essential for the functioning of the immune system, our body’s first line of defence.

In some preclinical studies, Vitamin D administration lowered the complication rate in patients infected with SARS CoV-1. The mechanisms behind this are still under investigation, but it seems that vitamin D reduces inflammation and cellular infiltration rate in the lungs via a complex mechanism related to the ACE2 receptor molecules, exactly where SARS CoV 1 and 2 enter and hijack the cell. 

ACE/ACE2 Ratio is not only critical for the prevention of complications (ARDS) in case of infectious disease but also vital for the bodies liquid homeostasis, cardiovascular health, protection of the lung tissue and kidneys.


Who Could Benefit The Most From a Supplementation?

That being said and knowing that vitamin D is a potent immune modifying micronutrient vulnerable adults, in particular, obese people, those over 70 years, people with comorbidities and those with dark skin colour could benefit during the COVID-19 outbreak from efficient supplementation protocols. 


However, the best way to fill up vitamin D storage is still the sun.


Many studies have shown that the body is most efficient at making vitamin D in the northern latitudes of our planet at noon during the summer months. For example, in the UK, 10-minutes of sunlight exposure around noon during summer three times per week is enough to maintain healthy levels among Caucasian adults. Another study found that 30- minutes of midday summer sun exposure in Oslo, Norway was equivalent to consuming 10,000–20,000 IU of vitamin D.

Vitamin D Deficiency And Health Issues

Unfortunately, indoor lifestyle and a circadian misalignment to natures time cues (Zeitgeber) profoundly interfere with a natural ability to protect ourselves from infectious diseases! It should be mentioned that vitamin D deficiency due to a life in an artificial environment is a global health issue that afflicts more than one billion children and adults worldwide.

The point here is that we are more and more alienated from a lifestyle we were evolved during millions of years which make us fragile and more susceptible to all kinds of health issues, including infectious diseases.

Vitamin D Levels And Respiratory Infections

Most research on vitamin D and respiratory infections are associations and dont show cause and effect. But considering evolutionary biology and comparing it to the modern lifestyle, they make a pretty strong case. Some randomized control studies even showed that increasing vitamin D levels can reduce respiratory infections by 50%. There can be no doubt that vitamin D is an effective immunomodulator in respiratory infections.

Please note that there’s no antidote that will keep us completely safe from any flue or COVID 19 and hygiene, social distancing and other measures are the only effective way protect ourselves and stop the spread of the disease.


However, there are small daily actions, that can help to optimize your immunity right now.

Solutions And Preventive Measures 


  1. Measure your vitamin D (25 OH vitamin D) levels regularly. Sweetspot: 75-100 nmol/ml (higher levels could have toxic side effects)
  2. Supplementation: 5000 UI/day is considered safe for healthy adults.
  3. Opt for time-restricted sunbathing during the summer months to store vitamin D.
  4. After supplementation (5000 UI/day) test your vitamin D levels after 8-12 weeks.

To ensure better absorption, it recommended combining vitamin D and K supplementation.


If you consider supplementation, check out one of my favourite choices :


  • Thorne Research - Vitamin D/K2 Liquid (Metered Dispenser) - Dietary Supplement with Vitamins D3 and K2 to Support Healthy Bones and Muscles - 1 fluid ounce (30 mL)

Stay healthy!