Vitamin D, Healthy Immune Function and Covid-19

As scientists are learning more about effective prevention and

treatment of Sars2 coronavirus, or Covid-19, new research is emerging regarding the potential benefits of Vitamin D.

Vitamin D is a fat-soluble vitamin that promotes cellular function and bone health.  Besides being a vitamin, however, Vitamin D actually is also a hormone that plays a role in cellular behavior. As a steroid hormone, it can enter into the cell nucleus, and change the way the cells behave. As an important regulator of human immune function, vitamin D may stimulate innate immune responses which provide front-line protection against infectious agents. It acts as an essential immunomodulator. 

When levels of Vitamin D are inadequate, our bodies lack basic immunity. Additionally, it also reduces inflammation.

Many cells in the human body have vitamin D receptors and need Vitamin D to function properly, including those in your skin and brain. Vitamin D is needed for normal bone mineralization and growth, maintenance of muscle strength and coordination, cardiovascular health, as well as strong and balanced immune function.

Recent research has shown that Vitamin D may play a role in keeping our lungs healthy, with higher levels of Vitamin D having positive effects on lung function and health. As such, Vitamin D increases resistance to respiratory tract pathogens such as Sars 2 coronavirus.

Recent studies from Spain in 2020 showed a correlation between Vitamin D and the incidence, severity, and mortality in Covid-19 patients with patients having higher levels of Vitamin D being more resistant to Covid19, with faster recovery and lower mortality. 

Low levels of Vitamin D have also been associated with hypertension, diabetes, and cardiovascular disease, which are risk factors in Covid-19.

Vitamin D is found in fish oil, mushrooms, egg yolks, and red meat. Most importantly it enters the skin through the ultraviolet radiation of sunlight. 

During the winter months in the northern hemisphere above the 35th latitude, Vitamin D deficiency becomes more prevalent in the general population.  Taking Vitamin D supplements is the best way to maintain adequate levels of vitamin D during the winter months. 

Low vitamin D levels linked to osteoarthritis progression in the knee

At a Glance

A new study shows that inadequate levels of vitamin D in the blood are linked to worsening progression of knee osteoarthritis.

 Read more about this research below. 

Osteoarthritis is the most common form of arthritis, affecting millions of people worldwide. It occurs when the protective cartilage on the ends of your bones wears down over time, eventually allowing bones to rub together. Osteoarthritis typically worsens gradually, but maintaining a healthy weight, staying active and some other treatments may help slow disease progression and improve joint function and reduce pain.

A new study published in AgRearch magazine indicates that low vitamin D levels may be related to an increased risk of developing osteoarthritis. Researchers at Tuft’s University analyzed data from a large study to investigate the possible interaction between blood levels of vitamin D and parathyroid hormone (PTH) on the progression of osteoarthritis. Vitamin D and PTH work together to regulate calcium and phosphorus metabolism.

Study participants were part of a longitudinal study known as the Osteoarthritis Initiative, were between 45 and 79 years of age, and had at least one knee with evidence of osteoarthritis. A total of 418 subject who met criteria were followed for 4 years, and their knee osteoarthritis progression was tracked using radiographs and related to vitamin D and PTH levels in the blood.

When compared to subjects with healthy vitamin D levels, those with low vitamin D levels (< 15 ng/ml or 37.5 mmol/L) had more than twice the risk of their osteoarthritis worsening throughout the study. Subjects with both low vitamin D and high PTH levels were more than 3 times more likely to have worsening symptoms than participants with normal concentrations of both PTH and vitamin D.

The results of this study indicate that vitamin D deficiency is likely a risk factor for osteoarthritis progression, and that maintaining healthy blood levels through adequate dietary and supplemental intake may be beneficial in adults with osteoarthritis.

Fang Fang Zhang and Sarah Booth. Low Vitamin D Linked to Osteoarthritis. AgResearch Magazine July 2015 - Vol. 63 No. 7. http://agresearchmag.ars.usda.gov/2015/jul/vitamin/

How Easy Is It to Get Enough Vitamin D?

How do you get vitamin D into your body?

Can you get vitamin D from your food?
Watch the video to learn what the scientists think.

Inadequate vitamin D levels are related to cognitive decline in the elderly

More new research on vitamin D suggests it may play a role in preserving cognitive health for the elderly.

At a Glance


A new study has confirmed previous research indicating a possible association between low vitamin D blood levels and an increased risk of cognitive decline in the elderly.   

Read more about this research below. 

In addition to its role in bone health, vitamin D also plays a role in mental health by protecting the brain in several ways: reducing the risk of cardiovascular disease and hypertension (diseases that affect the brain), providing antioxidant mechanisms, regulating calcium levels, supporting the immune system, enhancing nerve conduction, and by its role in detoxification. Many previous studies have concluded that inadequate vitamin D blood levels may be linked to a higher risk of cognitive impairment.  

A recent study published in the journal Neurology tested the hypothesis that low vitamin D blood levels are associated with risk of cognitive decline.  

The Italian population-based study included 1,927 elderly subjects. Serum vitamin D levels were measured at baseline, and cognitive function was measured with the Mini-Mental State Examination (MMSE). A MMSE score lower than 24 indicated cognitive dysfunction. Over a period of a 4.4 year follow-up, a decline of 3 or more points on the MMSE was considered clinically significant.  
 

Compared to subjects with sufficient vitamin D levels (>30 ng/ml or 75 nmol/L), the subjects with vitamin D deficiency (<20 ng/ml, or 50 nmol/L) or insufficiency (20-30 ng/ml or 50-75 nmol/L) were more like to have declining MMSE scores during the follow-up. Among the subjects with normal cognitive function (MMSE of 24 or higher) at the beginning of the study, those with deficient or insufficient vitamin D levels were 36% and 29% more likely to experience the onset of cognitive dysfunction in comparison to subjects with normal vitamin D levels. 

The results of this study confirm an independent association between vitamin D levels and mental decline in elderly adults. Although there is considerable variation from person to person, and testing prior to supplementation is generally recommended, most people need to take between 1,000 and 5,000 IU/day of vitamin D3 to achieve levels adequate to protect against cognitive decline.

Elena D. Toffanello et al. Vitamin D deficiency predicts cognitive decline in older men and women. Neurology. 2014 Nov 5. pii: 10.1212/WNL.0000000000001080. [Epub ahead of print]

Review: The Comparative Guide to Nutritional Supplements, 2011 Ed.

Since nutritional supplement products are not regulated by the US Food and Drug Administration, it is difficult for consumers to evaluate and compare them to as to quality. Many over the counter products only meet the government's minimum Required Daily Allowances for vitamins and minerals.


The Comparative Guide to Nutritional Supplements 2011 Consumer Edition  by Lyle MacWilliam http://www.comparativeguide.com/ is a helpful resource for learning about the appropriate use of nutritional supplements and how they contribute to optimal health, disease prevention, and anti-aging defense.

In the latest updated edition, over 1600 US and Canadian supplements were scientifically rated and compared, using 18 critical health supportive criteria to evaluate each product.

What I liked the most in this edition are the two chapters on the history and latest scientific findings on vitamin D.  There is an excellent summary of the overwhelming research confirming the beneficial effects of vitamin D in disease prevention, boosting immunity and strengthening bones.  While the recommended daily intake of vitamin D has been raised to 600 IU per day, there are many experts who believe it should be higher yet.  While the best way to get vitamin D is still from the sun, everyone living outside the tropics or a predominantly indoor lifestyle must supplement for the sake of health.

I found MacWilliam's Guide to be an excellent source of information when considering the various scientific ratings conducted of nutritional supplements for this book. The Guide includes comparative ratings of many popular brands of supplements, including those sold in drug and health stores with other less well known brands which are not available through such venues.

Vitamin D the Sunshine Factor

In recent years, scientists have learned much more about the crucial role played by Vitamin D in human health. Vitamin D is essential for good health, growth and strong bones.
Numerous studies have contributed to a realization that our bodies require far greater amounts of Vitamin D than had previously been recommended.
Vitamin D aids the absorption of calcium and phosphorus in our diet from the gut. Calcium and phosphorus are essential for the structure and strength of our bones. So, vitamin D is critical for building strong bones. In addition, vitamin D seems to be important for muscles and general health. Scientists have also found that vitamin D may also help to prevent other diseases such as cancer, diabetes and heart disease.
A lack of vitamin D is very common. Most foods contain very little vitamin D naturally, though some are fortified (enriched) with added vitamin D.
Vitamin D is a fat-soluble vitamin. The fact that it dissolves in fat is important, because it means the body can store it for future use. Unlike other vitamins, we do not need to get vitamin D from the food that we eat. This is a good thing because most foods contain very little vitamin D naturally. Foods that contain vitamin D include:
Oily fish (such as sardines, pilchards, herring, trout, tuna, salmon and mackerel). Egg yolk. Fortified foods (this means they have vitamin D added to them) such as margarine, some cereals, infant formula milk. Our main source of vitamin D is that made by our own bodies. It is mostly made in the skin by exposure to sunlight, and 90% of our vitamin D is made in the skin with the help of sunlight.
Ultraviolet B (UVB) sunlight rays convert cholesterol in the skin into vitamin D. Darker skins need more sun to get the same amount of vitamin D as a fair-skinned person. The sunlight needed has to fall directly on to bare skin (through a window is not enough). 2-3 exposures of sunlight per week in the summer months (April to September) are enough to achieve healthy vitamin D levels that last through the year. Each episode should be 20-30 minutes to bare arms and face. This is not the same as suntanning; the skin simply needs to be exposed to sunlight.
Note: The sun's rays can be damaging and sunburn should be avoided at all costs (mainly because it can increase your risk of skin cancer). This awareness has led to a more widespread use of sun screen and protective clothing to shield our skin from these harmful rays.
But in addition to most people spending most of their time indoors, the use of sun screens contributes to Vitamin D deficiency.
A mild lack of vitamin D may not result in obvious symptoms except general aches and pains. A more severe lack can cause serious problems such as rickets (in children) and osteomalacia (in adults), described below:
A recent study found that cases of rickets have been increasing in the UK due to vitamin D deficiency.
Treatment for vitamin D deficiency is with vitamin D supplements. Some persons are more at risk of vitamin D deficiency, and so are recommended to take vitamin D supplements routinely. These include all pregnant women, breast-fed babies, children under 5, and people aged 65 and over. Also, individuals who do not get much exposure to the sun, people with black or Asian skin types, and people with certain gut, liver or kidney diseases.
A recent study published in Environmental Health Perspectives reported that many American children are not getting enough vitamin D from sun exposure alone. Only some Caucasian children, who do not diligently wear sunscreen, were getting enough vitamin D, however this was only during the summer months. Other children had lower vitamin D levels in the summer, and all had lower levels throughout the rest of the year. This means that vitamin D must be supplied from another source.
Because so few foods contain vitamin D naturally, it has been added to many. Despite food fortification, however, the data in this study suggest that many American children still do not get enough vitamin D to meet the recommended dietary reference intake (DRI).
Vitamin D supplements may play an important role in getting to the recommended DRI of 600 IU daily (children ages 1 – 8).
Godar DE, Pope SJ, Burgess Grant W, Holick MF. Solar UV Doses of Young Americans and Vitamin D3 Production. 2011. Environmental Health Perspectives.