Vitamin D, the sunshine vitamin. It has been nicknamed that because the main source of it is sunlight. It’s synthesised in the skin in the response to exposure to UVB rays. It is also found in foods, but on a lesser scale. It is prominent in fatty fish, eggs, cod liver oil, and is also in a lot more items such as milk when the product is fortified.
Vitamin D has been in the news a lot recently. A few recent studies have shown a significant correlation between vitamin D deficiency in Covid-19 mortalities. Some news story headlines I’ve seen;
“Could Vitamin D be the key to beating coronavirus?”
“Covid-19 deaths linked to Vitamin D deficiency”
Headlines that really catch your eye! However, I certainly hope people read more into it, because by reading those headlines, some people may think a vitamin D tablet is the vaccine we all desire. As we have said all along in this crazy situation, please make sure you do your own research and never just trust a headline to give you all the information you need.
Vitamin D is without doubt a vital nutrient for our general health, and the number of people understood to have below recommended vitamin D levels worldwide is staggering. It is estimated that 30-50% of some countries have lower than normal Vitamin D levels. Interestingly, although the sun is a vital source of it, many countries with hotter climates tend to have an even higher deficiency rate. Researchers in Qatar found that 68.8% of children were deficient in Vitamin D despite the hot climate!
The role of vitamin D in keeping us healthy is nothing new. Previous research has shown that sufficient levels play a big role against fighting respiratory tract infections, such as “flu”. In fact, researchers have gone as far to say that it is one of the reasons these types of viral infections are so seasonal. Due to the lack of sunlight in the winter, vitamin D levels are naturally lower, and they have hypothesised that as being one of the reasons the flu is so much more prominent in the winter. Along with other reasons of course.
The mainstream information on vitamin D is around our skeletal system, however. Supplements are commonly marketed as a nutrient that will give you stronger bones, muscles and teeth. Which is of course true, and one of the many reasons we would always tell our clients how important it is to get enough of it. But let’s take a look at the other reasons why we recommend it. Vitamin D deficiencies have been shown time and time again to have a negative impact on the illnesses and conditions that make people more vulnerable to Covid-19.
VITAMIN D & COVID COMORBIDITIES
The Ageing Population:
Vitamin D status has been shown to reduce significantly with age, particularly in the over 70 population. In Italy, women over 70 were shown to have 35% lower Vitamin D levels than women under 70. The most logical reason for this being that the older population tend to avoid direct sunlight as much as possible, whereas the younger population are more likely to spend a significant amount of time in the sun. It has also been found that around 75% of the institutionalised over 70’s are vitamin D deficient.
Obesity & Type II Diabetes:
I have paired these two together as they are so closely related, with an estimated 85% of people with type II diabetes also being overweight or obese. A recent study on hospitalised Covid-19 patients in New York (therefore were treated as severe cases) found that 41.7% of patients admitted were clinically obese. It was shown as one of the strongest predictors in hospitalisation, behind age (65 years+) and hypertension. Of the hospitalised patients, 33.8% also had type II diabetes. So, there is no more hiding from it, more and more evidence is being produced to show the obese population and those with type II diabetes to be more at risk during this pandemic.
Vitamin D status has long been shown to be related to obesity. Many studies over the years have shown a relationship between low vitamin D levels and high body fat levels regardless of age, ethnicity or geographical area.
The role of vitamin D in type II diabetes is also strong. One study showed that people with higher vitamin D levels were less at risk of type II diabetes by 40%, compared to people with below recommended levels.
FIGURES FROM RECENT STUDIES
Let’s start with the main study that has been making the headlines. A study in Indonesia researched the results of 780 laboratory-confirmed Covid-19 cases. The table below shows the results from the study. Column 1 is Covid-19 cases with vitamin D deficiency, column 2 is cases with an insufficiency, and column 3 is cases sufficient in vitamin D.
Of those cases that were deficient in vitamin D, a whole 98.9% died. The cases that were insufficient, 87.8% died. And the cases that had adequate vitamin D levels, just 4.1% died. Quite astounding numbers, you can see why it has hit the headlines.
In another study, they looked at the number of cases and deaths per country. They then compared that number to the average populations vitamin D levels. As you can see from the graph below, there is an obvious relationship between the populations vitamin D levels and both the number of cases and most importantly, the mortality rate. The trend being, the lower the average vitamin D levels, the higher probability of both covid-19 cases and deaths. Of course there are a few outliers, probably based on how they have controlled the situation, such as Germany.
Below is a table from the same study, showing a breakdown of each European countries results, based on average vitamin D levels, and the number of cases and deaths confirmed (as of April 2020). Interestingly, look at the vitamin D levels of the Southern European countries with hotter climates, such as Spain and Italy.
When I first heard there may be a link between low vitamin D levels and death rate, my first thought was, “well surely that’s not the case, as Spain and Italy are the worst hit and their vitamin D levels should be high”. Their levels are among the lowest 25% in Europe! Now the main reason that is believed for this I mentioned earlier with the elderly population. It is more than likely because the hotter the climate is, the more likely the population is to avoid exposure to the sun. Skin pigmentation has also been shown to reduce the capability of the skin to absorb vitamin D from the UV rays. Pair this with their populations being slightly older on average, particularly Italy, and it could explain why their vitamin D levels are much lower than you would expect.
THE CHICKEN OR THE EGG SCENARIO
Here is my view on it and why I put in the title to not treat it as a magic pill. I have already seen reports of people taking this information as “all I need to do is take a vitamin D pill a day and I’ll be alright”.
The question I have for everyone is this; do you think it is probable that one vitamin, that potentially half of the world has insufficient levels of, can be the main reason for the 98.9% of deaths in the above study? Possible, maybe, but probable?
I am not downplaying the role that vitamin D has to play on our overall health. There are huge benefits to having sufficient levels of it, and it is one of the few supplements that I feel there is genuinely no reason to not be taking it. I will explain this a little more in our recommendations.
So the chicken or the egg scenario is this; is the increased chance of death due to low vitamin D levels, or is it because of the comorbidities (the ones discussed earlier in the blog) that are associated with low vitamin D levels, that increase the risk?
One of the trends we see with people with low vitamin D levels is a sedentary lifestyle. Two of the reasons given for low vitamin D levels in obese individuals is lower activity levels and less likely to be exposed to sunlight for a significant period. Excess fat storage has also been shown to lower the availability of vitamin D in the body, even when supplementing to increase intake.
So for me, that individual taking a tablet a day to boost their levels isn’t going to be enough to help protect them. It may help, but more is required. It is our lifestyles that need to change if we are to reduce our risk.
VITAMIN D RECOMMENDATIONS
As I said previously, vitamin D supplementation is a great, or even a necessary, option. The UK in the winter as you know can be very bleak, it can be days before we see any sunshine. This means our vitamin D intake is going to be much lower during this time. Therefore, the need for supplementation becomes greater.
UVB rays account for 90% of our vitamin D intake, so if we are not getting out in the sun, then we must ensure we are still getting enough. UK guidelines can vary, but generally it is recommended that our optimal blood levels are around 70-80nmol/l. If that is the case, then currently only 2 European countries are at optimal levels according to the study mentioned above.
It is very hard to tell just how much exposure we are getting to vitamin D through sunlight, which is why I would recommend supplementing anyway. Especially as generally, vitamin D supplements can be pretty cheap. If you can expose yourself to 15-30 minutes of midday sunlight that can boost your levels. However, absorption can vary from person to person based on pigmentation, amount of clothing on, ability of the body to absorb and store the vitamin, sun cream and how strong the UVB rays are. Quite a lot to think about, which is why we are better being safe than sorry by supplementing.
The NHS have recommended supplementing around 400 IU (international units) of vitamin D3, which is around 10 micrograms. Supplements will generally have both IU’s and microgram amounts so keep an eye out for them.
From a personal point of view, I feel this number is outdated and does not take into account the fact that many of us have insufficient levels, and we do not get much exposure to sunlight. Many supplements out there will provide a minimum of 2,500 IU’s, add to that plenty of sun exposure and getting some through our diet (oily fish, eggs, fortified products) and we are probably at a more effective number.
So please, get yourself out in the sun, take your supplement, eat good quality nutritious food, and keep on smiling and laughing. Yes, I recommend taking a vitamin D3 supplement, but our overall lifestyle has the biggest part to play here.
REFERENCES
https://link.springer.com/article/10.1007/s40520-020-01570-8
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2855046/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6682882/
https://www.researchgate.net/publication/280033254_Vitamin_D_Deficiency_Obesity_and_Diabetes
