Posted 24 April 2020
Today I am going to discuss COVID-19 and food supplements. Before anyone thinks I am about to become a snake oil salesman, let me hold you right there as I now have the data from a trial study looking at one particular nutrient and its correlation to severity of COVID-19 symptoms.
First, a brief on supplements generally.
Whenever the word ‘supplement’ is mentioned there will always be a big slice of the audience who will roll their eyes. “A waste of money”, “A big con”, “If you eat a balanced diet, you do not need supplements”.
There are key nutrients that we all need and certainly if you eat enough of the right foods containing those nutrients, prepared in a way that does not destroy those nutrients, then you are probably getting enough. But before you get too attached to that last sentence, I need to get my highlighter pen out (figuratively):
- what are the key nutrients?
- what are the ‘right’ foods?
- how do you know the foods contain those nutrients?
- how does food processing/preparation change the level of those nutrients?
- what is ‘enough’?
All too often the anti-supplement camp will brush over those details and just tell you to eat a balanced diet (whatever that is?). There is another camp at the other extreme who suggest taking supplements will solve pretty much everything. I am a pragmatist somewhere in the middle.
Certainly if you can give me good clear trial data that shows taking a nutrient supplement will improve a specific (or several) health measure(s) or outcome(s), I will listen. Also note, supplement does not necessarily mean a pill – it could be to include in your diet a real food that delivers a particular nutrient (or set of nutrients) that might otherwise be low in your diet. For example, my three musketeers of the nutrient-delivering real food world are liver, sardines and sunflower seeds. Between those three there are very few vitamin and mineral nutrients left out of the equation. For someone who does not normally include those in their diet, ‘supplementing’ with those real foods, could be beneficial.
If that is not practical, then supplementation by other means is a consideration.
Because I want to stick to COVID-19 and real data, I now have to narrow down that discussion to Vitamin D.
When COVID-19 started elbowing out other headlines, there were, certainly on Social Media, waves of posts suggesting eating x, y or z or taking supplements a, b or c would help. None of those claims at the time were evidence based: At best misguided, at worst harmful mis-information. Other than suggesting people look at specific nutrients that have possible positive effects on the immune system or outcomes from infection or respiratory disease, that had to be the limit of any discussion on supplements.
Today, I can be a little bit more bullish about Vitamin D and COVID-19 because I have some data. One study, early days, but it is a start.
I will summarise in the body of this post but at the end are all the numbers.
BACKGROUND OF THE STUDY
The study looked at the patient records of 212 COVID-19 patients hospitalised in South Asia. The records were of patients whose course of COVID-19 had completed – recovery or death.
The patients’ COVID-19 course was categorised as either Mild, Ordinary, Severe or Critical (precise definitions in the numbers at the end of this post).
Blood Vitamin D levels (serum [25(OH)D]) were measured, the standard bloodwork test for Vitamin D status. The measured levels were categorised into either Normal, Insufficient or Deficient levels (again, precise details at the end of the post).
RESULTS
Over 80% of those with Normal Vitamin D levels had a MILD COVID-19 infection.
Three quarters of those with DEFICIENT Vitamin D levels had a SEVERE or CRITICAL outcome.
The average serum Vitamin D levels in the MILD patients was nearly twice the average in the CRITICAL cases.
INTERPRETATION
Higher levels of Vitamin D in the blood are correlated with better COVID-19 outcome. All results were statistically significant.
DISCUSSION.
I am keen first to draw your attention to the word ‘correlated’. A study like this shows association but not cause, that is, the study shows people with higher Vitamin D levels are more likely to have better outcomes but it does not show that the Vitamin D caused the better outcome. It might be a causative relationship, but the study does not demonstrate that.
But being the pragmatist and as long as you keep your consumption of Vitamin D within ‘safe levels’, ensuring you have plenty of sources of Vitamin D dietary or otherwise, you have covered the ‘Vitamin D might help’ base.
Let me then just give some tips on Vitamin D sources:
- Vitamin D comes in two forms – D2 and D3. The former is found in plant material, the later in animals and fish. Humans struggle to absorb and process D2. Meat and fish are therefore far more superior as dietary sources that plant food.
- Cod liver oil is a great source of D3. You would need to eat 3kg of mushrooms to consume the same amount of Vitamin D in one teaspoon of cod liver oil. And the mushrooms provide D2 rather than D3, so the bio-availability would be low anyway.
- Vitamin D is fat soluble. If you have a low fat diet or you trim the fat off your meat, you are taking away the Vitamin D3 sources.
- Eggs, dairy, oily fish like sardines and pasture-raised meats are great sources of D3 but not as rich as cod liver oil.
- You do synthesise some Vitamin D in your skin on exposure to sunlight. But if you wear sunscreen, only expose limited areas of the skin or only for short periods, or are on cholesterol lowering drugs (cholesterol is the precursor to Vitamin D3 created in the skin) the quantity you will produce is small.
- If you to take a pill (rather than the oil or gel capsules) you will need to consume some fat at the same time to aid absorption.
An aside, but an interesting one and one that will lead to a future post, different ethnic minorities (as sub-populations) have different average serum levels of Vitamin D. We also know that the course of COVID-19 is correlated with ethnicity. The ethnicities with poorer COVID-19 outcomes are those that typically have lower Vitamin D levels.
For example, 60% of black Americans have serum Vitamin D levels that would be classified as ‘Deficient’; only 15% of White Americans fall into this category. At the other end of the scale, only 6% of Black Americans have ‘Normal’ Vitamin D levels compared to over 20% White Americans. Black Americans are significantly more likely to have poorer COVID-19 outcomes.
I again make this point that this is correlative, but is an interesting observation. I will discuss this more in another post.
THE VITAMIN D STUDY DETAIL:
The pre-print paper I have seen has not yet been peer-reviewed. That is an important part of the publication of any study – other academics review the paper to identify if there are weaknesses in the methods used, how the data has been processed and how the results have been analysed.
The purpose of the paper was to look at serum (blood) levels of Vitamin D and if that has any correlation to presented severity of COVID-19 symptoms. The study measured serum levels of 25-hydroxy vitamin D [25(OH)D], which is the standard measure of Vitamin D status.
The records of 212 were studied. For all patients, the course of COVID-19 had completed and so the patients had either recovered or died.
The 212 patients were divided into four groups according to their symptoms:
MILD: testing positive for COVID-19 (PCR testing as described in a previous post) but presenting mild clinical symptoms. No diagnosis of pneumonia.
ORDINARY: presenting with fever and respiratory symptoms with a confirmed diagnosis of pneumonia.
SEVERE: Hypoxia (oxygen saturation less than 93%) and respiratory distress (PaCo2>50mm Hg or PaO2<0 mm Hg). You may recall from my post looking at the anatomy of the virus, in severe infection, the cells (ATI cells to be precise) can collapse because the ATII cells are not producing enough surfactant. When this happens, gas exchange at the alveolar surface (bringing oxygen in and carbon dioxide out) is compromised leading to reduced oxygen levels in the blood – hypoxia – and respiratory distress as the innate response of the patient tries to increase rate and depth of breathing to over come this deficiency in oxygen.
CRITICAL: Cases with respiratory failure and consequently admitted for intensive medical care.
The serum Vitamin D levels of all 212 patients was measured and categorised:
Normal: If the serum Vitamin D level was 75 nmol/L or above
Insufficient: Vitamin D level between 51-74 nmol/L
Deficient: Vitamin D level at or below 50 nmol/L
RESULTS:
86% of patients with NORMAL Vitamin D levels presented MILD symptoms.
73% of patients wth DEFICIENT Vitamin D levels present SEVERE or CRITICAL conditions.
This difference was statistically significant at the 1% level.
The difference in Vitamin D levels between the SEVERE and CRITICAL groups was not significant.
The average Vitamin D level in the MILD group was 78 nmol/L
The average Vitamin D level in the ORDINARY group was 68 nmol/L
The average Vitamin D level in the SEVERE group was 53 nmol/L
The average Vitamin D level in the CRITICAL group was 43 nmol/L
These differences were statistically significant at the 1% level.
Increased serum Vitamin D levels diminished the risk of Critical or Severe outcomes: Patients were 7 times more likely to have a MILD outcome than a SEVERE outcome if their Vitamin D was in the Normal range (within 1 standard deviation of the mean of the Normal group). Those same patients were 20 times more likely to have a MILD outcome than have a CRITICAL outcome.