Cod liver oil for COVID prevention?  – an old remedy revisited

Is Vitamin A deficiency one of the reasons why many people suffer serious complications from Covid infection? Could Cod liver oil supplementation prevent Covid or its complications? Cod Liver Oil is a health remedy that is many centuries old. Should we all be taking it again?

Early Cod Liver Oil advertisement – presumably Magee was trying to make it taste better!

Ask any older person who grew up in the UK or northern Europe whether they had Cod Liver Oil as a child and they will generally pull a face! So, yes, they did take it. Yet, however distasteful the raw product may be, Cod Liver Oil was, (and still can be), a great and inexpensive preventative medicine – including against Covid 19.

I personally didn’t suffer from the daily spoonful of cod liver oil, but I did have plenty of coughs and colds as a child. However, it was in 1977, when I took my then 18-month-old daughter to Europe, that I discovered the benefits of cod liver oil. My baby daughter, like most other Australian children at the time suffered from recurrent ear and chest infections and so, when we reached Scandinavia, Northern England and Scotland, I couldn’t believe how well the children looked even though they were playing outside in rather dreary, cold weather. I asked the mothers their secret and they told me that the children took Cod Liver Oil every day!

The spoonful or the capsule of Cod Liver Oil – an easy choice

Since I was still breast feeding, I decided to take the Cod Liver Oil myself – but in the form of a capsule – not on a spoon! Once my daughter was weened, she took her own capsules – in fact she was happy to chew them (ugh). Anyway, this simple supplement worked like magic. My own respiratory health improved and so did my daughter’s – in fact neither of us experienced a chest or ear infection in the following years.

When I returned from the 1977 trip, I happened the speak with a professor who had undertaken extensive research on the cells that line the lungs and I asked him about Cod Liver Oil. He told me that the Vitamin A in Cod liver Oil would protect the endothelial cells that line the lung as well as all the other epithelial (skin and organ lining cells) of my body. So, I have taken one capsule daily ever since and haven’t suffered from any chest infection!

The History of Cod Liver Oil

Although historically Cod Liver Oil was widely used in the 18th, 19th and early 20th centuries to prevent ‘rickets’, which is a bone deformity caused by deficiency of Vitamin D, widespread fortification of milk with Vitamin D in the 1930’s led to many physicians stopping recommending Cod Liver Oil.

Although we tend to hear about children taking Cod Liver Oil, it was also taken by many adults, especially fishermen.

Excess Vitamin A is toxic and may be experienced by people who take excess Vitamin A supplements or who eat high amounts of liver which is high amounts of Vitamin A). This makes ‘getting the level of Vitamin A right’ complicated because overall it seems that many more people are Vitamin A deficient than sufficient or suffering from excess.

Are you likely to be deficient in Vitamin A?

If you live in Africa or Southeast Asia, you are likely to be deficient in Vitamin A because the foods commonly eaten in your countries do not contain much Vitamin A. If you live elsewhere in the world and you don’t eat liver and/or you are not eating foods in which Vitamin A is added, you could well be suffering from mild or even moderate Vitamin A deficiency. It is estimated that over 20% of the population in the developed world doesn’t reach at least two thirds of the recommended daily intake of Vitamin A and have blood and liver concentrations that are less than optimal.

Factors that affect your ability to absorb dietary Vitamin A

In addition to inadequate dietary intake, risk factors for Vitamin A deficiency include stress – which affects the intestine’s ability to absorb fat and/or very low-fat diets including vegetarianism – because dietary fat is necessary to absorb Vitamin A.

Excessive alcohol consumption also reduces the liver’s reserves of Vitamin A so like several other vitamins and minerals, if you regularly consume alcohol, you need to be conscious of your intake of vitamins, including Vitamin A.

The benefits of Vitamin A for good lung function

The benefits of Vitamin A have largely been ignored by medical researchers. There was considerable research undertaken into Vitamin A and lung development in the 1980’s but until recently this research area has been largely overlooked. I have referenced a couple of relevant publications below that each stress the importance of adequate Vitamin A for normal lung function. Some of the critical points listed in these publications are:

  • “During moderate vitamin-A-deficiency, the incidence for diseases of the respiratory tract is considerably increased and repeated respiratory infections can be influenced therapeutically by a moderate vitamin-A-supplementation” (Biesalski & Nohr, 2004)
  • “Vitamin A deficiency (VAD) is a remarkable public health problem……In fact, chronic VAD has been associated with histopathological changes in the pulmonary epithelial lining that disrupt the normal lung physiology predisposing to severe tissue dysfunction and respiratory diseases” (Timoneda et al. 2018).

Recently, however there has been a resurgence of interest in Vitamin A and Cod Liver Oil, especially with respect to Covid 19 infections. In Oslo (Norway) a clinical trial led by Arne Vasli Søraas is underway to test whether Cod Liver Oil prevents Covid and/or its complications. If this trial has positive outcomes, and cod liver oil supplementation again becomes popular, we may see many beneficial outcomes in overall respiratory health.

Biesalski & Nohr (2004) Importance of Vitamin A for lung function and development. Molecular Aspects of Medicine 24(6):431-40

Timoneda J et al (2018) Vitamin A deficiency and the Lung. Nutrients 10 (9): 1132

Please contact me with you comments and any questions about this post. I am available to give talks on this and related topics.

Published by Dr Judy

I am a PhD Geneticist and have spent many decades working in research related to reproduction and cancer. Both are affected by lifestyle, especially ageing and so I am passionate about teaching people how to change their lifestyles to optimise their health.

One thought on “Cod liver oil for COVID prevention?  – an old remedy revisited

  1. Dear Dr. Judy, I well remember taking a substance called “Agarol A” as. Child. It was a milky colour and we were given a spoonful each day. I’m sure it was Cod Liver Oil.
    I must try taking the Capsules again.
    Thank you for this valuable insight.
    Kind regards, Evelyne jones.

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