Smorgasbord Health Column – Project 101 – Resistance – Vitamin D Deficiency Part Two – Getting Sufficient – by Sally Cronin

Project 101 – Resilience is aimed at developing a strong  immune system and a body that can fight off disease at any age. One of the key factors in achieving that level of robust health is being a healthy weight. There have been a number of risk factors identified that put certain groups of the population at a higher risk of a critical outcome from being infected with Covid- 19 – one of these is a possible deficiency of Vitamin D.

A report that came out yesterday in one of the daily papers with claims that there is no evidence that Vitamin D will protect you from the disease. However, there are a great many studies that have identified that Vitamin D supports a healthy immune system which will assist the body as it fights an infection : University of Southampton Research

Yesterday I covered some of the functions in the body that require Vitamin D either to achieve a balance between two minerals such as calcium and magnesium in bone health including the prevention of rickets…or to ensure that the immune system does not go into overdrive or under perform.

How do we get sufficient Vitamin D?

Whilst we are designed to produce our own Vitamin D from the interaction of sunlight on our skin,  there two forms of the vitamin found in foods are D2 (ergocalciferol) is the one activated by sunlight in the plants that we eat plants and D3 (cholecalciferol) is found in animal foods. D3 is the one that is most commonly used in supplementation usually in combination with calcium as it is the most biologically usable and effective for humans.

The link to cholesterol

When sunlight hits the skin it reacts with the cholesterol in the cells.  Without cholesterol the production of Vitamin D would be impossible.

This does raise a question for me. I am very anti-statins unless it is essential as cholesterol is an essential element in many processes in the body. It would seem to me to be very short sighted to mass prescribe statins for over 50s, particularly in the Northern hemisphere, when that age group is likely to be deficient in Vitamin D.  You can read more about Cholesterol and its importance to the body: The Cholesterol Myth – Part One – and Statins the new research!

Plant source of Vitamin D2

It has been identified that Vitamin D2 that we source from plants is not absorbed as effectively by the body. This means that vegetarians and vegans need to make sure that they obtain sufficient sunshine and consider supplementation under the guidance of a qualified practitioner.

N.B. If you have a liver or kidney condition then you should not supplement without your doctor’s advice. When we take in Vitamin D from food or sunlight it firsts goes to the liver and gets converted to one form and then onto the kidney to be converted into another form before being active and usable. If you have a liver or kidney problem you will be unable to convert the vitamin and will need the already activated form on prescription from your doctor.

Vitamin D taken in excess can be toxic and you should not supplement regularly more than 1000 IU to 3000IU per day. The upper limit for safety has been set at 10,000 IU per day and if you are getting adequate sunlight provided vitamin D you should not need to supplement in summer months.

The recommended daily levels are confused as since 1997 when the original levels were set at between 200 and 600 IU An IU represents 5 micrograms. Researchers now believe that we need a minimum intake of 1000 IU rising as we age to 3000 IU which is the dosage that I take October to May daily. And sometimes during our Irish summers!!

Most of what we require on a daily basis is produced in the skin by the action of sunlight and many of us who suffer from depression through the dark winter months are actually missing around 75% of our required daily dose this represents over 2000IU of vitamin D for someone in their 70’s. Many in the Northern Hemisphere suffer from Seasonal Affective Disorder and I know that I am not at my best physically or mentally during the winter months if I do not supplement with Vitamin D.

Here is a little information about Seasonal Affective Disorder (SAD)

The typical symptoms of SAD include depression, lack of energy, increased need for sleep, a craving for sweets and weight gain. Symptoms begin in the fall, peak in the winter and usually resolve in the spring. Some individuals experience great bursts of energy and creativity in the spring or early summer. Susceptible individuals who work in buildings without windows may experience SAD-type symptoms at any time of year. Some people with SAD have mild or occasionally severe periods of mania during the spring or summer. If the symptoms are mild, no treatment may be necessary. If they are problematic, then a mood stabilizer such as Lithium might be considered. There is a smaller group of individuals who suffer from summer depression: More at Smorgasbord Health Column SAD

How much time should you spend in the sun?

There is quite a lot of information available regarding the amount of time that you need in the sunshine to produce sufficient Vitamin D and unfortunately it is also very confusing. Some researchers say that you only need 15 minutes per day in the sun and others recommend two to three hours of exposure. If you can consistently obtain 15 to 20 minutes of late morning sunshine on your forearms, chest area and your back, you should be able to build up your Vitamin D levels. When I was younger three months of summer would enable me to go through the winter months without noticing any impact. Now that I am in my late 60s I need to take a supplement to maintain adequate levels.

What is crucial is the type of ultraviolet light, the time of day, the latitude and altitude and amount of bare skin exposed.

Ultraviolet light is divided into 3 bands or wavelength ranges which are UV-C, UV-B and UV-A. UV-C is the strongest and it is the band that causes our skin to burn in a very short space of time. This band is absorbed by the ozone level and thankfully never reaches our skin – yet.

UV-A is responsible for our tans as it activates the pigment in our skin. Usually we will not burn in this range unless we are photosensitive (some anti-depressants and St. John’s Wort can cause this) or very high and frequent doses are used. This range is used for tanning beds and there have been incidences of skin cancer resulting from over use.

Until very recently this UV-A was not blocked in any sunscreens and of course sunbathers would lie out in extremely strong sunlight believing that they were protected completely from harmful rays. Of course they were not which is believed to be the reason for the increase in the level of skin cancers.

The ultraviolet wavelength we need to produce Vitamin D is UV-B and unfortunately despite its benefits also is the burning ray and the primary cause of sunburn.

It also however, produces the beneficial effects of stimulating Vitamin D production, causes special skin cells to produce melanin which protects our skin, and for those of us trying to lose weight, also stimulates a hormone MSH (Melanocyte Stimulating Hormone) that helps in weight loss and energy production.

A drawback is that although UV-A is present all through the day, the UV-B available is dependent on a number of factors including the angle of the sun rays and cloud cover as well as latitude and altitude. The upshot is that the most beneficial time to take advantage of the UV-B rays is in the peak burning zones of 10.00 a.m. to 2.00p.m.

The sensible approach is to build up you tan slowly and carefully over a period of time so that the melanin in your skin provides protection from burning. Start by getting five minutes exposure to very bright sunlight if you have very fair skin and then increase this as your tan builds. Walking at other times of the day will also benefit you and try to expose as much skin as is decently acceptable (don’t frighten the tourists) You need to try and reveal around 85% of your skin to be effective.

I don’t advise anyone to sit in scorching sunshine in the middle of the day for hours – If you do make sure you have adequate protection to begin with and then reduce the factor down to 8 over a period of time.

N.B.Any sun blocks over 8 will not allow the UV-B rays through to produce Vitamin D so when you are ready and you have sufficient protection in your own skin reduce the sunblock to under 8.

Food sources of Vitamin D

Our ancestors mainly worked outside until the industrial revolution and activities such as farming, fishing and hunting meant that we were exposed to sunlight throughout the day depending on the latitude and altitude of our immediate vicinity.

Those not lucky enough to get adequate sunshine would have instinctively sought other sources of Vitamin D from food. In those days it was the intestines, livers, kidneys, skin and fat of the animals they caught as well as seafood, oily fish and insects. It is obvious from this list how many foods have disappeared from our plates in the last 100 years.

When was the last time that you ate liver, kidneys, the fat on your steak or the crispy skin on your chicken. We certainly have been told not to eat most of these to preserve our health but ironically it means that we are also missing out on viable sources of Vitamin D.

This has limited the available food sources of the vitamins and some of them are rather inadequate anyway.

eggsAn egg contains approximately 124 IU with a 100g serving of herring or tinned salmon providing just over 400 IU. Dairy products such as milk contain the vitamin but an 8oz glass only contains 100 IU unless it has been fortified. You will find many more dairy products and also orange juice that is now fortified with Vitamin D. However, this does mean that packaged products such as cereals, come with other additives, including too much sugar.

Pork fat contains 2,800 IU per 100gms so start eating the crackling again (do not attempt if trying to lose weight. Herrings contain 680 IU, Oysters contain 640 IU (would need a lot more than a dozen) Sardines 500IU. Mackeral 450 IU and butter 56IU

Salmon contains 450 IU per 100gm and tinned or fresh tuna 155 IU per 100gm are good sources of the vitamin and well worth including regularly in your diet.

Mushrooms that have been grown exposed to UV light have varying amounts of Vitamin D and you need to read the labels.. I buy some Irish ones that are slightly more expensive but have a reasonable level.

This compares to 2,000 IU to 5000IU produced from sunlight dependent on the factors we have already covered.

Cod liver oil

As children we were given spoonfuls of cod liver oil and thanks to that simple breakthrough in the early 1900’s we did not get rickets.

I do recommend that everyone take high quality supplement during the winter months, or if unable to be outside to take advantage of sunshine.. Apart from the Vitamin D you will also be supplying your body with an excellent source of Omega 3 Fatty Acids essential for a great many of our bodies functions. Cod liver oil also contains rich amounts of vitamin A and the whole package will help protect you against age related diseases.

Today if you cannot face a tablespoon of the oil, you can obtain high quality cod liver oil capsules. There are lots to choose from so I suggest you shop around to find the best quality you can.

As we get older our skin thins and we are less able to manufacture Vitamin D naturally, which is when supplementation is really quite important.. It is a good idea to take not only cod liver oil but also an additional supplement of calcium, magnesium and Vitamin D. This is important for both men and women to maintain the correct Acid/alkaline balance and also to balance hormone levels during midlife when breast and prostate cancer is more of a risk.

©Sally Cronin – Just Food for Health – 1998 – 2023


I am a qualified nutritional therapist with twenty-two years experience working with clients in Ireland and the UK as well as being a health consultant on radio in Spain. Although I write a lot of fiction, I actually wrote my first two books on health, the first one, Size Matters, a weight loss programme 20 years ago, based on my own weight loss of 154lbs. My first clinic was in Ireland, the Cronin Diet Advisory Centre and my second book, Just Food for Health was written as my client’s workbook. Since then I have written a men’s health manual, and anti-aging programme, articles for magazines and posts here on Smorgasbord.

If you would like to browse my health books and fiction you can find them here: My books and reviews 2020

Your feedback is always welcome and if you do find that following any of the programmes that I have shared are beneficial then it would be great to hear about it.. you can email me on


47 thoughts on “Smorgasbord Health Column – Project 101 – Resistance – Vitamin D Deficiency Part Two – Getting Sufficient – by Sally Cronin

  1. Thanks Sally… didn’t realise the effect of over 8 sunblocks. I suppose perhaps once a week or so maybe leave off the sunblock if like me, you can’t tolerate Vit D supplements?

    Liked by 1 person

  2. Thanks for this. I’ve been taking a Vitamin D supplement for over a year now. My husband had read up on it and said I needed to take it because I’m very fair-skinned and need a factor 50 sun cream to prevent me burning when I’m gardening. I was initially sceptical but am now an evangelical convert!

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  3. That pork crackling looks mouth-wateringly delicious! I woke up this morning wondering if by self-isolating for so long we may all have lowered immune systems as we’ve not had to fight off infections.

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    • There is a risk for an extended period of time but we should be fine after three months. We will have to be extra cautious however about rushing into crowded situations and why it is a good idea to start slowly with family and close friends. I am sure it is one of the reasons that care homes and long term health facilities have been so vulnerable, not only the proximity to each other but the fact that their immune systems have not been exercised in a long time. xx

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  4. Sal,thanks for another excellent and informative edition. So, Vit D seems to be a trickster. We get most from the sun, if we are ‘t wearing sunscreen, but we could get burnt without the sunscreen, lol.. Do you know how long unprotected exposure it would take to get 2000mcgs ? Also, in the summer we don’t need as much supplementation. But would you say only the days we get those rays to not take the supplementation or don’t take daily at all in summer if? Vit D the trickster, lol. Sadly, I don’t like anything on the food list that gives it except salmon and tuna and liver, lol. I’m such a finnicky eater I have to supplement. ❤

    Liked by 1 person

  5. I’ve been nursing my absurdly white legs to fifteen minutes a day for the last month. Not much change, but at least their not the color of eggs anymore. 🤣

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  6. I have to log my food intake for a couple weeks, Sally. I eat one egg, some mushroom, about 3 oz. Salmon or pork or chicken every day, cook veggies with olive oil. But my specialist prescribed D3 50 mcg a day and I take the liquid form (5 drops). I get some D3 from animal fat already. So I may have to reduce to 2 or 3 drops of liquid D3 a day. We got adequate sunlight here and winter is just a teasing season for us. It was cloudy the last few days but I got my first tan when wearing short sleeves top.

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  8. Thank you, Sally, for all this info. We take D3 daily 1000mg. When we go to Aruba we will not need it being out in the sun all day. We do need to use 70 or 50 sunscreen because we burn if we don’t. I hope we get there this year but it’s still up in the air about safety traveling. Sigh! Thanks for all your expertise! Stay safe and well, my friend! 💕😘🤗

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  15. This sunscreen vs sunshine is a tricky one. I have a sun damage spot on my face. Although not suspicious, the doctor said to keep an eye on it, and not to go out without sunscreen if there is any hint of sun. In fact, she said, more or less, that I should use it unless it’s pouring with rain!
    I read a while ago that there is a problem with rickets in Arab countries where people, especially women, but also some men, cover themselves to avoid the sun. And even those who don’t, spend most of their time indoors.
    In Dubai, people go from airconditioned apartments into airconditioned metro stations, then walk through an airconditioned tubes to the airconditioned Malls. No chance of a sunbeam hitting them!
    In those cases, and in my own, I suppose supplements would help, but I’m reluctant, believing we should be able to get what we need from our diet, and other natural means. After all, animals and our ancestors didn’t have supplements.

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    • Thanks Viv.. rickets is on the increase in younger children which does not bode well for the future. Vitamin D is one that I do believe should be taken in supplement form, particularly for women post menopausal who have lost the protection of their hormones, and particularly if you are not going out much. Living in Madrid for 17 years with 250 days of sunshine I banked quite a bit of Vitamin D, however I took from December to the end of March when it became warmer for me to sit outside again.. Here with 250 days of rain I take for a lot longer in the year. Whilst there are foods that contain Vitamin D they are not as numerous as the other nutrients which is flour, bread, milk etc tends to be fortified. The decision is yours but I do suggest perhaps having a word with your pharmacist or in boots for a low doseage Vitaman D to take one a day throughout the year. It is essential for not just our immune and bone health but other important functions for health…hugsx

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