Food rich in vitamin D

Food rich in vitamin D counters metabolic syndrome, diabetes and a host of other serious diseases, including the coronavirus; it also contributes to delaying the rapid progression of frailty in the older person. Recommended is about 800 IU per day but some are suggesting far more to prevent illness.

Over and above these common conditions, researchers at NW university have found a strong correlation between a vitamin-D deficiency and worse outcomes from the virus during the current pandemic.

However the study published in Scientific Reports that high dose vitamin D supplementation significantly reduced inflammatory markers in those infected with the C-19 virus have now been withdrawn; there were concerns about the methodology.

Further research concludes that a low level of vitamin D is associated with an increased risk of transmission of the virus and suffering from long Covid. But did not affect the clinical outcome once infected; unless deficient in this cholesterol-derived steroid hormone.

There is now very strong consensus in the scientific community that in the main, important nutrients like vitamin D need to be sourced from our food and in this instance from low but adequate exposure to sunshine.

Salmon and mushroom dinner is rich in vitamin D.

This page was last updated by Bernard Preston on 9th March, 2024.

"Recommendations for vitamin D in the generally healthy population really should focus on food."

- Professor JoAnn Manson, Harvard Medical School

The philosophy behind food rich in vitamin-D is all about doing whatever we can to help ourselves. It springs from a dread of serious disease and a loathing of taking so much medication; and supplements too.

Prevention is better than a cure is trotted out in many conversations but let's face it, largely ignored. In reality the ostrich-mentality is prevalent; disease will not touch me or my family and if it does then we are confident that our doctor has a solution.


So where do you get vitamin-D if it is so vitally important?

In the Tropics sunshine contains daily the required strength of ultraviolet light to produce sufficient vitamin-D in your skin; but the chances are that you live far north or south of the equator.

An outdoor life then would not be sufficient; and a couch-potato would be in serious trouble unless they ate particularly well.

There is and rightly so, a fear of a dreadful malignant skin-condition known as a melanoma; however we have gone totally overboard in trying to protect ourselves from sunshine.

Recommendations to seriously limit exposure to sunlight to prevent melanomas conflict with the need to protect bone strength and other serious diseases; through adequate vitamin D levels.

It should still be the main source so that we do not have to rely totally on food rich in vitamin D for our well-being; and supplements have little proven merit.

Plus vitamin-D specifically from sunshine gives us protection against the internal malignancies; so how do we balance these concerns?

Only mad dogs and Englishmen[1] go out for prolonged periods in the midday sun, and then a screening creme will be necessary; but for the rest of the sane world, a broad-brimmed hat and some full exposure to ultraviolet light on the arms and legs but not on your face and ears, is absolutely essential.

Take an apple and go for a stroll at lunchtime; and then you get the triple benefit.

Temperate zones

In Temperate regions between the Tropics and the polar areas, probably where you live the sunlight is never strong enough to produce adequate vitamin-D in winter; but during the rest of the year you can get adequate amounts.

In the polar regions the sun is never strong enough year-round; food rich in vitamin D is vital.

Ultraviolet light for vitamin D

There are two types of ultraviolet light, UVA and UVB but only the latter generates vitamin-D; both contribute to melanomas.

Our skin manufactures vitamin D by using UVB in sunshine to break open one of the aromatic rings in a precursor of cholesterol, according to bioengineer Annelise Barron; this enables our bodies to manufacture a potent antiviral chemical called LL-37.

Those who are vitamin D deficient are four times more likely to die if infected by C-19.

The proportion of UVB is greatest around midday, so one gains larger amounts of useful sunshine at noon; but early and late there is more UVA and thus the benefit to risk ratio is lower[2].

"Levels of 25-hydroxyvitamin D in the intervention group (with supplements) increased to a less than expected degree."

- JAMA Dermatology

So a short exposure in the middle of the day is more beneficial; you need less time to get your quota and surprisingly less damage from UVA.

So perhaps the English are not so mad after all.

As a rule of thumb, a quarter of an hour in the sun around noon, three days a week in midsummer would be adequate. This is undoubtedly one of the reasons that gardeners are more healthy; they have greater amounts of vitamin D.

"There is increasing evidence that exposure to plants and green space and particularly to gardening, is beneficial to mental and physical health."

- Clinical Medicine (PMC6334070)

On the shoulders of summer you would need half an hour.

Luckily it is fat soluble, so it is stored in the body for the long winter months when exposure to sun has far less benefit; that is when food rich in vitamin D is especially important.

So perhaps take your walks for a short period in the middle of the day; and then go indoors or apply sunblock. Always wear a proper hat to protect the ears and nose; not just a peak.

Covid-19 and vitamin D

Researchers led by Prof Vadim Backman were skeptical of many of the theories on how people react to the Covid-19 virus after noticing unusual and unexpected differences in deaths from the disease from one country to another. However when they examined vitamin D levels they discovered a strong correlation; this would explain why the illness is so much more deadly in the depths of winter when people are exposed to less sunlight[4].

Vitamin D helps lower C-reactive protein, an inflammatory marker[5].

Vitamin D not only enhances the normal immune-system, it also prevents it from becoming dangerously overactive; it's that which kills, says he.

A cytokine storm results; it is a highly inflammatory condition provoked by an overactive immune-system.

Prevention is an important aspect for the control of infectious diseases, state researchers writing in Clinical Nutrition; keep vitamin D levels up.

He continues that adequate levels of vitamin-D will not protect us from contracting the virus; but their research indicates it will halve the rate of serious complications and death. You may still get sick but you will not die.

It also explains why children are less prone to severe responses to the virus; their immature immune systems are unlikely to provoke these cytokine-storms.

How does the virus gain access into our bodies?

The C-19 virus gains access to our cells by binding onto the ACE2 receptor, a part of normal cell function that regulates blood pressure amongst other things. It has a sugar spike to which the coronavirus attaches; it does this more readily in those who have raised capillary glucose explaining why the obese and diabetics are more prone to a severe inflammatory infection.

This receptor in the lungs is also up-regulated by some hypertensive drugs making it more receptive to the virus. The majority of those who experience a cytokine storm have either raised blood pressure or glucose; or worse still both.

There is general agreement amongst doctors that keeping your blood glucose level well below 10 mmol/L [180 mg/dL] is associated with a lower mortality rate among patients with T2D and COVID-19.

Part of the secret is to enjoy certain spices that help regulate blood glucose on a daily basis; the cinnamon and diabetes link is well established in the literature. Even more important of course is to strictly limit refined carbohydrate at this time if we are not to succumb after exposure to the C-19 virus; and the flu too of course.

And at all times if we hope to reach happy, vibrant old age, free from cardiovascular and other diseases associated with raised blood glucose, food rich in vitamin-D and adequate sunshine remain central.

Almost 50% of the American population is either wholly or pre-diabetic. It is increasing rapidly in South Africa too, with rates more than doubling since 2000[7].

More than one in ten frank diabetics hospitalised with C-19 die within one week.

Risk of death is higher from both types of diabetes when infected by the C-19 virus, but is even more dangerous for those with T1D.

Delaying anything sweet or starchy and taking a walk after meals, in the early morning helps to counteract the "dawn phenomenon" that occurs in both T1D and T2D; in over a half of diabetics blood glucose rises ominously in the wee small hours.

This is perhaps why an early dinner and a brunch, breaking the "fast" later helps with weight loss.

Classic signs of diabetes

Well known symptoms of diabetes are increased thirst, frequent urination and weight loss; and constant hunger too. Less commonly known are blurred-vision, tingling in the feet and yeast infections; and inflammation of the penis, known as balantis.

A vitamin D deficiency is an independent risk factor for diabetic peripheral neuropathy. The reason is that chronically raised blood glucose causes oxidative stress which damages the tiny capillaries supplying the nerves.

Diabetics usually also have abnormal glucagon secretion by the alpha-cells in the pancreas; this serves to raise not only blood glucose but also triglycerides above 250 mg/dL (2.82 mmol/L).

So common and deadly is diabetes that everyone over 45 should be routinely tested. A fasting blood glucose level above 126 mg/dL (7 mmol/L) confirms the diagnosis.

A blood glucose level about 200 mg/dL (11.1 mmol/L) two-hours after a starchy, sugary meal would also lead to a high level of suspicion.

An HbA1c level over 6.5% also confirms the chronic raised level of blood glucose; many think it should normally be considerably lower than that, say under 5.8pc. The Nutrition Network recommends a goal of less than 5.0.

Minimum goals for diabetics

A 5% weight-loss for obese diabetics would have an immediate benefit. That can be readily achieved by reducing refined-starches and increased physical activity which should where possible include some high intensity stuff such as jogging.

The goal should be walking at least half an hour per day, particularly immediately after starchy food; ten-minutes after each meal would be ideal.

Type-2 diabetes can be completely reversed by very low carbohydrate food (less than 20 - 50 grams per day) but this must be monitored by a suitably qualified medical doctor or coach.

Insulin must frequently be reduced by at least a half, otherwise there is risk of diabetic-coma.

Metformin is frequently recommended but it is contraindicated in those with kidney disease. It reduces an unexplained phenomenon known as paradoxical-gluconeogenesis.

"Overall, it's recommended that small to moderate amounts of vitamin D are adequate; and among the healthy population, most people do not need screening or supplements."

- Prof JoAnn Manson

Fatty fish

Fatty-fish has plenty of vitamin D, containing about 200 - 300 IU per 100g; an average serving.

Salmon is particularly rich at 360-IU.

Our smoked-salmon dip recipe is a delicious way to protect yourself from the ravages of these nasty diseases.

A one gram cod-liver oil softgel contains only about 200 IU. You will be shocked at the price to get you enough vitamin D; sunshine is far cheaper and more effective.

Our mackerel recipes are another way to supply our needs; clearly we have to look for multiple sources on a daily basis. There are disturbing comments from researchers about the ineffectiveness of taking supplements and the dangers of unexpected consequences; like the increase in prostate tumours from taking alpha-tocopherol, the most common form of vitamin E in capsules.

Luckily fatty fish is also the best source of anti-inflammatory omega 3.

"Let thy food be thy medicine, and medicine be thy food."

Hippocrates (460 - 370 BC)

  • Pilchard fish cakes ...

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Food rich in vitamin-D and moderate amounts of sunshine are necessary. These recipes for mussels are interesting if you are fortunate enough to live in a place like Holland. Shellfish in general are a good source.

Mushroom and eggs

A typical serving of mushrooms supplies about 20 IU of vitamin D; not very much.

This sauteed mushroom recipe is one of our favourites.

One egg also provides about 20 - 30 IU; not a huge amount either but it all helps.

Eggs Florentine supplies not only the vitamin-D but also all the benefits of spinach; those on typical grocery store food are woefully short of magnesium. Adequate sunshine remains important. 

Food rich in vitamin D

Food rich in vitamin-D is also strongly linked to less osteoporosis and a stronger immune system; make sure you get it from sunshine and these meals or there is serious illness on the way.

Perhaps oddly since vitamin-D is so important for bone strength, it not normally listed in those four absolutely needed to prevent premature aging known as frailty syndrome. I am not sure why.


So just how much vitamin-D do you need? Can you get enough from your smoked salmon dip recipe? For the first fifty years of your life, you require about 200 IU per day. After that, scientists advise a rapidly increasing amount to protect your bones against osteoporosis.

More sunshine with fatty fish, eggs and mushrooms is needed; 400 - 600 IU and perhaps a lot more is recommended.

The long and the short of it is that vitamin-D is so important in the body to protect you against invading bugs, gives you good bone strength and stimulate your immune system. Plus it has a huge role to play in the management of diabetes and thus cardiovascular disease.

Depending on the latitude where you live, fatty fish, mushrooms and eggs are important. Walking benefits are absolutely vital, especially if you are in the temperate zone in which case you will not get adequate vitamin-D in winter.

The alternative is colds, flu and broken bones; and a weak immune system. Think of meals rich in vitamin D if you want to be robust and strong and have the protection of omega-3. And of course the very best of protein is in seafood and eggs.

This becomes all the more relevant the older you get; maybe an occasional cod-liver oil softgel and regular smoked salmon dip recipe.

"There are hundreds of Randomised Control Trials. The results simplify into one sentence; vitamin D supplements do not improve health outcomes."

- John Mandrola, MD

The exception to this finding is in a diabetic peripheral neuropathy; there are studies that show that vitamin D supplementation stimulates "nerve growth factor." This leads to regeneration of the axons.

Dementia prevention

Nutrition is a complex science and even the experts regularly contradict one another. It means we all have the responsibility to use our own common sense in an attempt to make the right judgements.

Researchers from the Hotchkiss Brain Institute in Calgary, far north, have found that there is indeed strong correlation between vitamin D supplements and a lower risk of developing cognitive problems[11].

But it would seem only in those with low levels of vitamin D; more research is needed.

In any case low vitamin D levels in the plasma is associated with a host of other conditions.

It does seem clear that those living far from the equator should either enjoy food rich in vitamin D or take supplements in the winter.

Age-related blindness

Vitamin D is central in protecting our bodies from many diseases; one of them is age-related macular degeneration, the most common cause of blindness in the elderly.

Acting along with two phytonutrients, lutein and zeaxanthin, vitamin D has a proven role in preventing blindness in the older person.

At lutein macular degeneration you will find a simple-test you can do at home to detect the onset of AMD.

Fish soup is rich in vitamin D. Adding the "nutritional value of mushrooms" makes them another priceless food. Find out more using Site Search in the menu bar above.

Vitamin d supplements

"Cummings and Rosen point out that these findings, along with other VITAL trial data, show that no subgroups classified on the basis of baseline 25-hydroxyvitamin D levels, including those with levels <20 ng/mL, benefited from vitamin supplementation[10]."

It would appear yet again that there is little proven benefit from taking vitamin D supplements; in fact some studies say there could be harm.

An update on the effectiveness of vitamin D supplements in patients suffering from multiple sclerosis again confirms they have no value; although those with known low levels were excluded[12].

The science is pointing to the fact that food rich in vitamin D is the way to go; and more sunshine. This principle applies to virtually all micronutrients.


Your smoked salmon dip recipe is one of the richest sources of anti-inflammatory omega 3, over and above being a prime food rich in vitamin D; do you suffer from a lot of anger in your joints, muscles and blood vessels? Our organs are often affected too; for example, ulcerative colitis.

Then look to food for the solution to inflammation; enjoy these meals daily and you will be able to get off those nasty pills, or at least drastically reduce them. Is a life without medication a pipe-dream?

Not if you start thinking about subjects like food rich in vitamin D long before illness strikes.

"Researchers saw that among those who had a BMI below the median of 31, there was a significant 24% reduction in diabetes risk by taking vitamin D. But those who had a BMI at the median of 31 or above had no decrease whatsoever."

- Prof JoAnn Manson, Harvard Medical School.


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Did you know that anti-inflammatory drugs kill about 12,000 Americans every year, just from a bleed in the gut? That is not including the increased levels of heart disease and catastrophic strokes associated with NSAIDs.

Anti-inflammatory omega 3 comes in the main from fatty fish, freshly ground flax seed and walnuts; if you are not having at least one of those regularly, you will be having pain in your body.

Obesity and Multiple Sclerosis

For unknown reasons, though a vitamin-D deficiency is suspected, obese children are twice as likely to develop multiple sclerosis later in life as compared to those with a normal BMI. This large study in the USA focused on women3.

Munger et al[6] published their research in the journal Neurology showing that women with vitamin-D levels below 30 nmol/L had a 43% higher risk of developing MS. This explains why those living nearer to the equator are far less likely to get the disease.

A daily walk in the sun, with a hat on and no sunscreen, has profoundly important benefits for our well-being.

Those who are obese have nearly a 2-fold risk of being vitamin D deficient; the exact mechanism for this is not completely understood but it is probably associated with little or no UV B exposure to sunlight.

"Lifestyle modifications resulted in a 58% reduction in type 2 diabetes, and metformin resulted in about a 31pc decrease; much larger drops than seen with high-dose vitamin D."

- Prof JoAnn Manson

Researchers have found that most of those suffering from T2DM can be put completely into remission without the use of any drugs by using food as medicine.


There is great concern that little is done to prevent malignant tumours in the today's medical management; largely the focus is on early diagnosis and treatment.

"Preventive efforts in middle-aged and older adults today are largely limited to screening and vaccination efforts."

- Dr. Heike Bischoff-Ferrari of the University Hospital Zurich

Researchers in Europe sought to see the combined effect of three programmes, each known to help in the prevention of malignant tumours in their own right; vitamin D, omega-3 and exercise.

A third of women suffering from a malignant breast tumour have low vitamin D levels; and with chemotherapy are likely to develop an untreatable and sometimes permanent peripheral neuropathy.

"In fact novel treatments aim to block multiple pathways for tumour development by combining several agents. We translated this concept into prevention of neoplasms."

- Dr. Heike Bischoff-Ferrari

The results were very encouraging; over a three-year period there was a 61% lower risk of suffering from a malignant tumour[8].

The amount of vitamin D was a high dose compared to current recommendations which is 800 IU per day. Participants received more than three times that amount.

Omega 3 was 1g per day of the three different fatty acids. Purslane plant is one of the few vegetable sources of all of them, a common weed in many gardens; generally freshly-ground flaxseed and fatty fish are recommended.

30 minutes of midday sun, depending on latitude obviously will provide more than 10,000 IU of vitamin D. There appears to be general agreement of wearing a hat to keep radiation off the face and neck; but exposing as much of the rest of the body to small amounts daily.



Scientist writing in the journal Melanoma Research found that regular use of vitamin D was associated with fewer cases of this horrific tumour.

They were based in Finland, in the far north of the Temperate Zone, so comparable results with vitamin D from sunshine was not possible.

It's no coincidence that cold-water fatty fish found far north and south is the richest source of vitamin D. Scientists are unanimous; there are no dissenting voices.

"Let thy food be thy medicine, and medicine be thy food."

Hippocrates (460 - 370 BC)

VITAL trial

The large, well-designed VITAL trial after following 26,000 US adults for 12 years again concluded that we must get it from sunshine and our food; D3 supplements did not help a wide array of conditions including cancer, cardiovascular disease or reduce the risk of fractures; regardless of whether extra calcium pills were taken or not.

The two exceptions are autoimmune diseases like lupus and advanced cancer; small doses of supplementary vitamin D helped by 22 and 17%.

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