The sunshine diet EVERYONE should be on

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FOR lunch today I am eating a fillet of grilled fresh trout with a soy glaze, served with wasabi mayonnaise. It is a dish that now forms part of my weekly menu plan. As a food writer and chef, I thought I had always eaten well: in season, fresh, organic food, and not too much fat.

But three years ago I was sitting in my GP’s surgery and was astonished to discover I was missing one vital ingredient. ‘You will be taking this for life,’ he said, writing a prescription for a vitamin D supplement 3.2 times higher than those normally available in pharmacies.

I had arrived there, due to feeling tired and a bit ‘down’, and experiencing achy legs, expecting the blood tests he had taken two weeks earlier to have shown a thyroid or blood sugar problem.

But at the back of my mind was something more sinister. I was 54 and entering that period when a health check

If you can’t be better than your competition, just dress better. ANNA WINTOUR

will be accompanied by thoughts of cancer. So, when he announced I had the lowest vitamin D level of all his patients, I initially felt relieved. Then rather foolish when the doctor pointed out the severity of the problem.

A deficiency as severe as mine can lead to debilitating disease and now — as the Mail revealed last week — a higher likelihood of death from Covid-19.

Anglia Ruskin University has found European populations with lower vitamin D levels have had a significantly higher death rate. Another study, carried out in Indonesia, revealed 98.9 per cent of Covid-19 patients with a vitamin D deficiency died.

Previous studies have shown vitamin D can help treat respiratory infections, so it may be useful when it comes to fighting Covid-19, too.

‘Vitamin D has an anti-inflammatory action, particularly if it’s given at higher doses,’ says Professor Adrian Martineau, a clinical professor of respiratory infection and immunity.

‘The overactive inflammatory response in patients with Covid-19 seems to be implicated with poor prognosis. If vitamin D can reduce this response, it might prevent the patient from deteriorating.’

A study in the British Medical Journal in 2017, which reviewed data from 25 clinical trials, showed the vitamin can also help prevent acute respiratory infections.

PROFESSOR Martineau, who was the lead author of the review, says: ‘When vitamin D is made in the skin it gets converted in the liver to a form that circulates around the body. This creates a natural antibiotic substance in the lining of the airways that can bash viruses and bacteria, killing them.

‘It is a generic effect — it’s not directed against specific viruses or bacteria, and we don’t know yet whether that would work against Covid-19. The results of our research showed that people with the lowest levels of vitamin D — less than 25 nanomoles per litre — tended to benefit more than those with the higher levels.’

Those at greatest risk of a vitamin D deficiency are also those who appear to be at higher risk of Covid19 — the elderly, people with darker skin and those who are obese. Being overweight also increases risk because high body fat can make it harder for vitamin D to circulate around the body.

A study by Professor Martineau, involving around 12,000 people, is looking at whether vitamin D deficiency is a risk factor for Covid-19.

Since I learned of my deficiency, I have taken it very seriously. So why don’t we all? Why are we not routinely tested in adulthood? A chronic lack of the ‘sunshine vitamin’ — we produce it when exposed to sunlight — causes bone disease, such as osteoporosis, and has been linked to weight gain.

My doctor, who also trained in psychiatry, mentioned that my deficiency may be linked to bereavement. I had lost both my mother, my sister and her teenage child in the previous 24 months.

‘Sadness can cause people to walk around looking down, so they do not get enough ultraviolet (UV) rays from the sun,’ he said.

Nowadays, I am that odd person walking down the street with my face turned skywards like a sunflower. Yet this, and my daily prescribed supplements, are not the only ways in which I can boost my vitamin D levels.

Returning to that delicious umami trout fillet, there are foods rich in vitamin D that should become an essential part of any diet.

The list is not long. At its centre is oily fish, including salmon, tuna, sardines, mackerel and trout. Vitamin D is fat-soluble, so these have the

highest proportion. Those with bad memories of school dinners may be horrified to hear liver — specifically ox (beef) liver — is a good source. But fear not: you can prepare it in a tasty way.

A source suitable for vegetarians and vegans is mushrooms. However, to obtain the vitamin, they must be sliced and left in the sunlight first. Mushrooms, like our skin, absorb UV light when exposed to it, converting it into vitamin D.

Egg yolks also contain the vitamin, but a mainly plant-based diet high in vitamin D would rely on fortified food. These include cereals, juice, yoghurt, milk (including soya and oat milk) and cheese.

Cod liver oil is also a powerful source. According to health experts, one in five adults are vitamin D deficient, so supplements will certainly help a lot of us here.

‘If everyone took the recommended 10 micrograms a day, who knows, it may help reduce susceptibility to Covid-19,’ says Professor Martineau.

What is clear is that, due to the pandemic, a change to our diet has never been more essential to staying well.

With a few small changes, we can eat our way to health. Here’s how to do it…