Sunshine for the Immune System

Despite a growing awareness of its importance to our wellbeing, vitamin D deficiency is estimated to affect over 10 million people in the UK. In fact, 1 in 5 adults and children are deficient in this ‘sunshine’ vitamin.

What is Vitamin D?

Unlike other nutrients, vitamin D isn’t really a vitamin at all. It’s a hormone, made by your body as you are exposed to sunlight.

Why are so many deficient?

In the UK we apparently don’t get enough vitamin D because there isn’t enough sun! However, I think that this problem is more complex.

I believe the real obstacle is that we don’t get enough TIME in the Sun.

We’re a nation of desk addicts that rarely take a lunch break as opposed to other Europeans who regularly take time off during daylight hours for leisurely lunches. 

Our children have a more indoors lifestyle thanks to too much homework, TV, computers and video games as well as a fear of letting them play on the streets as I used to do as a child. To top it off, skin cancer awareness has been heightened in recent years and sunscreen is liberally applied at any sign of a small ray of light for fear of burning.

And yes, whilst burning is never good, just 20-30 minutes a day of decent sunlight (between the hours of 11 am and 3 pm) is all you need to get enough vitamin D. And unlike other nutrients it’s free this way; no need for expensive supplements or modified diets.

Three important reasons we need vitamin D

  1. Essential to our immune system

Vitamin D plays an essential role in our immune system.  In research studies, individuals with lower vitamin D levels were more likely to self-report a recent upper respiratory tract infection than those with sufficient levels (reference).

One double blind placebo study showed that vitamin D administration resulted in a 42% decrease in the incidence of flu (reference). A low vitamin D level in the Winter, due to little sun exposure, is almost certainly why flu epidemics occur in the cooler and cloudier months.

During the World War’s, before antibiotics were discovered, doctors used sunlight to heal wounds. They observed that sunshine and fresh air were disinfectants, before the link between sun exposure, vitamin D and the immune system was made (reference).

2. Essential for healthy bones

Parents who are concerned about their kids getting enough calcium, may be interested to know that Vitamin D plays a big role in bone metabolism. Vitamin D acts to increase calcium in the blood stream by improving your ability to absorb calcium from food and reducing the amount of calcium lost in urine.

So, if your child doesn’t have enough Vitamin D in their body, then all the milk and cheese in the world won’t give them strong bones.

3. Deficiency may cause low mood

It’s well recognised that sunshine puts a smile on our face. But is this more than just the warmth on our skin and the freedom to get out and about?

Seasonal affective disorder or SAD is a mood disorder which causes depression in the Winter when there is relatively little sunshine. It coincides with a drop in Vitamin D levels in the body.

I know I can certainly feel low by the end of Winter and crave some sunshine. Several studies have suggested that SAD may be due to the low levels of vitamin D and its effect on serotonin levels, our brain’s happy hormone.  

Spring has arrived

It’s estimated to be 19 degrees C and beautifully sunny tomorrow (Sunday 5th April). Now that Spring has finally arrived, and we’re in the middle of a pandemic, it’s even more important then ever to top up our levels of vitamin D. However, this may prove challenging as we are stuck indoors due to (sensible) government advice to stay home.

April is an ideal time to get some vitamin D, as the sun’s rays aren’t too strong, and our bodies are in desperate need of it after the long Winter. With this in mind, how can we maximise our levels of Vitamin D?

1) Get some SUN

90% of our vitamin D comes from the sun. I’ve known friends in California who were vitamin D deficiency from applying sunscreen before leaving home.

The NHS advises that all the vitamin D you need in these months should come from the sun. So, expose yourself to 10-15 minutes every day from April to October before applying sun factor. That means your wearing a short sleeved or vest top. If you have dark skin, you may need longer.

Whilst we’re in quarantine, this may mean sitting in the garden, on a balcony or even by an open window. Get the kids watering the garden or washing the car! Exposing skin is vital, as you can’t synthesise vitamin D through clothes.

Current government guidelines allow us to take a walk outside as long as we maintain the two metre social distancing rule. So, if you’re well, take advantage of this and find an quiet spot to walk.

2) Eat Vitamin D foods

10% of your vitamin D intake comes from the food you eat. Vitamin D is a fat-soluble vitamin, which means you need to eat fat to get it, so let go of your fat phobia. Moderate amount of fat is good for you as long as it’s the natural kind (none of these man-made margarines – that’s a whole another blog post). Oily fish such as mackerel, sardines, salmon and tuna, egg yolks and real butter are best; other types of dairy don’t contain significant amounts of vitamin D unless they’ve been fortified, and in the UK we don’t fortify milk. Mushrooms are good vegan source of vitamin D – especially maitake and morel.

3) Supplement

Okay, let’s say you’re wrinkle and fat phobic, pregnant or breastfeeding and want to boost your Vitamin D levels.

Well, there are plenty of supplements on the market for you to pick from.

One of my favourites is Biocare Nutrisorb D3 which comes in liquid drop form which makes it easy to give to kids and absorption rates are good. They have adult ones too (no affiliate gains here).

The UK Scientific Advisory Committee on Nutrition (SACN) advises that everyone supplement vitamin D during autumn and winter and the Department of Health recommends that high risk groups (those under 5, over 65, people with darker skin, or those that cover their skin when outside) take a supplement all year round.

My one hundred year old granny, living in a care home, took this supplement all year round, and walked in the garden every day.

She loved the fact that she had her own private Doctor and Nutritional Therapist in the family, and took great pride in consulting us both and taking her vitamins.


I would say that this amount of vitamin D3 (10ug/400iu) is a good baseline, minimum level required. It’s a great level for a small child’s daily amount for example.

Optimum amounts for an older child or adult are more likely to be 25ug/1000iu a day.

If you don’t get any sun at all or you always wear sunscreen – I’d personally take more – 2000iu a day.

If you suspect deficiency you can always get tested.

But supplementing at this amount is considered safe.

As a hormone, D3 can be stored in the body, so taking a larger dose once a week also works.

Sometimes it’s easier to remember this way too.

I have a high dose supplement with 5000iu that I give to the children around once a week for example.

If someone is potentially very deficient, e.g. hasn’t seen the sun FOREVER – like Alex working in a hospital all summer without a break or summer holiday, or those in care homes you can load dose.

This means giving the high dose 5000iu every day for two weeks to top levels up. Then move down to taking it around twice a week = the maintenance dose.

4) Free supplements

Pregnant women and children aged five or under who qualify for the Healthy Start scheme can get free supplements containing vitamin D.

Find out what the NHS says about who should take vitamin D supplements.

Are you making sure you’re getting enough vitamin D?

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