• Danny Johnson Training

Why you really, really, really need The D!

There's a lot to like about winter. I LOVE the light on a freeze cold morning, warm socks, cozy fires, etc.

I am not going to list all the things I don’t like about winter, but right up there must be catching a cold, and feeling a bit blue when January comes.

In this post I’m going to explain why so much of that is down to your levels of vitamin D, AKA the ‘sunshine vitamin’ (and hence a lack of it in winter).


Vitamin D is a superstar vitamin. More correctly, it’s actually a hormone. If levels are too low, this is bad news for health. Cancer, osteoporosis, rickets in children, asthma, multiple sclerosis (and other autoimmune diseases), heart disease, diabetes and dental problems; they are all linked to vitamin D deficiency [source: PLoS One. 2013;8(3):e58725.]


  • Sun cream - Your body makes vitamin D after contact with the sun’s UV rays but, but we have become sun cream fanatics so you might not be getting enough straight-up sun to make it .

  • Age - Ageing affects production of vitamin D, your body is less good at turning the rays from the sun into vitamin D. Specifically, the kidneys are less good with age at turning it to the active form of calcitriol.

  • Kidney or liver disease of any kind also means vitamin D is not converted to the active form.

  • Tummy troubles - Problems with the digestive system (and I’m not talking about disease here – just an imbalance that may cause anything from a few manageable symptoms to more serious trouble ‘downstairs’) mean the digestive tract does not absorb the vitamin D as well.

  • Lack of sleep - Just as you need sunlight to make vitamin D, you need sleep to actually use it.

  • Stress - The presence of the stress hormone cortisol reduces the uptake of vitamin D by special vitamin D receptors. It literally sits there, in the body, without being able to be used. What a waste!

  • Skin colour - The darker your skin, the less vitamin D you will make. This is due to the higher levels of melanin in your skin that protect against UV light. By blocking the sun’s rays, it also curbs the body’s ability to make the pre-cursor to the active vitamin D.

  • Nightshift workers and anyone else who doesn’t spend much time in the sunlight, including children wearing sun cream all the time and babies. Quite simply, you need the sun on your skin.


1. Depression or anxiety (including mood changes or irritability)

2. Bone softening (low bone density), fractures

3. Feeling tired all the time/ decreased performance

4. Muscle cramps and weakness

5. Joint pain (especially back and knees)

6. Difficulty regulating your blood sugar levels/ post lunch energy crash

7. Low immunity

8. Slow wound healing

9. Low calcium levels in the blood

10. Unexplained weight gain

Symptoms like these are commonly overlooked because they don’t feel life threatening, and they’re often dismissed as normal, everyday aches and pains you have to deal with. But you don’t have to put up with these symptoms of ill health!


If any of the above resonates with you, then you should definitely get tested.

You can ask your doctor for it,orconsider getting it checked out privately, the test is not expensive but it could change your enjoyment of your life. It’s a finger prick test, so there’s not blood draw involve and you can do it easily at home, just get in touch with us to arrange the test.

If you do take a test and you’re very low, you’ll need an intense 4-6 weeks supplementation at a high dose and then re-testing to see the impact it’s had. There is such a thing as too much vitamin D (known as vitamin D toxicity). You’d have to be going some way to get there, but it is possible, which is why it is essential you know your levels before you start guzzling any supplements.


  • Get yourself some sun. Recommended sunlight exposure is between 10 and 30 minutes a day with no sun cream.

  • If getting out in the sun is not an option, sit in front of a light box that supplies 10,000 lux of full-spectrum light for 30 minutes every morning. This is an especially good option for winter months, for night shift. Bit of a faff, but it’s an option.

  • Take a supplement. You can take a generic 1,000 IU dose as an adult (but not children without consulting your GP) BUT, if you’ve no idea what your blood levels are, how to you know how much you should be taking.

  • Eat naturally vitamin D-rich foods like oily fish (salmon, sardines, fresh tuna, trout, halibut, mackerel, et.), high quality cod liver oil, egg yolks and liver. Do not be fooled into thinking the fortified foods are the same or have similar benefits. Fortified foods (like cereals, margarine and some yoghurts) contain a synthetic version of the vitamin known as D2 (the natural form is D3). Research shows this is less effective at raising levels of vitamin D in the blood.


#Vitamins #Nutrition #Health #Winter


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