Vitamin D – Should We All Supplement?

Vitamin D – What is it and why do we need it?

Vitamin D is possibly one of the most important nutrients in the body, and sadly the diet, however healthy, does little to deliver enough. Back in August 2016, headlines suggested that even the UK’s NHS had reformed it’s thinking and that in the UK, we all need daily supplementation of vitamin D3 during the winter months. So here are some of the facts to help you make an informed decision about vitamin D supplements and whether you actually need them.

Most people know about vitamin D because it is associated with sun – sunlight kicks off a series of physiological reactions when the sun shines directly on the skin resulting in synthesis of vitamin D. This is essential for calcium absorption and phosphate levels in the body, but is also essential for ensuring healthy teeth, bones and muscle, good mood, immunity, memory, hormone balance and beyond. 

How much do we need?

The recommendation for adults is 10mcg a day and throughout March to September we should be able to produce enough without supplementing if we spend 20 minutes per day in direct summer strength sunlight, without SPF. However, in the UK we all know that summer doesn’t always mean sunshine and blue skies, so what steps can we take to ensure we still get enough?

Diet: Oily fish and mushrooms are a good dietary sources and some foods are fortified with vitamin D, including some breakfast cereals (sadly the latter are often processed and refined, and full of sugar – check the label!)

Supplements: Public Health England is now recommending adults and even children take a daily supplement containing 10mcg/400iu of vitamin D, especially during autumn and winter.

Supplements: safe or necessary?

Having excess vitamin D in your body over a long period of time could increase calcium levels too much, potentially leading to liver, kidney and bone damage. However, with a limit of 100mcg and other studies showing that even as much as 250mcg a day doesn’t cause toxicity, it’s unlikely to be a problem for most people. 

As busy urbanites with fast paced jobs, often involving long hours and endless meetings, not to mention that early morning workout, the trend of modern living is leaning towards more indoor lifestyles. Couple this with the fact that we’re actively avoiding the sun due to worries about ageing skin, it is no wonder that many aren’t getting as much vitamin D as they should be. Recent figures reflect this with deficiency becoming more prevalent globally.

Signs of deficiency

While the signs may be subtle, muscle, joint and bone pain or weakness could mean you have vitamin D deficiency. Thyroid issues, poor immunity, changes to mood, seasonal effective disorder (SAD) and low energy are also common side effects.

There are also people in risk groups who could be more prone to deficiencies such as strict vegans, people with milk allergies, people with dark skin and from African, Mediterranean, Afro-Caribbean and South Asian backgrounds who may want to consider a daily supplement year round. You may also want to consider daily supplementation if you are not outdoors often or cover up in the sun.

In my clinic I find that when people have been deficient and then take vitamin D for the first time, they notice feeling better in all sorts of ways, from better mood, immunity, memory and skin health!

What should I supplement with?

I recommend getting tested first through your GP. You can also send off for home testing kits before deciding whether to supplement or not. 

  • If you don’t want to do a test, a safe dose is 400iu/10mg over winter months.
  • If you are low in vitamin D, you can take up to 2000iu/50mgfor 2 months before retesting. 
  • Pregnant women should consult their doctors, as they may need to take more.
  • Children over 2 can also supplement in the winter months, though be sure to use a product designed for children, and dose should not exceed 400iu/10mcg.

Disclaimer: Certain supplements are used for different reasons and a one-size-fits-all approach shouldn’t be adopted. In addition, pregnant women and anyone on medication should always consult a doctor before embarking on a supplements programme. As with all articles on, this is no substitution for individual medical or nutritional advice.