I’ve been saying this for years, and now it’s official: the Scientific Advisory Committee on Nutrition (SACN), after an extensive review of the data from studies, suggests everyone over the age of one needs vitamin D supplements. Let’s look at why.
What is vitamin D?
Despite its name, vitamin D is not a vitamin as such; it’s actually a group of fat-soluble steroid hormones that you get primarily from either sun exposure or supplementation, and a bit from diet.
Vitamin D is needed in many body processes and can influence genetic expression that produces many of its wide-ranging health benefits.
Vitamin D from the diet or dermal (skin) synthesis from sunlight is biologically inactive; activation requires enzymes action in the liver and kidneys.
Why do we need vitamin D?
There’s probably a lot we don’t know yet about what vitamin D does for us, but we do know it’s needed for good:
Bone strength*
Muscle function
Cardiovascular function
Brain development
Respiratory system function
DNA repair
Metabolic processes
Energy levels
It also helps protect against
Cancer
Cardiovascular disease
Autoimmune diseases
Influenza
*The processes by which vitamin D works are numerous and complex – too much to put here. However, by way of a small example, calcium and phosphorus are essential for developing the structure and strength of your bones, and you need vitamin D to absorb these minerals – you can ingest as much calcium and phosphorus as you want, but if you are low in vitamin D, you won’t be able to make use of them.
How can we get vitamin D?
1: UVB sunshine at around midday is best (1pm if on winter/daylight saving times); you don’t need to be out long. UVA sunlight just gives you a tan: it does not help vitamin D formation.
NOTE: You also need cholesterol to make vitamin D, so if you’re on a low-cholesterol diet that will not help you. (Unless you have familial hypercholesterolaemia, following a low-cholesterol diet is a bad practice in a number of ways and not recommended.)
NOTE: Vitamin D is not made instantaneously (it takes up to a day after exposure) so when you’ve been out in the sun and want a shower, just soap wash your pits and bits rather than your whole body.
2: Through diet – but this is not enough unless you eat lots of oily fish and liver and eggs: look upon dietary vitamin D as a helpful and necessary adjunct rather than a primary source
3: Vitamin D supplements – go for good quality D3
Who needs vitamin D supplements?
You are more likely to need supplementation if you:
- Are older (our ability to make vitamin D diminishes with age)
- Work indoors
- Don’t get outside much
- Always use sunscreen/clothe arms and legs
- Eat a diet high in grains
- Eat a diet low in cholesterol and fat
- Eat a lot of processed/ready-made/junk food
- Live further north
How much vitamin D, and when?
The SACN say to consume 10mg (micrograms) of vitamin D each day in the winter months in order to protect bone and muscle health: I would say to get your vitamin D levels checked and then take it from there: some of you may be fine and others will need more than 10mg.
Make sure you go for a supplement that gives you the vitamin D3 form. Go for good quality, and if you don’t fancy tablets, get drops.
It’s best to take vitamin D in the morning as if you take it later in the day, it can keep you awake at night.
NOTE: If you’re taking high dose vitamin D supplements, you also need to take vitamin K2.
Further (detailed) reading: https://en.wikipedia.org/wiki/Vitamin_D