Vitamin D: How much is enough?

Vitamin D: How much is enough?

1 in 5 of us in the UK are estimated to have insufficient blood levels of Vitamin D for good health; we simply can’t produce enough of it from the sunshine alone and especially for those of us in Northern Europe. The half-life of this vitamin is 3-6 weeks, so even gathered stores over the summer rapidly decline by the time we get to the deeper winter months.


Vitamin D is a major nutrient if you are looking to achieve great health. But with so many of us experiencing low levels and deficiency, we take a deep dive on why we need to supplement and how much.

Table of Contents:

How do we receive vitamin D in the body?

Virtually every cell in the body has a vitamin D receptor, which, when bound to this vitamin, can influence the expression of more than 200 genes. Throughout the year, we need to ensure our vitamin D levels are stocked up as this nutrient is famously known for being an immune system nutrient and playing a big role in preventing autoimmune disease. As well as helping your immune system, having the correct vitamin D dosage is also highly critical for these other key areas of health:

Menstrual and gynaecological health

Vitamin D has a hormone-like action in the body so it's needed for healthy menstruation. Low levels of this vitamin are particularly common in conditions such as PCOS and endometriosis. In endometriosis low levels are implicated in disease progression (becoming worse).


Great levels of vitamin D are required to achieve healthy conception in women and men.


The correct vitamin D dosage is critical for Mum and baby’s health in pregnancy and postpartum stages.

Teen Health

Vitamin D is an essential nutrient for developing teens.

Mood and Mental Health

There is a strong association between low levels of Vitamin D and:

  • Low mood,
  • Depression,
  • Psychiatric conditions,
  • Cognitive problems and in cognitive decline (dementia and so forth).

For this reason, ensuring you know the correct vitamin D dosage for you is important.

Perimenopause & Menopause

Low vitamin D levels worsen symptoms of perimenopause and menopause. With these lower levels, the body won’t be supported enough to manage these life-stages well.

Heart, bone and teeth health

All of these elements in the body need excellent levels of vitamin D to maintain health in these areas.


Vitamin D has a close relationship with sleep. To find out more about the importance of why you need Vitamin D for great sleep, read our insightful article.

What are the daily impacts that affect the correct vitamin D dosage we receive?

Whilst official recommendations state supplementation of Vitamin D between October and March each year, for so many of us, this won’t be enough to maintain good health. Particularly if you are in a key life stage or when looking to achieve a health goal or relieve symptoms. You may need to supplement for the full 12 months of the year.

1 in 5 of us in the UK are estimated to have insufficient blood levels of Vitamin D for good health; we simply can’t produce enough of it from the sunshine alone and especially for those of us in Northern Europe. The half-life (the length of time it lasts in your body) of this vitamin is 3-6 weeks, so even gathered stores over the summer rapidly decline by the time we get to the deeper winter months.

Additionally, factors which can affect our vitamin D levels further include:

  • Sunscreens,
  • Longer office working hours,
  • Medical conditions,
  • Colour of our skin,
  • Medications such as statins,
  • Our age (those above 65 years of age have 4-times lower capacity to produce it in their skin compared to younger adults).

Our dietary habits have changed somewhat too. Currently, only only 10% of our Vitamin D intake can come via our diet. This means that we will rely on sunshine and supplementation. If you are looking to slightly improve your Vitamin D intake through your diet, food rich in the nutrient include:

  • Oily fish
  • Whole-fat dairy
  • Egg yolks
  • Red meat
  • Fortified food

How much vitamin D do I need to take?

The Department of Health recommends that everyone over the age of four should take 10 micrograms (400iu) of vitamin D every day. The particular time to take it would be from October to March.

All pregnant, breastfeeding women and at-risk groups (such as people from ethnic minority groups with dark skin, elderly people in care homes and those who wear clothing that cover most the skin) should take a daily supplement containing 10 micrograms (400iu) of Vitamin D. However, consider that many people in the UK do not get good access to consistent sunlight due to work (offices) and 'typical British' summer weather (cloudy days and rain).

All babies from birth up to one year of age should take 8.5 to 10 micrograms (340iu to 400iu) of vitamin D per day (particularly those being breastfed). Babies fed infant formula will not need vitamin drops until they are receiving less than 500ml (about a pint) of infant formula a day, as these products are fortified with vitamin D.

Children between the age of one and four should take 10 micrograms of vitamin D supplements all year round.

People aged 65 years and over and people not exposed to much sun should also take a daily supplement containing 10 micrograms (400iu) of vitamin D.

However, in today’s modern world, these official recommendations should be seen as the ‘minimum’. more often than not, these official figures often confuse the public and It's very common to see adults only supplementing this minimum. This is a concern if that same adult falls into a risk category and does not get access to additional sunshine either. Pregnant and breastfeeding women are a concern because they are ‘giving away’ Vitamin D to their developing baby in the womb, or afterwards via their milk.

If you have recently been unwell, your levels can have dropped. This is due to the immune system having used up stores to fight and heal infection. If you have an autoimmune or inflammatory condition, you will need really good levels to stay on top of symptoms and to lessen them.

If you are looking to conceive or about to go through assisted fertility such as IVF, we recommend getting your levels checked in advance. Please note that many fertility clinics do not check Vitamin D levels as standard so please request this or check with your normal GP.

Teens ‘gobble’ up Vitamin D, as their skeleton grows at the most rapid rate of any other lifestage. Without the correct levels of vitamin D, a teens' sleep, mood and hormone balance will suffer. It is useful to know teens require adult, not child doses.

In terms of what is the right dose for you, we always recommend speaking to an expert and do consider getting your levels checked. Our expert Nutrition team can discuss your own Vitamin D requirements during a free 15-minute Video Nutrition consultation. Book your nutritionist consultation now. 

What about Vitamin D toxicity?

Vitamin D toxicity but this is rare. A person would need to be taking very large doses over a longer period of time. The real modern risk or ‘epidemic’ is Vitamin D insufficiency and deficiency. If you are at all concerned, speak to our Nutrition team and/or your GP.

Should we supplement with Vitamin D?

As we’ve already established, sunshine is arguably not a reliable source of vitamin D. This is partly due to needing sufficient solar radiation, depending on the season and there are associated risks of skin aging and cancer. Notably, all of Europe gets insufficient UVB intensity during the months November to the end of March. Which results in minimal skin production of vitamin D during the winter season, independent of age.

When deciding to supplement vitamin D, choose wisely. We recommend opting for high-quality well-absorbed forms. More natural food forms provide both the active and stored forms, ready for your body to use easily. A study conducted showed that Food-Grown® vitamin D includes both the ‘stored’ (25-hydroxy) and biologically ‘active’ (1-25 hydroxy) forms of vitamin D3. The body will always need to convert any ‘stored’ form of vitamin D3 into the ‘active’ form for it to do its various jobs like supporting calcium absorption. This makes supplementing in the ‘active’ form preferential. A highly absorbable and biologically active form may also minimise the need for ‘megadosing’.

For more information regarding vitamin D dosages or your nutritional health, talk to one of our nutritionists. What Supplements Should You take?, take our 60-second quiz to find the right supplements for you.


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