Vitamin D Deficiency: Track Your Diet

TL;DR: Around 1 in 5 UK adults is vitamin D deficient, largely because our latitude limits sunlight-driven synthesis from October to March. The NHS recommends everyone takes a 10 microgram supplement during autumn and winter. Dietary sources (oily fish, eggs, fortified foods) help but rarely provide enough on their own. Tracking your intake shows you where the gaps are.

Vitamin D is sometimes called the "sunshine vitamin" — and that is precisely why so many of us in the UK struggle to get enough. Our northern latitude means that for roughly half the year, sunlight simply is not strong enough for our skin to produce vitamin D. Public Health England estimates that around 1 in 5 adults and 1 in 6 children have low vitamin D levels, making it one of the most widespread nutritional shortfalls in the country.

Why the UK Has a Vitamin D Problem

Vitamin D is unique among nutrients because our primary source is not food — it is sunlight. When UVB rays hit our skin, they trigger vitamin D synthesis. But the UK sits between 50 and 60 degrees north, which creates a fundamental problem:

The result is that diet and supplements become critically important, particularly from October through to March.

How Much Vitamin D Do You Need?

The NHS and SACN (Scientific Advisory Committee on Nutrition) recommend the following daily amounts:

GroupDaily AmountNotes
Adults and children (1+)10 micrograms (400 IU)Year-round for at-risk groups; autumn/winter for everyone
Babies (0-12 months, not formula-fed)8.5-10 microgramsFrom birth if breastfed; formula milk is already fortified
Pregnant and breastfeeding women10 microgramsThroughout pregnancy and breastfeeding

Source: NHS — Vitamin D; SACN Vitamin D and Health Report

NHS Supplement Advice

The NHS recommends that everyone considers taking a daily supplement containing 10 micrograms of vitamin D during autumn and winter. Some groups should supplement all year round: people who are rarely outdoors, those in care homes, people who cover most of their skin, and those with dark skin.

Best Dietary Sources of Vitamin D in the UK

Very few foods naturally contain significant vitamin D. This is why it is difficult to get enough from diet alone — but every little helps, and combining dietary sources with supplements during the darker months is the recommended approach.

FoodVitamin D per ServingNotes
Salmon (100g, fresh)10-13 microgramsWild salmon tends to contain more than farmed
Mackerel (100g)8-9 microgramsTinned is nearly as good as fresh
Sardines (100g, tinned)4-5 microgramsAffordable and widely available in UK supermarkets
Herring/kippers (100g)5-8 microgramsA traditional British breakfast option
Egg yolks (2 large eggs)2-3 microgramsFree-range eggs may contain slightly more
Fortified cereals (30g serving)1-2.5 microgramsCheck labels — fortification varies between brands
Fortified plant milks (200ml)1.5-2 microgramsMost major UK brands now fortify with vitamin D
Fortified spreads (10g)1-1.5 microgramsFlora and similar brands fortify their products
Mushrooms (UV-exposed, 80g)2-5 microgramsLook for "vitamin D enriched" on the pack — UV-treated varieties provide significantly more
Red meat (100g)0.5-1 microgramA minor contributor, but adds up over a week

Source: Public Health England — McCance and Widdowson's Composition of Foods; BDA

As you can see, even eating salmon every day would only just meet the 10 microgram target — and most people do not eat oily fish that frequently. This is precisely why the NHS recommends supplements alongside dietary sources.

Seasonal Variation: A Year-Round Strategy

Your vitamin D needs and sources shift throughout the year. Understanding this seasonal pattern helps you plan ahead rather than reacting to deficiency symptoms.

April to September (sunshine months)

October to March (vitamin D winter)

Tracking your vitamin D intake becomes particularly valuable during the autumn and winter months, when you cannot rely on sunshine to fill the gaps.

Track Your Vitamin D Intake Daily

NutraSafe tracks vitamin D and 20+ other micronutrients automatically from a comprehensive UK food database. See whether your diet is contributing enough — especially during the darker months.

Download NutraSafe Free

How to Track Your Vitamin D Intake

Because vitamin D comes from relatively few foods, tracking it is straightforward once you know what to look for.

Step 1: Identify your dietary sources

Start by noting which vitamin D-containing foods you eat regularly. If you eat oily fish twice a week, fortified cereal daily, and eggs a few times a week, you are building a reasonable baseline. If none of these feature regularly in your diet, that is a clear signal that supplementation is especially important for you.

Step 2: Log consistently for a week

Track everything you eat for at least 7 days. An app like NutraSafe can automatically calculate your vitamin D intake from each food, giving you a clear daily total without needing to look up values manually.

Step 3: Compare to the 10 microgram target

Most UK adults get between 2-4 micrograms of vitamin D per day from food alone. If your tracking confirms this pattern, the gap between your dietary intake and the 10 microgram recommendation highlights exactly why supplements are advised.

Step 4: Adjust and supplement wisely

Use your tracking data to make practical changes: adding a tin of sardines to lunch, choosing fortified plant milk, or switching to UV-enriched mushrooms. Combine dietary improvements with a 10 microgram supplement during autumn and winter (or year-round if you are in a higher-risk group).

Signs of Vitamin D Deficiency

Vitamin D deficiency often develops slowly, and symptoms can be vague and easily attributed to other causes. Watch for:

In children, severe deficiency can cause rickets (soft, weak bones). In adults, prolonged deficiency can lead to osteomalacia, causing bone pain and muscle weakness. These conditions are preventable with adequate vitamin D intake.

When to See Your GP

If you have symptoms of vitamin D deficiency, your GP can arrange a blood test to check your levels. This is especially important if you are pregnant, have darker skin, rarely go outdoors, have a condition affecting nutrient absorption (such as coeliac disease or Crohn's), or are over 65. Do not take high-dose supplements without medical guidance.

Choosing the Right Supplement

If you are buying a vitamin D supplement in the UK, here is what to look for:

Vitamin D supplements are available from pharmacies and supermarkets across the UK, typically costing just a few pounds for several months' supply. In England, some people are eligible for free Healthy Start vitamins.

Frequently Asked Questions

Why is vitamin D deficiency so common in the UK?

The UK sits between latitudes 50-60 degrees north, meaning from October to March the sun is too low in the sky for our skin to produce vitamin D. Combined with indoor lifestyles, frequent cloud cover, and the fact that very few foods naturally contain significant vitamin D, around 1 in 5 UK adults has low levels. People with darker skin tones are at even higher risk because melanin reduces the skin's ability to synthesise vitamin D from sunlight.

How much vitamin D do I need per day?

The NHS recommends 10 micrograms (400 IU) of vitamin D per day for everyone aged 1 and over. During autumn and winter, the NHS advises everyone to consider a supplement at this level. Some groups — including people who rarely go outside, those in care homes, and people with darker skin — should consider supplementing throughout the entire year.

What are the best food sources of vitamin D in the UK?

The best dietary sources include oily fish (salmon provides 10-13 micrograms per 100g, mackerel around 8-9 micrograms), egg yolks, fortified breakfast cereals, fortified plant milks, fortified spreads, and UV-exposed mushrooms. Red meat provides small amounts. However, diet alone typically provides only 2-4 micrograms per day in the UK, which is well below the recommended 10 micrograms.

Should I take vitamin D supplements all year round?

The NHS advises everyone to consider a 10 microgram supplement during autumn and winter (October to March). Certain groups should take it all year round: people who rarely go outdoors, those who habitually cover most of their skin when outside, people living in care homes, and people with dark skin. Choose vitamin D3 (cholecalciferol), which is more effective at raising blood levels than D2.

Can you get too much vitamin D?

Yes. The NHS warns against taking more than 100 micrograms (4,000 IU) of vitamin D per day, as it can cause a dangerous build-up of calcium in the body (hypercalcaemia), which can weaken bones and damage the kidneys and heart. You cannot overdose on vitamin D from sunlight or food alone — the risk comes exclusively from excessive supplementation. Stick to the recommended 10 micrograms daily unless your GP advises otherwise.

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Last updated: February 2026