Author – Phoebe Chan – BSc (Hons) Nutrition and Human Health
Getting enough vitamin D is essential for maintaining strong bones, muscles, and overall health. While we can make vitamin D from sunlight, many people still need supplements to meet their daily needs, especially in the winter months. This guide explains the correct way to take vitamin D, when to take it, who might need a supplement, and the benefits it can provide.
Why Vitamin D Matters
Vitamin D helps regulate the amount of calcium and phosphate in the body. These nutrients are needed to keep bones, teeth, and muscles healthy. A lack of vitamin D can lead to bone deformities such as rickets in children and bone pain caused by osteomalacia in adults.
Dosage
From late March or early April to the end of September, most people should get enough vitamin D naturally from sunlight. However, between October and early March, sunlight alone is not sufficient.
- Children from the age of 1 year and adults need 10 mcg of vitamin D a day.
- This includes pregnant and breastfeeding women and people at risk of vitamin D deficiency.
- Babies up to the age of 1 year need 8.5 to 10 mcg of vitamin D a day.
People at Risk of Vitamin D Deficiency
The UK Department of Health and Social Care recommends that adults and children over 4 years should take a daily supplement containing 10 mcg of vitamin D throughout the year if they:
- Are not often outdoors – for example, if they are frail or housebound
- Live in an institution such as a care home
- Usually wear clothing that covers most of their skin when outdoors
People with darker skin tones (for example, those with African, African-Caribbean, or South Asian backgrounds) may also struggle to make enough vitamin D from sunlight.
Best Time to Take Vitamin D
Vitamin D is a fat-soluble vitamin, meaning it is absorbed best in your bloodstream when paired with foods containing healthy fats. For this reason, taking vitamin D supplements with a meal can enhance absorption (2).
Studies have found:
- Taking vitamin D with the largest meal of the day increased blood levels by about 50% after 2–3 months (3).
- Consuming vitamin D with a high-fat meal boosted blood levels by 32% after 12 hours compared with a fat-free meal (4).
You can boost absorption by pairing vitamin D with nutritious fats such as:
- Avocados
- Nuts
- Seeds
- Fatty fish (salmon, sardines)
- Full-fat dairy products
- Eggs (2)
Morning vs Evening
Some people prefer taking supplements in the morning as it is easier to remember. However, there is some evidence that taking vitamin D at night may interfere with sleep. A 2021 review found that vitamin D can influence melatonin production, and taking it close to bedtime may lower melatonin levels, potentially disrupting sleep (5).
Effects of Taking Too Much Vitamin D
Taking too many vitamin D supplements over a long period of time can cause calcium to build up in the body (hypercalcemia). This can weaken bones and damage the kidneys and heart.
- Most people will get enough with 10 mcg daily.
- Do not exceed 100 mcg (4,000 IU) per day as it may be harmful.
- Children aged 1–10 should not exceed 50 mcg (2,000 IU) daily.
- Infants under 12 months should not have more than 25 mcg (1,000 IU) daily.
Benefits of Vitamin D
May fight disease
- Low levels are linked with an increased risk of multiple sclerosis (6).
- Deficiency has been linked with heart disease, including high blood pressure, stroke, and heart failure, though more research is needed (7).
May regulate mood and reduce depression
- A review of 7,543 people found that vitamin D supplementation improved symptoms of low mood (8).
- Low vitamin D levels may increase the risk of depression, anxiety, and fibromyalgia symptoms (9).
May support weight loss
- People with higher body weight are more likely to have low vitamin D (10).
- In one study, women taking calcium and vitamin D lost more weight than those on a placebo, possibly due to appetite suppression (11).
Frequently Asked Questions
How can I raise my vitamin D levels?
Spend more time in the sun, include vitamin D-rich foods in your diet, and take supplements when needed.
When is the best time to take vitamin D?
With a fat-containing meal, ideally at lunch or dinner.
Can I take too much vitamin D?
Yes, high doses over time can cause vitamin D toxicity and lead to kidney problems, heart issues, and high calcium levels.
Who needs to take a vitamin D supplement?
Those with limited sun exposure, older adults, people with darker skin, and vegans or vegetarians are more likely to need supplements.
References
- https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/
- https://www.healthline.com/nutrition/best-time-to-take-vitamin-d#take-it-with-food
- https://onlinelibrary.wiley.com/doi/10.1002/jbmr.67
- https://pubmed.ncbi.nlm.nih.gov/25441954/
- https://www.sciencedirect.com/science/article/pii/S1087079220301222
- https://pubmed.ncbi.nlm.nih.gov/29243029/
- https://pubmed.ncbi.nlm.nih.gov/31172459/
- https://pubmed.ncbi.nlm.nih.gov/32365423/
- https://pubmed.ncbi.nlm.nih.gov/32022867/
- https://pubmed.ncbi.nlm.nih.gov/33792853/
- https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/calcium-plus-vitamin-d-supplementation-and-fat-mass-loss-in-female-very-lowcalcium-consumers-potential-link-with-a-calciumspecific-appetite-control/623D71E0A965E910C48903089FA7B56C
