Vitamin D and energy: why you might be low and how to fix it
Vitamin D and energy are more closely linked than it seems: low levels are among the most common shortfalls, especially in regions with long winters. Here is what vitamin D does, where to find it and what to do if you're low.
Vitamin D and energy are connected through your overall wellbeing: vitamin D is needed for bones, muscles and the immune system, and low levels can add to a feeling of tiredness. The sun is the main source, so deficiency is especially common in winter.
Vitamin D takes part in dozens of processes in the body. Deficiency is especially widespread in regions with long winters and few sunny days — for example, in many parts of Kazakhstan and Northern Europe.
What does the body need vitamin D for?
Above all, vitamin D helps the body absorb calcium and maintain strong bones.
According to the NIH Office of Dietary Supplements, vitamin D is also needed by muscles to move, by nerves to carry signals and by the immune system. That's why a shortfall shows up not in one organ but in how you feel overall.
How does vitamin D affect energy levels and mood?
Vitamin D works on the body as a whole: bones, muscles, immunity — and through them, on how energetic you feel.
A deficiency can add to feelings of tiredness and muscle weakness. But fatigue has many causes, from poor sleep to sharp blood sugar swings, covered in "Sugar and energy". So don't blame everything on vitamin D right away.
Vitamin D deficiency and energy levels: why do you run low?
A shortfall happens when your skin gets little sun and you don't get enough vitamin D from food.
The main source of vitamin D is production in the skin under sunlight. In winter, with an indoor, sedentary lifestyle and with age, this production drops.
- Long winters and short days.
- Indoor work and few daytime walks.
- Older age — the skin makes vitamin D less efficiently.
- Covering clothing and constant sunscreen.
The winter energy slump often coincides with seasonal low mood — see "Seasonal low mood".
Which foods contain vitamin D?
There isn't much vitamin D in everyday foods, but you can add some to your diet.
- Oily fish — salmon, mackerel, sardines.
- Egg yolk.
- Fortified foods — some types of milk, yogurt and cereal.
- Mushrooms grown under light.
Oily fish also provides omega-3 — more in "Omega-3 fatty acids".
How to correct low vitamin D?
It's best to work on three fronts: sun, food and — if a deficiency is confirmed — supplements as advised by your doctor.
- Spend time outdoors during daylight hours, even in winter.
- Include oily fish, egg yolks and fortified foods in your diet.
- If a deficiency is confirmed, discuss supplements and dosage with your doctor.
How are vitamin D and bones connected?
Vitamin D matters not only for energy but also for bone strength, especially with age. More about bones in "Bone health after 50".
Who should get their vitamin D level checked?
People who rarely get sun, live at northern latitudes or are older should have their vitamin D level checked.
- People who spend almost the whole day indoors.
- People living in regions with long winters.
- Older adults.
- People who have felt unexplained tiredness for a long time.
- People who rarely eat fish or eggs.
A blood test will show whether you're actually deficient and help your doctor choose the right plan. Without one, don't take supplements "just in case": too much vitamin D can do harm as well.
If fatigue lasts for weeks, don't stop at guesses: get tested and discuss the results with your doctor. To support energy during the day, many people use the X39 patch — according to the company, it helps you feel more energy. The patch doesn't make up for vitamin D.