Vitamins
More than one nutrient is low at the same time
Vitamin D (25-OH) and Vitamin B12 are both down. Several nutrients running low together is usually about intake or absorption rather than any one food — and it matters, because a B12 deficiency and a folate deficiency look identical in a blood count, so the one that was not measured still matters.
- Vitamin D (25-OH)14 ng/mL
30% below 20 ng/mL, where the low range starts
- Vitamin B12246 pg/mL
200–300 pg/mL is the borderline band
Know more · what to do · what to ask
Your skin makes vitamin D from sunlight, and it governs how well you absorb calcium. Indoor lifestyles make low values extremely common — tiredness and body aches are typical, subtle signs. Common reasons for a low Vitamin D (25-OH): Limited sun exposure; Darker skin synthesizes vitamin D more slowly; Low dietary intake.
What to do
- Get 15–20 minutes of midday sun on arms and legs most days — through glass doesn't count, and sunscreen blocks the wavelength that makes vitamin D.
- Eat the few foods that carry it: egg yolk, oily fish, fortified milk. Diet alone rarely fixes a deficiency, which is why sunlight and a doctor's plan matter more here.
- Ask your doctor which form to take and for how long — replacement plans vary a lot depending on how low your level is, so there is no single answer here.
Retest: Recheck in 3–6 months, and not within 3 months of starting replacement — vitamin D moves slowly, so an early test just shows the old number.
Don't stack several supplements that each contain vitamin D; it is fat-soluble, so it accumulates. Bring the labels to your appointment.
Food & habits · Vitamin D (25-OH)
Eat more
- Fortified milk or curd
- Mushrooms left in sunlight
- Fortified breakfast cereal
- 20 minutes of midday sun on arms and legs
Go easy on
- Relying on food alone to fix it
- Long periods spent entirely indoors
Best avoided
- High-dose supplements without a blood test
- Guessing your own supplement amount
Move
- Vitamin D deficiency does not limit exercise — outdoor activity in daylight is actually part of the fix.
- 5 days a week: a 30-minute walk outdoors in daylight
- 2 days: light strength exercises using body weight or water bottles
People with kidney disease, sarcoidosis, or those already taking calcium supplements should check with a doctor before increasing vitamin D intake.
Ask your doctor: “Should we look at absorption (and my diet pattern) rather than just replacing these?" If you are vegetarian, on metformin, or on long-term acid-reducing medicine, say so — each of those changes the answer.”