Vitamin D, B12 and C: when to supplement, when it is marketing

Pe scurt: Vitamin D, B12 and C — doses, real indications and myths. Deficiency in Romania, evidence-based supplementation, the risk of “megadoses”, CNAS reimbursement.

Vitamin supplements are the largest category in Romanian pharmacies after classic OTC. The global industry exceeds 50 billion USD a year, and marketing constantly pushes ideas about "energy", "immunity", "antioxidants". The scientific reality is more nuanced: there are clear cases of deficiency with an indication for a supplement, but also many situations where the supplement changes nothing.

Vitamin D — the only one where most Romanians actually have a deficiency

National studies (INSP, the "N. Paulescu" National Institute of Diabetes, Nutrition and Metabolic Diseases) have shown that >60% of the Romanian adult population has 25(OH)D <30 ng/mL in the cold months. The cause: latitude, pollution, a sedentary indoor life, darker skin in some populations, age >65.

Recommended doses

CategoryDaily doseSerum 25(OH)D target
Infant 0-12 months400 IU30-50 ng/mL
Child 1-18 years600-800 IU30-50 ng/mL
Adult 19-70 years800-2000 IU30-50 ng/mL
Elderly >70 years1000-2000 IU30-50 ng/mL
Pregnancy / breastfeeding1000-2000 IU30-50 ng/mL
Confirmed deficiency <20 ng/mL50,000 IU/week for 6-8 weeks, then maintenance>30 ng/mL

Forms and RO products

  • Vigantol Oil — oily drops, 12 drops = 8000 IU (watch the exact dose by age).
  • D3 Vitamin (Hartington), DiBase, ViDe-3, ZyMad — vials of 50,000- 100,000 IU loading doses.
  • OsteoCare, Ideos, CalciCare — combined with calcium, indicated in the elderly with osteopenia.

Mostly OTC; high therapeutic doses (50,000 IU caps) are P-RF. CNAS reimbursement in osteoporosis and hypoparathyroidism.

Vitamin B12 — vegans, the elderly, gastric atrophy

B12 (cyanocobalamin / methylcobalamin) is essential for DNA synthesis, myelination, erythropoiesis. The dietary sources are exclusively animal (meat, eggs, milk). True deficiency occurs in:

  • Vegans and strict vegetarians.
  • The elderly with atrophic gastritis (over 65 — incidence 10-30%).
  • Patients with gastric resection, bypass, ileal Crohn's disease.
  • Chronic PPI users (omeprazole >5 years) — a moderate risk.
  • Chronic metformin users — check B12 annually.
  • Biermer's disease (pernicious anaemia) — autoimmune, lack of intrinsic factor.

Doses: for a confirmed deficiency — 1000 μg/day orally for 1 month, then 1000 μg/week × 4, then 1000 μg/month maintenance; or i.m. injections (Cyanocobalamine, Vitamina B12 Atb) in patients with compromised absorption.

Supplementation in people without a risk factor and without symptoms (neuropathy, macrocytic anaemia, glossitis, paraesthesia) — without demonstrated benefit. Excess B12 does not cause toxicity (excreted in urine), but it does not give you "energy" if you do not have a deficiency.

Vitamin C — the most overrated case

Ascorbic acid is an essential antioxidant, a cofactor in collagen synthesis, the absorption of non-haem iron. The daily adult requirement: 75-90 mg (women/men). A medium orange (130 mg), a kiwi (90 mg) or a serving of peppers (95 mg) covers the ration.

What the clinical evidence shows:

  • The common cold: Cochrane meta-analyses (Hemilä & Chalker) — daily supplementation does NOT prevent colds in the general population; it slightly reduces the duration (~8% adults, ~14% children). Massive doses at onset — marginal or absent benefit.
  • Scurvy: rare in RO; doses of 100-1000 mg/day cure it quickly.
  • Iron absorption: 100-200 mg with oral iron — increases absorption. Useful in treated iron-deficiency anaemia.
  • General antioxidant: inconsistent evidence; high doses (>2000 mg/day) — a risk of oxalate kidney stones, osmotic diarrhoea.

Pragmatic conclusion: do not supplement >200 mg/day chronically if you have no indication. The marketing of "1000 mg" and "effervescent" is more cosmetic.

Vitamin C in the RO pharmacy — examples

  • Cebion 1 g, Vitamin C Forte (Hartington), Redoxon — effervescent.
  • Cevigen 250-500 mg — tablets.
  • Injectable ascorbic acid — used perioperatively/in oncology, off-label for some indications.

When a vitamin is marketing, not medicine

  • A "megadose" of 5000-10,000 IU vit. D without tests and without a risk factor — a risk of hypercalcaemia, vascular calcifications.
  • "Premium multivitamins" with 25 ingredients — a combination without demonstrated synergies; many nutrients below the active dose.
  • "Vitamins for immunity" — no study has shown that a multivitamin reduces the incidence of infections in well-nourished people.
  • "Vitamins for hair/nails" — biotin at supraphysiological doses can distort thyroid tests (TSH, fT4) — caution.

How to decide pragmatically

  1. Do you have tests? Check 25(OH)D, B12 (possibly serum MMA / homocysteine at "borderline" values), ferritin.
  2. Are you in a clear risk group? (vegan, elderly >65, post-bariatric, IBD, chronic PPI, chronic metformin).
  3. Do you have symptoms compatible with deficiency? (chronic fatigue, paraesthesia, muscle weakness).
  4. If yes to any — a supplement at the appropriate dose, recheck at 3-6 months.
  5. If not — a varied diet, 15 min/day of sun exposure, without aggressive "preventive" supplementation.

Reimbursement and prices

Vitamin D therapeutic forms (caps 25,000-50,000 IU) are partially reimbursed on List B/C2 in osteoporosis, hypoparathyroidism. Injectable vitamin B12 — List B in documented deficiencies. Vitamin C OTC. For OTC supplements, prices differ substantially between Catena, Dona, Help Net, Tei, Dr.Max — a comparator on HartaFarmacii.

Frequently asked questions

Can I take 4000 IU of vitamin D daily?
In a known deficiency, yes. Prophylactically, without tests, a dose of 800-2000 IU is enough and safer.
Does oral B12 work the same as the injection?
Yes, in most cases. Exceptions: severe pernicious anaemia, post-resection malabsorption.
Effervescent vs. tablet C?
Bioequivalent. The effervescent one has sodium — caution in hypertensives.
Can I take D and calcium together?
Yes, a synergy. Caution with hypercalcaemia if you have kidney stones or sarcoidosis.
Which vitamin gives "energy"?
None, on its own, gives you energy if you do not have a deficiency. A feeling of fatigue needs investigation: anaemia, thyroid, sleep, depression.
Does vitamin C prevent cancer?
Large studies — no, beyond the amount from food.

Other vitamins and minerals: short guides

Folic acid

A clear recommendation: any woman of fertile age planning a pregnancy — 400 μg of folic acid daily, starting 1-3 months before conception and continuing at least through the first trimester. It reduces the risk of neural tube defects by >70%. With a history of a child with spina bifida or antiepileptic medication — 4-5 mg/day (Acidum Folicum 5 mg, Rx). Folic acid is also on the CNAS C2 List — 90% reimbursement in pregnancy.

Iron

Iron deficiency is the most frequent nutritional deficiency in the world. In RO, the prevalence of iron-deficiency anaemia in women aged 20-50 exceeds 15%. Supplementation — as iron sulfate (Sorbifer Durules, Tardyferon), iron glycinate or iron(III)-hydroxide polymaltose (Maltofer). The therapeutic dose for anaemia: 80-160 mg of elemental iron/day, ideally on an empty stomach with vitamin C, away from coffee/tea/calcium/PPI. The expected response: haemoglobin rises ~1 g/dL at 2 weeks; total treatment 3-6 months to refill the ferritin stores.

Magnesium

True deficiency is rarer than the marketing suggests — it occurs in chronic diarrhoea, alcoholism, chronic PPI use, diuretics. For nocturnal muscle cramps, restless legs syndrome, the evidence is modest. Forms with good absorption: citrate, glycinate, malate. The oxide (the cheapest) — poor bioavailability, a laxative effect.

Zinc

Studies (Cochrane Hemilä) — zinc 75-100 mg/day in the first 24h from onset reduces the duration of a cold in adults. Watch the duration — chronic zinc >40 mg/day interferes with the absorption of copper and iron.

Omega-3

EPA + DHA from fish oil — a modest benefit on triglycerides (a 20-30% reduction at doses of 2-4 g/day of active substance), a less clear effect on primary cardiovascular prevention (REDUCE-IT with icosapent ethyl — positive; VITAL — neutral). A recommendation of DHA 200 mg/day in pregnancy for fetal development.

Multivitamins: when they make sense, when they don't

Cases where a basic multivitamin (such as Centrum, Supradyn, Pharmaton) may make sense:

  • An adult with a restricted diet (vegan, prolonged hypocaloric diet, post-hospital malnutrition).
  • An elderly person with reduced appetite and polypharmacy.
  • Pregnancy (specific prenatal formulations — Elevit, Femibion).
  • Post-bariatric, IBD, cystic fibrosis.

Cases where it adds no value:

  • A healthy adult with a varied diet.
  • For generic "energy", "immunity", "antioxidants" — without a clear indication.
  • For "cancer prevention" — meta-analyses (PHS-II, SELECT) — neutral or slightly negative for beta-carotene/vitamin E.

Rules for the informed buyer

  1. Read the ingredient list — CFU, micrograms/IU, the specific chemical form.
  2. Compare the price per active dose — a "premium" product at 10x the price of a generic often contains the same molecule at the same dose.
  3. Check the certifications — in the EU, supplements are notified to ANMDMR/MoH but not pre-approved; third-party certifications (USP, GMP, ISO 22000) add confidence.
  4. Beware of "megadoses" — many vitamins have safety ceilings (UL — Tolerable Upper Level): D 4000 IU, B6 100 mg, niacin 35 mg, A 3000 μg.
  5. Supplements do not replace medicines with a clear indication (statins, antihypertensives, antidiabetics).

Sources

  • EFSA — Dietary Reference Values for vitamins
  • Endocrine Society — Vitamin D guidelines 2024
  • Cochrane — Vitamin C for the common cold (Hemilä & Chalker)
  • Cochrane — Zinc for the common cold
  • ANMDMR — SmPCs for injectable cyanocobalamin, colecalciferol, iron sulfate
  • INSP / IDNB Paulescu — national vitamin D deficiency data
  • BNF — vitamins chapter
  • NIH Office of Dietary Supplements — fact sheets
  • USPSTF — Vitamin and mineral supplements for prevention of cardiovascular disease and cancer 2022