Vitamin D and Omega-3 have a larger effect on depression than antidepressants

Original Article ↗ Hacker News Discussion ↗

Evidence and effect sizes

  • Thread centers on a 2024 meta‑analysis claiming vitamin D has a very large effect size on depression, larger than standard antidepressants; several commenters find this implausible and note other meta‑analyses showing null or only modest effects.
  • Statisticians point out: effect sizes are easy to misinterpret; many powerful drugs (eg, pain meds, hypnotics) also show modest standardized effect sizes on paper.
  • Others note many vitamin D/Omega‑3 trials show strong effects in small studies that shrink or disappear in larger, higher‑quality RCTs.

Vitamin D: dose, units, and safety

  • Original article had a serious typo: “5000 mg” vs 5000 IU, later corrected; this significantly eroded trust.
  • Prolonged high doses of vitamin D can cause hypercalcemia, kidney damage and other toxicity; case reports exist, though some users report very high self‑experimental dosing without obvious harm.
  • Disagreement over “safe” chronic doses: some cite 800–1000 IU/day, others 4000 IU as an upper limit, others 8000–10,000 IU as likely safe in many but not all people.
  • Strong repeated advice: get serum 25(OH)D measured, then titrate dose and re‑check; individual responses vary widely.
  • Several note magnesium is required for vitamin D metabolism and may be depleted by high‑dose D; some suggest co‑supplementation with magnesium and vitamin K2.

Omega‑3: forms, sources, and ratios

  • Distinction emphasized between:
    • ALA (plant omega‑3 from flax, chia, hemp)
    • EPA/DHA (marine or algae omega‑3) – most trials and claimed antidepressant effects are for EPA/DHA.
  • Multiple commenters argue ALA conversion to EPA/DHA is inefficient, so seeds are poor substitutes if you’re targeting the antidepressant evidence; recommend fish or algae‑based EPA/DHA.
  • Some focus on omega‑6:omega‑3 balance and widespread high omega‑6 intake from seed oils; hypothesized link via inflammation and possibly depression.

Lifestyle, light, and other factors

  • Exercise repeatedly cited as at least as important as any pill; many suspect most benefit people attribute to supplements coincides with starting a broader “health kick”.
  • Seasonal Affective Disorder (SAD) is a major theme:
    • People in high latitudes report winter depression despite outdoor time.
    • Bright‑light exposure (very high lux indoor lighting, light boxes, or light‑glasses) helped some dramatically, not others.
  • Caffeine: several report large improvements in anxiety/ADHD‑like symptoms after completely stopping caffeine; others rely on it and accept the trade‑offs.
  • Sleep, outdoor time, diet quality, and social connection are repeatedly described as central.

Antidepressants vs supplements

  • Many anecdotes where SSRIs/SNRIs/other meds were “night and day” and sometimes life‑saving, especially for severe or chronic depression and anxiety.
  • Others report minimal benefit, severe side‑effects (sexual dysfunction, withdrawal, emotional blunting, somatic effects), or years lost cycling through meds.
  • Several clinicians and the article’s author stress supplements should augment, not replace, antidepressants when those are working; some vitamin D trials included participants already on antidepressants and still saw incremental benefit.
  • Some participants criticize over‑prescription and lack of root‑cause workup (vitamin levels, thyroid, hormones, ADHD, sleep apnea, trauma), but others counter that for many people there may be no clear “root cause” beyond neurobiology.

Deficiency vs treatment; individual variability

  • Important distinction made: correcting a deficiency (vitamin D, B12, omega‑3, magnesium, etc.) can alleviate depressive symptoms when deficiency is causal or contributory; that’s different from a universal antidepressant effect in otherwise replete people.
  • Multiple reports of documented deficiencies (very low D, B12, omega‑3) where supplementation clearly improved mood, energy, or seasonal depression.
  • Many others report no noticeable change from months of supplementation.
  • Strong theme: depression is heterogeneous—different people have very different drivers (biology, trauma, lifestyle, chronic illness), so average effect sizes may hide subgroups who benefit a lot or not at all.

Cautions about online medical advice

  • Several comments warn that HN repeatedly amplifies self‑experimentation and megadosing trends (vitamin D, melatonin, psychedelics) without adequate safety context.
  • Recurrent advice:
    • Don’t treat blog posts or comment threads as medical directives.
    • Use lab testing (vitamin D, B12, thyroid, lipids, etc.) and clinician guidance, especially for high‑dose, fat‑soluble vitamins.
    • Be wary of simple narratives: “pharma bad, supplements good” or “it’s just a chemical imbalance” or “just think differently.”