These are conditions with an established causal link to a specific nutrient deficiency — not associations, but documented cause and effect.
Scurvy — vitamin C
NIH ODS states that insufficient vitamin C intake causes scurvy, "characterized by fatigue or lassitude, widespread connective tissue weakness, and capillary fragility."
Rickets and osteomalacia — vitamin D
The NHS states that vitamin D deficiency can lead to rickets in children and osteomalacia — bone pain from soft bones — in adults.
Xerophthalmia and night blindness — vitamin A
NIH ODS describes xerophthalmia as the most common clinical sign of vitamin A deficiency, with night blindness as the first sign. It notes xerophthalmia affects the cornea and "can eventually lead to permanent blindness," and that vitamin A deficiency is among the top causes of preventable blindness globally.
Megaloblastic anemia — B12 or folate
NIH ODS documents megaloblastic anemia as a consequence of B12 deficiency. The NHS treats B12 and folate deficiency anaemia together, since folate deficiency produces the same picture.
Pernicious anemia — a cause, not a consequence
Worth distinguishing. NIH ODS describes pernicious anemia as "an irreversible autoimmune disease that affects the gastric mucosa," which causes B12 deficiency by eliminating intrinsic factor. It is upstream of the deficiency, not downstream.
Iron deficiency anemia — iron
NIH ODS notes that iron deficiency affects gastrointestinal function, immune function and body temperature regulation, and is most common in young children, women of reproductive age, and pregnant women.
Neural tube defects — folate
NIH ODS notes B12 deficiency in pregnancy "might cause neural tube defects, developmental delays, failure to thrive, and anemia" in infants. Folate's role in neural tube defects is the basis for fortification programs internationally.
Keeping this in proportion
Most of these are severe endpoints of prolonged, significant deficiency — not what mild insufficiency looks like. Recognizing the names is useful; reading symptoms backwards into a diagnosis is not. That is a clinician's task.
Our free assessment focuses on the risk factors worth discussing.
References
- NIH ODS — Vitamin C
- NIH ODS — Vitamin A
- NIH ODS — Vitamin B12
- NIH ODS — Iron
- NHS — Vitamin D
- NHS — Vitamin B12 or folate deficiency anaemia
This article summarizes published guidance from the sources linked above. It is general information, not medical advice, and it cannot tell you whether you personally have a deficiency. Only a clinician ordering the right test can do that. If you have symptoms that concern you, speak to a doctor.