B12

Vitamin supplementation is not universally necessary for people eating a varied diet. UK-specific evidence-based indications: vitamin D (10 mcg/day for all UK adults — SACN 2016), folic acid (400 mcg/day before and during early pregnancy — NICE), vitamin B12 (vegans and strict vegetarians), iron (only if deficiency confirmed by blood test). A SACN review concluded there is no consistent evidence that multivitamins benefit well-nourished UK adults.

Older adults face specific nutritional vulnerabilities — reduced absorption, polypharmacy interactions, and physiological changes affecting metabolism. This article reviews the evidence on supplements with genuine indication in older populations.

UK evidence-based supplements for vegetarians: B12 is essential for vegans and recommended for low-dairy vegetarians (SACN); vitamin D 10 mcg/day for all UK adults regardless of diet (SACN 2016); iodine 150 mcg/day for those limiting dairy (SACN 2014); omega-3 as algal oil (EPA+DHA) if not eating oily fish. Iron: test first — do not supplement without confirmed deficiency. Lacto-ovo vegetarians eating dairy and eggs regularly have fewer critical gaps.

Several nutrients have strong evidence for brain development: DHA (EFSA authorises 100 mg/day claim for infant brain development), iodine (SACN 2014: deficiency associated with cognitive impairment in children; UK vegetarians/vegans at risk), iron (deficiency in early life causes irreversible cognitive deficits — NICE recommends testing before supplementing), choline (UK has no RNI; most diets adequate). Folic acid prevents neural tube defects (NICE: 400 mcg/day in first trimester). B12: critical for myelin development in vegan/vegetarian infants.

Vegetarian diets can fully support evidence-based weight management goals with appropriate planning. The primary challenge is hitting protein targets (1.6–2.0g/kg/day) without meat — achievable with legumes, dairy, eggs, tofu, and tempeh. Iron requires paired vitamin C consumption for non-haem absorption. B12 supplementation is essential for vegans. Omega-3 from ALA (flaxseed, walnuts) converts poorly to EPA/DHA — algal oil supplementation is recommended.