What do systematic reviews say?

Staple foods fortified with vitamin A vs same unfortified staple foods

It is very uncertain whether staple foods fortified with vitamin A changes subclinical vitamin A deficiency (serum/plasma retinol 70 μmol/L or… compared with same unfortified staple foods (very low certainty).

• Fortification of staple foods with vitamin A for vitamin A deficiency 2019 · Cochrane Headline outcomes only
  RR 0.45 [0.19, 1.05]
  2 studies · 993 participants
  Very low

Staple foods fortified with vitamin A vs same unfortified staple foods

• Fortification of staple foods with vitamin A for vitamin A deficiency 2019 · Cochrane Headline outcomes only
  no estimate extracted
  3 studies · 1829 participants
  Very low

Staple food fortified with vitamin A plus other micronutrients vs same unfortified staple foods

Staple foods fortified with vitamin A plus other micronutrients probably leads to lower subclinical vitamin A deficiency (serum/plasma retinol 0.70 μmol/L… compared with same unfortified staple foods (moderate certainty).

• Fortification of staple foods with vitamin A for vitamin A deficiency 2019 · Cochrane Headline outcomes only
  RR 0.27 [0.16, 0.49]
  3 studies · 923 participants
  Moderate

Staple food fortified with vitamin A plus other micronutrients vs same unfortified staple foods

• Fortification of staple foods with vitamin A for vitamin A deficiency 2019 · Cochrane Headline outcomes only
  no estimate extracted
  4 studies · 1009 participants
  Low