TABLE 3.

Iron efficacy studies with DFS monitored using Hb alone or a combination of iron status biomarkers¹

Reference, country	Subjects2	Duration	DFS	Additional iron3	Inflammation4	Impact5
Monitored using Hb alone
Nadiger et al. (45), India	546 children aged 5–15 y, 2 boys and 2 girls groups6	12 mo	FePO4 plus Na H sulfate	15 mg/d	Not measured	Anemia decreased in boys (54%–19%) and girls (16%–3%)
Working Group Report (46), India	c.12,000 subjects of all ages, groups7	12 mo	FePO4 plus Na H sulfate	15 mg/d	Not measured	Anemia decreased in all test groups
Asibey-Berko et al. (41), Ghana	182 women aged 15–45 y, 3 groups	8 mo	DFS 1a	10 mg/d	Not measured	No change in anemia
Reddy and Nair (47), India	947 children aged 6–15 y, 4 groups	9 mo	DFS 2	Salt (1 mg Fe/g) provided	Not measured	No change in anemia
Monitored using a combination of iron status biomarkers
Zimmermann et al. (48), Morocco	377 children aged 6–15 y, 2 groups	9 mo	DFS 4	10 mg/d	Not measured	SF increased, TfR, ZPP, and IDA (35%–8%) decreased
Zimmermann et al. (49), Morocco	158 children aged 6–15 y, 2 groups	10 mo	DFS 5	18 mg/d	Not measured	SF and BIS increased, TfR, ZPP, and IDA (30%–5%) decreased
Wegmüller et al. (50), Côte d'Ivoire	123 children aged 5–15 y, 2 groups8	6 mo	DFS 5	10 mg/d	Inflammation excluded	No change in Hb; SF, TfR, and BIS increased
Andersson et al. (42), India	458 children aged 5–15 y, 3 groups	10 mo	DFS 5	12 mg/d	Not measured	SF and BIS increased, ZPP, TfR, ID (56%–34%), and IDA (15%–7%) decreased
Andersson et al. (42), India	458 children aged 5–15 y, 3 groups	10 mo	DFS 1b	12 mg/d	Not measured	SF and BIS increased, ZPP, TfR, ID (52%–35%), and IDA (12%–4%) decreased
Haas et al. (43), India	212 women aged 18–55 y, 2 groups	8 mo	DFS 1b	12 mg/d	>22%	No change in Hb; SF and BIS increased, TfR and ID (26%–9%) decreased

¹BIS, body iron stores; CRP, C-reactive protein; DFS, double-fortified salt; DFS 1a, double-fortified salt with nonencapsulated ferrous fumarate; DFS 1b, double-fortified salt with Nutrition International encapsulated ferrous fumarate; DFS 2, double-fortified salt with ferrous sulfate plus sodium hexametaphosphate; DFS 4, double-fortified salt with ferrous sulfate encapsulated with partially hydrogenated soybean oil; DFS 5, double-fortified salt with micronized ground ferric pyrophosphate; Hb, hemoglobin; ID, iron deficiency; IDA, iron deficiency anemia; SF, serum ferritin; TfR, transferrin receptor; ZPP, zinc protoporphyrin.

²Unless otherwise stated, all studies were randomized and placebo controlled with approximately the same number of subjects in each group. Subjects aged 5–15 y were of both sexes.

³The additional iron consumed per day over the study duration was calculated by dividing the combined amount of iron consumed on test days (excluding weekend days and school holidays if the test meal was not consumed) by the total number of days in the study duration.

⁴Inflammation based on CRP (50), or on CRP plus α-1-acid-glycoprotein (43).

⁵Reported increases or decreases of iron status parameters relative to control were statistically significant (at least P < 0.05). More precision on the statistical significance is given in the text. No change in iron status parameters is reported when differences relative to control were P > 0.05.

⁶Study not randomized but made in 4 residential schools, with control schools having fewer than half the subjects that were in the test schools.

⁷Study not randomized but made in 4 control and 4 test villages in different regions of India.

⁸Study made in a malaria-endemic area.