Dietary inulin intake and age can significantly affect intestinal absorption of calcium and magnesium in rats: a stable isotope approach

Table 4 Effect of age and inulin intake and their interaction on intestinal absorption and retention of Mg in rats

	Cont 3 Mo	Cont 6 Mo	Cont 11 Mo	Cont 21 Mo	Inulin 3 Mo	Inulin 6 Mo	Inulin 11 Mo	Inulin 21 Mo	inulin	age	interaction
Administered ²⁵ Mg, μg	2553 ± 71	2511 ± 22	2499 ± 26	2504 ± 38	2485 ± 30	2518 ± 30	2527 ± 39	2536 ± 35	NS	NS	<0.0005
Fecal ²⁵ Mg enrichment, %	47.9 ± 7.1	51.9 ± 7.4	54.6 ± 12.3	54.1 ± 8.1	33.9 ± 20.3	41.0 ± 19.9	47.4 ± 13.9	65.7 ± 17.6	NS	0.0007	0.027
Fecal ²⁵ Mg level, μg/g	149 ± 26	184 ± 34	205 ± 44	204 ± 38	51 ± 33	70 ± 35	91 ± 31	120 ± 35	<0.0001	<0.0001	NS
Fecal ²⁵ Mg excretion, μg	1138 ± 201	1157 ± 229	1311 ± 200	1366 ± 177	358 ± 224	430 ± 206	673 ± 205	757 ± 184	<0.0001	<0.0001	NS
Intestinal ²⁵ Mg absorption, μg	1415 ± 187	1354 ± 225	1188 ± 199	1137 ± 175	2127 ± 224	2087 ± 208	1855 ± 232	1780 ± 186	<0.0001	<0.0001	NS
Intestinal ²⁵ Mg absorption %	55.5 ± 7.5	54.0 ± 9.0	47.5 ± 8.0	45.4 ± 7.0	85.6 ± 8.9	82.9 ± 8.2	73.3 ± 8.4	70.2 ± 7.2	<0.0001	<0.0001	NS
Urinary ²⁵ Mg enrichment, %	29.3 ± 2.7	29.1 ± 3.5	28.0 ± 3.7	28.2 ± 2.32	34.2 ± 3.8	35.5 ± 2.4	33.5 ± 3.7	36.7 ± 6.5	<0.0001	NS	NS
Urinary ²⁵ Mg excretion, μg	398 ± 64	323 ± 36	298 ± 80	292 ± 88	699 ± 91	792 ± 167	633 ± 146	551 ± 164	<0.0001	0.003	NS
²⁵ Mg retention, μg	1017 ± 189	1031 ± 225	890 ± 179	845 ± 142	1428 ± 216	1295 ± 192	1221 ± 242	1228 ± 165	<0.0001	0.011	NS
²⁵ Mg retention, %	39.8 ± 7.3	41.1 ± 9.0	35.6 ± 7.1	33.7 ± 5.7	57.8 ± 8.9	51.5 ± 7.8	48.3 ± 9.2	48.4 ± 6.5	<0.0001	0.008	NS

Values are mean ± SD, n = 10 animals.
The rats were given ²⁵Mg after 14 days of inulin intake (7.5%), and fecal non-absorbed ²⁵Mg isotope was determined in a 4d feces and urine pools.

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