Anti-Nutrient

Molecule:

Phytic Acid

Foods:

Bran of grains and pseudo-grains, all kind of seeds, nuts, legumes, potatoes.
Phytic Acid

How to Neutralize:

Birds and ruminant animals: phytase enzyme. Partially by soaking, cooking, fermenting, sprouting.

Negative Effects:

Binding with minerals of food in the gut: deficiency of iron, zinc, calcium and other minerals. Reduces the digestibility of starches, proteins, and fats.


Phytic acid occurs naturally throughout the plant kingdom and is present in considerable quantities within many of the major legumes and oilseeds. This includes soybean, rapeseed and cotton seed. Matyka et al. (1993) reported that about 62-73% and 46-73% of the total phosphorus within cereal grains and legume seeds being in form of organically bound phytin phosphorus, respectively. As phytic acid accumulates in storage sites in seeds, other minerals apparently chelates to it forming the complex salt phytate (Erdman, 1979). Studies by Martinez (1977) revealed that in oilseeds, which contain little or no endosperm, the phytates are distributed throughout the kernel found within subcellular inclusions called aleurone grains or protein bodies. Whole soybeans have been reported to contain 1-2% phytic acids (Weingartner, 1987; Osho, 1993). The major part of the phosphorus contained within phytic acid are largely unavailable to animals due to the absence of the enzyme phytase within the digestive tract of monogastric animals. Nwokolo and Bragg (1977) reported that in the chicken there is a significant inverse relationship between phytic acid and the availability of calcium, magnesium, phosphorus and zinc in feedstuffs such as rapeseed, palm kernel seed, cotton seed and soybean meals. Phytic acid acts as a strong chelator, forming protein and mineral-phytic acid complexes; the net result being reduced protein and mineral bioavailability (Erdman, 1979; Spinelli et al., 1983; Khare, 2000). Phytic acid is reported to chelate metal ions such as calcium, magnesium, zinc, copper, iron and molybdenum to form insoluble complexes that are not readily absorbed from gastrointestinal tract. Phytic acid also inhibits the action of gastrointestinal tyrosinase, trypsin, pepsin, lipase and “-amylase (Liener, 1980; Hendricks and Bailey, 1989; Khare, 2000). Erdman (1979) stated that the greatest effect of phytic acid on human nutrition is its reduction of zinc bioavailability.


Phytate in foods and significance for humans: food sources, intake, processing, bioavailability, protective role and analysis


Abstract

The article gives an overview of phytic acid in food and of its significance for human nutrition. It summarises phytate sources in foods and discusses problems of phytic acid/phytate contents of food tables. Data on phytic acid intake are evaluated and daily phytic acid intake depending on food habits is assessed. Degradation of phytate during gastro-intestinal passage is summarised, the mechanism of phytate interacting with minerals and trace elements in the gastro-intestinal chyme described and the pathway of inositol phosphate hydrolysis in the gut presented. The present knowledge of phytate absorption is summarised and discussed. Effects of phytate on mineral and trace element bioavailability are reported and phytate degradation during processing and storage is described. Beneficial activities of dietary phytate such as its effects on calcification and kidney stone formation and on lowering blood glucose and lipids are reported. The antioxidative property of phytic acid and its potentional anticancerogenic activities are briefly surveyed. Development of the analysis of phytic acid and other inositol phosphates is described, problems of inositol phosphate determination and detection discussed and the need for standardisation of phytic acid analysis in foods argued.


Phytate content of foods: effect on dietary zinc bioavailability

Abstract

The phytate content of several foods is presented. Published zinc values were used to calculate phytate:zinc molar ratios. These ratios can be used to estimate the relative risk of having an inadequate intake of zinc. They may be used in planning menus to select the combination of foods that will supply the most available zinc to the daily diet. On the basis of animal experiments to date, a daily phytate:zinc molar ratio of 10 or less is thought to be acceptable in providing adequate dietary zinc, and daily ratios consistently above 20 may jeopardize zinc status. Many factors other than the daily dietary phytate:zinc molar ratio influence zinc nutriture, but the ratio concept is a tool which may contribute to a more accurate assessment of zinc status.

Food Name
Food Group
Protein (g)
Fat (g)
Carbohydrates (g)
Calories
Starch (g)
SucroseG
Glucose (g)
Fructose (g)
Lactose (g)
Maltose (g)
Alcohol (g)
Water (g)
Caffeine (mg)
Theobromine (mg)
Sugar (g)
Fiber (g)
Calcium (mg)
Iron (mg)
Magnesium (mg)
Phosphorus (mg)
Potassium (mg)
Sodium (mg)
Zinc (mg)
Copper (mg)
Flouride (mcg)
Manganese (mg)
Selenium(mcg)
Vitamin A(IU)
Retinol (mcg)
Beta Carotene (mcg)
Alpha Carotene (mcg)
Vitamin E (mg)
Vitamin D (mcg)
Lutein and Zeaxanthin
Vitamin C (mg)
Thiamin (B1) (mg)
Riboflavin (B2)(mg)
Niacin(B3)(mg)
Vitamin B5(mg)
Vitamin B6 (mg)
Folate (B9) (mg)
Choline (mg)
Cholesterol (mg)
Saturated Fat (g)
Net Carbs
Cereals ready-to-eat, OAT BRAN FLAKES, HEALTH VALLEY
Breakfast Cereals
10
3
78
380
NULL
NULL
NULL
NULL
NULL
NULL
0
3.4
0
0
22
8
80
2.88
143
343
340
380
2.2
0.319
NULL
2.903
26.5
0
0
0
0
0.53
0
203
120
0.75
0.85
10
0.896
1
200
22.9
0
1
70
Vital wheat gluten
Cereal Grains and Pasta
75.16
1.85
13.79
370
NULL
NULL
NULL
NULL
NULL
NULL
0
8.2
0
0
0
0.6
142
5.2
25
260
100
29
0.85
0.182
NULL
NULL
39.7
0
0
0
0
0
0
0
0
0
0
0
0
0
0
NULL
0
0.272
13.19
Cereals ready-to-eat, wheat and bran, presweetened with nuts and fruits
Breakfast Cereals
7.1
5.6
76.2
385
NULL
NULL
NULL
NULL
NULL
NULL
0
8.5
0
0
23.6
9.7
43
9.82
120
294
382
245
2.73
0.473
NULL
2.474
17.3
1364
410
0
0
2.32
1.8
0
0
0.68
0.77
9.09
0.775
0.91
182
28.5
0
0.8
66.5
Soybean, curd cheese
Legumes and Legume Products
12.5
8.1
6.9
151
NULL
NULL
NULL
NULL
NULL
NULL
0
70.9
0
0
1.6
0
188
5.6
228
222
199
20
1.72
0.38
NULL
0.889
16.8
42
0
25
0
0.6
0
0
0
0
0.14
0.5
0.116
0.07
22
62.5
0
1.172
6.9
Cereals ready-to-eat, POST, Shredded Wheat n' Bran, spoon-size
Breakfast Cereals
10.93
2.06
80.65
339
NULL
NULL
NULL
NULL
NULL
NULL
0
3.14
0
0
0.75
14.7
44
3.87
174
418
391
0
3.13
0
NULL
NULL
8.2
0
0
0
0
1.09
0
236
0
0.2
0.08
5.2
NULL
0.08
30
23.1
0
0.43
65.95
Babyfood, peas and brown rice
Baby Foods
3.4
0.5
11.49
64
0.68
NULL
NULL
NULL
NULL
NULL
0
84.1
0
0
2.89
2.5
14
1.5
25
52
93
6
0.46
0.08
39.4
NULL
1.2
390
0
228
11
0.07
0
1261
3
0.1
0.08
1.4
NULL
0.06
16
14.7
0
0.1
8.99
Peanut butter, reduced sodium
Legumes and Legume Products
24
49.9
21.83
590
NULL
NULL
NULL
NULL
NULL
NULL
0
1.1
0
0
9.29
6.6
41
1.9
159
317
747
203
2.78
0.515
NULL
NULL
7.5
0
0
0
0
9.05
0
0
0
0.12
0.11
13.69
NULL
0.45
92
63.5
0
7.716
15.23
Corn flour, whole-grain, white
Cereal Grains and Pasta
6.93
3.86
76.85
361
NULL
NULL
NULL
NULL
NULL
NULL
0
10.91
0
0
0.64
7.3
7
2.38
93
272
315
5
1.73
0.23
NULL
0.46
15.4
3
0
1
0
0.42
0
5
0
0.246
0.08
1.9
0.658
0.37
25
21.6
0
0.543
69.55
Corn flour, yellow, masa, enriched
Cereal Grains and Pasta
8.46
3.69
76.59
363
66
NULL
NULL
NULL
NULL
NULL
NULL
9.79
NULL
NULL
NULL
6.4
138
8.5
93
231
262
5
1.8
0.209
NULL
0.376
10.5
214
0
97
63
NULL
0
6
0
1.475
0.805
9.932
0.192
0.475
209
NULL
0
0.532
70.19
Cornmeal, whole-grain, white
Cereal Grains and Pasta
8.12
3.59
76.89
362
NULL
NULL
NULL
NULL
NULL
NULL
0
10.26
0
0
0.64
7.3
6
3.45
127
241
287
35
1.82
0.193
NULL
0.498
15.5
3
0
1
0
0.42
0
5
0
0.385
0.201
3.632
0.425
0.304
25
21.6
0
0.505
69.59
Cornmeal, white, self-rising, bolted, with wheat flour added, enriched
Cereal Grains and Pasta
8.41
2.85
73.43
348
NULL
NULL
NULL
NULL
NULL
NULL
NULL
10.33
NULL
NULL
NULL
6.3
299
4.95
54
651
207
1319
1.39
0.139
NULL
NULL
NULL
0
0
NULL
NULL
NULL
0
NULL
0
0.713
0.433
5.202
0.383
0.385
264
NULL
0
0.4
67.13
Wheat flour, white, all-purpose, enriched, calcium-fortified
Cereal Grains and Pasta
10.33
0.98
76.31
364
NULL
NULL
NULL
NULL
NULL
NULL
NULL
11.92
NULL
NULL
NULL
2.7
252
4.64
22
108
107
2
0.7
0.144
NULL
0.682
NULL
0
0
NULL
NULL
0.06
0
NULL
0
0.785
0.494
5.904
0.438
0.044
183
NULL
0
0.155
73.61
Wheat flour, white, all-purpose, unenriched
Cereal Grains and Pasta
10.33
0.98
76.31
364
NULL
NULL
NULL
NULL
NULL
NULL
0
11.92
0
0
0.27
2.7
15
1.17
22
108
107
2
0.7
0.144
NULL
0.682
33.9
0
0
0
0
0.06
0
18
0
0.12
0.04
1.25
0.438
0.044
26
10.4
0
0.155
73.61
Wheat flour, white, all-purpose, enriched, unbleached
Cereal Grains and Pasta
10.33
0.98
76.31
364
NULL
NULL
NULL
NULL
NULL
NULL
0
11.92
0
0
0.27
2.7
15
4.64
22
108
107
2
0.7
0.144
NULL
0.682
33.9
2
0
1
0
0.23
0
79
0
0.785
0.494
5.904
0.438
0.044
183
NULL
0
0.155
73.61
Wheat flour, white (industrial), 9% protein, bleached, enriched
Cereal Grains and Pasta
8.89
1.43
77.32
367
68.01
0.26
0.03
0.03
0
0.22
0
11.85
0
0
0.54
NULL
20
5.06
20
85
131
2
0.94
0.165
NULL
0.628
11.4
0
0
0
0
0.05
0
18
0
0.736
0.445
5.953
0.187
0.037
170
10.4
0
0.34
77.32
Wheat flour, white (industrial), 9% protein, bleached, unenriched
Cereal Grains and Pasta
8.89
1.43
77.32
367
68.01
0.26
0.03
0.03
0
0.22
0
11.85
0
0
0.54
2.4
20
1.26
20
85
131
2
0.94
0.165
NULL
0.628
11.4
0
0
0
0
0.05
0
18
0
0.194
0.072
1.198
0.187
0.037
31
10.4
0
0.34
74.92
Wheat flour, white (industrial), 10% protein, bleached, enriched
Cereal Grains and Pasta
9.71
1.48
76.22
366
64.48
0.2
0.03
0.03
0
0.23
0
12.01
0
0
0.49
2.4
20
5.06
25
107
149
2
1.02
0.188
NULL
0.818
14.6
0
0
0
0
0.05
0
18
0
0.736
0.445
5.953
0.248
0.037
170
10.4
0
0.302
73.82
Wheat flour, white (industrial), 10% protein, bleached, unenriched
Cereal Grains and Pasta
9.71
1.48
76.22
366
64.48
0.2
0.03
0.03
0
0.23
0
12.01
0
0
0.49
2.4
20
1.26
25
107
149
2
1.02
0.188
NULL
0.818
14.6
0
0
0
0
0.05
0
18
0
0.194
0.072
1.198
0.248
0.037
31
10.4
0
0.302
73.82
Wheat flour, white (industrial), 10% protein, unbleached, enriched
Cereal Grains and Pasta
9.71
1.48
76.22
366
64.48
0.2
0.03
0.03
0
0.23
NULL
12.01
NULL
NULL
0.49
2.4
20
5.06
25
107
149
2
1.02
0.188
NULL
0.818
14.6
0
NULL
0
0
0.38
0
18
0
0.736
0.445
5.953
0.248
0.037
170
10.4
NULL
0.302
73.82
Wheat flour, white (industrial), 13% protein, bleached, enriched
Cereal Grains and Pasta
13.07
1.38
72.2
362
61.22
0.16
0.03
0.03
0
0.87
0
12.82
0
0
1.1
2.4
24
5.06
35
119
128
2
1.6
0.187
NULL
0.624
26.2
0
0
0
0
0.05
0
18
0
0.736
0.445
5.953
0.386
0.045
170
10.4
0
0.189
69.8
Wheat flour, white (industrial), 13% protein, bleached, unenriched
Cereal Grains and Pasta
13.07
1.38
72.2
362
61.22
0.16
0.03
0.03
0
0.87
0
12.82
0
0
1.1
2.4
24
1.26
35
119
128
2
1.6
0.187
NULL
0.624
26.2
0
0
0
0
0.05
0
18
0
0.194
0.072
1.198
0.386
0.045
31
10.4
0
0.189
69.8
Wheat flour, white (industrial), 15% protein, bleached, enriched
Cereal Grains and Pasta
15.33
1.41
69.88
362
59.52
0.15
0.03
0.03
0
0.71
0
12.85
0
0
0.92
2.4
17
5.06
38
128
120
2
1.16
0.195
NULL
0.569
28.1
0
0
0
0
0.05
0
18
0
0.736
0.445
5.953
0.427
0.045
170
10.4
0
0.272
67.48
Wheat flour, white (industrial), 15% protein, bleached, unenriched
Cereal Grains and Pasta
15.33
1.41
69.88
362
59.52
0.15
0.03
0.03
0
0.71
0
12.85
0
0
0.92
2.4
17
1.26
38
128
120
2
1.16
0.195
NULL
0.569
28.1
0
0
0
0
0.05
0
18
0
0.194
0.072
1.198
0.427
0.045
31
10.4
0
0.272
67.48
Wheat flour, white, cake, enriched
Cereal Grains and Pasta
8.2
0.86
78.03
362
NULL
NULL
NULL
NULL
NULL
NULL
0
12.51
0
0
0.31
1.7
14
7.32
16
85
105
2
0.62
0.139
NULL
0.634
4.9
0
0
0
0
0.02
0
3
0
0.892
0.43
6.79
0.458
0.033
186
10.4
0
0.127
76.33
Wheat flour, white, tortilla mix, enriched
Cereal Grains and Pasta
9.66
10.63
67.14
405
NULL
NULL
NULL
NULL
NULL
NULL
NULL
10.08
NULL
NULL
NULL
NULL
205
7.05
21
210
100
677
0.64
0.1
NULL
0.614
NULL
0
0
NULL
NULL
1.64
0
NULL
0
0.735
0.493
5.82
0.394
0.04
136
11.1
0
4.1
67.14
Wheat, sprouted
Cereal Grains and Pasta
7.49
1.27
42.53
198
NULL
NULL
NULL
NULL
NULL
NULL
0
47.75
NULL
NULL
NULL
1.1
28
2.14
82
200
169
16
1.65
0.261
NULL
1.858
42.5
0
0
NULL
NULL
NULL
0
NULL
2.6
0.225
0.155
3.087
0.947
0.265
38
NULL
0
0.206
41.43
Oat flour, partially debranned
Cereal Grains and Pasta
14.66
9.12
65.7
404
NULL
0.5
0.1
0
NULL
NULL
0
8.55
0
0
0.8
6.5
55
4
144
452
371
19
3.2
0.437
NULL
4.019
34
0
0
0
0
0.7
0
180
0
0.692
0.125
1.474
0.201
0.125
32
29.9
0
1.607
59.2
Oat bran, cooked
Cereal Grains and Pasta
3.21
0.86
11.44
40
NULL
NULL
NULL
NULL
NULL
NULL
NULL
84
NULL
NULL
NULL
2.6
10
0.88
40
119
92
1
0.53
0.066
NULL
0.964
7.7
0
0
NULL
NULL
NULL
0
NULL
0
0.16
0.034
0.144
0.217
0.025
6
NULL
0
0.163
8.84
Rice bran, crude
Cereal Grains and Pasta
13.35
20.85
49.69
316
NULL
0.5
0.2
0.2
NULL
NULL
0
6.13
0
0
0.9
21
57
18.54
781
1677
1485
5
6.04
0.728
NULL
14.21
15.6
0
0
0
0
4.92
0
220
0
2.753
0.284
33.995
7.39
4.07
63
32.2
0
4.171
28.69
Wheat bran, crude
Cereal Grains and Pasta
15.55
4.25
64.51
216
NULL
NULL
NULL
NULL
NULL
NULL
0
9.89
0
0
0.41
42.8
73
10.57
611
1013
1182
2
7.27
0.998
NULL
11.5
77.6
9
0
6
0
1.49
0
240
0
0.523
0.577
13.578
2.181
1.303
79
74.4
0
0.63
21.71
Wheat germ, crude
Cereal Grains and Pasta
23.15
9.72
51.8
360
NULL
NULL
NULL
NULL
NULL
NULL
NULL
11.12
NULL
NULL
NULL
13.2
39
6.26
239
842
892
12
12.29
0.796
NULL
13.301
79.2
0
0
NULL
NULL
NULL
0
NULL
0
1.882
0.499
6.813
2.257
1.3
281
NULL
0
1.665
38.6
Corn bran, crude
Cereal Grains and Pasta
8.36
0.92
85.64
224
NULL
NULL
NULL
NULL
NULL
NULL
0
4.71
0
0
0
79
42
2.79
64
72
44
7
1.56
0.248
NULL
0.14
16.5
71
0
32
21
0.42
0
1355
0
0.01
0.1
2.735
0.636
0.152
4
18.1
0
0.13
6.64
Bread, rice bran, toasted
Baked Products
9.7
5
47.3
264
NULL
NULL
NULL
NULL
NULL
NULL
0
35.9
0
0
5.08
5.3
75
3.92
76
174
212
292
1.38
0.182
NULL
1.521
31.2
1
0
0
0
0.71
0
51
0
0.568
0.293
6.662
0.26
0.208
79
15.9
0
0.771
42
Bread, wheat germ, toasted
Baked Products
10.7
3.3
54.3
293
NULL
NULL
NULL
NULL
NULL
NULL
0
29.3
0
0
4.14
2.3
100
3.88
38
175
285
621
1.46
0.202
NULL
1.259
30.5
4
0
2
0
0.57
0
58
0.3
0.332
0.379
4.548
0.34
0.096
112
22.1
1
0.738
52
Muffins, wheat bran, toaster-type with raisins, toasted
Baked Products
5.5
9.4
55.5
313
NULL
NULL
NULL
NULL
NULL
NULL
0
27
0
0
23.07
8.2
39
2.83
21
284
177
527
0.44
0.12
NULL
0.433
20.3
190
56
1
0
0.98
NULL
48
0
0.204
0.287
2.317
0.18
0.056
30
NULL
9
1.5
47.3
Rolls, dinner, oat bran
Baked Products
9.5
4.6
40.2
236
NULL
NULL
NULL
NULL
NULL
NULL
0
44
0
0
6.67
4.1
85
4.14
33
115
121
413
1.02
0.136
NULL
0.754
29.3
0
0
0
0
0.48
0
44
0
0.448
0.289
4.954
0.428
0.045
95
14.6
0
0.619
36.1
Muffins, oat bran
Baked Products
7
7.4
48.3
270
NULL
NULL
NULL
NULL
NULL
NULL
0
35
0
0
8.22
4.6
63
4.2
157
376
507
393
1.84
0.33
NULL
2.63
11
0
0
0
0
0.66
0
13
0
0.262
0.095
0.42
1.01
0.161
89
6.6
0
1.087
43.7
Muffins, wheat bran, dry mix
Baked Products
7.1
12
73
396
NULL
NULL
NULL
NULL
NULL
NULL
NULL
4.8
NULL
NULL
NULL
NULL
36
3.6
87
480
200
700
1.5
0.2
NULL
2.666
18
0
0
NULL
NULL
NULL
NULL
NULL
0
0.36
0.28
5
0.669
0.282
85
NULL
0
2.939
73
Bread, reduced-calorie, oat bran
Baked Products
8
3.2
41.3
201
NULL
NULL
NULL
NULL
NULL
NULL
0
46
0
0
3.52
12
57
3.15
55
139
102
459
1.05
0.291
NULL
1.101
20.6
2
0
1
0
0.28
0
42
0
0.354
0.203
3.763
0.492
0.103
81
14.6
0
0.445
29.3
Bread, reduced-calorie, oat bran, toasted
Baked Products
9.5
3.8
49.2
239
NULL
NULL
NULL
NULL
NULL
NULL
0
35.7
0
0
4.2
14.3
68
3.75
55
144
122
547
1.19
0.147
NULL
1.006
24.5
1
0
2
0
0.33
0
48
0
0.338
0.217
4.032
0.166
0.087
82
16.1
0
0.53
34.9
Bread, rice bran
Baked Products
8.9
4.6
43.5
243
NULL
NULL
NULL
NULL
NULL
NULL
0
41
0
0
4.67
4.9
69
3.61
80
178
215
269
1.31
0.184
NULL
1.585
28.7
3
0
0
0
0.65
0
49
0
0.653
0.3
6.81
0.776
0.268
86
18.7
0
0.709
38.6
Bread, wheat bran
Baked Products
8.8
3.4
47.8
248
NULL
NULL
NULL
NULL
NULL
NULL
0
37.8
0
0
9.68
4
74
3.07
81
185
227
486
1.35
0.221
NULL
1.668
31
0
0
0
0
0.32
0
54
0
0.397
0.287
4.402
0.536
0.176
105
18.7
0
0.779
43.8
Bread, oat bran
Baked Products
10.4
4.4
39.8
236
NULL
NULL
NULL
NULL
NULL
NULL
0
44
0
0
7.7
4.5
65
3.12
35
141
147
353
0.89
0.135
NULL
0.779
30
5
2
0
0
0.44
0
46
0
0.504
0.346
4.831
0.581
0.073
81
18.7
0
0.697
35.3
Bread, oat bran, toasted
Baked Products
11.4
4.8
43.7
259
NULL
NULL
NULL
NULL
NULL
NULL
0
38.5
0
0
8.46
4.9
71
3.43
34
116
123
387
1.05
0.128
NULL
0.76
33
5
2
0
0
0.48
0
48
0
0.443
0.343
4.778
0.114
0.04
69
16.1
0
0.766
38.8
Peanuts, all types, oil-roasted, without salt
Legumes and Legume Products
28.03
52.5
15.26
599
NULL
4.03
0.08
0.08
0
0
0
1.45
0
0
4.18
9.4
61
1.52
176
397
726
6
3.28
0.533
NULL
1.845
3.3
0
0
0
0
6.91
0
0
0.8
0.085
0.089
13.825
1.202
0.461
120
55
0
8.686
5.86
Tofu, raw, firm, prepared with calcium sulfate
Legumes and Legume Products
17.27
8.72
2.78
144
NULL
NULL
NULL
NULL
NULL
NULL
NULL
69.83
NULL
NULL
NULL
2.3
683
2.66
58
190
237
14
1.57
0.378
NULL
1.181
17.4
166
NULL
NULL
NULL
NULL
0
NULL
0.2
0.158
0.102
0.381
0.133
0.092
29
NULL
0
1.261
0.48
Tofu, raw, regular, prepared with calcium sulfate
Legumes and Legume Products
8.08
4.78
1.87
76
NULL
NULL
NULL
NULL
NULL
NULL
0
84.55
0
0
0.62
0.3
350
5.36
30
97
121
7
0.8
0.193
NULL
0.605
8.9
85
NULL
NULL
NULL
0.01
0
NULL
0.1
0.081
0.052
0.195
0.068
0.047
15
28.8
0
0.691
1.57
Tofu, dried-frozen (koyadofu), prepared with calcium sulfate
Legumes and Legume Products
52.43
30.34
8.3
470
NULL
NULL
NULL
NULL
NULL
NULL
NULL
5.78
NULL
NULL
NULL
1.2
2134
9.73
181
483
20
6
4.9
1.179
NULL
3.689
54.3
0
0
NULL
NULL
NULL
0
NULL
0.7
0.494
0.317
1.189
0.415
0.286
92
NULL
0
4.388
7.1
Tofu, fried, prepared with calcium sulfate
Legumes and Legume Products
18.82
20.18
8.86
270
NULL
NULL
NULL
NULL
NULL
NULL
NULL
50.52
NULL
NULL
NULL
3.9
961
4.87
95
287
146
16
1.99
0.398
NULL
1.495
28.5
0
0
NULL
NULL
NULL
0
NULL
0
0.17
0.05
0.1
0.14
0.099
27
NULL
0
2.918
4.96
Tofu, salted and fermented (fuyu), prepared with calcium sulfate
Legumes and Legume Products
8.15
8
5.15
116
NULL
NULL
NULL
NULL
NULL
NULL
0
70.01
0
0
NULL
NULL
1229
1.98
58
73
75
2873
1.56
0.376
NULL
1.174
17.3
0
0
NULL
NULL
NULL
0
NULL
0.2
0.157
0.101
0.379
0.132
0.091
29
NULL
0
1.157
5.15
Beans, pinto, mature seeds, canned, drained solids, rinsed in tap water
Legumes and Legume Products
7.04
0.97
20.77
117
NULL
NULL
NULL
NULL
NULL
NULL
0
70
0
0
NULL
NULL
64
1.27
30
96
234
212
0.59
0.26
NULL
0.37
NULL
NULL
NULL
NULL
NULL
NULL
0
NULL
0.1
0.05
0.019
0.262
NULL
NULL
21
NULL
0
NULL
20.77
Beans, small white, mature seeds, cooked, boiled, with salt
Legumes and Legume Products
8.97
0.64
25.81
142
NULL
NULL
NULL
NULL
NULL
NULL
NULL
63.24
NULL
NULL
NULL
10.4
73
2.84
68
169
463
238
1.09
0.149
NULL
0.51
1.3
0
0
NULL
NULL
NULL
0
NULL
0
0.236
0.059
0.272
0.251
0.127
137
NULL
0
0.166
15.41
Beans, pinto, mature seeds, canned, solids and liquids, low sodium
Legumes and Legume Products
4.6
0.56
15.18
82
NULL
NULL
NULL
NULL
NULL
NULL
0
78.19
0
0
1.02
4.6
47
1.47
33
92
276
146
0.56
0.162
NULL
0.318
3.7
0
0
0
0
0.55
0
0
0.7
0.052
0.016
0.268
0.136
0.135
24
20.8
0
0.116
10.58
Beans, yellow, mature seeds, cooked, boiled, with salt
Legumes and Legume Products
9.16
1.08
25.28
144
NULL
NULL
NULL
NULL
NULL
NULL
0
62.98
0
0
0.34
10.4
62
2.48
74
183
325
241
1.06
0.186
NULL
0.455
1.3
2
0
0
0
0.94
0
0
1.8
0.187
0.103
0.708
0.229
0.129
81
35.2
0
0.279
14.88
Beans, white, mature seeds, cooked, boiled, with salt
Legumes and Legume Products
9.73
0.35
25.09
139
NULL
NULL
NULL
NULL
NULL
NULL
NULL
63.08
NULL
NULL
0.34
6.3
90
3.7
63
113
561
242
1.38
0.287
NULL
0.636
1.3
0
0
0
0
0.94
0
0
0
0.118
0.046
0.14
0.229
0.093
81
35.1
0
0.091
18.79
Broadbeans (fava beans), mature seeds, cooked, boiled, with salt
Legumes and Legume Products
7.6
0.4
19.65
110
NULL
NULL
NULL
NULL
NULL
NULL
NULL
71.54
NULL
NULL
1.82
5.4
36
1.5
43
125
268
241
1.01
0.259
NULL
0.421
2.6
15
0
9
0
0.02
0
0
0.3
0.097
0.089
0.711
0.157
0.072
104
30.6
0
0.066
14.25
Chickpeas (garbanzo beans, bengal gram), mature seeds, cooked, boiled, with salt
Legumes and Legume Products
8.86
2.59
27.42
164
NULL
NULL
NULL
NULL
NULL
NULL
NULL
60.21
NULL
NULL
4.8
7.6
49
2.89
48
168
291
243
1.53
0.352
NULL
1.03
3.7
27
0
16
0
0.35
0
0
1.3
0.116
0.063
0.526
0.286
0.139
172
42.8
0
0.269
19.82
Lentils, mature seeds, cooked, boiled, with salt
Legumes and Legume Products
9.02
0.38
19.54
114
NULL
NULL
NULL
NULL
NULL
NULL
NULL
69.64
NULL
NULL
1.8
7.9
19
3.33
36
180
369
238
1.27
0.251
NULL
0.494
2.8
8
0
5
0
0.11
0
0
1.5
0.169
0.073
1.06
0.638
0.178
181
32.7
0
0.053
11.64
Peas, split, mature seeds, cooked, boiled, with salt
Legumes and Legume Products
8.34
0.39
20.51
116
NULL
NULL
NULL
NULL
NULL
NULL
NULL
69.49
NULL
NULL
2.9
8.3
14
1.29
36
99
362
238
1
0.181
NULL
0.396
0.6
7
0
4
0
0.03
0
0
0.4
0.19
0.056
0.89
0.595
0.048
65
32.8
0
0.054
12.21
Lentils, pink or red, raw
Legumes and Legume Products
23.91
2.17
63.1
358
47.62
NULL
NULL
NULL
NULL
NULL
NULL
7.82
NULL
NULL
NULL
10.8
48
7.39
59
294
668
7
3.6
1.303
NULL
1.716
0
58
0
35
0
NULL
0
NULL
1.7
0.51
0.106
1.495
0.348
0.403
204
NULL
0
0.379
52.3
Lentils, raw
Legumes and Legume Products
24.63
1.06
63.35
352
49.9
1.47
0
0.27
0
0.3
0
8.26
0
0
2.03
10.7
35
6.51
47
281
677
6
3.27
0.754
NULL
1.393
0.1
39
0
23
0
0.49
0
0
4.5
0.873
0.211
2.605
2.14
0.54
479
96.4
0
0.154
52.65
Lentils, mature seeds, cooked, boiled, without salt
Legumes and Legume Products
9.02
0.38
20.13
116
NULL
NULL
NULL
NULL
NULL
NULL
0
69.64
0
0
1.8
7.9
19
3.33
36
180
369
2
1.27
0.251
NULL
0.494
2.8
8
0
5
0
0.11
0
0
1.5
0.169
0.073
1.06
0.638
0.178
181
32.7
0
0.053
12.23
Nuts, almond butter, plain, without salt added
Nut and Seed Products
20.96
55.5
18.82
614
0.08
4.34
0.02
0
0
0.07
0
1.64
NULL
NULL
4.43
10.3
347
3.49
279
508
748
7
3.29
0.934
NULL
2.131
2.4
1
0
1
0
24.21
0
1
0
0.041
0.939
3.155
0.318
0.103
53
52.1
0
4.152
8.52
Nuts, almonds, honey roasted, unblanched
Nut and Seed Products
18.17
49.9
27.9
594
NULL
NULL
NULL
NULL
NULL
NULL
NULL
1.7
NULL
NULL
NULL
13.7
263
2.83
240
400
560
130
2.6
0.97
NULL
2.003
NULL
0
0
NULL
NULL
NULL
0
NULL
0.7
0.114
0.953
2.819
0.258
0.085
32
NULL
0
4.73
14.2
Nuts, almonds, dry roasted, with salt added
Nut and Seed Products
20.96
52.54
21.01
598
0.73
4.75
0.01
0.01
0
0.09
0
2.41
0
0
4.86
10.9
268
3.73
279
471
713
498
3.31
1.099
NULL
2.232
2
1
0
1
0
23.9
0
1
0
0.077
1.197
3.637
0.321
0.136
55
52.1
0
4.092
10.11
Nuts, almonds, oil roasted, with salt added
Nut and Seed Products
21.23
55.17
17.68
607
0.56
4.38
0.04
0
0
0.14
0
2.8
0
0
4.55
10.5
291
3.68
274
466
699
339
3.07
0.955
NULL
2.46
4.1
1
0
1
0
25.97
0
1
0
0.092
0.781
3.665
0.229
0.118
27
52.1
0
4.208
7.18
Nuts, almonds, oil roasted, with salt added, smoke flavor
Nut and Seed Products
21.43
55.89
17.86
607
NULL
NULL
NULL
NULL
NULL
NULL
NULL
2.8
NULL
NULL
3.57
10.7
286
3.86
286
NULL
679
548
NULL
NULL
NULL
NULL
NULL
0
NULL
NULL
NULL
25.13
NULL
NULL
0
NULL
NULL
NULL
NULL
NULL
NULL
NULL
0
3.571
7.16
Nuts, almonds, oil roasted, lightly salted
Nut and Seed Products
21.23
55.17
17.68
607
0.56
4.38
0.04
0
0
0.14
0
2.8
0
0
4.55
10.5
291
3.68
274
466
699
143
3.07
0.955
NULL
2.46
4.1
1
NULL
1
0
25.97
NULL
1
0
0.092
0.781
3.665
0.229
0.118
27
52.1
0
4.207
7.18
Nuts, almond butter, plain, with salt added
Nut and Seed Products
20.96
55.5
18.82
614
0.08
6.14
0.02
0
0
0.1
0
1.64
0
0
6.27
10.3
347
3.49
279
508
748
227
3.29
0.934
NULL
2.131
2.4
1
0
1
0
24.21
0
1
0
0.041
0.939
3.155
0.318
0.103
53
52.1
0
6.55
8.52
Nuts, hazelnuts or filberts
Nut and Seed Products
14.95
60.75
16.7
628
0.48
4.2
0.07
0.07
0
0
0
5.31
0
0
4.34
9.7
114
4.7
163
290
680
0
2.45
1.725
NULL
6.175
2.4
20
0
11
3
15.03
0
92
6.3
0.643
0.113
1.8
0.918
0.563
113
45.6
0
4.464
7
Nuts, hazelnuts or filberts, blanched
Nut and Seed Products
13.7
61.15
17
629
0.93
3.35
0.07
0.07
0
0
0
5.79
NULL
NULL
3.49
11
149
3.3
160
310
658
0
2.2
1.6
NULL
12.65
4.1
40
0
23
2
17.5
0
NULL
2
0.475
0.11
1.55
0.815
0.585
78
NULL
0
4.669
6
Nuts, hazelnuts or filberts, dry roasted, without salt added
Nut and Seed Products
15.03
62.4
17.6
646
1.1
4.75
0.07
0.07
0
0
0
2.52
NULL
NULL
4.89
9.4
123
4.38
173
310
755
0
2.5
1.75
NULL
5.55
4.1
61
0
36
1
15.28
0
NULL
3.8
0.338
0.123
2.05
0.923
0.62
88
NULL
0
4.511
8.2
Nuts, walnuts, black, dried
Nut and Seed Products
24.06
59.33
9.58
619
0.24
1
0.05
0.05
0
0
0
4.56
0
0
1.1
6.8
61
3.12
201
513
523
2
3.37
1.36
NULL
3.896
17
40
0
24
0
2.08
0
9
1.7
0.057
0.13
0.47
1.66
0.583
31
32.1
0
3.483
2.78
Nuts, walnuts, english
Nut and Seed Products
15.23
65.21
13.71
654
0.06
2.43
0.08
0.09
0
0
0
4.07
0
0
2.61
6.7
98
2.91
158
346
441
2
3.09
1.586
NULL
3.414
4.9
20
0
12
0
0.7
0
9
1.3
0.341
0.15
1.125
0.57
0.537
98
39.2
0
6.126
7.01
Nuts, walnuts, glazed
Nut and Seed Products
8.28
35.71
47.59
500
NULL
NULL
NULL
NULL
NULL
NULL
NULL
6.28
NULL
NULL
32.14
3.6
71
1.29
NULL
NULL
232
446
NULL
NULL
NULL
NULL
NULL
0
NULL
NULL
NULL
NULL
NULL
NULL
0
NULL
NULL
NULL
NULL
NULL
NULL
NULL
0
3.571
43.99
Nuts, walnuts, dry roasted, with salt added
Nut and Seed Products
14.29
60.71
17.86
643
NULL
NULL
NULL
NULL
NULL
NULL
0
4.39
0
0
3.57
7.1
71
2.57
151
329
459
643
2.98
1.487
NULL
NULL
5
19
0
11
0
0.9
0
8
1.4
0.521
0.298
2.217
NULL
0.526
91
38
0
5.357
10.76
Seeds, sesame seeds, whole, dried
Nut and Seed Products
17.73
49.67
23.45
573
NULL
NULL
NULL
NULL
NULL
NULL
0
4.69
0
0
0.3
11.8
975
14.55
351
629
468
11
7.75
4.082
NULL
2.46
34.4
9
0
5
0
0.25
0
0
0
0.791
0.247
4.515
0.05
0.79
97
25.6
0
6.957
11.65
Seeds, sesame seeds, whole, roasted and toasted
Nut and Seed Products
16.96
48
25.74
565
NULL
NULL
NULL
NULL
NULL
NULL
NULL
3.3
NULL
NULL
NULL
14
989
14.76
356
638
475
11
7.16
2.47
NULL
2.496
34.4
9
0
NULL
NULL
NULL
0
NULL
0
0.803
0.251
4.581
0.051
0.802
98
NULL
0
6.722
11.74
Seeds, sesame seed kernels, toasted, without salt added (decorticated)
Nut and Seed Products
16.96
48
26.04
567
NULL
NULL
NULL
NULL
NULL
NULL
0
5
0
0
0.48
16.9
131
7.78
346
774
406
39
10.23
1.457
NULL
1.427
34.4
66
0
40
0
0.25
0
0
0
1.205
0.466
5.438
0.68
0.146
96
25.6
0
6.722
9.14
Seeds, sesame flour, partially defatted
Nut and Seed Products
40.32
11.89
35.14
382
NULL
NULL
NULL
NULL
NULL
NULL
NULL
6.61
NULL
NULL
NULL
NULL
150
14.3
362
810
425
41
10.7
1.432
NULL
1.403
NULL
69
0
NULL
NULL
NULL
0
NULL
0
2.53
0.27
12.6
2.76
0.152
29
NULL
0
1.634
35.14
Seeds, sesame flour, low-fat
Nut and Seed Products
50.14
1.75
35.51
333
NULL
NULL
NULL
NULL
NULL
NULL
NULL
7.1
NULL
NULL
NULL
NULL
149
14.22
338
757
397
39
10
1.425
NULL
1.396
NULL
64
0
NULL
NULL
NULL
0
NULL
0
2.516
0.269
12.533
2.745
0.142
29
NULL
0
0.201
35.51
Seeds, sesame meal, partially defatted
Nut and Seed Products
16.96
48
26.04
567
NULL
NULL
NULL
NULL
NULL
NULL
NULL
5
NULL
NULL
NULL
NULL
153
14.55
346
774
406
39
10.23
1.457
NULL
1.427
NULL
66
0
NULL
NULL
NULL
0
NULL
0
2.573
0.275
12.816
2.807
0.146
30
NULL
0
6.722
26.04
Nuts, almonds
Nut and Seed Products
21.15
49.93
21.55
579
0.72
3.95
0.17
0.11
0
0.04
0
4.41
0
0
4.35
12.5
269
3.71
270
481
733
1
3.12
1.031
NULL
2.179
4.1
2
0
1
0
25.63
0
1
0
0.205
1.138
3.618
0.471
0.137
44
52.1
0
3.802
9.05
Nuts, almonds, blanched
Nut and Seed Products
21.4
52.52
18.67
590
1
4.46
0.03
0
0
0.14
0
4.51
0
0
4.63
9.9
236
3.28
268
481
659
19
2.97
1.027
NULL
1.835
3.2
7
0
4
0
23.75
0
1
0
0.191
0.711
3.5
0.314
0.115
49
52.1
0
3.953
8.77
Nuts, almonds, dry roasted, without salt added
Nut and Seed Products
20.96
52.54
21.01
598
0.73
4.75
0.01
0.01
0
0.09
0
2.41
0
0
4.86
10.9
268
3.73
279
471
713
3
3.31
1.099
NULL
2.232
2
1
0
1
0
23.9
0
1
0
0.077
1.197
3.637
0.321
0.136
55
52.1
0
4.092
10.11
Nuts, almonds, oil roasted, without salt added
Nut and Seed Products
21.23
55.17
17.68
607
0.56
4.38
0.04
0
0
0.14
0
2.8
0
0
4.55
10.5
291
3.68
274
466
699
1
3.07
0.955
NULL
2.46
4.1
1
0
1
0
25.97
0
1
0
0.092
0.781
3.665
0.229
0.118
27
52.1
0
4.208
7.18
Nuts, almond paste
Nut and Seed Products
9
27.74
47.81
458
NULL
NULL
NULL
NULL
NULL
NULL
0
14.08
0
0
36.25
4.8
172
1.6
130
258
314
9
1.48
0.454
NULL
0.856
4.2
0
0
0
0
13.54
0
1
0.1
0.082
0.414
1.422
0.113
0.036
73
28.5
0
2.629
43.01
Nuts, brazilnuts, dried, unblanched
Nut and Seed Products
14.32
67.1
11.74
659
0.25
2.33
0
0
0
0
0
3.42
0
0
2.33
7.5
160
2.43
376
725
659
3
4.06
1.743
NULL
1.223
1917
0
0
0
0
5.65
0
0
0.7
0.617
0.035
0.295
0.184
0.101
22
28.8
0
16.134
4.24
Lentils, sprouted, cooked, stir-fried, with salt
Vegetables and Vegetable Products
8.8
0.45
21.25
101
NULL
NULL
NULL
NULL
NULL
NULL
NULL
68.7
NULL
NULL
NULL
NULL
14
3.1
35
153
284
246
1.6
0.337
NULL
0.502
0.6
41
0
NULL
NULL
NULL
0
NULL
12.6
0.22
0.09
1.2
0.571
0.164
67
NULL
0
0.053
21.25
Lentils, sprouted, raw
Vegetables and Vegetable Products
8.96
0.55
22.14
106
NULL
NULL
NULL
NULL
NULL
NULL
NULL
67.34
NULL
NULL
NULL
NULL
25
3.21
37
173
322
11
1.51
0.352
NULL
0.506
0.6
45
0
NULL
NULL
NULL
0
NULL
16.5
0.228
0.128
1.128
0.578
0.19
100
NULL
0
0.057
22.14
Lentils, sprouted, cooked, stir-fried, without salt
Vegetables and Vegetable Products
8.8
0.45
21.25
101
NULL
NULL
NULL
NULL
NULL
NULL
NULL
68.7
NULL
NULL
NULL
NULL
14
3.1
35
153
284
10
1.6
0.337
NULL
0.502
0.6
41
0
NULL
NULL
NULL
0
NULL
12.6
0.22
0.09
1.2
0.571
0.164
67
NULL
0
0.053
21.25

6.1. Definition 


Phytate, also known as phytic acid or myo-inositol hexaphosphate (IP6), is another commonly considered “anti-nutrient” widely distributed in amongst the plant kingdom. It primarily serves as storage for plant phosphate, as an energy source, and antioxidant for germinating seeds [180]. Phytate is produced during seed development and can account for 60–90% of total phosphorus content in cereal grains, nuts, seeds, and legumes [181]. Structurally, phytate (IP6) is made up of six phosphate groups, attached to an inositol ring, with the ability to bind up to 12 protons total. These phosphate groups act as strong chelators, readily binding to mineral cations, particularly Cu2+, Ca2+, Zn2+, and Fe3+ [182]. These complexes are insoluble at neutral pH values (6–7), and cannot be digested by human enzymes, thus could decrease mineral bioavailability in high-phytate, homogenous diets [12]. Low-income, developing countries that rely predominantly on grains and legumes as dietary staples are of special concern for zinc deficiency and/or insufficiency [183]. The chelating properties of phytate also allow it to act as an antioxidant, lending possible protective traits [180]. Ensuring an appropriate phytate to mineral ratio minimizes the negative effects of phytate on mineral absorption in vulnerable populations. 


6.2. Background 


Phytate is found in a wide array of plant foods, with the highest concentrations occurring in cereals, legumes, nuts, seeds and pseudocereals [182]. In cereals, phytate is mainly found in the outermost layer, and in legumes is found within the endosperm and cotyledons [180]. Reported daily intake of phytate for vegetarians and other rural inhabitants in developing countries is estimated to be 2000–2600 mg, while mixed diets may contain as low as 650 mg of phytate [184]. Growing methods, seasons, and cultivars can have a significant impact on phytate content [185–187]. Shi et al. reported phytate content in Canadian grown peas, lentils, fava beans, chickpeas, and common beans to be 9.93–12.40 mg/g, 8.56–17.1 mg/g, 19.65–22.85 mg/g, 11.33–14 mg/g and 15.64–18.82 mg/g, respectively. Soybeans contained the highest amount, at 22.91 mg/g [19]. However, Wang and colleagues reported Canadian lentil, chickpea and bean cultivar values to be much less, containing 7.2–11 mg/g, 9.6–10.6 mg/g and 9.9–13.8 mg/g, respectively [188,189]. Split varieties of lentils and peas contain more phytate, since much of the hull is lost during processing [19]. Unprocessed cereals generally have similar phytate value to that of legumes, though processed cereals contain significantly less. For instance, wild rice contains between 12.7 and 21.6 mg/g, but polished rice, only 1.2–3.7 mg/g [184]. Upon processing, phytate content can be significantly reduced in many grains, seeds, and legumes. 


6.3. Effects of Cooking/Processing 


Processing techniques such as soaking, fermentation, sprouting, germinating, and cooking can significantly alter phytate content in grains and legumes, allowing for increased mineral availability (Table 2). Cooking of legumes for 1 h at 95 ◦C resulted in up to a 23% loss in yellow split peas, 20–80% loss in lentils, and 11% loss in chickpeas. Only a marginal reduction of 0.29% was noted in black beans [19]. Utilizing the natural phytases present in cereals and legumes has proven to be a valuable tool in reducing phytate. Phytases are enzymes capable of hydrolyzing phytate. Soaking seeds in fresh water, a traditional preparation method, reduced phytate values in millet, maize, rice, and soybean by 28, 21, 17, and 23%, respectively [190]. No IP6 was found in the soaking water, implying that the phytate was hydrolyzed by endogenous cereal phytases. Although soaking reduced phytate, it also resulted in significant losses of iron and zinc in the soaking water. For this reason, soaking did not lower the phytate/iron ratio, and only had minor impacts on the phytate/zinc ratio [190]. Mineral loss could be partially mitigated by cooking rice in the soaking water, as the seeds will ‘recover’ the leached minerals. Germination of foods can further reduce phytate, as endogenous phytases are activated to free the phosphate from phytate to be used for energy. Germinating chickpeas and pigeon peas reduced phytate concentrations by over 60%, while still preserving mineral content [191,192]. Fermentation, such as the natural leavening of bread, has also been found to significantly reduce phytate. It is elucidated that along with activity of bacterial phytases, lactic acid bacteria activate endogenous cereal phytates by lowering the pH of the dough to ~4–5. Slight acidification with lactic acid produces similar results [193]. Additional research by Castro-Alba et al. demonstrated that inoculation of quinoa, amaranth, and canihua with L. plantarum 299v reduced phytate concentrations by 47–51%, 12–14%, and 25–27%, respectively. Accessibility of iron, zinc and calcium was also increased in the fermented flours [194]. Furthermore, L. plantarum species from supplements (L. plantarum 299v), or from fermented vegetables (L. plantarum spp.), have been found to improve iron bioavailability from high phytate meals [195,196]. In a study performed by Scheers et al., iron absorption increased from 13.6 to 23.6% in the low phytate meal, and 5.2 to 10.4% in the high phytate meal, when eaten alongside fermented vegetables. Zinc absorption changed minimally [195]. The exact mechanism is unknown but may be due to an increase in ferric iron [195,197]. Supporting microbiome health through the consumption of fermentable fibers and other prebiotics also lowers cecal pH values, allowing for an increased solubility of zinc and iron [198–200]. High-phytate foods such as beans are rich in fermentable fibers, which have a beneficial effect on cecal pH by increasing SCFA production [201,202]. This effect may lend insight into the phenomenon of phytate adaption, in which non-heme iron absorption can be partially negated by the consumption of a high-phytate diet [203]. 


6.4. Safety 


As discussed, phytate is viewed as an ‘anti-nutrient’ because it can chelate iron, calcium, and zinc, limiting absorption of these minerals (Table 1). Chelation, however, is dependent on the proportion of phytate to metal ions, as well as pH [204]. The ideal molar ratio of phytate to iron is ~0.4, with an inhibitory effect in ratios above 1. For zinc, ratios higher than 15 may inhibit absorption rates, with optimal ratio of below 5. Calcium absorption has been shown to be impeded by molar ratios above 0.17 [182]. 


6.5. Human Studies 


Many studies support the hypothesis that phytate negatively impacts zinc bioavailability [205,206], however a study on young children, aged 8–50 months, found phytates to not have a discernable effect on zinc absorption [207]. An increase of 500 mg/day of dietary phytate led to less than a 0.04 mg/day reduction in zinc absorption. The largest variance in absorption rates occurred based on age, height and weight [207]. The relationship between dietary phytate and iron bioavailability may be more complex than that of zinc. Even after removal of 90% of IP6 in sorghum flour through phytase treatment, no improvement in iron bioavailability was observed [208]. Removing fiber was found to have a more significant impact on iron absorption, demonstrating an independent effect of fiber in phytate-rich foods. Also, despite higher phytate concentration, animal models have found whole-wheat flour to result in greater iron absorption than refined white flour [209]. Nonetheless, due to phytate’s overall impact on zinc and iron absorption, it is recommended that DRIs be increased for these minerals to account for bioavailability values [210,211]. The addition of complementary foods high in ascorbic acid (vitamin C) may allow consumers enjoy the benefits of phytate-rich foods, while offsetting phytate’s inhibitory effect on mineral absorption [212]. Although phytates are viewed by many in a negative light, they may actually act as beneficial antioxidants by their ability to chelate excess iron, thereby preventing damaging Fenton reactions from taking place [204]. Fenton reactions are oxidative reactions involving iron and hydrogen peroxide, producing hydroxyl radicals and other reactive oxygen species (ROS) [213]. Not only can excess iron contribute to ROS through the Fenton reaction, but research has linked heme-iron to microbial dysbiosis, hyperproliferation of colon cells and altered intestinal barrier function [214]. Since only a small amount of heme is absorbed in the small intestine, up to 90% may reach the colon [214]. When eaten alongside heme-rich foods, phytate acts as ‘nature’s iron regulator’, attenuating possible heme-induced damage. Animal studies have demonstrated a protective role of IP6 against iron-induced lipid peroxidation in the colon [215]. However, human trials validating phytate’s elucidated antioxidant effects are limited. In one randomized cross over trial, Sanchis et al. reported significant reductions (~25%) of advanced glycation end-products (AGEs) in patients with type 2 diabetes mellitus supplemented with 1 g of IP6 [216]. Considering the deleterious effects AGEs have on microvascular and macrovascular function in type 2 diabetes (T2DM), dietary phytates could be promising tools in the treatment of T2DM. Phytate may also possess other beneficial effects, yet much of this research is still in its infancy. The mechanisms of action of IP6 include enhanced immunity, inhibition of inflammatory, cytokines, caspase modification, regulation of phase I and II enzymes, and decreased cell proliferation [180,215]. IP6 has also been shown to decrease kidney stone risk [217], dental calculi [218], osteoporosis risk [219], and help prevent age-related cardiovascular calcification [220,221]. Furthermore, adequate consumption of phytate-rich foods was found to prevent abdominal aortic calcification in patients with chronic kidney disease [180,222]. Future research is needed to identify the exact physiological mechanisms behind phytate, but research thus far supports the inclusion of phytate-rich foods into a balanced diet. 


6.6. Conclusions 


Since its discovery, the role of phytate in human nutrition has been a controversial topic. On one hand, phytate may decrease the bioavailability of essential minerals, while on the other hand, acts as a potent antioxidant. Phytates should not significantly impair mineral status when included as part of a diverse and balanced diet, especially if using traditional processing methods such as soaking, germinating, fermenting, and cooking. Consuming complementary foods rich in ascorbic acid and certain probiotic bacteria could also have beneficial impacts on mineral absorption from high-phytate meals. Overall, by consuming a colorful, plant-based diet, the benefits of phytate containing foods to human health exceed the impacts on mineral absorption.