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(Looking at the Science on Raw vs. Cooked Foods--continued, Part 2G)
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Effects of cooking on minerals
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Since heating itself does not affect mineral levels, other factors in the diet have more bearing. Here, we shall compare the mineral content between raw and cooked foods. Though minerals are not lost due to heat, but are usually leached if cooked in boiling water, steaming is probably the best cooking method with respect to mineral loss. Otherwise, heating doesn't destroy minerals.
Since minerals remain better preserved than vitamins (especially if steaming is used instead of boiling), other factors than cooking, such as variety in the diet and (perhaps) soil mineralization and fertilization, are more important in ensuring adequate mineral intake.
Again, the table below represents mineral content but not bioavailability: some antinutritional factors in plants must be taken into account in this regard, such as phytates (which are present in unsprouted grains) and oxalates (present in spinach and rhubarb). Another example is iron, which is more available in heme form (as in red meat) than in non-heme form (in plants).
MINERAL LEVELS IN RAW VS. COOKED FOODS
(uncorrected for water loss)
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(Note: Amounts are expressed in units per 100g portion of food.
In the table below, "boiled" = boiled, drained, without salt.)
Food
|
Water Content
|
Mineral Assay (all amounts = mg)
|
Ca
|
Fe
|
Mg
|
P
|
K
|
Na
|
Zn
|
Cu
|
Mn
|
Broccoli, raw |
91%
|
48
|
.88
|
25
|
66
|
320
|
27
|
.40
|
.045
|
.23
|
Broccoli, boiled |
91%
|
46
|
.84
|
24
|
59
|
290
|
26
|
.38
|
.043
|
.22
|
Beef liver, raw |
69%
|
6
|
6.8
|
19
|
320
|
320
|
73
|
3.9
|
3.3
|
.26
|
Beef liver, braised |
66%
|
7
|
6.8
|
20
|
400
|
230
|
70
|
6.1
|
4.5
|
.41
|
Beef liver, pan-fried |
56%
|
11
|
6.3
|
23
|
460
|
360
|
110
|
5.4
|
4.5
|
.42
|
Carrots, raw |
88%
|
27
|
.50
|
15
|
44
|
320
|
35
|
.20
|
.047
|
.14
|
Carrots, boiled |
87%
|
31
|
.62
|
13
|
30
|
230
|
66
|
.30
|
.13
|
.75
|
Almonds, dried |
4%
|
270
|
3.7
|
290
|
520
|
730
|
11
|
2.9
|
.94
|
2.3
|
Almonds, dry roasted |
3%
|
280
|
3.8
|
300
|
550
|
770
|
11
|
4.9
|
1.2
|
2.0
|
Mung bean sprouts, raw |
90%
|
13
|
.91
|
21
|
54
|
150
|
6
|
.41
|
.16
|
.19
|
Mung bean sprouts, boiled |
94%
|
12
|
.65
|
14
|
28
|
101
|
10
|
.47
|
.12
|
.14
|
Tomatoes, red, raw |
94%
|
5
|
.45
|
11
|
24
|
220
|
6
|
.09
|
.074
|
.10
|
Tomatoes, boiled |
92%
|
6
|
.56
|
14
|
31
|
280
|
11
|
.11
|
.093
|
.13
|
Mackerel, Atlantic, raw |
63%
|
12
|
1.6
|
76
|
220
|
310
|
90
|
.63
|
.073
|
.01
|
Mackerel, cooked, dry heat |
53%
|
15
|
1.6
|
97
|
280
|
400
|
83
|
.94
|
.090
|
.02
|
We can note in the above table that in a number of cases the values for minerals are higher in the cooked food than when raw (even allowing for differences due to water loss). As with the earlier table on vitamins, some inconsistencies in this regard are unavoidable, since different varieties of a food may have differing mineral contents, and differing samples may have been used. Since one would not expect cooking to increase mineral content (obviously impossible), we can safely assume that such differences are due to such variation in the food samples measured. This in itself is quite interesting, however, for the following reason.
Mineral losses from cooking are so low that they are overshadowed by background variation in nutrient samples. Whatever actual differences there may be between raw and cooked foods with respect to minerals, the data available here shows that in many cases they are simply not significant enough to be clearly distinguishable against the background level of variation and sampling error that normally exists between food samples. It appears, then, that mineral content of a food is probably more variable from sample to sample (according to season, horticultural practice, climate, soil, etc.) than whether or not it is cooked or raw. Hence, we see that under close examination, the alleged huge differences between raw and cooked foods--with respect to minerals, at least--are not in evidence.
GO TO NEXT PART OF ARTICLE
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(Does Cooking Render Minerals "Inorganic" or Less Assimilable?)
Return to beginning of article
SEE REFERENCE LIST
SEE TABLE OF CONTENTS FOR: PART 1 PART 2 PART 3
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GO TO PART 1 - Is Cooked Food "Toxic"?
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GO TO PART 2 - Does Cooked Food Contain Less Nutrition?
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GO TO PART 3 - Discussion: 100% Raw vs. Predominantly Raw
Back to Research-Based Appraisals of Alternative Diet Lore