Saturday, January 17, 2009

On the Mythical Properties of Coconut Oil

My dear wife has the book, Eat Fat, Lose Fat, by nutritionist Mary Eng and Sally Fallon. This book advocates oil-centric diets with scientific-seeming arguments about the benefits of coconut oil. It reads like faddish pseudoscience to me, although I think it is well established that Atkin's like high fat diets do lead to weight loss -- although at the expense other negative health effects.

Coconut oil, while a saturated fat, is made from shorter chain fatty acids, and it is more easily metabolized by the liver than longer fatty acids, most especially palmitic or oleic.

I think that the widespread negative opinion of coconut oil was informed by data like the fatty acid source table at the bottom of this post. That table that lumped all saturated acids shorter than C-16 together. That table certainly makes coconut oil seem awful. Learning that there are more medium length oils reopens the topic.

There is a very sensible article on coconut oil by Craig Hassel on the University of Minnesota website. He addresses the coconut oil fad, and concludes that it is not as bad as people thought a decade ago. While coconut oil contains 60% medium fatty acids of C-12 or less, it also contains 40% palmitic and myristic acids which are known to increase blood cholesterol. His point about the health effect of coconut oil, that it depends the other food which coconut oil displaced in the diet. If one replaces butterfat with coconut oil, great. If one replaces olive oil, then the effect on cholesterol will be negative.

This conclusion avoids the discussion of the secondary medical benefits of the acids, most specifically caprylic and lauric. I need to read up on that further. Caprylic is only present at 12% though. My intuition is that caprylic acid may be more medicinal than other fatty acids, and that it should be used with care: in controlled amounts.


Source:

Table of Fatty Acids
Acid
Name
Structure
Melt
Point
Graphic Chime
SATURATED
Lauric CH3(CH2)10COOH
+44
Graphic Chime
Palmitic CH3(CH2)14COOH
+63
. Chime
Stearic CH3(CH2)16COOH
+70
Graphic Chime
UNSATURATED
Oleic CH3(CH2)7CH=CH(CH2)7COOH
+16
Graphic Chime
Linoleic CH3(CH2)4(CH=CHCH2)2(CH2)6COOH
-5
Graphic Chime
Linolenic CH3CH2(CH=CHCH2)3(CH2)6COOH
-11

Chime
Arachi-
donic
CH3(CH2)4(CH=CHCH2)4(CH2)2COOH
-50
Graphic Chime

Data from: http://www.elmhurst.edu/~chm/vchembook/551fattyacids.html

Below is an even better table:








































.
fatty acid percentage in oil
Seeds
Polyunsaturated
Monounsaturated
Saturated
Name
Fat Content in seed

(%)

LNA

18:3w3

(%)

LA

18:2w6

(%)

LNA+LA

w3+w6

(%)

18:1w9

(%)

18:0

(%)

16:0

(%)

Total

(%)

hemp
35
20
60*
80
12
2
6
8
chia
30
30
40
70
-
-
-
-
kukui
30
29
40
69
-
-
-
-
flax
35
58
14
72
19
4
5
9
pumpkin
46.7
0-15
42-57
57
34
0
9
9
soybean
17.7
7
50
57
26
6
9
15
walnut
60
5
51
56
28
5
11
16
wheat germ
10.9
5
50
55
25
18
0
18
evening primrose
17
-
81**
81
11
2
6
8
safflower
59.5
-
75
75
13
12
-
12
sunflower
47.3
-
65
65
23
12
-
12
grape
20
-
71
71
17
12
-
12
corn
4
-
59
59
24
17
-
17
sesame
49.1
-
45
45
42
13
-
13
rice bran
10
1
35
36
48
17
-
17
cottonseed
40
-
50
50
21
25
-
25
rape(canola)
30
7
30
37
54***
7
-
7
peanut
47.5
-
29
29
47
18
-
18
almond
54.2
-
17
17
78
5
-
5
olive
20
-
8
8
75
16
-
16
avocado
12
-
10
10
70
20
-
20
coconut
35.3
-
3
3
6
0
91
91
palm kernel
35.3
-
2
2
13
0
85
85
beech
50
-
32
32
54
8
-
8
brazil
66.9
-
24
24
48
24
-
24
pecan
71.2
-
20
20
63
7
-
7
pistachio
53.7
-
19
19
65
9
-
9
hickory
68.7
-
17
17
68
9
-
9
filbert
62.4
-
16
16
54
5
-
5
macadamia
71.6
-
10
10
71
12
-
12
cashew
41.7
-
6
6
70
18
-
18
neem
40
1
20
21
41
20
-
20









* Includes up to 2% GLA - Gamma Linolenic Acid

** Includes 9% GLA

*** Includes up to 5%erucic acid


* Includes up to 2% GLA -
Gamma Linolenic Acid

** Includes 9% GLA

*** Includes up to 5%erucic acid