Continuing the discussion from [[Official] Introducing Soylent 1.1], in reply to @Tark 's criticism of canola oil (http://discourse.soylent.me/t/official-introducing-soylent-1-1/17138/115):
[quote=“Tark, post:115, topic:17138, full:true”]
It is about the gamma tocopherol kind of vit E which canola oil has, not the alpha tocopherol kind found in other oils.[/quote]
That isn’t a study, it’s an article published by University Relations. According to the link in the article, it refers to this study:
Isoforms of vitamin E differentially regulate inflammation and lung function (P5136)
Yes, the study is about alpha-tocopherol versus gamma-tocopherol. Vitamin E refers to ten different compounds; alpha and gamma are most common in diets. The body gets rid of most of the gamma, and the alpha is what’s primarily in our blood and tissues.
Vitamin E refers to a group of ten lipid-soluble compounds that include both tocopherols and tocotrienols.1 Of the many different forms of vitamin E, γ-tocopherol is the most common in the North American diet. γ-Tocopherol can be found in corn oil, soybean oil, margarine, and dressings. α-tocopherol, the most biologically active form of vitamin E, is the second-most common form of vitamin E in the diet.
The author of the Northwestern study has worked long and hard on a many studies illustrating how and why alpha tocopherol is beneficial, while gamma is damaging. This study does a good job of clearly connecting blood levels of gamma with breathing problems in humans. The author previous detailed a potential mechanism of the damaging effect in other studies.
Importantly, the study is not dedicated to determining exactly how much of what oils are safe and/or what consumption leads to particular blood levels of gamma.
The Northwestern study does not, in fact, call out canola oil, it calls out soy oil:
These differences in serum γ-tocopherol are consistent
with European diets rich in olive oil, which is low in γ-
tocopherol, and American diets rich in soy oil, which is
high in γ-tocopherol 1.
A tablespoon of soy oil has 1.1mg of alpha, but 8.7 mg of gamma.
A tablespoon of corn oil has 1.9 alpha and 8.2 gamma.
Both of these oils, very common in North America, are rather high in gamma, and may be the reason we have higher blood levels. (Again, this study was not about determining what leads to those blood levels).
Compared to soy and corn oils, canola is an “also-ran;” one tablespoon has 2.4 mg alpha and 3.8 mg gamma.
In contrast, a tablespoon of olive oil has 1.9 alpha and .1 gamma; it provides less good E than canola, but provides a lot less of the bad E. Sunflower oil has 5.6 alpha and .7 gamma.
But the type of vitamin E is just one consideration for which oils are healthier; olive looks better than canola on gamma tocopherol, but canola looks better than olive on other factors. Regardless, canola is not in the same class as corn and soy.
Importantly, the canola oil in Soylent is not the sole source of Vitamin E. The formula is directly supplemented with dl-alpha-tocopherol, and the amount of additional Vitamin E they add is greater than the amount in the canola oil. In the end, the ratio of alpha to gamma in Soylent is much higher than what you find in canola oil.
So the total vitamin E in Soylent is much higher in alpha tocopherol than gamma tocopherol, unlike the typical North American diet, which is higher in gamma than alpha (per Wikipedia reference above.)
In my opinion, the more important complaint to make about Vitamin E in Soylent is about the amount and type Rosa Labs uses to supplement.
They only supplement to 100% of the DV of Vitamin E, which is 30 IU. There is considerable academic discussion around Vitamin E levels; the RDA and DV are closer to “avoid deficiency disease” levels than to “maintain best health” levels, according to recent research, even after the RDA was raised in 2000.
What’s more, they are supplementing with dl-alpha-tocopherol, a version of Vitamin E which is less bioavailable than d-alpha-tocopherol. Naturally occurring Vitamin E is d-alpha; dl-alpha is a synthentically produced form which is not bio-identical.
What’s important is the amount of RRR-alpha-tocopherol in the blood, and dl-alpha gets substantially less into the blood than the natural d-alpha form:
RRR-alpha-tocopherol (natural or d-alpha-tocopherol):
IU x 0.67 = mg RRR-alpha-tocopherol.
Example: 100 IU = 67 mg
(100 IU of natural vitamin E provides 67 mg of RRR-alpha-tocopherol)
all-rac-alpha-tocopherol (synthetic or dl-alpha-tocopherol):
IU x 0.45 = mg RRR-alpha-tocopherol.
Example: 100 IU = 45 mg
(100 IU of synthetic vitamin E provides 45 mg of RRR-alpha-tocopherol)
In my opinion, if you’re only going to supplement up to the minimum, you should at least use the most bioavailable form.
I, personally, take supplements which provide a lot more alpha, and it’s in the form d-alpha-tocopherol, which good supplements use. A brief glance shows that even most ‘cheap’ multivitamins use d-alpha tocopherol.