On reading a page dedicated to vegans

[Cloud]

Hello all, 

yesterday I was reading this page http://rawfoodsos.com/for-vegans/ , and two points appear especially important to me: 

• <<3. Secure a source of vitamin K2, pronto>>
• and also this other paragraph: <<Keep in mind that it’s not what you eat—it’s what you absorb (or convert). Some diet-scrupulous vegans use programs like Cron-o-Meter to track their nutrient intake and ensure they’re hitting the RDA for vitamins, minerals, and amino acids. Unfortunately, these programs don’t distinguish between vitamin K1 or K2, don’t have RDAs set for nonessential amino acids like taurine, usually record beta carotene as “vitamin A” and don’t adjust for its abysmally low absorption rate...>>

 

what do you think about them? thanks!

[Dean Pomerleau]

Regarding K2, I believe it is important for bone health, not just for vegans. I eat 5g of natto per day (see [1]), which I purchase (frozen) at my local asian market. I also take one of these K2 supplement capsules every couple days.

 

I also agree that absorption is very important and can be an issue, particularly for people who depend on plant-based sources of minerals, esp iron. For example, in the past, despite CRON-o-meter telling me I get more than adequate iron from my diet (several hundred percent of the RDI), I've become anemic, and therefore have supplemented with additional iron (as ferrous sulfate) for many years now in order to keep my hemoglobin and ferritin at the low end of their reference ranges (12-13 g/dL and ~30 ng/ml, respectively), while allowing me to regularly donate blood.

 

--Dean

 

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[1] J Bone Miner Metab. 2000;18(4):216-22.

Intake of fermented soybean (natto) increases circulating vitamin K2
(menaquinone-7) and gamma-carboxylated osteocalcin concentration in normal
individuals.

Tsukamoto Y(1), Ichise H, Kakuda H, Yamaguchi M.

Author information:
(1)Central Research Institute, Mitsukan Group Co., Ltd., Aichi, Japan.

Changes in circulating vitamin K2 (menaquinone-7, MK-7) and gamma-carboxylated
osteocalcin concentrations in normal individuals with the intake of fermented
soybeans (natto) were investigated. Eight male volunteers were given sequentially
fermented soybeans (natto) containing three different contents of MK-7 at an
interval of 7 days as follows: regular natto including 775 micrograms/100 g (MK-7
x 1) or reinforced natto containing 1298 micrograms/100 g (MK-7 x 1.5) or 1765
micrograms/100 g (MK-7 x 2). Subsequently, it was found that serum MK-7 and
gamma-carboxylated osteocalcin concentrations were significantly elevated
following the start of dietary intake of MK-7 (1298 or 1765 micrograms/100 g).
Serum undercarboxylated osteocalcin concentrations were significantly decreased
by dietary MK-7 (1765 micrograms/100 g) supplementation. Moreover, the changes in
serum MK-7 level with the frequency of dietary natto intake were examined in 134
healthy adults (85 men and 39 women) without and with occasional (a few times per
month), and frequent (a few times per week) dietary intake of regular natto
including MK-7 (775 micrograms/100 g). Serum MK-7 and gamma-carboxylated
osteocalcin concentrations in men with the occasional or frequent dietary intake
of natto were significantly higher than those without any intake. The present
study suggests that intake of fermented soybean (natto) increases serum levels of
MK-7 and gamma-carboxylated osteocalcin in normal individuals.

PMID: 10874601

[Michael R]

Hello all,

yesterday I was reading this page http://rawfoodsos.com/for-vegans/ , and two points appear especially important to me:

 

<<3. Secure a source of vitamin K2, pronto>>

I generally agree, though (a) the author overstates the confidence we can have about a distinctive role for K2 at normal dietary doses, and (b) there are far higher priorities for most vegans (such as making sure that they get enough B12 and omega-3 fatty acids).

 

Keep in mind that it’s not what you eat—it’s what you absorb (or convert). Some diet-scrupulous vegans use programs like Cron-o-Meter ... Unfortunately, these programs don’t distinguish between vitamin K1 or K2,

True. There is very little data available on food sources of K2, and all of it is from small sample size. However, as a vegan there's really only one food source available anyway (natto), so you don't need nutrition software to know whether you're getting any given amount or not.

 

don’t have RDAs set for nonessential amino acids like taurine,

By definition, you can't have an RDA for a nonessential nutrient ;) . In any case, more or less the same considerations just outlined for K2 apply for taurine: if you're interested in exogenous taurine at a level within even an order of magnitude of a typical omnivorous diet, you're going to need a supplement. See this discussion of taurine for vegans.

 

usually record beta carotene as “vitamin A”

COM has both beta-carotene and (total) vitamin A.

 

and don’t adjust for its abysmally low absorption rate...>>

Actually, to the extent that one can adjust for this, it's already factored in. However, it is true that the extent to which one can adjust for it is very limited: it depends on "food matrix, food processing, dosage, fat in the meal [including avocado fat and fat replacers such as sucrose polyesters (SPE)], other carotenoids in the meal, and dietary fiber" (more) and "Conversion efficiency depends at least in part on the individual’s vitamin A status, BMI, and comorbidities [and] Genetic factors" (more). Most CR people eat such enormous quantities of b-c that I don't think it's plausible that anyone without a crippling mutation in one of these pathways (one of which, eg, gives one carotenemia at normal dietary intake of carotenoids) is going to be deficient. An expert consensus conference on beta-carotene requirements  "organized by the Institute of Biological Chemistry and Nutrition, University of Hohenheim, Stuttgart, and was cosponsored by DSM Nutritional Products Ltd" (who, amongst other things, sell beta-carotene raw material for supplements) concluded that "7 mg/d [of beta-carotene would be adequate] to ensure that at least 95% of the population consumes the recommended intake of total vitamin A. Individuals with reduced conversion efficiencies due to a genetic variability in β-carotene metabolism might need to increase their daily β-carotene or preformed vitamin A intake. However, much more research is needed to define new recommended intake levels if the large inter-individual variation in β-carotene conversion efficiency is taken into account."