After reading about natto, I expected it to be a horrendous food that I'd be able to choke down once a week at best, but I had some earlier and found it to be completely inoffensive. I'm now thinking about eating it every day, but I wonder if it would be too much K2 at that point. I'm consuming a lot of K1 every day via 2 cups of lightly steamed spinach and a stalk of steamed broccoli, so I'm not sure if some kind of clotting issue could arise as a result of too much total vitamin K.
I suspect that it is not at all out of the realm of possibility that a Japanese person could eat a serving of it every day (along with plenty of K1 as well), and it seems that they would have made the association if people were dropping dead.
I wouldn't worry about getting too much K2 out of natto, I would rather worry about the phytoestrogens and lectins in the soy as well as its goitrogenic properties. Even though it's fermented, some nasties are just very hard to eliminate completely.
Here is an interesting bit: http://blog.cholesterol-and-health.com/2010/10/fermentation-does-not-neutrailize.html
K2 doesn't play any part in the blood clotting properties of K1, so don't worry about total vit. K consumption.
Here is a lengthy, but really interesting article on K2, also by Chris Masterjohn: http://www.westonaprice.org/abcs-of-nutrition/175-x-factor-is-vitamin-k2.html
I suppose that's a good point. I wonder if 50g a day would do more harm than good. Seems like the broccoli could mitigate the phytoestrogens and the lectins should be largely diminished by the fermentation. I take fairly substantial doses of iodine from eating Laminaria digitata a few times a week, so a goiter is nigh on impossible.
According to that article, K1 maxes out at about 200µg, so the 1600µg that I take in stops being relevant at that point. And, as you said, it doesn't have a synergistic effect with K2.
Overall, I think I'll have 1 serving a day and see how things go. It's not out of the ordinary for me to eat a couple dozen eggs in a week and I love hard cheese and chicken liver, so I am already getting a fair amount of K2, but I think this boost could be beneficial.
Thanks for the help.
P.S. I had some this morning for breakfast and I will say that it is a food best served for dinner. I read that the smell was like ammonia, but I find it to be more reminiscent of coffee or chocolate or something along those lines, but the texture is not something you want to wake up to.
Natto is high in nutrients and seems to have a lot of health benefits; I first heard about it in Tim Ferris' "4-Hour Body," and I want to try it sometime soon. However, I won't be eating it more than once a week. Why? I'm not so concerned about estrogen and such, but according to the USDA database, 1 cup of natto has almost 10mg Omega-6 (PUFA is 2/3 total fat). If you're eating natto regularly, it'll really mess up your 3/6 ratios.
I love natto so much I was eating it every day.
Natto has a good amount of iron. I was eating alot of red meat and natto everyday for a couple of months was throwing off my body. When I cut back on the natto, my symptoms went away. At one point I think I was getting too much iron which can be toxic and damaging to vital organs.
The soy content was messing up my hormones also. I was having quicker menstrual cycle and bleeding alot. Very unusual for me. My cycle has been alot less last exaggerated but not back to normal.
This was just my experience and everyone will respond differently.
I listened to an interview by a dr. who did some great research on vitamin K and she said there were not any toxicity concerns for too much K. Whatever anyone's opinion on Dr. Mercola, the interview with the dr who wrote of Vit. K is on his site. Check it out and make your own opinion.
Btw, would you share how you're eating your natto? Soy sauce, mustard? I'm eager to try it but would like some tested ways to eat it. Thanks :)
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