Tuesday, May 25, 2010

"The dose is the poison"

Yes it always possible to eat too much of a good thing. A case report in this week's New England Journal of Medicine and reported in today's New York Times mirrors a question I recently received on this blog about the safety of consumption of raw Brassica vegetables related to thyroid gland dysfunction.

Even before this incidence was reported, I have already been making inquiries into the medical literature and to three researchers I know that have extensive knowledge of the effect of Brassica vegetables (raw and cooked) in humans to try to sort out "myth from reality" about the recommendations on various websites to not eat any raw Brassica vegetables due to possible suppression of thyroid function.

I am relying on the guidance from these 3 researchers (and those to whom they refer me for even more information) to try to come up with a "bottom line" recommendation regarding how much raw and fermented Brassica consumption is indeed both safe and/or beneficial that is based on evidence (in addition to taking into consideration, but by no means relying exclusively, on how someone's mother traditionally cooked and ate and felt in the "old country").

Stay tuned, but in the meantime, please don't eat 2-3 #'s of anything for months on end, raw or cooked. I remember the early hey-day of "soy is a wonder food" when I routinely was contacted by people trying to eat a pound of tofu a day or drink a liter of soy milk daily. Gosh, how boring, boring, boring let alone remembering that no population has a healthy dietary pattern of such rigidity and exclusion of so many other foods.

I'm sorry, I know it's not very "sexy", but I will predict that the bottom line will be variety, variety, variety of types, amounts, and ways of production (raw, cooked, fermented). As I said, stay tuned!

Where kale is still more than decoration on my plate but I have NEVER eaten 1# of kale (let alone 2-3#!), raw or cooked, on any one day in my life and nor would I ever professionally recommend doing so! :-)

Diana Dyer, MS, RD


TeacherPatti said...

I was about to say that I never ate a pound of anything but then I remembered that a pound is just 2 cups worth of stuff and I have most certainly, on many occasions, drank a pound or more of beer. A pint is a pound the whole world round! :)

Diana Dyer said...

True, true 2 cups of a liquid (but not kale!) is ~1#, and I also have consumed a pound of beer (once I discovered tasty micro-brews), but again, the dose is the poison here, too. :-)

Kateri said...

That was interesting. When I was growing up, my mom would always add a sprinkle of kelp powder to raw cabbage salad--which was supposed to help protect the thyroid. I eat by the motto, "lots of variety and everything in moderation."

Roasted Garlicious said...

i LOVE brassicas..... i hope it's not true.. but then again i don't eat a pound a day either... the brassicas love my garden.. this year i got a ton of volunteer brassica babies.. umm could be cauliflower or broccoli.. and every year for the past few years the Kale has over wintered and seeded it's little heart out.. can't be all bad :D

Tree Collards said...

What did you ever determine on this subject?
Thanks for all the great info on your Blog.

Diana Dyer said...

HI Tree Collards!
Thanks for stopping by. I made more comments on this subject at this post: http://www.365daysofkale.com/2011/05/article-food-omnivores-and-vegetarians.html

Come by again!

Nicole said...

Hi Diana

I am looking to do some research involving kale (juiced) and wondered if you had any more insight on what is 'too much'.
Each of my participants will consume 100mL (approx 1 bunch) of kale, 3 times a week for 3 weeks. Is this safe? What are possible negative side effects of too much?

Thank you!

Diana Dyer said...

Thanks for visiting my kale blog. You have asked a very good question, however I am sorry I cannot give you a 'professional' response to your question. I do not know the objective of your research, or if your research needs approval by an IRB (institutional review board). My recommendation is to seek the guidance of those scientists who are doing Brassica research on human subjects. You will easily find who the names of those people (their contact info is often listed) by reading throughout the scientific literature already published on PubMed.

That is the best professional advice I can give you.
Diana Dyer, MS, RD