I came across this article in the newspaper a few days ago about the dangers of excess beta-carotene.
I eat large amounts sweet potatoes and carrots to full my exercise, should I be concerned?
I'm going to have to look into this more, try to find what studies they're basing their conclusions on. It was my understanding that the cancer-causing beta-carotene was the one found in vitamins, NOT whole foods. This paragraph from the article seems to support my recollection: "The findings also might explain why, in a decades-old clinical trial, more people who were heavily *supplemented* with beta-carotene ended up with lung cancer than did research participants who took no beta-carotene at all. The trial was ended early because of that unexpected outcome."
In fact, the researchers aren't really talking about the effects of beta-carotene in whole foods. And it appears the whole purpose of their study is to understand why the artificial beta-carotene in the test on male smokers and asbestos workers created a higher incidence of lung cancer. So they can genetically engineer crops with increased beta-carotene for populations who are lacking vitamin A in their diets.
What I take away from this article is that the beta-carotene in our carrots and sweet potatoes is in no way the same as the beta-carotene used in the study that caused an increase in lung cancer. There is a danger when we isolate vitamins and minerals from the whole foods they came from because, as the researchers themselves stated, we don't fully understand how all the properties in a whole food work together to make it nourishing.
I remember reading somewhere this might be due to B12 deficiency and that B12 was indeed recommended so that beta-carotene is used in a good way.
So the question is, if you do have adequate amount of B12 (dairy has plenty), is it ok to consume beta-carotene (carrots and sweet potatoes)?
The question this raised for me, is if these caratenoids have anti-A activity.. perhaps the negative effect observed is from people with already minimal vitamin A (retinol) in their diet getting even worse activity.
I consume alot of carotene from sweet potato and pumpkin (~1kg a day) and this has been a good reminder to diversify my starch sources. My retinol status is quite good though (alot of liver in particular) and with some hope outweighed the negative effect on vitamin A produced by the caratenoids.
My first course of action is less sweet potato and more pumpkin.. while I look for some whiter starches (or purple :D ).
Looks like I have to look for another source of carbs. I was consuming 3-4 pounds of sweet potatoes daily as well as carrots and a lot of leafy greens. This just goes to show the superiority of animal products.
here's a comment i found under another article on the same research http://www.nutraingredients.com/Research/Researchers-reveal-dark-side-to-high-beta-carotene-intake
The "shockwaves" referred to over a dated trial which used synthetic beta-carotene on already sick people (smokers) simply illustrate that old myths die hard. There is no evidence that the intake of natural mixed carotenes is in any way harmful.
And as for the current supposedly negative findings (if verified) would it not be a more reasonable view that such molecules are simply a self-limiting factor placed in foods by a wise Creator? In this way a possible oversupply of Vitamin A in the body is prevented. It explains the well-known fact that a high intake of natural mixed carotenes results only in health benefits. Because the above seems self-evident, one needs to ask the following question.
Is this report (as presented) just another attempt by vested interests to tarnish everything natural and to promote their own agenda?
Comment by Edward Jackson
Good timing on the study.
I was just eating a ton of carrots and sweet potatoes the last few months. I am now slowing down, stopping carrots completely.
Ran into skin problems, but they might have been due to other things like stress.
I am now decreasing my beta carotene consumption and increasing my retinol consumption.
I would have assumed that artificial supplementation was the only way to take in harmful amounts, but the amounts of carrot/sweet potato mentioned above make me wonder.
Polar bear and beaver liver are not eaten because their vitamin a content is so hight as to be potentially lethal.
Check the nutritional info on the vegetables in question, perhaps here: http://ndb.nal.usda.gov/ and adjust your consumption accordingly.
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