Active Low-Carber Forums
Atkins diet and low carb discussion provided free for information only, not as medical advice.
Home Plans Tips Recipes Tools Stories Studies Products
Active Low-Carber Forums
A sugar-free zone


Welcome to the Active Low-Carber Forums.
Support for Atkins diet, Protein Power, Neanderthin (Paleo Diet), CAD/CALP, Dr. Bernstein Diabetes Solution and any other healthy low-carb diet or plan, all are welcome in our lowcarb community. Forget starvation and fad diets -- join the healthy eating crowd! You may register by clicking here, it's free!

Go Back   Active Low-Carber Forums > Main Low-Carb Diets Forums & Support > Low Carb Health & Technical Forums > Nutrition & Supplements
User Name
Password
FAQ Members Calendar Mark Forums Read Search Gallery My P.L.A.N. Survey


Reply
 
Thread Tools Display Modes
  #1   ^
Old Thu, Jun-14-01, 20:14
tamarian's Avatar
tamarian tamarian is offline
Forum Founder
Posts: 19,570
 
Plan: Atkins/PP/BFL
Stats: 400/223/200 Male 5 ft 11
BF:37%/17%/12%
Progress: 89%
Location: Ottawa, ON
Default Vitamin C?

Thursday June 14 6:06 PM ET

Lab Study Finds Vitamin C Dangers

By PAUL RECER, AP Science Writer

WASHINGTON (AP) - The vitamin C pills taken by millions of health-conscious Americans may actually help produce toxins that can damage their DNA, a step toward forming cancer cells, a laboratory study suggests.

In a study appearing Friday in the journal Science, University of Pennsylvania researchers said they found in test tube experiments analyzing the action of vitamin C that the nutrient can act as a catalyst to help make a toxin that can injure DNA, the body's genetic code.

The findings do not mean that vitamin C causes cancer, said Ian A. Blair, lead author of the study, but the research does sound a warning about the use of vitamin C pills.

``Vitamin C can do some good things, but it can do some bad things as well,'' Blair said. ``If you really wanted to be cautious, you just wouldn't use supplementation (vitamin pills.)''

Instead of pills, Blair said people can get all the nutrients they need through a balanced diet, particularly fruits, vegetables and grains.

Balz Frei, a professor at the Linus Pauling Institute at Oregon State University, said the Blair study ``is an important finding in understanding the chemistry of vitamin C.'' He cautioned that the results come from a test tube study, which involves chemicals in glass lab dishes, and that the same action may not occur in living animals.

In the study, Blair and his colleagues analyzed the effects of vitamin C on lipid hydroperoxide, a compound produced in the body from fat in the diet. Lipid hydroperoxide can be converted in the cell into agents, called genotoxins, that can damage DNA.

Blair said his group found that vitamin C was highly efficient in converting lipid hydroperoxide into the gene-damaging toxins.

``Just because you damage DNA doesn't mean you'll get cancer,'' Blair said. ``The cell has an exquisite repair mechanism for lesions in the DNA.''

Blair said the research may explain the failure of studies that have attempted to show vitamin C can protect against cancer.

``There are two camps - people who think vitamin C supplementation is good for you and those who think it is bad for you,'' he said. ``There is a paucity of any scientific evidence that it is really good for you.''

Vitamin C supplementation includes not just pills, but also the addition of artificial forms of the nutrient to foods, such as juices, cereals and even candies.

The popularity among health-conscious Americans for popping vitamin C pills was boosted by Linus Pauling, a Nobel-prize-winning chemist who advocated large doses of the vitamin. He routinely took 15 grams daily and was 93 years old when he died in 1994.

However, Frei, a nutrient expert at the institution named for Pauling, said such large doses of vitamin C have not been proven to be beneficial in clinical studies.

``The Linus Pauling Institute does not endorse megadoses,'' Frei said. ``Our advice is to eat a healthy diet rich in fruits and vegetables.''

Vitamin C is an antioxidant. It neutralizes oxygen free radicals, which are metabolic products in the cell that can damage DNA. Some researchers have speculated that because of its antioxidant action, large doses of the vitamin could prevent cancer, strengthen the immune system and prevent the common cold.

Clinical studies, though, have been disappointing, said Frei.

``Vitamin C does not prevent a cold,'' he said, although some studies suggest the nutrient may hasten recovery.

Vitamin C can help patients lower high blood pressure, and Frei said some studies have suggested that ``people in a disease state,'' such as an infection, may be helped by vitamin C.

Asked if healthy people benefit from vitamin C supplements, he said: ``I don't think we could say that.''

The Institute of Medicine (news - web sites), an arm of the National Academy of Sciences (news - web sites), recommends that women need 75 milligrams of vitamin C daily and 90 milligrams for men. Smokers need an additional 35 milligrams. These are levels easily achieved by a balanced diet.

Much more than that is generally useless, said Frei. A healthy body can absorb about 200 milligrams a day and the surplus is carried away with urine.

http://dailynews.yahoo.com/h/ap/200...ertainty_3.html
Reply With Quote
Sponsored Links
  #2   ^
Old Thu, Jun-14-01, 20:39
doreen T's Avatar
doreen T doreen T is offline
Forum Founder
Posts: 37,199
 
Plan: LC paleo/ancestral
Stats: 241/188/140 Female 165 cm
BF:
Progress: 52%
Location: Eastern ON, Canada
Question

I was just reading this very article on Medline ...

It's hard to know what to do, so much conflicting information on the subject of vitamins and supplements. They're seeing more and more, that isolating a single vitamin and taking it as a single supplement is useless... the vitamin needs other important micronutrients in order to do its job. Vitamin C requires bioflavinoids among others. A lot of supplement manufacturers are now adding phytonutrients and plant extracts to provide these other essentials.

Once again, we'll have to see how the lab-based study in the petri-dish translates in the human body.

I take 250 mg vitamin C (with bioflavinoids) twice a day ... it enhances calcium absorption ... But when I have a cold or flu, I bump up the dose, and it does seem to shorten the duration of the illness.

Doreen
Reply With Quote
  #3   ^
Old Thu, Jun-14-01, 22:30
r.mines's Avatar
r.mines r.mines is offline
Senior Member
Posts: 1,383
 
Plan: Atkins
Stats: 162/124/120 Female 5'1"
BF:
Progress: 90%
Location: Vancouver,BC
Default

I always take my vites with food. I guess I always felt they were dietary additives, not replacements. Though I was taking 500 mgs a day, maybe I'll start breaking the tablets in half (they'll last twice as long, too!).

Well, no point panicking yet, too much water will kill you too!

Rachel
Reply With Quote
  #4   ^
Old Fri, Jun-15-01, 04:58
DebDaCajun's Avatar
DebDaCajun DebDaCajun is offline
Registered Member
Posts: 66
 
Plan: Dr. Bernstein
Stats: 290/270/150
BF:
Progress:
Location: Shreveport, LA
Default

I just find it particularly ironic that an institute named after Linus Pauling is saying, in so many words, that Pauling was not entirely right about vitamin C. Personally, I think Linus Pauling was DA MAN and if he lived to be 93 he must have been doing SOMETHING right. I don't plan to do anything different than what I have been (a Centrum every day and 500mg when I start to feel ill).
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
An interview with the originator of the Homocysteine Theory of Heart Disease Voyajer LC Research/Media 2 Fri, Sep-06-02 16:42
Sep 2002 study shows supplementing with Vitamin C or E reduce risk of heart disease Voyajer Nutrition & Supplements 0 Fri, Sep-06-02 15:17
On Studies showing Vitamin Supplements as worthless Voyajer LC Research/Media 1 Sat, Jul-27-02 00:22
Vitamin D may cut risk of type 1 diabetes in children: study doreen T Dr.Bernstein & Diabetes 0 Fri, Nov-02-01 12:30
Vitamin C Study Premature and Inconclusive tamarian Nutrition & Supplements 1 Fri, Jun-15-01 20:06


All times are GMT -6. The time now is 06:56.


Copyright © 2000-2024 Active Low-Carber Forums @ forum.lowcarber.org
Powered by: vBulletin, Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.