For years, it was thought that megadoses of Vitamin E were good for you. "Even many cardiologists took high doses of Vitamin E," The Early Show medical correspondent Dr. Emily Senay told co-anchor Harry Smith. "They really thought it would help for things like heart disease and even cancer.
"But that's out of favor now. And now there's even more evidence in a new study that it should continue to go out of favor."
Senay explains that Vitamin E is essential for good health: It's a powerful antioxidant. You need it in your diet. It helps protect cells from damage.
But, she adds, people who take Vitamin E supplements in the hope of preventing heart disease and cancer sometimes consume daily megadoses that can be 100 times more than they need.
The recommended daily intake of Vitamin E for most adults is 22 international units. A typical multi-vitamin contains around 30 to 40 units. Mega-dose supplements contain from 400 to 800 units or higher, which is turning out to be quite a high dose, according to the study.
It is "a meta-analysis," Senay says. "That means they threw together all of the previous studies that have been done and looked to see if they could find a benefit. They were looking at mortality as their outcome and didn't find a benefit. Not only did they not find a benefit, but they found it can increase your risk of mortality.
"They found people who were taking 400 international units a day actually had a 10 percnt increased risk of death compared to people who were taking less than 200 international units a day.
"This is consistent with what the American Heart Association was already saying, which is that high doses of Vitamin E don't protect your heart."
"I don't think we really know the answer" to why that is, Senay continued. "In the lab, it looks like it works. There may be something about the way that it is in food that makes it work better than when it's not in food."
Senay cautioned that, "There is a criticism of this study, which is many of the studies they pooled together included people who had some chronic illnesses, so the the mortality rate would be higher anyway."
Still, Senay points out, Vitamin E "didn't help anybody."
Should people taking megadoses of Vitamin E stop? "You should consider stopping. These researchers and others say the upper limit of 1500 international units a day, which is what many people are getting when they take the high-dose supplements, is really too high and needs to come down."
So what's the best way to get the Vitamin E we do need?
"Food, food, food," Senay exclaimed. "Great sources of Vitamin E include certain vegetable oils, nuts, and green leafy vegetables. If you're taking a multivitamin, that's probably OK. You're not going to overdose on that. But eat a great diet. That is kind of the solution to so many things."