Indiscriminate use of high-dose Vitamin E supplementation can do more harm than good, a new study has warned.
"There were so many conflicting reports about Vitamin E and its effect on various diseases, particularly heart disease, that we wanted to set the record straight, says Prof. Dov Lichtenberg of Tel Aviv University's Sackler School of Medicine.
Study co-author Dr. Ilya Pinchuk said: "Our new study shows that some people may be harmed by the treatment, whereas others may benefit from it. Now we're trying to identify groups of people that are most likely to benefit from the effects of Vitamin E."
The researchers evaluated the results of the prominent studies measuring the health benefits of Vitamin E but reached varying conclusions. There have been many previous publications on the subject.
Analysis of the results of all these past publications together revealed that subjects who did not take a Vitamin E supplement enjoyed more quality-adjusted-life-years (QALY), a standard parameter used in medicine to assess the effect of medical interventions.
Dr. Pinchuk said: "To explain the meaning of this parameter, consider a participant who was healthy during the first 10 out of 20 years of the study, but then suffered a stroke and became dependent on others throughout the following 10 years.
"The QALY during the first 10 years of healthy life is 10, but after the stroke the quality of life is only half of what this person had before. Therefore, the second decade is considered the equivalent of merely 5 years of healthy life and in sum a person's QALY is 15," Dr. Pinchuk added.
The researchers examined data from more than 300,000 subjects in the US, Europe and Israel.
"Our major finding was that the average quality-adjusted life years (QALY) of Vitamin E-supplemented individuals was 0.30 less than that of untreated people. This, of course, does not mean that everybody consuming Vitamin E shortens their life by almost 4 months. But on average, the quality-adjusted longevity is lower for vitamin-treated people. This says something significant," Dr. Pinchuk said.
The results were recently reported in ATVB, a leading journal of cardiology, and discussed in the journal BioFactors.