The study, published in the November issue of Diabetes Care (27: 2767), follows on the heels of a much mediatised meta-analysis released two weeks ago, which linked high dose vitamin E supplements to a higher overall risk of death.
Like this review, the new study also measured the effects of high dose (400IU) of vitamin E.
Its timely release could help supplement marketers reduce the negative impact of the earlier trial, even though marketing supplements to diabetes patients still presents significant challenge to the industry.
The research team, led by Dr Andrew Levy of the Faculty of Medicine, had earlier demonstrated that diabetics with a particular form of a blood protein called haptoglobin had as much as a 500 per cent increased risk of developing heart disease.
The new study shows that when these at-risk patients, who have the 2-2 form of haptoglobin, took 400 international units of vitamin E daily, they reduced their risk of heart attack by 43 per cent, and their risk of dying of heart disease by 55 per cent.
About 40 per cent of diabetics have the 2-2 form of haptoglobin, according to the Israel-based researchers, while the rest have the 1 -1 or 2-1 forms. When the others took the same vitamin E supplements, they did not show any significant reduction of cardiovascular risk resulting from vitamin E therapy.
The emerging science on vitamin E has been causing peaks and troughs in demand for a number of years. Manufacturers of the vitamin at last week's Health Ingredients Europe show confirmed that the John Hopkins trial released earlier this month had already done some damage.
"Studies that are able to obtain this type of high media attention do have a significant impact on sales. For example, positive studies in the mid 90's had significant positive effect on vitamin E sales," noted Thomas Breisach, spokesman for DSM Nutritional Products, one of the largest manufacturers of the synthetic vitamin.
"According to feedback from some customers, there is a short term drop in vitamin E business in the week since the story ran."
W.H Leong, vice president of natural vitamin E tocotrienols manufacturer Carotech, also said that several customers had enquired about the study.
But a large-scale, five-year study of some 2,000 diabetics with haptoglobin 2-2, being conducted in northern Israel, is expected to corroborate Dr Levy's findings, giving the supplement industry further support for this vitamin.
Dr Levy's latest study analyzed serum samples that had been stored from the Heart Outcomes Prevention Evaluation (HOPE) trial of 2000, designed to study the effect of antioxidant therapy such as vitamin E on cardiovascular risk. The results of that study showed no benefit from vitamin E therapy on cardiovascular risk.
However, Dr Levy says that this study did not segregate patients according to their haptoglobin type, analyzing instead the benefits of vitamin E in all patients. When he studied the serum samples from the HOPE study according to haptoglobin type, he found a greatly reduced risk in both heart disease and death.
"If this larger study confirms our findings, the public health implications will be huge. Vitamin E would represent an inexpensive and safe way to reduce the risk of cardiovascular death and heart attack in a significant proportion of diabetic patients," he said.
Diabetes has already increased by one-third during the 1990s, due to the prevalence of obesity and an ageing population. The worldwide numbers are expected to climb from 194 million people to more than 333 million diabetics by 2025, according to the International Diabetes Federation.
Food and supplement makers are increasingly looking at ways to help slow the onset of the disease or to reduce the increased risk of related diseases.