Vitamin E Intake Improves Fatty Liver Disease
NEW YORK—Vitamin E has been shown effective in treating nonalcoholic steatohepatitis (NASH), an obesity-associated chronic liver disease that can lead to cirrhosis, liver cancer and death, according to a new study published in the New England Journal of Medicine. NASH also is related to or a part of type 2 diabetes, lipid disorders and cardiovascular disease.
"There is an increasing prevalence of nonalcoholic steatohepatitis in this country, something that is directly related to the obesity epidemic," said Dr. Joel Lavine, co-chair of the Network's steering committee and a co-author of the study. "The good news is that this study showed that cheap and readily available vitamin E can help many of those with the condition. We also looked at the drug pioglitazone, which showed some benefits, although not as dramatic as with vitamin E."
In the Pioglitazone or Vitamin E for NASH Study (PIVENS), investigators randomly assigned 247 nondiabetic adults with biopsy-confirmed NASH to receive vitamin E, pioglitazone or placebo. Vitamin E functions as an antioxidant while pioglitazone improves the sensitivity of cells to insulin, a hormone that controls both sugar and fat metabolism.
After 96 weeks of treatment, vitamin E improved all features of NASH with the exception of the amount of scar tissue in the liver; 43 percent of those treated with vitamin E met the primary endpoint of the trial, which was a composite of the scores for several features of NASH indicative of disease activity, compared with only 19 percent of those who received a placebo. Pioglitazone also improved many features of NASH and met the primary endpoint in 34 percent of individuals who received it but fell short of statistical significance. Pioglitazone treatment led to an average weight gain of 10 pounds over the 96-week duration of the study. Liver enzyme tests also improved in those who received either pioglitazone or vitamin E. Upon stopping the medications, the liver enzymes worsened again suggesting the need for long-term treatment.
- NewYork-Presbyterian Hospital: Vitamin E Effective for "Silent" Liver Disease
Use of Multi-Vitamins & risk of breast cancer: No need for concern
The recent media reports regarding the claimed association between the use of multi-vitamins and cancer are centred on an epidemiological study conducted in Sweden. These "epidemiological" studies typically look at a sample of women who have developed breast cancer and ask them about their use of vitamins in preceding years, and compare this with another sample of women of the same age who have not developed breast cancer.
Two epidemiological studies have released their results recently in the same week with opposite findings. The aforementioned Swedish study, which has been widely reported in the media, followed 35,000 women over a 10 year period.1 The women completed a questionnaire on a range of factors, including their use of vitamins. It was subsequently concluded that there was an association between the reported regular use of multi-vitamins and the incidence of breast cancer. In particular, it seemed that there was a relatively small increase in risk (a 19% increase above the normal risk) of developing breast cancer over the 10 years in women who reported that they were regular users of multi-vitamins. As the researchers have acknowledged, it is possible that something they did not measure was responsible for this link. Of course, it is also possible that some women may not have reported their multi-vitamin use accurately, or that their use changed over the 10 year period.
In contrast, a study in Puerto Rico, involving 268 women with recently diagnosed breast cancer and 457 women without breast cancer, found a 33% decrease in breast cancer risk associated with multi-vitamin use when women were questioned about their vitamin and dietary supplement intake over the previous 5 years.2
Other studies that have examined the association between taking multi-vitamins and the development of breast cnacer have not produced any conclusive findings. For example, a large study among 2968 breast cancer cases diagnosed between 2004 and 2007, and 2982 control women from Wisconsin, USA, found no association between multi-vitamin supplement use and the risk of breast cancer.3
To show if multi-vitamins are associated with cancer, a carefully designed prosepective randomised clinical trial is required, where, for example, 50% of a large sample of women take multi-vitamins over an extended period of years, and 50% don't. The subsequent rates of breast cancer are then compared after ruling out any other possible underlying differences beetween the two sub-groups (e.g. family history of breast cancer). There have been no studies of this type; to the best of our knowledge, published studies examining the association between taking multi-vitamins and the development of breast cancer have not produced any conclusive findings.
It is important to realise that epidemiological studies cannot prove that multi-vitamins either cause or protect against breast cancer. As stated on the Australian Cancer Council's website, it is important to keep the results of the Swedish study in perspective. There are well-established risk factors that are obesity, physical inactivity and drinking alcohol that are much more significant risk factors for breast cancer.
1. Larsson SC, Akesson A, Bergvist L, Wolk A. Multivitamin use and breast cancer incidence in a prospective cohort of Swedish women. Am J Clin Nutr; 2010; 91:1268-72.
2. American Association for Cancer Research (AACR) 101st Annnual Meeting: Abstract 4568. Presented April 18m 2010,
3. Meulepas JM, Newcomb PA, Bernett-Hartman AN, Hampton JM, Trentham-Dietz A. Multivitamin supplement use and risk of invasive breast cancer. Public Health Nutr 2009: 1-6.