Vitamin Information Center

A new study by the National Cancer Institute has found that people with one or more chronic illness are the primary factor behind the use of dietary supplements. Cancer survivors also contribute to the use of supplements, although not specifically as cancer treatments.

Dr. Melissa Farmer Miller, the study’s lead author, told Reuters that its important for cancer patients to inform their physicians about any non-prescription medications or natural products they may be taking, as a lack of information exists on the risks and benefits of many supplements. In addition, there may be potential for drug interactions with medications, such as tamoxifen, that many cancer survivors may be taking.

“We really are just beginning to build an evidence base on the benefits of dietary supplements,” said Miller, of the National Cancer Institute in Bethesda, Maryland.

“Even if there’s not a benefit, there is a potential for them to cause harm,” she said, noting that the use of supplements is growing among all Americans.

To determine whether cancer survivors are using supplements at greater rates than the general population, Miller and her team analyzed information from 1,844 cancer survivors and compared it with a random sampling of 7,343 people with no history of cancer.

The team found that vitamins were the only type of supplement use independently associated with having a cancer diagnosis. However, those participants with a  chronic illness were 82 percent more likely than those without a chronic disease to be using two or more supplements, regardless of whether or not they also had cancer.

Other factors associated with the use of dietary supplements were greater physical activity, consumption of fruits and vegetables, being female, being of older age and the use of other alternative and complementary medicines.

Miller said it was not possible at this time to conclude whether or not people living with cancer should either take supplements, or avoid them.

“The primary message should always be to promote a healthy diet,” she said.

She said that doctors and other cancer patient caregivers should be up to date on the literature about various supplements, and should be aware of any supplements their patients may be taking. Cancer patients should also be informed as much as possible about any supplement before they take it, Miller added, noting that it can often be tough due to the lack of regulatory oversight of dietary supplements in the U.S. and the  limited information available on their risks and benefits.

“Consumers are really kind of out there on their own, and should confer with their health care providers about supplement use.”

Dr. Miller‘s report was published in the March 2008 issue of the Journal of the American Dietetic Association.

A summary of the report can be viewed at http://www.adajournal.org/article/S0002-8223(07)02206-7/abstract.

The increased risk of lung cancer with vitamin E was small.

“Vitamin E supplements ‘could cause up to 27 per cent increase in lung cancer’”, according to a news story in the Daily Mail. Several other news sources report a study of more than 77,000 people that found a “slight but significant increase” in lung cancer risk with a moderate to high intake of vitamin E supplements. The reports also say the study sounded a similar warning for beta-carotene supplements.

The study behind the news report looked at the use of supplemental vitamins (multivitamins, vitamin C, vitamin E and folate) and new cases of lung cancer. Overall, the study found no protective effect of supplements on lung cancer. It also found a barely significant increase in risk of lung cancer associated with vitamin E supplementation. The increased risk was small – a five per cent increase in risk for every 100mg of vitamin E taken per day over 10 years – and this translated to a small increase in the participants with lung cancer.

By far the largest predictor of lung cancer from this large study was smoking, with most cases occurring in current or past smokers.

Where did the story come from?Dr Christopher Slatore and colleagues from the University of Washington, the VA Puget Sound Health Care System, the University of North Carolina at Chapel Hill, and the Fred Hutchinson Research Centre, Seattle carried out the research. The research was supported by a grant from the National Cancer Institute.

The study was published in the peer-reviewed: The American Journal of Respiratory and Critical Care Medicine.

What kind of scientific study was this?In this cohort study, the researchers aimed to investigate the links between supplemental multivitamin use, vitamin, C, E and folate, and incidence of lung cancer.

This study - the VITAL study (VITamins And Lifestyle) - was set up to examine the effects of long term supplement use on lung cancer in people aged between 50 and 76 in Washington state.

The researchers mailed 364,418 questionnaires between October 2000–December 2002 asking about medical history, cancer risk, supplement use and diet. Responses were obtained from 21.3% of those sent the questionnaire and this provided 77,719 people for analysis.

The questionnaire asked the participants about their supplement and vitamin use in the 10 years leading up to the start of the study. Supplement intake was classified as current, past, or never used, with specific details about the extent of use (e.g. dose per day, per week etc.). From this data, the researchers calculated the amount of multivitamins taken over 10 years, and the quantities of individual vitamins by looking at those contained in multivitamins (estimated from a reference manual) and from individual supplement tablets.

The researchers also examined other factors that could have an effect on lung cancer risk, such as smoking (years and number of cigarettes per day), age, sex, past cancer history, family history, airways disease, ethnicity, education, marital status, BMI and diet. They carried out statistical analysis of relationships between lung cancer and supplement use allowing for age, sex and smoking. They tested whether any of the other factors were affecting any observed link between these relationships and took into account those that were in their final analysis.

The participants were monitored to see if they developed lung cancer. For this, the researchers used a cancer registry called SEER, which, they said, contains accurate and complete information on cancer and lung cancer histology. The researchers excluded people who had already been diagnosed with lung cancer at the beginning of the study, those whose cancer was only diagnosed after they had died, and those who had relevant data missing. The participants were followed up until they withdrew from the study, moved out of the catchment area, died, or when the study terminated in December 2005.

What were the results of the study?The analysis included 77,126 subjects who were followed for an average of four years. Of these, 521 developed lung cancer with most cases occurring in current or previous smokers. Few cases developed in people who had never smoked.

There was no link between risk of lung cancer and use of multivitamins, vitamin C, or folate, at any dosage for 10 years. The participants’ age, sex and smoking status were taken into account.

When the researchers looked at vitamin E alone, they found a minimal link to lung cancer (all lung cancers) – with a five per cent increase in risk with every 100mg increase in dose of vitamin E taken per day over 10 years. This result was only just statistically significant.

When the researchers looked at risk for different types of lung cancer, they found that vitamin E was associated with an increased risk in non-small cell lung cancer (the most common type). They say that this amounted to a “28% increased risk of lung cancer at a dose of 400mg/day for 10 years”.

Looking at risk of cancer by vitamin use and dividing people into categories of current and ex-smokers, they only found statistical significance between lung cancer and highest dose vitamin E in current smokers.

What interpretations did the researchers draw from these results?The researchers concluded that no supplement protected against lung cancer; however, vitamin E was associated with a small increase in risk, especially in smokers.

What does the NHS Knowledge Service make of this study?This study looked for associations between lung cancer risk and supplement use in a large number of people. However, the links between vitamin E and lung cancer should be considered in context:

• The researchers found no protective effect of any type of vitamin for lung cancer.
• The increased risk from vitamin E overall was quite small - a five per cent increase per 100mg per day – and was of borderline statistical significance.
• The researchers report that the risk was  “largely confined to current smokers” with minimal cases occurring in non-smokers.
• There may have been errors in the participants’ 10-year history of vitamin use. The usage was estimated by the participants themselves and it is possible that their vitamin use may have been inconsistent over that time period. Likewise, the researchers may have introduced inaccuracies when they estimated the amount of each individual vitamin contained in multivitamin tablets.
• Although there was an increased risk associated with vitamin E, it cannot be assumed that it was caused by the supplement itself. There could be other reasons causing the increase in risk that have not been taken into account.
• The results cannot be reliably generalised outside of the predominantly white, US population from which the data was obtained. The researchers also point out that the study had a smaller proportion of current smokers than is present within the actual US population as a whole.

Sir Muir Gray adds…I see no evidence of vitamin E deficiency in England and so therefore no need for taking extra vitamin E.

Since advice about what to eat for optimal health has evolved over time with advances in nutrition science, dietary recommendations are sometimes seen as contradictory. However, a review of three leading dietary guides by researchers at the National Cancer Institute found their essential recommendations are consistent despite the different methodologies used to create the guides.

The NCI researchers compared recommendations and nutrient values of the United States Department of Agriculture’s MyPyramid; the National Heart, Lung and Blood Institute’s DASH Eating Plan and Harvard’s Healthy Eating Pyramid. The study showed that, even though the guides were derived from different types of nutrition research, they share consistent messages: Eat more fruits, vegetables, legumes and whole grains; eat less added sugar and saturated fat; and emphasize plant oils.

Recommendations are similar regarding almost all food groups for both types and amounts of foods people should eat. Primary differences were seen in the types of recommended vegetables and protein sources and the amount of recommended dairy products and total oil. Overall nutrient values were also similar for most nutrients, except vitamin A, vitamin E and calcium.

The researchers conclude: “The evidence base for optimal diets continues to evolve. However, inherent in these guides is a pattern of eating that focuses on nutrient-rich foods and limited calories from added sugar and solid fat.”

This research was published in the March 2008 issue of the Journal of the American Dietetic Association.

TORONTO — A new U.S. study contradicts the notion that high blood levels of vitamin D might help protect men from developing prostate cancer - a finding that is likely to add to the public’s confusion over the possible benefits of the sunshine nutrient. Laboratory studies of cells have suggested that high doses of vitamin D may reduce prostate cancer from developing, but international research that has looked at the disease and the effect of vitamin D in different groups of men has shown inconsistent results.

In the study by the National Cancer Institute, researchers compared vitamin D concentrations in the blood of 749 men diagnosed with prostate cancer with those of 781 men without the disease.

Vitamin D concentration was measured in a blood sample taken at enrolment in the study and participants were followed for up to eight years.

“Our main findings are higher levels of vitamin D were not associated with a decreased risk of prostate cancer,” lead author Jiyoung Ahn said Tuesday from Bethesda, Md. “However, we did see some evidence of an increased risk of aggressive disease associated with the higher concentration of vitamin D.”

But Ahn stressed that the latter finding was not statistically strong and more research is needed to determine whether too much vitamin D actually increases the risk of a prostate cancer being more aggressive.

The study was published online Tuesday in the Journal of the National Cancer Institute.

Commenting on the study, Reinhold Vieth of Toronto’s Mount Sinai Hospital said he is not surprised by the NCI researchers’ results, but he suggests the link between prostate cancer risk and vitamin D is related to seasonal changes in the amount of the nutrient in the body.

“What I think happens is that this phenomenon of higher risk relates not just to a flat-out how high is your vitamin D,” said Vieth, who specializes in vitamin D research. “The thing that causes risk with regards to cancer … is fluctuation.”

Vitamin D, required for proper cell growth and regulation, is made when the skin is exposed to sunlight. But people in northern countries such as Canada become deficient in the nutrient during winter months when the sun’s rays are at their weakest.

“Higher vitamin D is good because it seems to make cells behave properly,” said Vieth.

But when levels drop as fall and winter set in, the body’s cells have to adjust to having less of the nutrient - and it is this continual adjustment that may upset the way cells proliferate, he said.

The bigger the fall in vitamin D levels, the harder it is for cells in the body - in this case, prostate cells - to adjust, he said, noting that tumours can arise when regulation of cell growth goes awry.

Vieth said the public has good reason to be confused about the role of vitamin D in cancer prevention, particularly when it comes to prostate cancer, because there has been so much conflicting research.

Until more is known, he said, there is no simple answer.

The best way to avoid the seasonal vitamin D yo-yo is to maintain a stable level in the blood by taking dietary supplements year-round, he said, suggesting that 1,000 IUs daily for adults would be an adequate amount.

Last June, the Canadian Cancer Society recommended that adults consider taking a vitamin D supplement of 1,000 IUs daily during fall and winter, while darker-skinned and older people should think about taking the little white pills year-round.

Health Canada currently recommends 200 IUs for adults 19 to 50 years of age. Last September, it released a statement saying recommendations by various organizations to boost intake were premature, and a comprehensive review was needed before it would revise its own recommendations.

Women who smoke are no more likely to develop lung cancer than men, US researchers have concluded.

There had been conflicting evidence on women’s risk, but the National Cancer Institute study of over 450,000 people found no gender difference.

The study published in Lancet Oncology found a difference of only 0.9% between the risk for men and that for women.

The most recent UK statistics show that in 2006, 23% of men and 21% of women were cigarette smokers.

Lung cancer kills around 30,000 people a year in the UK.

‘Vigorous efforts needed’

The researchers analysed data on smoking habits, diet, exercise and alcohol use for 279,214 men and 184,623 women aged between 50 and 71 living in eight US states.

They then looked at lung cancer rates.

The difference in risk for women and men who smoked was just 0.9%.

Men and women who smoke more than two packs per day were about 50 times more likely to develop lung cancer than people who had never smoked.

The team, led by Dr Neal Freedman, said their study benefited from its size, giving reliable findings

They conclude: “Our findings suggest that women are not more susceptible than men to the carcinogenic effects of cigarette smoking in the lung.

“Vigorous efforts should continue to be directed at eliminating smoking in both sexes.”

Andy McEwen, assistant director of tobacco studies at Cancer Research UK’s Health Behaviour Research Centre, said: “Smoking has a devastating effect on the health of people trapped by their tobacco addiction.

“The risk of a smoker, male or female, developing lung cancer is 15 times greater than that of a non-smoker and smoking continues to be the biggest preventable cause of death for men and women.”

“Smoking accounts for the vast majority of cases of lung cancer worldwide.

“More has to be done to help all smokers to quit if we are to prevent future deaths from lung cancer.”

By Michelle Carolla

Americans spend more than $7 billion a year on vitamins. But how do you know if you need vitamins and supplements?

A study in the Journal of American Medical Associations reports insufficient vitamin intake is an apparent cause of chronic disease. The American diet does not normally provide adequate amounts of vitamins.

Mary Ellen Scarborough, a registered dietician, told News 13 what’s important is what you eat. Eating whole, fresh foods and not processed, fatty foods is the best way to ensure you’re getting the proper amount of vitamins. Continue Reading…