In the News: “Multi” Use Cuts Cancer Risk;
Flavonoids & Prostate Health
Daily “Multi” Reported to Reduce Cancer Risk
Consistent use of a daily multi-vitamin and mineral supplement can pay a healthy dividend for men according to a study (1) newly published in the Journal of the American Medical Association.
The Harvard investigators who conducted the study report an 8% decrease in total cancer occurrence. The reduction in total cancer rate was found to be 12% when they removed prostate cancer from the analysis (no effect on prostate cancer rate was seen). Regular multi use also lessened the risk of dying from cancer by 12%, though that figure was just shy of reaching statistical significance.
The study is unique in a number of ways. It’s the first and only large-scale placebo-controlled trial (the most rigorous type of study) to evaluate a multi-supplement in the prevention of cancer, with over 14,600 physicians 50 years or older participating. Secondly, the physicians were followed for a long time – 11 years on average, with up to 14 years of treatment for some of them.
The study’s findings are important both from a public health and an individual perspective. An 8% decrease in cancer risk may seem modest. But with more than 1.6 million new cancer cases diagnosed yearly in the US, this risk reduction translates into about 130,000 cancers prevented every year.
Along with healthy habits such as not smoking and eating a diet rich in fruits and vegetables, adding a daily multi supplement may well make a meaningful contribution to cancer prevention. As one researcher affiliated with the Fred Hutchinson Cancer Research Center points out, other than quitting smoking there’s no single measure one can take that’s been shown to reduce cancer risk by nearly 10%.
The physicians who took part in the trial were healthy, with good dietary and lifestyle habits. Over 2/3 of them exercised regularly and only 4% smoked (though 40% were former smokers). They were also diligent about taking the supplements over time.
Can consistently taking a good quality ‘multi’ also lower the risk for cancer in less healthy or younger people, women, and those or who aren’t health professionals? While this study can’t provide those answers, it’s reasonable to believe that the impact in the general population could be even greater.
The study also goes a long way in confirming that balanced multis are generally safe to take (adverse effects in the supplement group were minor, with supplement takers slightly more likely to have rashes than those taking the placebo).
Dietary Flavonoids Linked to Prostate Cancer
While multi-supplement use does not appear to reduce the risk of prostate cancer, eating foods rich in compounds known as flavonoids just might offer some hope.
A study (2) presented this month at an international conference on cancer prevention reports that men with the highest intake of total flavonoids had a 25% lower risk of aggressive prostate cancer than those consuming the least total flavonoids. In addition, the risk for aggressive prostate cancer was even lower in men younger than 65, and in current smokers with the highest levels of flavonoid intake. The study included 920 Afro-American and 977 Caucasian men who were newly diagnosed with prostate cancer.
They found that no one type of flavonoid appeared to be responsible for the protective effect. This suggests that it’s important to consume a variety of plant-based foods in the diet, rather than to focus on one specific type of flavonoid or flavonoid-rich foods. Top contributors to total flavonoid intake among the participants were citrus fruits and juices, tea, grapes, berries, onions and greens.
While further research will need to confirm the study’s findings, eating more flavonoid-rich foods is of benefit to overall health.
Gaziano JM, et al. Multivitamins in the prevention of cancer in men—The Physicians’ Health Study II randomized controlled trial. JAMA, Published online ahead of print October 17, 2012.
Steck S, et al. Increased Flavonoid Intake: Reduced Risk for Aggressive Prostate Cancer. 11th Annual AACR International Conference on Frontiers in Cancer Prevention Research, Anaheim, CA, Oct.16-19, 2012.
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