In our new brochure, Cancer Survivors' 8 Ways to Stay Healthy After Cancer, we really push the importance of exercise as a way to boost mood, improve overall health, and possibly cut the risk of cancer recurrence.
Backing up this latter benefit is a new prostate cancer study that found that regular brisk walking could cut the risk of cancer progression after initial diagnosis (study). Researchers out of the University of California San Francisco and the Harvard School of Public Heath followed close to 1,500 men with localized prostate cancer (cancer that has not spread beyond the prostate), noted their activity levels, and kept track of whose cancer progressed to more advanced, serious states.
What they found was that regular brisk walking (3 mph or faster) - regardless of how long a man walked - cut the risk of progression nearly in half compared to men who walked at a leisurely pace (less than 2 mph). Longer walking was linked to an even lower risk. Compared to men who walked fewer than 3 hours a week at a less-brisk pace, those who walked 3 or more hours a week at a brisk pace had a 57 percent lower risk of cancer progression.
For many people who have gone through cancer diagnosis and treatment, the last thing they want to do is fight off the mental and physical fatigue from the whole experience and head out the door for a brisk walk. But more and more evidence backs the benefits of doing just that. In addition to possibly lowering the risk of recurrence and providing a great mental boost it also helps lower the risk of other chronic diseases like heart disease, stroke, and diabetes, which remain important concerns for most cancer survivors.
It's a win-win-win for survivors, who can start to collect the benefits by lacing up and taking some quick steps around the block.
Wednesday, May 25, 2011
Tuesday, May 24, 2011
Vitamin D does not protect against premenopausal breast cancer
In a predominantly premenopausal population, Eliassen and colleagues evaluated plasma vitamin D levels (25-hydroxyvitamin D) and risk of invasive breast cancer (see article).
During up to 10 years of follow-up after blood samples were collected some 613 cases of breast cancer were confirmed in this cohort. In a detailed analysis that accounted for breast cancer risk factors and many of the issues surrounding blood vitamin D levels (such as season of blood collection, age, and levels of obesity) the authors found no evidence for a protective association. In fact, risk tended to increase with higher vitamin D levels. Risk did not vary for ER positive or ER negative tumors.
Overall, these prospective data do not support any protective benefit for higher vitamin D levels against breast cancer among premenopausal women.
Related CNiC Posts
Tuesday, May 10, 2011
Keep Fish on the Menu: Omega-3s and Prostate Cancer
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| Photo: courtesy practicalowl |
While we could write a post about each of these pieces, Dr. Len Lichtenfeld of the American Cancer Society did a nice job putting the small mammogram study in context (Dr Len's Blog), as did our Harvard colleagues at the Nutrition Source for the less-than-perfect salt/heart disease study (Nutrition Source).
But we'll say a few things about the fats and prostate cancer study by Brasky et al, which appeared in the American Journal of Epidemiology (study)(Brasky, 2011).
This was a case-control study that looked at blood levels of omega-3 fatty acids and how they might be related to prostate cancer risk. It was a fairly large study, with 1,658 men with prostate cancer (cases), 1,803 without prostate cancer (controls), and some pretty surprising results.
For a little background, there are a number of types of omega-3 fatty acids.
- Alpha-linolenic acid (ALA) is largely found in vegetable oils (especially soybean and canola oils), nuts (especially walnuts), and flax seeds (and their oil), and leafy green vegetables.
- Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are found mainly in fish. The body can also convert ALA into these types of omega-3s in the body, though this only accounts for a small amount of EPA and DHA in the body.
Results for prostate cancer, though, have so far been a bit up-in-air. Some studies have found that ALA (the type of omega-3 found in some vegetable oils) may increase the risk of serious prostate cancer (Giovanucci, 1993; Gann, 1994; Ramon, 2000), while others have found that DHA (the type of omega-3 largely from fish) actually lowers the risk of serious prostate cancer (Leitzmann, 2004; Szymanski, 2010).
The new Brasky et al study mixes these findings up further by showing nearly the opposite. It found that those with the highest blood levels of DHA had 2.5 times the risk of high grade prostate cancer compared to those with the lowest levels.
It was a result opposite of what the author's - and what many other researchers - expected. And it's the type of finding that can leave people, once again, reeling from mixed messages, not knowing if they should embrace omega-3's or shun them.
But this study on its own shouldn't change the healthy habits people follow. First, although it was a well-designed study, there were only a small number of cases of high-grade prostate cancer in the study population - just 125 total, compared to over 1,500 of low-grade cases. Such small high-grade numbers can leave more room for chance findings. The high-grade lesions were also generally small and unsymptomatic, so it's unclear if they'd develop further into something more serious or deadly.
Next, there are some pretty solid data from multiple studies showing protection from DHA. Ed Giovannucci, ScD, Professor of Nutrition and Epidemiology at the Harvard School of Public Health says that while the role of fatty acids in prostate cancer requires more study, currently there's more evidence of prostate cancer benefits than risks from consuming DHA-rich foods, like fish, noting that "a recent meta-analysis of fish intake and prostate cancer mortality found a highly significant 63 percent reduction in risk of fatal prostate cancer in the high fish consumers." (Szymanski, 2010).
So, for now, recommendation for a healthy diet should stay the same. It's important to focus on fruits, vegetables and whole grains. Keep red meat to a minimum. Avoid unhealthy fats, like trans fats and saturated fats. And eat more healthy fats, like monounsaturated and polyunsaturated fats. To be especially prostate-conscience, choose healthy fats that are low in ALA, like olive oil, corn oil, and peanut oil.
But, if you'd rather not track the alphabet soup of Omega-3's (ALA, EPA, DHA), that's OK for now, too. Overall, a diet rich in omega-3's of all types currently has a big health advantage over a diet low in omega-3's, since omega-3's have been clearly shown to lower the risk of heart disease, which kills over 400,000 people each year in the United States, compared to 28,000 for prostate cancer.
Other steps that can help lower the risk of prostate cancer include:
- Eating a diet low in animal fat; cut back on red meat, whole milk and cheese
- Eating more tomato-based foods like salsa and red spaghetti sauce
- Avoiding too much calcium; stick to the recommended 1,000 to 1,200 milligrams a day for most adults
Related Websites
Your Disease Risk - Prostate Cancer
References
Brasky TM, Till C, White E, et al. Am J Epi. 2011; Early online, April 24.
Gann PH, Hennekens CH, Sacks FM, et al. J. Natl Cancer Inst. 1994; 86:281-6.
Giovannucci E, Rimm EB, Stampfer MJ, et al. J Natl Cancer Inst. 1993; 85:1571-9.
Leitzmann MF, Stampfer MJ, Michaud DS, et al. Dietary intake of n-3 and n-6 fatty acids and the risk of prostate cancer. Am J Clin Nutr. 2004; 80:204-16.
Ramon J, Bou R, Romea S, et al. Cancer Causes Control. 2000; 34:607-14.
Szymanski KM, Wheeler DC, Mucci LA. Am J Clin Nutr. 2010; 92:1223-33
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