HOW TO PREVENT CANCERS

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tomatoes juice can prevent prostate cancer

Tuesday, December 3, 2013 0 comments

tomato juice

Tomato juice for the health benefits are:
- Powerful antioxidants that are useful for the body's defenses against free radicals.
- Content lyopene in tomatoes can prevent prostate cancer
- To maintain ideal body weight for those who are dieting to lose weight and can increase appetite for a moderate increase in weight as well as the recovery period after illness
- Preventing constipation (difficult bowel movements)
- Glycogen levels can stabilize liver function

PSA Screening: Task Force Recommends Against Prostate Cancer Test

Friday, October 7, 2011 0 comments

Despite the widespread use of the prostate-specific antigen (PSA) test for prostate cancer, it's been known for many years that it had murky benefits, especially in the face of its well-demonstrated risks - like impotence, incontinence, and unnecessary surgery.

Now, as reported in a very good article in the New York Times, the US Preventive Services Task Force appears set to recommend against widespread screening for prostate cancer in men age 50 and older, with the primary justification being that testing simply doesn't save lives - a key criteria for any cancer screening test.

For more on the PSA testing issue, see our 8 Ways video below. For more on the cancer screening issue in general, see our page: Quick Principles of Screening.

Keep Fish on the Menu: Omega-3s and Prostate Cancer

Tuesday, May 10, 2011 0 comments

Photo: courtesy practicalowl

If you tracked the health news last week, you may be suffering a bit of whiplash from all the double takes of unexpected headlines: “Mammograms plummet among women under 50” (MSNBC); “Study questions value of salt reduction in healthy people” (Boston Globe); and “Heart-healthy omega-3’s not healthy for prostate” (US News and World Report).

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.

Omega-3's are generally seen as a "healthy" fat, since numerous studies have shown them to lower the risk of heart disease and stroke. Omega-3's have anti-inflammatory properties and can help regulate genetic function, and these same properties have pushed the hypothesis that they could help reduce the risk of cancer as well.

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

How are those New Years' Resolutions?

Friday, January 7, 2011 0 comments

If you needed another reason to lace up your sneakers and keep your New Years' resolution to be active, this week offered 2:

1) Our team published, in collaboration with colleagues at the American Cancer Society, research on the role of physical activity in colon cancer and colon cancer mortality. There is a strong and consistent body of evidence showing physical activity reduces colon cancer risk. This new study examined whether the consistency of physical activity matters.

We often get this question at CNiC - can I start now? Is it too late? What we found is that consistent physical activity does matter for colon cancer mortality. Does this mean if you haven't been active before now it is too late and you shouldn't bother starting? Absolutely not. It is important to look at this study in the context of the previous work and see the big picture -- physical activity matters for colon cancer risk and mortality. Starting earlier seems to be better, but it doesn't appear it is ever too late to start either.

And of course, the other thing to remember is that physical activity isn't just beneficial for colon cancer - it reduces risk of other cancers AND heart disease AND stroke AND diabetes AND osteoporosis. And physical activity improves the quality of life as well - you FEEL better.

2) Providing another reason to be active - colleagues of ours published a report on the benefit of physical activity after a prostate cancer diagnosis. Among men diagnosed with non-metastatic prostate cancer, those who were physically active after diagnosis were less likely to die and less likely to die of prostate cancer. Overall mortality risk was reduced with activity equivalent to 30 minutes a day of brisk walking. The study suggested more vigorous physical activity may be necessary to reduce risk of prostate cancer specific death.

When the days are short and the temperatures cold, it can be hard to find the motivation to be physically active, even for our team. As we've said before - anything that gets you up and moving is good - even short breaks. And if you think you don't have time, remember our tips. Physical activity is a place where you get enormous "bang for your buck!"

Quick Facts About Soy and Health

Monday, May 10, 2010 0 comments

Soy foods have been studied a great deal for their potential protection against a range of chronic conditions, including breast and prostate cancer, heart disease, osteoporosis, and menopausal symptoms.

It’s not known exactly how a diet rich in soy results in such benefits. It could be due to some of the individual components of soy, such as isoflavones which have some qualities similar to naturally occurring hormones. Or it could be the collective make up of soy, all its components together, which have the beneficial effects.

Because most pre-menopausal symptoms are linked to dropping levels of the hormone estrogen, it’s been considered that soy, and the insoflavones it contains, could help mimic natural estrogen and therefore quell things like hot flashes. Current evidence, though, suggests that soy intake actually has little impact on hormone levels. Still, research also suggest that a diet rich in soy may reduce menopausal symptoms (1).

The potential cardiovascular benefits from higher soy intake may be due to soy’s being a healthier replacement for some higher fat choices. Soy has only about 20 percent of its calories from fat, which is predominantly “healthy” polyunsaturated fat (2), whereas chicken can have nearly half of its calories from fat, and beef can have as much as 80 percent of its calories from fat, much of it in the form of “unhealthy” saturated fat. Studies looking at the relationship between soy intake and heart disease suggest that a diet rich in soy can improve blood pressure, blood cholesterol, and insulin levels (3).

Much of the interest in the links between soy intake and cancer risk is motivated by the historically low breast and prostate cancer risk among Asians, whose diets are traditionally high in soy. Detailed reviews by Wu and colleagues shows that at high intakes typical of Asian diets, soy is significantly related to a reduced risk for breast cancer, and the effect may be strongest for high intake in childhood and adolescence. A meta-analysis found that diets with high amounts of soy (20 mg per day of isoflavone) in Asian women was associated with a decreased risk for breast cancer, compared to Asian women consuming lower amounts (5 mg daily) (4). What this means for most American women is unclear. Studies in the US have typically not found a link between soy intake and breast cancer, but this could largely be due to widely different diets between the two regions. The highest intake in the US is typically 80 percent below the lowest intake in Asia (0.3 mg isoflavones/day in the US versus 25-50 mg isoflavones/day in Asia, which is equivalent to 1 g of soy food versus 80-160 g of soy food). Should diets shift to resemble those of Asia, it’s more than likely that studies would begin to reveal breast cancer benefits with soy as well.

Looking at the data on soy and prostate cancer, a number of studies show benefits from a higher intake of soy and soy-products. Soy milk intake was shown to be inversely related to risk of prostate cancer among US men in the Seventh Day Adventist Cohort study (5). As soy milk consumption went up, the risk of prostate cancer went down. A similar relationship has been seen between total soy intake and the risk of prostate cancer in other cohort and case-control studies (6), even though the amount of the effect on risk varied a bit from study to study. The only potential evidence that soy might increase the risk of prostate cancer comes from research of fermented soy (Miso), which has been positively related to risk in some studies.

Overall, there is currently little evidence that a diet high in soy is bad for health, and a growing body of evidence that it could have substantial health benefits. Realizing such potential benefits though, would likely take intake levels beyond what most people in the US typically eat.

Literature cited:

Kurzer, M.S., Soy consumption for reduction of menopausal symptoms. Inflammopharmacology, 2008. 16(5): p. 227-9.
van Ee, J.H., Soy constituents: modes of action in low-density lipoprotein management. Nutr Rev, 2009. 67(4): p. 222-34.
Carlson, S., et al., Effects of botanical dietary supplements on cardiovascular, cognitive, and metabolic function in males and females. Gend Med, 2008. 5 Suppl A: p. S76-90.
Wu, A.H., et al., Epidemiology of soy exposures and breast cancer risk. Br J Cancer, 2008. 98(1): p. 9-14.
Jacobsen, B.K., S.F. Knutsen, and G.E. Fraser, Does high soy milk intake reduce prostate cancer incidence? The Adventist Health Study (United States). Cancer Causes Control, 1998. 9(6): p. 553-557.
Jian, L., Soy, isoflavones, and prostate cancer. Mol Nutr Food Res, 2009. 53(2): p. 217-26.