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Category: nutrition

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This study found that greater intake of dietary nitrate and green leafy vegetables was associated with a 20 percent to 30 percent lower risk of primary open-angle glaucoma (POAG), which is the most common form of glaucoma. Glaucoma can lead to vision loss and even blindness (if left untreated).There is evidence that nitric oxide has a role in primary open-angle glaucoma, and that dietary intake of nitrates is beneficial. Green leafy vegetables (iceberg lettuce, romaine lettuce,  mustard, or chard, cooked spinach, and raw spinach) were found to be most beneficial, as well as kale and collard greens. Those who ate the most green leafy vegetables ate about 1.5 servings per day, versus .3 servings daily in the lowest intake group.

Dietary nitrate is predominately derived from green leafy vegetables, which contribute approximately 80% of nitrate intake. But they are found as well in other vegetables, such as beets and carrots. It should be pointed out that those who consumed the most dietary nitrate in this study also consumed more fruits and vegetables, and so also consumed more dietary carotenoids, vitamin C, vitamin E, flavonoids, folate, and vitamin A. Bottom line: try to eat fruits and vegetables daily, especially green leafy vegetables (e.g., a salad). From Science Daily:

Higher dietary nitrate, green leafy vegetable intake associated with lower risk of glaucoma

Greater intake of dietary nitrate and green leafy vegetables was associated with a 20 percent to 30 percent lower risk of primary open-angle glaucoma, according to a study published online by JAMA Ophthalmology.

Elevated intraocular pressure and impaired autoregulation of optic nerve blood flow are implicated in primary open-angle glaucoma (POAG; optic nerve damage from multiple possible causes that is chronic and progresses over time). Evidence suggests that nitrate or nitrite, precursors for nitric oxide, is beneficial for blood circulation. Jae H. Kang, Sc.D., of Brigham & Women's Hospital and Harvard Medical School, Boston, and colleagues evaluated the association between dietary nitrate intake, derived mainly from green leafy vegetables, and POAG. The researchers followed up participants biennially in the prospective cohorts of the Nurses' Health Study (63,893 women; 1984-2012) and the Health Professionals Follow-up Study (41,094 men; 1986-2012). Eligible participants were 40 years or older, were free of POAG, and reported eye examinations. Information on diet was updated with questionnaires.

During follow-up, 1,483 incident cases of POAG were identified. Participants were divided into quintiles (one of five groups) of dietary nitrate intake (quintile 5, approximately 240 mg/d; quintile 1, approximately 80 mg/d). The researchers found that greater intake of dietary nitrate and green leafy vegetables was associated with a 20 percent to 30 percent lower POAG risk; the association was particularly strong (40 percent-50 percent lower risk) for POAG with early paracentral visual field loss (a subtype of POAG linked to dysfunction in blood flow autoregulation). 

Published on Leave a comment on Eat More Berries, Less Erectile Dysfunction?

This study showed an association of eating lots of flavonoid rich foods (strawberries, blueberries, cherries, blackberries, red wine, apples, pears, and citrus products) and lower rates of erectile dysfunction. A higher intake of several flavonoids also reduces diabetes and cardiovascular disease risk. Keep in mind that erectile dysfunction is thought to be of vascular etiology (the cause) and so shares risk factors (such as hypertension, obesity, and smoking) with cardiovascular disease. Studies have shown that lifestyle factors such as plenty of exercise, being of normal weight, and a Mediterranean style diet rich in whole grains, fruit, vegetables, nuts, legumes, and olive oil was associated with both lower rates of erectile dysfunction and an improvement in erectile function in men. So don't focus just on the flavonoids, but on the whole lifestyle package. From Science Daily:

Blueberries, citrus fruits, red wine associated with reduced erectile dysfunction

Flavonoid-rich foods are associated with a reduced risk of erectile dysfunction -- according to a new collaborative study from the University of East Anglia (UEA) and Harvard University. Research published in The American Journal of Clinical Nutrition reveals that eating foods rich in certain flavonoids is associated with a reduced risk of erectile dysfunction in men, with the greatest benefit in those under 70. Of all the different flavonoids, Anthocyanins (found in blueberries, cherries, blackberries, radishes and blackcurrant), flavanones and flavones (found in citrus fruits) were found to offer the greatest benefits in preventing the condition.

It is already known that increased exercise can improve erectile function, but this research shows that eating a flavonoid-rich diet is as good for erectile function as briskly walking for up to five hours a week. The study also showed that a higher total fruit intake was associated with a 14 per cent reduction in the risk of erectile dysfunction. And that a combination of consuming flavonoid-rich foods with exercise can reduce the risk by 21 per cent.

More than 50,000 middle aged men were included in this large population based study. They were asked about their ability to have and maintain an erection sufficient for intercourse -- dating back to 1986. Data on dietary intake was also collected every four years.....More than one third of the men surveyed reported suffering new onset erectile dysfunction. But those who consumed a diet rich in anthocyanins, flavones and flavanones were less likely to suffer the condition.

Prof Cassidy said: "The top sources of anthocyanins, flavones and flavanones consumed in the US are strawberries, blueberries, red wine, apples, pears, and citrus products.""We also found that the benefits were strongest among younger men," she added. The team also looked at other lifestyle factors and found that men who consumed a high intake of anthocyanins and flavanones and who were also physically active had the lowest risk of erectile dysfunction.

Published on Leave a comment on Sugar in Western Diet and Breast Cancer

This study was done in mice, but...it may apply to humans. The researchers found that sugar intake in mice comparable with levels in Western diets (in humans) led to increased breast tumor growth and metastasis.They specifically found that table sugar and high fructose corn syrup "was responsible for facilitating lung metastasis and 12-HETE production in breast tumors" in mice. So, at the very least, think about eliminating high fructose corn syrup from the diet - read labels and definitely eliminate soda (a huge source of added high fructose corn syrup).From Science Daily:

Sugars in Western diets increase risk for breast cancer tumors and metastasis

The high amounts of dietary sugar in the typical Western diet may increase the risk of breast cancer and metastasis to the lungs, according to a study at The University of Texas MD Anderson Cancer Center.The findings, published in the Jan. 1, 2016 online issue of Cancer Research, demonstrated dietary sugar's effect on an enzymatic signaling pathway known as 12-LOX (12-lipoxygenase).

"We found that sucrose intake in mice comparable to levels of Western diets led to increased tumor growth and metastasis, when compared to a non-sugar starch diet," said Peiying Yang, Ph.D., assistant professor of Palliative, Rehabilitation, and Integrative Medicine. "This was due, in part, to increased expression of 12-LOX and a related fatty acid called 12-HETE." Previous epidemiological studies have shown that dietary sugar intake has an impact on breast cancer development, with inflammation thought to play a role.

"The current study investigated the impact of dietary sugar on mammary gland tumor development in multiple mouse models, along with mechanisms that may be involved," said co-author Lorenzo Cohen, Ph.D., professor of Palliative, Rehabilitation, and Integrative Medicine. "We determined that it was specifically fructose, in table sugar and high-fructose corn syrup, ubiquitous within our food system, which was responsible for facilitating lung metastasis and 12-HETE production in breast tumors." Cohen added that the data suggested that dietary sugar induces 12-LOX signaling to increase risks for breast cancer development and metastasis.

Identifying risk factors for breast cancer is a public health priority, say the authors. The researchers state that moderate sugar consumption is critical, given that the per capita consumption of sugar in the U.S. has surged to over 100 lbs. per year and an increase in consumption of sugar-sweetened beverages has been identified as a significant contributor to an epidemic of obesity, heart disease and cancer worldwide.

The MD Anderson team conducted four different studies in which mice were randomized to different diet groups and fed one of four diets. At six months of age, 30 percent of mice on a starch-control diet had measurable tumors, whereas 50 to 58 percent of the mice on sucrose-enriched diets had developed mammary tumors. The study also showed that numbers of lung metastases were significantly higher in mice on a sucrose- or a fructose-enriched diet, versus mice on a starch-control diet.

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Two recent studies found health problems associated with low levels of vitamin D: higher risk of stress fractures and also increased severity of IBS (Irritable Bowel Syndrome) symptoms. From Science Daily:

Low levels of vitamin D may increase risk of stress fractures in active individuals

Vitamin D plays a crucial role in ensuring appropriate bone density. Active individuals who enjoy participating in higher impact activities may need to maintain higher vitamin D levels to reduce their risk of stress fractures, report investigators in The Journal of Foot & Ankle Surgery.

The role of vitamin D in the body has recently become a subject of increasing interest owing to its many physiologic effects throughout multiple organ systems. Vitamin D is an essential nutrient that can behave as a hormone. It is obtained through diet and through the skin when exposed to the sun's rays. It is essential for bone development and remodeling to ensure appropriate bone mass density. Low levels of vitamin D can lead to osteoporosis, osteomalacia, decreased bone mineral density, and risk of acute fracture.

Investigators tested the serum concentration of 25(OH)D, which is used to determine vitamin D status, in patients with confirmed stress fractures....Using the standards recommended by the Vitamin D Council (sufficient range 40 to 80 ng/mL), more than 80% of these patients would have been classified as having insufficient or deficient vitamin D levels. According to the standards set by the Endocrine Society (sufficient range 30 to 100 ng/mL), over 50% had insufficient levels.

"Based on these findings, we recommend a serum vitamin D level of at least 40 ng/mL to protect against stress fractures, especially for active individuals who enjoy participating in higher impact activities," explained Dr. Miller. "This correlates with an earlier study of 600 female Navy recruits who were found to have a twofold greater risk of stress fractures of the tibia and fibula with a vitamin D level of less than 20 ng/mL compared with females with concentrations above 40 ng/mL.

From Science Daily: Large proportion of IBS sufferers are vitamin D deficient

A large proportion of people living with Irritable Bowel Syndrome (IBS) are vitamin D deficient, a new study has found. Researchers from the University of Sheffield discovered a significant association between a patient's vitamin D levels and the severity of their IBS symptoms, particularly the extent to which IBS affects their quality of life.

The study, which is the first of its kind, found that out of 51 IBS patients tested 82 per cent exhibited insufficient vitamin D levels....IBS is a chronic and debilitating functional disorder of the gastrointestinal (GI) tract which affects around 10-15 per cent of the western population. Little is known about why and how the condition develops, although it is known that diet and stress can make symptoms worse. 

Published on Leave a comment on Drinking Coffee May Improve Athletic Endurance and Performance

A University of Georgia review study of the research literature shows that drinking coffee (instead of a caffeine supplement) improves athletic endurance performance. Also, that caffeine from coffee has ergogenic benefits—that it enhances physical performance. More beneficial effects of coffee! From Medical Xpress:

Coffee may improve athletic endurance performance, review finds

The caffeine in a morning cup of coffee could help improve athletic endurance, according to a new University of Georgia review study....To research the issue, Higgins reviewed more than 600 scholarly articles and screened them for those that focused only on caffeinated-coffee conditions, measured the caffeine dose and measured an endurance performance. Of these, nine randomized control trials specifically used coffee to improve endurance."Previous research has focused on caffeine itself as an aid to improve endurance," Higgins said.

 Looking at the nine trials, Higgins found that between 3 and 7 milligrams per kilogram of body weight of caffeine from coffee increased endurance performance by an average of 24 percent. The amount of caffeine in a cup of coffee can vary from 75 mg to more than 150, depending on the variety and how it's roasted and brewed. 

In the nine trials, participants either cycled or ran after drinking coffee. They then exercised vigorously and the results were measured. In a majority of cases, endurance was noticeably improved after the use of coffee.When researching the effects of caffeine from coffee, Higgins found two important discoveries: that caffeine from coffee has ergogenic benefits—that it enhances physical performance—and that more research is needed on the use of caffeine from coffee versus pure caffeine use.

"While there is a lack of high-quality research on coffee as a source of caffeine, there is an abundance of research on pure caffeine," he said. "It's surprising how little we know about caffeine from coffee when its endurance effects could be just as beneficial as pure caffeine."

Higgins said that coffee shouldn't be dismissed as less beneficial for endurance. He found that coffee appears to be just as helpful as taking caffeine in the form of powder or tablets.... Higgins says that more research is needed before giving official recommendations to athletes, especially since the amount of caffeine in a cup of coffee can vary depending on how it's prepared.

Published on Leave a comment on Could Apigenin Be Considered a Brain Food?

The important thing learned from this study (though it was done in the laboratory and not directly on humans) is that it supports that apigenin (in the same chemical group as flavonoids) is important for neuron formation and for strengthening connections between brain cells. Flavonoids are known to positively affect memory and learning, and to preserve and enhance brain function. Apigenin is found in many fruits and vegetables, but common sources are parsley, celery, celeriac, thyme, chamomile, grapefruit, onions, oranges, red wine, and spices such as rosemary, oregano, thyme, basil, and coriander. Another good reason to eat a variety of fruits and vegetables. From Medical Xpress:

Plant compound found in spices and herbs increases brain connections

Brazilian researchers from D'Or Institute for Research and Education (IDOR), Federal University of Rio de Janeiro (UFRJ) and Federal University of Bahia (UFBA) have demonstrated in laboratory that apigenin, a substance found in parsley, thyme, chamomile and red pepper, improves neuron formation and strengthens the connections between brain cells.

Previous experiments with animals had already shown that substances from the same chemical group as the apigenin, known as flavonoids, positively affect memory and learning. Many studies highlight the potential of flavonoids to preserve and enhance brain function. While the effectiveness of flavonoids for brain health is not an entirely new concept, this research is the first to show the positive effects of apigegin directly on human cells and the first to unraveling its mechanism.

The scientists observed that just by applying apigenin to human stem cells in a dish they become neurons after 25 days - an effect they would not see without the substance. Moreover, the neurons that were formed made stronger and sophisticated connections among themselves after being treated with this natural compound."Strong connections between neurons are crucial for good brain function, memory consolidation and learning", says neuroscientist from IDOR and UFRJ Stevens Rehen, leader author of the paper published today atAdvances in Regenerative Biology.

The research team conducted by Rehen demonstrated that apigenin works by binding to estrogen receptors, which affect the development, maturation, function, and plasticity of the nervous system. This group of hormones is known to delay the onset of psychiatric and neurodegenerative disorders such as schizophrenia, depression, Alzheimer's and Parkinson's disease. However, the use of estrogen-based therapies is limited by the increased risk of estrogen-dependent tumors and cardiovascular problems.

Researchers believe apigenin can be used as an alternative approach on future treatments for neurodegenerative diseases as well as in neuronal differentiation strategies in laboratory. "We show a new path for new studies with this substance", points out Rehen. "Moreover, flavonoids are present at high amounts in some foods and we can speculate that a diet rich in flavonoids may influence the formation of neurons and the way they communicate within the brain."

Published on Leave a comment on Beneficial Foods: Blackberries, Red Raspberries, and Black Raspberries

It seems that a lot has been written about the health benefits of some berries, such as blueberries, while other berries have been neglected. This study focused on red raspberries, black raspberries, and blackberries. While the study was done in Poland, it was pointed out that these berries are also commonly grown in the USA. Red raspberry, black raspberry, and blackberry fruits are abundant in dietary phytochemicals such as flavonols, phenolic acids, ellagitannins, vitamins C and E, folic acid, and β-sitosterol. Many of these bioactive compounds exhibit antioxidant activity. Anthocyanins and other phenolic compounds such as ellagitannins and ellagic acid, which distinguish raspberry from other berries, occur in high levels and are mainly responsible for their broad beneficial health properties (including anti-inflammatory, antimicrobial, and antiviral activities).

For these reasons, the researchers said that "raspberry and blackberry fruits can be regarded as natural functional foods". Another term for functional foods is nutraceutical, which is a food containing health-giving additives and having medicinal benefit. From Science Daily:

Looking for the best antioxidant fruit? Search no further than black raspberries

As far as healthy foods go, berries make the top of the list. They contain potent antioxidants, which decrease or reverse the effects of free radicals -- natural byproducts of energy production that can play havoc on the body and that are closely linked with heart disease, cancer, arthritis, stroke or respiratory diseases.

Unsurprisingly, the benefits of berries are extoled in one study after another....The research published now in Open Chemistry suggests that black raspberries grown in Central Europe show greater health benefits than their better known cousins -- raspberries or blackberries.

A group of researchers led by Anna Małgorzata Kostecka-Gugała measured the content of phenolics and anthocyanins in black raspberries, red raspberries and blackberries, assessing their antioxidant potential and health benefits. They were able to confirm that the antioxidant activity of natural products correlates directly with their health promoting properties.

It turns out that the amount of antioxidants in black raspberries was three times higher than the other fruits under investigation. Remarkably, the number was even higher for phenolics or the amount of anthocyanines -- with black raspberries topping their humble cousins by over 1000%. But most interestingly, black raspberries seem to be characterized by a higher content of secondary metabolites, which have been proved beneficial for human health.

Published on Leave a comment on Can Cruciferous Vegetables Fight Cancer?

Reading this recent study, I was struck by how the results are evidence for eating sulforaphane containing foods, such as kale, cauliflower, brussels sprouts, broccoli, and cabbage for health and preventing cancer (due to anti-tumor activity). It is debatable whether it is support for taking supplements (here a sulforaphane supplement called BSE), even though the researchers were testing the supplement. Seven days of taking a supplement without "serious adverse events" (but they did have minor ones such as "mild abdominal discomfort") is too short a length of time for any support for a product. The real test would be seeing what health effects, both positive and negative, are after a year or two of taking the supplement.

Numerous other studies have found that eating foods are linked to good health, while taking supplements are linked to various health problems. Some scientists speculate that it's because the doses in supplements are too high - that they're much higher than what is found in foods. Also, supplements may be missing important nutrients that are found in foods. Bottom line: eat real foods for health and and cancer prevention, including several servings a week of cruciferous vegetables (cauliflower, cabbage, garden cress,bok choy, broccoli, brussels sprouts and similar green leaf vegetables). From Futurity:

Can A Broccoli Sprout Pill Fight Cancer?

A compound in broccoli sprouts may not only help prevent cancer but also treat it. Sulforaphane is found in vegetables such as kale, cauliflower, and cabbage—and in particularly high concentrations in young broccoli sprouts. Sulforaphane also is available as a dietary supplement called BSE.

Researchers at the Texas A&M Health Science Center Institute of Biosciences and Technology, along with collaborators in Oregon, had previously found that sulforaphane could inhibit colon and prostate cancer cells in the laboratory. They’ve now shown that it seems to help humans as well. A paper published in the journal Clinical Epigenetics hints at the biological pathways involved and suggests BSE is generally safe.

“We have not seen any serious adverse events in healthy volunteers who consumed BSE pills for seven days,” says Praveen Rajendran, an assistant professor at Texas A&M University, although some people did experience mild abdominal discomfort.

In a separate clinical study, 28 human volunteers over the age of 50, who were undergoing routine colonoscopies, were surveyed for their cruciferous vegetable-eating habits. When their colon biopsies were examined, those who ate more servings were found to have higher levels of expression of the tumor suppressor gene p16 than those who ate few or no cruciferous vegetables.

This effect on p16 held even for people who didn’t eat these vegetables every single day, which may seem strange, as a single serving of sulforaphane is generally cleared from the body in less than 24 hours. “This hints at the possibility that epigenetic mechanisms are initially triggered by sulforaphane and its metabolites, and downstream mechanisms could be sustained, at least in the short-term, even after compounds are eliminated from the body.” In other words, eating vegetables containing sulforaphane may change your genes and help your body fight tumor growth.

However, it’s not all good news. In animal models, sulforaphane was shown to generally inhibit the development of colon cancer, but it’s a bit of a two-edged sword. Sulforaphane induces a protein called Nrf2, which has beneficial antioxidant and detoxifying effects—and is obviously good for fighting cancer. Later in the development of cancer, though, Nrf2 can also have a role in tumor growth and can even enhance the buildup of plaque in the arteries.

Published on Leave a comment on Some Health Benefits of Eating Tree Nuts Daily

A newly published study reviewed 61 studies that looked at daily tree nut consumption on cardiovascular risk factors and found many health benefits. Tree nut (walnuts, almonds, pistachios, macadamia nuts, pecans, cashews, hazelnuts, and Brazil nuts) consumption lowers total cholesterol, LDL cholesterol, triglycerides, and ApoB, the primary protein in LDL cholesterol. It appeared that nut dose is more important than nut type in lowering cholesterol. The beneficial health effects are greater at about 60 grams (about 2 oz or 2 servings) or more nuts consumed per day, but positive health effects are also found at one serving per day. Five studies found that 100 g nuts per day lowered concentrations of LDL cholesterol by up to 35 mg/dL - an effect size comparable to some statin regimens.

Tree nuts are rich in unsaturated fats, soluble fiber, antioxidants, and phytosterols, which produce beneficial effects on serum lipids, blood pressure, and inflammation. Most studies have looked at walnut and almond consumption, but studies found positive benefits for all types of nuts consumed. From Medical Xpress:

Study finds tree nut consumption may lower risk of cardiovascular disease

A new study published in the American Journal of Clinical Nutrition found that consuming tree nuts, such as walnuts, may lower the risk of cardiovascular disease. After conducting a systematic review and meta-analysis of 61 controlled trials, one of the authors, Michael Falk, PhD, Life Sciences Research Organization, found that consuming tree nuts lowers total cholesterol, triglycerides, LDL cholesterol, and ApoB, the primary protein found in LDL cholesterol. These are key factors that are used to evaluate a person's risk of cardiovascular disease. Walnuts were investigated in 21 of the 61 trials, more than any other nut reviewed in this study.

"Our study results further support the growing body of research that tree nuts, such as walnuts, can reduce the risk of cardiovascular diseases," said Dr. Falk. "Tree nuts contain important nutrients such as unsaturated fats, protein, vitamins and minerals. Walnuts are the only nut that provide a significant amount (2.5 grams per one ounce serving) of alpha-linolenic acid (ALA), the plant-based form of omega-3s."

Beyond finding that tree nuts lower total cholesterol, triglycerides, LDL cholesterol and ApoB, researchers also found that consuming at least two servings (two ounces) per day of tree nuts, such as walnuts, has stronger effects on total cholesterol and LDL. Additionally, results showed that tree nut consumption may be particularly important for lowering the risk of heart disease in individuals with type 2 diabetes.

Of 1,301 articles surveyed, 61 trials met eligibility criteria for this systematic review and meta-analysis, totaling 2,582 unique participants. Trials directly provided nuts to the intervention group rather than relying solely on dietary advice to consume nuts. The dose of nuts varied from 5 to 100 g/day and most participants followed their typical diet.

Published on Leave a comment on Lifestyle Habits That May Protect Men From Lethal Prostate Cancer

Data from 2 huge studies was analyzed and found that vigorous exercise and other healthy habits seems to cut the chance of developing aggressive and lethal prostate cancer up to 68 percent in men over 60. The beneficial lifestyle habits are: weekly vigorous exercise or activity to the point of sweating, at least 7 servings of tomatoes a week, at least one serving of fatty fish per week, reduced intake of processed meat, and being a long-term non-smoker.

Interestingly, vigorous activity or exercise to sweating - ideally up to 3 hours a week - showed the biggest association with a 34 % reduced risk of aggressive prostate cancer.

From Science Daily: Working up a sweat may protect men from lethal prostate cancer

A study that tracked tens of thousands of midlife and older men for more than 20 years has found that vigorous exercise and other healthy lifestyle habits may cut their chances of developing a lethal type of prostate cancer by up to 68 percent.

While most prostate cancers are "clinically indolent," meaning they do not metastasize and are nonlife-threatening, a minority of patients are diagnosed with aggressive disease that invades the bone and other organs, and is ultimately fatal. Lead author Stacey Kenfield, ScD, of UCSF, and a team of researchers at UCSF and Harvard, focused on this variant of prostate cancer to determine if exercise, diet and smoke-free status might have life-saving benefits.

In the study, published in the Journal of the National Cancer Institute, the researchers analyzed data from two U.S. studies: the Health Professionals Follow-Up Study that tracked more than 42,000 males ages 40 to 75, from 1986 to 2010; and a second, the Physicians' Health Study that followed more than 20,000 males ages 40 to 84, from 1982 to 2010.

To gage the effects of lifestyle habits, the researchers developed a score based on the results of the health professionals survey, then applied it to the physicians' study. They assigned one point for each affirmative response to questions about regular intense exercise that induced sweating, body mass index (BMI) under 30, tobacco-free status for a minimum of 10 years, high intake of fatty fish, high intake of tomatoes and low intake of processed meat.

The researchers identified 576 cases of lethal prostate cancer in the health professionals' group and 337 cases in the physicians' group. Participants with 5 to 6 points in the health professionals' group had a 68 percent decreased risk of lethal prostate cancer and a 38 percent decreased risk was observed in the physicians' group for the same comparison.

"We estimated that 47 percent of lethal prostate cancer cases would be prevented in the United States if men over 60 had five or more of these healthy habits," said Kenfield, assistant professor in the Department of Urology at UCSF Medical Center, and formerly of the Department of Medicine at Harvard Medical School in Boston, where the study was initiated.

"It's interesting that vigorous activity had the highest potential impact on prevention of lethal prostate cancer. We calculated the population-attributable risk for American men over 60 and estimated that 34 percent of lethal prostate cancer would be reduced if all men exercised to the point of sweating for at least three hours a week," Kenfield said.

The researchers also calculated that lethal prostate cancer among American men over 60 would be cut by 15 percent if they consumed at least seven servings of tomatoes per week and that 17 percent would be spared this diagnosis if they consumed at least one serving of fatty fish per week. Reducing intake of processed meats would cut the risk by 12 percent, they reported. In contrast, the population-attributed risk for smoking was 3 percent, largely because the majority of older American men are long-term nonsmokers.