The prostate is can be a troublesome little gland. It is prone to painful infections and inflammation (prostatitis), enlargement that interferes with urination (benign prostatic hyperplasia, or BPH), and cancer. Prevention is the best medicine, something exercise can help with. Exercise has also been shown to help treat various prostate-related conditions.

Although relatively few studies have looked at the impact of exercise specifically on prostate health, the ones that have suggest that regular physical activity can be good for this walnut-sized gland.

BPH prevention. In the ongoing Harvard-based Health Professionals Follow-up Study, men who were more physically active were less likely to suffer from BPH. Even low- to moderate-intensity physical activity, such as walking regularly at a moderate pace, yielded benefits.

Prostatitis treatment. Italian researchers conducted a randomized controlled trial (considered the gold standard of medical research) in men with chronic prostatitis. Those in the aerobic exercise group walked briskly three times a week. A comparison group did non-aerobic exercise (leg lifts, sit ups, and stretching) three times a week. At the end of 18 weeks, men in both groups felt better, but those doing aerobic exercises reported less prostatitis pain, less anxiety and depression, and better quality of life.

Prostate cancer progression. In a study of more than 1,400 men diagnosed with early-stage prostate cancer, men who walked briskly (not leisurely) for at least three hours a week were 57% less likely to have their cancer progress than those who walked less often and less vigorously. In an analysis from the Health Professionals Follow-up Study, men diagnosed with localized prostate cancer who engaged in vigorous activity at least three hours each week had a 61% lower chance of dying from the illness, compared to men who engaged in vigorous activity less than one hour a week.

How to get started

A well-rounded exercise program that includes a half-hour of physical activity on all or most days of the week delivers solid health benefits. And you needn’t perform this activity all at once; you can break it up into three 10-minute segments.

As always, talk to your doctor before beginning an exercise program. He or she can help you develop a routine based on your health and fitness level.

Legumes play an important role in traditional diets in many parts of the world. They are low in fat, are good sources of protein and fiber, and contain a variety of micronutrients and phytoestrogens (plant estrogens). Phytoestrogens have received a lot of attention for their ability to fight not only cancer, but also heart disease and osteoporosis. They help balance hormones in the body and thus are thought to be particularly valuable for the hormone-dependent cancers: breast cancer and prostate cancer. It is well known that male hormones play a role in prostate cancer development.

Despite their advantages, legumes play a minor role in most Western diets. The typical Western based diet (lower in vegetables and legumes and higher in animal-based foods) can cause an increase in both male and female hormones (androgens and estrogens), while a plant-based diet tends to lower these hormones. This is the basis for the role of diet in the development of hormone-dependent cancers.

Soy foods, such as tofu, soy milk, soy beans, and vegetarian burgers, seem to be particularly rich in cancer-fighting properties. This is at least partially due to a form of phytoestrogen, called isoflavones, that is found primarily in soy. It appears to help prevent prostate cancer by binding to male hormone receptors in the prostate, thus reducing the stimulating effect of male hormones on prostate cell growth.

Epidemiological studies have shown that high levels of isoflavones are often associated with low rates of breast, colon, and prostate cancer. This has been used to explain why countries such as Japan and China that typically consume large amounts of soy have lower risks of these diseases.

The difficulty with consuming soy for reducing risk of prostate cancer is the lack of clinical trial evidence to support its use. As with any dietary component, it is difficult to isolate the effect of a particular food type to prove its effectiveness. One prospective study, including over 12,000 men, did evaluate consumption of soy milk. It found that those who drank soy milk regularly had a reduced risk of prostate cancer. The relationship held up after other factors were controlled for. Other studies need to be done to further establish the benefits of soy. In the meantime, getting more soy foods into your diet can be healthy for many reasons, and lowering your risk of prostate cancer may be one of these.

The prostate gland depends on testosterone for growth and development. Prostate cells, both noncancer and cancer, do too. This is why prostate cancer is sometimes referred to as a hormone-dependent cancer. Higher levels of circulating testosterone lead to higher concentrations in the prostate, and this appears to increase the risk of clinically significant prostate cancer. However, higher testosterone levels are not consistently found in prostate cancer patients, so there is more to the relationship.

A possible protective role of exercise has been proposed based on its ability to lower testosterone levels and to boost the immune system. Exercise causes a temporary reduction in testosterone, so regular exercise can reduce long-term exposure to testosterone. And chronic exercise has been shown to increase the number and activity of natural killer cells, which are part of the immune system that attack cancer cells.

Based on these effects, it seems that exercise should be beneficial, but the evidence concerning the impact of exercise on prostate cancer risk is inconclusive. In a review of 17 epidemiological studies of varying quality, 9 showed a beneficial effect, 5 no effect, and the other 3 actually showed an increased risk related to exercise or physical activity. None of the studies, however, provided conclusive proof, but taken together, they seem to support a weak beneficial effect of regular exercise on prostate cancer risk.

The challenge is proving that men who exercise regularly develop less prostate cancer when all other factors are the same. This requires a prospective long-term randomized study, and this probably will never be done. The best long-term prospective studies that looked at habitual physical activity in adulthood are encouraging, however.

A study of nearly 18,000 alumni of Harvard University showed that those who maintained a high level of physical activity were about half as likely to develop prostate cancer after the age of 70 as those who were least active. Another prospective study evaluated the level of physical fitness, as well as physical activity, on the risk of prostate cancer. Higher fitness levels were associated with lower risk in men under 60, but not in older men. And men who expended more than 1,000 kcal per week in exercise had lower risk than those who did not get this much exercise. The best long-term study of men's health is the Health Professionals Follow-up Study. It began in 1986 and has followed over 47,000 men in various health occupations since then. Data was collected in the beginning, and periodically through the study, on many factors including physical activity. The only positive result through 1994 was that at least 3 hours per week of vigorous physical activity was associated with a reduced risk of metastatic prostate cancer. But no relationship was observed between physical activity and the incidence of total or advanced prostate cancer. The same study, however, found an inverse relation between physical activity and BPH, more activity meant a lower likelihood of urinary symptoms or surgery for BPH. Walking 2–3 hours per week was enough to lower the risk of BPH.

The bottom line is that questions remain about the relation between exercise and prostate cancer, but there is no question that regular exercise is good for general health. So, it is wise to get some moderate exercise on most days of the week, and you may be protecting yourself from prostate problems, too.

Boston, MA – Men who do weight training regularly—for example, for 30 minutes per day, five days per week—may be able to reduce their risk of type 2 diabetes by up to 34%, according to a new study by Harvard School of Public Health (HSPH) and University of Southern Denmark researchers. And if they combine weight training and aerobic exercise, such as brisk walking or running, they may be able to reduce their risk even further—up to 59%.

This is the first study to examine the role of weight training in the prevention of type 2 diabetes. The results suggest that, because weight training appears to confer significant benefits independent of aerobic exercise, it can be a valuable alternative for people who have difficulty with the latter.  

The study will be published online in Archives of Internal Medicine on August 6, 2012. 

“Until now, previous studies have reported that aerobic exercise is of major importance for type 2 diabetes prevention,” said lead author Anders Grøntved, visiting researcher in the Department of Nutrition at HSPH and a doctoral student in exercise epidemiology at the University of Southern Denmark. “But many people have difficulty engaging in or adhering to aerobic exercise. These new results suggest that weight training, to a large extent, can serve as an alternative to aerobic exercise for type 2 diabetes prevention.” 

Type 2 diabetes is a major public health concern and it’s on the rise. An estimated 346 million people worldwide have type 2 diabetes, and diabetes-related deaths are expected to double between 2005 and 2030, according to the World Health Organization. More than 80% of these deaths occur in low- and middle-income countries. 

The researchers, including senior author Frank Hu, professor of nutrition and epidemiology at HSPH, followed 32,002 men from the Health Professionals Follow-up Study from 1990 to 2008. Information on how much time the men spent each week on weight training and aerobic exercise came from questionnaires they filled out every two years. The researchers adjusted for other types of physical activity, television viewing, alcohol and coffee intake, smoking, ethnicity, family history of diabetes, and a number of dietary factors. During the study period, there were 2,278 new cases of diabetes among the men followed. 

The findings showed that even a modest amount of weight training may help reduce type 2 diabetes risk. The researchers categorized the men according to how much weight training they did per week—between 1 and 59 minutes, between 60 and 149 minutes, and at least 150 minutes—and found that the training reduced their type 2 diabetes risk by 12%, 25%, and 34%, respectively, compared with no weight training. Aerobic exercise is associated with significant benefits as well, the researchers found—it reduced the risk of type 2 diabetes by 7%, 31%, and 52%, respectively, for the three categories above. 

The researchers also found that the combination of weight training and aerobic exercise confers the greatest benefits: Men who did more than 150 minutes of aerobics as well as at least 150 minutes of weight training per week had a 59% reduced risk of type 2 diabetes. 

Grøntved said that further research is needed to confirm the results of the study as well as to analyze whether or not the findings can be generalized to women. 

“This study provides clear evidence that weight training has beneficial effects on diabetes risk over and above aerobic exercise, which are likely to be mediated through increased muscle mass and improved insulin sensitivity,” said Hu. “To achieve the best results for diabetes prevention, resistance training can be incorporated with aerobic exercise.” 

Other HSPH authors included Eric Rimm, associate professor in the Departments of Epidemiology and Nutrition, and Walter Willett, Frederick John Stare Professor of Epidemiology and Nutrition and chair of the Department of Nutrition. 

Support for the study was provided by the National Institutes of Health (DK58845 and CA55075). 

“A Prospective Study of Weight Training and Risk of Type 2 Diabetes Mellitus in Men,” Anders Grøntved, Eric B. Rimm, Walter C. Willett, Lars B. Andersen, Frank B. Hu, Archives of Internal Medicine, online August 6, 2012.

The foods we eat can affect our risk of developing certain types of cancer. High energy and high fat diets can lead to obesity and are generally thought to increase the risk of some cancers. Plant-based diets high in fresh fruits, vegetables, legumes and wholegrain foods may help to prevent cancer.

Diet is just one of the lifestyle factors that influence the risk of developing cancer. Smoking, obesity, alcohol, sun exposure and physical activity levels are also important. Although some foods can affect cancer risk, there is no evidence that specific foods can cause or cure cancer.

Food and some common cancers
Some common cancers (and how they are affected by what we eat) include:

• Lung cancer – this is the leading cause of death from cancer in the world and smoking is mostly responsible. There is convincing evidence that diets high in vegetables and fruits are protective against lung cancer. It is thought that compounds called carotenoids (present in significant amounts in fruits and vegetables), as well as vitamin E, are probably responsible for some of this effect. However, the use of antioxidant supplements, such as beta-carotene and vitamin E, has not been proven to be effective in either prevention or treatment of lung cancer and may, in fact, increase the risk of developing cancer in those who smoke. While fruits and vegetables may offer some degree of protection, not smoking in the first place is by far the best prevention.

• Breast cancer – this is the most common type of cancer in women in the world. There is an increased risk of breast cancer with factors such as rapid early growth, greater adult height and weight gain in adulthood. Much of the risk of developing breast cancer involves factors that influence oestrogen levels during a woman’s reproductive life, such as age of menarche (first period), number of pregnancies and breastfeeding practices. Post menopausal women who are carrying too much weight, especially around their middle, have more than twice the average risk of breast cancer. Diets high in mono-unsaturated fat and high in vegetables and fruits may reduce the risk, while alcohol consumption increases the risk.

• Prostate cancer – a quarter of all new cancers diagnosed in men in UK is prostate cancer. Vegetables, soy in particular may decrease the risk, while a high fat diet that comprises mostly animal fat sources (such as dairy products, fatty meats and takeaway foods) may increase the risk. Lycopene is a potent antioxidant found in tomatoes, tomato-based products, watermelon and strawberries. It may also help lower the risk of prostate cancer.

• Bowel cancer – this is the fourth most common cancer in the world. Up to 70 per cent of cases can be prevented by following a healthy lifestyle. Keeping a healthy weight, being physically active and a diet high in vegetables and fibre are protective, while consuming a large amount of red meat (especially processed meat) and alcohol may increase the risk.

Foods to ‘eat less’
Foods to limit in your diet or eat less of include:

• Fatty processed red meats

• Highly processed foods that are low in fibre

• Heavily salted and pickled foods.

Foods to ‘eat more’
The strongest protective anti-cancer effect has been shown with:

• Vegetables, especially raw vegetables or salads

• Leafy green vegetables

• Carrots

• Tomatoes

• Citrus fruits

• Cruciferous vegetables like broccoli, cabbage, brussels sprouts, bok choy and other Asian greens.

Include more of these vegetables and fruits in your diet along with other varieties.

Seven a day
Eating seven or more serves daily of a variety of grains, grain products, legumes, roots and tubers will also provide protective benefits against cancer. The less processed the grains, the better. Diets high in refined starch and refined sugar may increase the risk of stomach cancer and bowel cancer.

Meat and bowel cancer
There is now convincing scientific evidence that eating processed meat increases bowel cancer risk. The World Cancer Research Fund (WCRF) has recently recommended that people avoid eating processed meat. Processed meats are any meat that has been preserved by curing, salting or smoking, or by adding chemical preservatives. These meats include hot dogs, ham, bacon and some sausages and burgers.

It is recommended that children are not given processed meats at all. This is because many of the habits we develop as children last into adulthood. Substitutes for processed meats that are recommended for children include poultry or fish, low fat cheese or small amounts of lean meat.

The WCRF also recommends limiting the amount of fresh red meat we eat to 500g (cooked weight) a week. This is because there is convincing evidence that red meat also increases a person’s risk of bowel cancer.

Some research suggests that eating burnt or charred meat may increase cancer risk, but the evidence is unclear.

Fats and cancer
There has been a great deal of interest in the possible association between fat and cancer. Current evidence does not indicate a direct link between fat intake and particular types of cancer (with the possible exception of prostate cancer). However, a high fat diet may lead to obesity, which is a risk factor for several cancers including cancer of the colon, breast, kidney, oesophagus, gallbladder and endometrium.

Supplements are not the answer
Results of studies that show a protective effect of foods containing certain nutrients should not be taken to mean that these nutrients, when isolated and taken as supplements, will provide the same benefits for cancer prevention. In some cases, there has been an increased risk of cancer in those people who take nutrient supplements at doses higher than the amount of that nutrient normally eaten in foods.

Suspect foods examined
While a high energy, low fibre diet may increase a person’s risk of developing cancer, some individual foods have also been singled out as potentially causing cancer (carcinogenic). These include:

• Artificial sweeteners – such as aspartame, saccharin and cyclamate. Laboratory rats can develop bladder cancer if fed huge amounts of saccharin or cyclamate, although this is at levels thousands of times greater than a normal diet. International studies agree that humans aren’t affected in the same way. Artificial sweeteners are considered safe to eat.

• Cured, pickled or salty foods – there is no conclusive evidence that red meat causes cancer. However, bacon and other cured or pickled meats contain a substance called nitrate, which has the potential to cause cancer in laboratory animals when eaten in huge doses. How this research relates to humans isn’t clear. To be on the safe side, it is best to limit the amount of cured meats in the diet because they are generally high in fat and salt. Salt has also been associated with an increased risk of stomach cancer and should be consumed in limited amounts.

• Burnt or barbecued foods – a group of carcinogenic substances called polycyclic aromatic hydrocarbons (PAHs) can be produced if foods are overheated or burnt. Although charred or smoked foods could contain traces of PAHs, experts agree that the amount in the average UK diet is too low to be considered a significant cancer risk. However, when cooking, it’s best to use relatively low temperature methods wherever possible. These include steaming, boiling, poaching, stewing, casseroling, braising, baking, stir-frying, microwaving or roasting. Avoiding char-grilled meats and foods would also be smart.

• Peanuts – some laboratory animals can develop cancer after eating peanuts that are contaminated with toxin-producing moulds. However, peanuts sold in the UK are generally uncontaminated and contamination is routinely screened for.

• Alcohol – consuming alcohol increases the risk of cancers of the mouth, pharynx, larynx, oesophagus, breast and liver. The risk is even greater in those people who smoke. Alcohol has also been associated with colon, breast and rectal cancers. Men should drink less than two standard drinks a day and women less than one standard drink a day.

Treating cancer with food
While food plays an important role in preventing some cancers, the therapeutic value of food in treating existing cancer is less clear. It is true that a person with cancer needs excellent nutrition in order to better cope with the physical demands of the illness and the rigours of medical treatment. However, claims that particular foods, vitamins or micro nutrients can kill cancer cells should be viewed with scepticism To date, there is little scientific proof that a particular food or supplement can cure cancer or destroy cancer cells.

Recently some Japanese studies have found that green tea may delay the development and spread of certain cancers. Other studies have suggested that soy may also have a similar effect. Although this work is preliminary, it may suggest a more important role for food in the treatment of cancer in the future.

Nutrition for the person with cancer is important for many reasons, including:

• The immune system needs bolstering to fight at full strength.

• The diet may be adjusted to cope with various symptoms, such as constipation, diarrhoea or nausea.

• Loss of appetite or an increased metabolism means that high energy foods may need to be included in the daily diet.

• Extra protein may be needed to help prevent loss of muscle from weight loss.

Things to remember

• High fat, low fibre diets may increase the risk of many cancers, including bowel, lung, prostate and uterine cancers.

• You can reduce your risk of developing cancer by eating more fresh fruits, leafy green vegetables and wholegrain foods.

• Even though diet can influence your risk of developing cancer, there is little evidence that special foods can be used to cure existing cancers.