Best Diet To Prevent Prostate Cancer

Written by Dr. Steve Chaney on . Posted in diet and prostate cancer

Reducing Your Risk Of Developing Aggressive Prostate Cancer

Author: Dr. Stephen Chaney

 

best diet to prevent prostate cancerIs there a best diet to prevent prostate cancer?

Prostate cancer is like a tale of two entirely different cancers. For most men, prostate cancer is both inevitable and relatively benign. For example, in one study scientists performed a histological examination of the prostate in men who had died of other causes. They reported detecting prostate cancer in 28% of men who died at age 30-39 and 75% of men who died at age 85. That has lead to the oft-quoted saying: “Most men die with prostate cancer rather than from prostate cancer.”

However, in a small percentage of cases, the prostate cancer turns aggressive and becomes a killer. And, there is some evidence that the incidence of aggressive prostate cancer is increasing. It is this aggressive form of prostate cancer that we want to avoid.

The prevention of aggressive prostate cancer has been controversial. The clinical studies have been conflicting. In part, that is because many of the previous studies did not distinguish between benign and aggressive prostate cancer.

More recent studies have focused specifically on the most aggressive forms of prostate cancer. These studies have provided greater clarity. I will summarize the American Cancer Society’s recommendations of foods to eat and foods to avoid below.

However, while the American Cancer Society’s recommendations are helpful, it is more useful to focus on the overall diet rather than individual foods. The current study (A. Castello et al, The Journal Of Urology, 199: 430-437, 2018) does just that. It compares the effect of the Western Diet, a Prudent Diet, and the Mediterranean diet on the risk of developing aggressive prostate cancer.

What is the best diet to prevent prostate cancer?

How Was The Study Done?

best diet to prevent prostate cancer studyThis study was part of the Multicase-Controlled Study On Common Tumors in Spain (MCC-Spain) program. MCC-Spain was conducted in 7 Spanish provinces between September 2008 and December 2013. From this larger population base the authors selected 754 subjects with histologically confirmed prostate cancer and 1,277 matched controls. The ages of men included in this study ranged from 38 to 85 years old.

All the participants in this study participated in an extensive computerized questionnaire to gather information on sociodemographic and lifestyle factors, personal and family medical history, height and weight. The questionnaire included a detailed food frequency questionnaire to assess their diet over the previous year. These questionnaires were administered by trained personnel in face-to-face interviews to assure accuracy.

The authors used a program they had developed previously to analyze the food frequency information and calculate the subject’s adherence to 3 different diets. These diets were:

  • The Western Diet: This diet is characterized by a high intake of high-fat dairy products, refined grains, processed and red meats, caloric drinks, sweets, convenience foods and sauces, and by a low intake of low-fat dairy products, whole grains, vegetables and fruits.
  • The Prudent Diet: This diet is characterized by low-fat dairy products, whole grains, vegetables, fruits, and juices. This is essentially a lacto-ovo-vegetarian diet, which has been shown to reduce the risk of some cancers.
  • The Mediterranean Diet: This diet is characterized by a high intake of fish, boiled potatoes, vegetables, legumes, fruits, whole grains, vegetable oil and olives.

The study compared the adherence to each of these diets to the risk of developing an aggressive form of prostate cancer. Two independent assays were used to identify aggressive tumors.

Best Diet To Prevent Prostate Cancer

 

best diet to prevent prostate cancer foodsThe results of the study were as follows:

  • High adherence to the Western diet tended to increase the risk of aggressive prostate cancer. However, the results were not statistically significant, possibly due to the small number of participants with high adherence to a Western diet in this population.
  • High adherence to the Prudent diet had no effect on aggressive prostate cancer risk, although it does decrease the risk of some cancers.
  • High adherence to the Mediterranean diet decreased the risk of aggressive prostate cancer between 32% and 51% depending on the assay used to identify aggressive tumors.

While the authors preferred to focus on whole diets rather than individual foods, they pointed out that the biggest differences between the Mediterranean diet and the Prudent diet were increased consumption of fish and olives and decreased consumption of dairy. They considered the difference in fish consumption to be the most significant difference.

The authors cited previous studies showing that while fish consumption had no effect on prostate cancer incidence, it did significantly decrease prostate cancer mortality. This suggests that fish and fish oil may reduce the progression of benign prostate tumors into more aggressive forms of prostate cancer.

The authors concluded: “If other researchers confirm these results, the promotion of the Mediterranean dietary pattern might be an efficient way of reducing the risk of developing advanced prostate cancer. Dietary recommendations should consider whole patterns instead of focusing on individual foods.”

Of the 3 diets above, the Mediterranean Diet certainly seems to be the best diet to prevent prostate cancer.

What Does The American Cancer Society Say About Diet And Prostate Cancer?

 

best diet to prevent prostate cancer american cancer societyBased on the best available data, the American Cancer Society has made some very specific recommendations for reducing the risk of prostate cancer. They are:

#1: Control Weight.

#2: Be More Active.

#3: Eat Healthy. By that they mean:

Choose foods and drinks in amounts that help you get to and maintain a healthy weight.

  • Read food labels to become more aware of portion sizes and calories. Be aware that “low-fat” or “non-fat” does not necessarily mean “low-calorie.”
  • Eat smaller portions when eating high-calorie foods.
  • Choose vegetables, whole fruit, legumes such as peas and beans, and other low-calorie foods instead of calorie-dense foods such as French fries, potato chips and other chips, ice cream, donuts, and other sweets.
  • Limit your intake of sugar-sweetened beverages such as soft drinks, sports drinks, and fruit-flavored drinks.
  • When you eat away from home, be especially mindful to choose food low in calories, fat, and added sugar, and avoid eating large portion sizes.

Limit how much processed meat and red meat you eat.

  • Minimize your intake of processed meats such as bacon, sausage, lunch meats, and hot dogs.
  • Choose fish, poultry, or beans instead of red meat (beef, pork, and lamb).

Eat at least 2½ cups of vegetables and fruits each day.

  • Include vegetables and fruits at every meal and snack.
  • Eat a variety of vegetables and fruits each day.
  • Emphasize whole fruits and vegetables; choose 100% juice if you drink vegetable or fruit juices.
  • Limit your use of creamy sauces, dressings, and dips with fruits and vegetables.

Choose whole grains instead of refined grain products.

  • Choose whole-grain breads, pasta, and cereals (such as barley and oats) instead of breads, cereals, and pasta made from refined grains, and brown rice instead of white rice.
  • Limit your intake of refined carbohydrate foods, including pastries, candy, sugar-sweetened breakfast cereals, and other high-sugar foods.

While these recommendations focus on foods rather than diets, they sound a lot like the Mediterranean diet. The only thing that is missing from the American Cancer Society recommendations is olives and olive oil.

Final Thoughts

The American Cancer Society and this study agree that red and processed meats should be minimized in our diet. There is evidence from previous studies that both increase the risk of developing aggressive prostate cancer. The American Cancer Society replaces red and processed meat with fish and poultry. The Mediterranean diet replaces them with fish and legumes. I would be leery of any diet that places a heavy emphasis on red meat consumption.

Don’t think these dietary recommendations are just important for men. In a previous study the same authors reported that adherence to a Western diet increased the risk of developing breast cancer and adherence to the Mediterranean diet reduced risk. In addition, previous studies suggest that red meat consumption also increases the risk of breast cancer.

 

The Bottom Line:

 

A recent study looked at the effect of adherence to a Western Diet, a Prudent Diet, and a Mediterranean diet on the risk of developing aggressive prostate cancer. The study found:

  • High adherence to the Western diet tended to increase the risk of aggressive prostate cancer.
  • High adherence to the Prudent diet had no effect on aggressive prostate cancer risk.
  • High adherence to the Mediterranean diet decrease the risk of aggressive prostate cancer between 32% and 51% depending on the assay used to identify aggressive tumors.
  • Based on their study and previous studies, the authors suggested that fish and fish oil may reduce the progression of benign prostate tumors into more aggressive forms of prostate cancer.

The authors concluded: “If other researchers confirm these results, the promotion of the Mediterranean dietary pattern might be an efficient way of reducing the risk of developing advanced prostate cancer. Dietary recommendations should consider whole patterns instead of focusing on individual foods.”

The authors have also reported similar results for the effects of these 3 diets on the risk of developing breast cancer in women.

For the American Cancer Society recommendations on reducing prostate cancer risk and other details, read the article above:

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

 

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Latest Article

A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

For more details read the article above.

 

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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