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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The Truth About Vitamin D

Posted December 11, 2018 by Dr. Steve Chaney

Does Vitamin D Reduce Risk Of Heart Disease & Cancer?

Author: Dr. Stephen Chaney

 

the truth about vitamin dYou have every right to be confused. One day you are told that vitamin D reduces your risk of heart disease and cancer. The next day you are told vitamin D makes has no effect on those diseases. You are told vitamin D is a waste of money. What should you believe?  What is the truth about vitamin D?

In mid-November a major clinical study called VITAL was published. It examined the effect of vitamin D and omega-3s on heart disease and cancer risk. Last week I wrote about the omega-3 portion of the study. This week I will cover the vitamin D portion of the study.

Once again, if you rely on the media for your information on supplementation, you are probably confused. Headlines ranged from “Vitamin D Is Ineffective For Preventing Cancer And Heart Disease to “Vitamin D Lowers Odds Of Cancer Death.” What is the truth?

The problem is that reporters aren’t scientists. They don’t know how to interpret clinical studies. What they report is filtered through their personal biases. That is why I take the time to carefully evaluate the clinical studies, so I can provide you with accurate information. Let me sort through the dueling headlines and give you the truth about vitamin D, cancer, and heart disease.

How Was The Study Designed?

the truth about vitamin d studyThe VITAL study (JE Manson et al, New England Journal of Medicine, DOI: 10.1056/NEJMoa1811403) enrolled 25,871 healthy adults (average age = 67) in the United States. The study participants were 50% female, 50% male, and 20% African American. None of the participants had preexisting cancer or heart disease. The characteristics of the study group were typical of the American population at that age, namely:

  • The average BMI was 28, which means that most of the participants were significantly overweight.
  • 7% of them had diabetes.

Study participants were given questionnaires on enrollment to assess clinical and lifestyle factors including dietary intake. Blood samples were taken from about 65% of the participants to determine 25-hydroxyvitamin D levels (a measure of vitamin D status) at baseline and at the end of the first year. The participants were given either 2,000 IU of vitamin D/day or a placebo and followed for an average of 5.3 years.

There were two important characteristics of the participants in this study that may have influenced the outcome.

  • The average 25-hydroxyvitamin D level of participants at the beginning of the study was 31 ng/ml (78 nmol/L). The NIH considers 20-50 ng/ml (50-125 nmol/L) to be the optimal level of 25-hydroxyvitamin D for most physiological functions. This means that study participants started in the middle of the optimal range with respect to vitamin D status.

[Note: The NIH defines the 20-50 ng/ml range as “adequate.”  However, I know many of my readers like to aim beyond adequate to reach what they consider to be “optimal.”  In the case of vitamin D, that might not be a good idea. The NIH considers anything above 50 ng/ml as associated “with potentially adverse effects.”  For that reason, I will refer to the 20-50 ng/ml range as optimal for this article. I wouldn’t want to encourage my readers to be aiming for above 50 ng/ml.]

  • Only 12.7% of participants had 25-hydroxyvitamin D levels below 20 ng/ml, which the NIH considers to be inadequate. The results with this group were not statistically different from the study participants with optimal vitamin D status, but it is not clear that there were enough people in this subgroup for a statistically valid comparison with participants starting with an optimal vitamin D status.
  • At the end of the first year, 25-hydroxyvitamin D levels in the treatment group increased to 42 ng/ml (105 nmol/L), which is near the upper end of the optimal range. Thus, for most of the participants, the study was evaluating whether there was a benefit of increasing vitamin D status from the middle to the upper end of the optimal range.
  • The study allowed subjects to continue taking supplements that contained up to 800 IU of vitamin D. While the authors tried to correct for this statistically, it is a confounding variable.

Does Vitamin D Reduce The Risk Of Cancer?

 

the truth about vitamin d and cancerYou may remember from last week that omega-3s were more effective for reducing heart disease risk than for reducing cancer risk. What is the truth about vitamin D and cancer risk?   The results are reversed for vitamin D, so I will discuss cancer first.

The study reported that vitamin D supplementation did not reduce a diagnosis of invasive cancer of any type, breast cancer, prostate cancer, or colon cancer during the 5.3-year time-period of this study. This was the result that was reported in the abstract and was what lazy journalists, who never read past the abstract, reported.

However, the rest of the study was more positive. For example, occurrence of invasive cancer of any type was reduced by:

  • 23% in African-Americans.
  • 24% in patients with a healthy body weight.

Several previous studies have suggested that vitamin D may be more effective at preventing cancer in people with a healthy body weight, but the mechanism of this effect is currently unknown.

Most previous studies have not included enough African-Americans to determine whether they respond more favorably to vitamin D supplementation. However, African-Americans have a higher risk of cancer, so this finding deserves follow-up.

In addition, when the study looked at deaths from cancer, the results were very positive. For example:

  • Cancer deaths during the 5.3-year study period were reduced by 17%.
  • The longer vitamin D supplementation was continued the more effective it became at reducing cancer deaths. For example,
  • When the authors excluded cancer deaths occurring during the first year of supplementation, vitamin D reduced cancer deaths by 21%.
  • When the authors excluded cancer deaths occurring during the first two years of supplementation, vitamin D reduced cancer deaths by 25%.

Finally, no side effects were noted in the vitamin D group.

 

Does Vitamin D Reduce The Risk Of Heart Disease?

 

the truth about vitamin d and heart diseaseThe VITAL study also looked at the effect of vitamin D on heart disease risk. What is the truth about vitamin D and heart disease?  The results from this study were uniformly negative. There was no effect of vitamin D supplementation on all major cardiovascular events combined, heart attack, stroke, or death from heart disease. Does that mean vitamin D has no role in reducing heart disease risk? That’s not clear.

The authors had a thought-provoking explanation for why the results were negative for heart disease, but positive for cancer. Remember that the participants in this trial started with a 25-hydroxyvitamin D level of 31 ng/ml and increased it to at least 42 ng/ml with vitamin D supplementation.

The authors stated that previous studies have suggested the 25-hydroxyvitamin D level associated with the lowest risk for heart disease is between 20 and 25 ng/ml. If that is true, most of the participants in this trial were already in the lowest possible risk for heart disease with respect to vitamin D status before the study even started. There would be no reason to expect additional vitamin D to further reduce their risk of heart disease.

In contrast, the authors said that previous studies suggest the 25-hydroxyvitamin D level associated with the lowest risk of cancer deaths is above 30 ng/ml. If that is true, it would explain why vitamin D supplementation in this study was effective at reducing cancer deaths.

However, previous placebo-controlled clinical studies have also been inconclusive with respect to vitamin D and heart disease. My recommendation would be to think of adequate vitamin D status as part of a holistic approach to reducing heart disease – one that includes a heart-healthy diet and a heart-healthy lifestyle – rather than a “magic bullet” that decreases heart disease risk by itself.

As for heart-healthy diets, I discuss the pros and cons of various diets in my book, “Slaying The Food Myths.”  As I discuss in my book, the weight of scientific evidence supports primarily plant-based diets that include omega-3s as heart healthy. As an example, the Mediterranean diet is primarily plant-based and is rich in healthy oils like olive oil and omega-3s. It is associated with reduced risk of both heart disease and cancer.

 

What Is The Truth About Vitamin D?

 

the truth about vitamin d signThere is a lot of confusion around the question of whether vitamin D reduces the risk of cancer. This study strengthened previous observation suggesting that vitamin D supplementation decreases cancer deaths. However, it is also consistent with previous studies that have failed to find an effect of vitamin D on cancer development. How can we understand this apparent discrepancy? The authors provided a logical explanation. They pointed out that:

  • Cancer development takes 20-30 years while this clinical study lasted only 5.3 years. That means that vitamin D supplementation only occurred at the tail end of the cancer development process. In fact, the cancer was already there in most of the patients in the study who developed cancer. It just had not been diagnosed yet. In the words of the authors: “Given the long latency for cancer development, extended follow-up is necessary to fully ascertain potential effects [of vitamin D supplementation].”
  • In contrast, none of the patients had been diagnosed with cancer when they entered the trial. That means that the patients were diagnosed with cancer during the 5.3-year study period. They were receiving extra vitamin D during the entire period of cancer treatment. Thus, the effect of vitamin D on reducing cancer deaths was easier to detect.

What Does This Study Mean For You?

the truth about vitamin d questionsVitamin D Is Likely To Decrease Your Risk Of Dying From Cancer: When you combine the results of this study with what we already know about vitamin D and cancer, the results are clear. Vitamin D appears to reduce your risk of dying from cancer. More importantly, the longer you have been supplementing with vitamin D, the greater your risk reduction is likely to be.

Vitamin D May Decrease Your Risk Of Developing Cancer: Association studies suggest that optimal vitamin D status is associated with decreased cancer risk, especially colon cancer risk. However, the long time for cancer development means that we may never be able to prove this effect through double-blind, placebo-controlled clinical trials.

Holistic Is Best: When you combine the VITAL study results with what we already know about vitamin D and heart disease, it appears that supplementing with vitamin D is unlikely to reduce your risk of developing heart disease unless you are vitamin D deficient. However, a holistic approach that starts with a healthy, primarily plant-based diet and makes sure your vitamin D status is adequate is likely to be effective.

The same is likely true for cancer. While the latest study suggests that vitamin D supplementation reduces your risk of dying from cancer, those vitamin D supplements are likely to be even more effective if you also adopt a healthy diet and lifestyle.

How Much Vitamin D Do You Need? The optimal dose of vitamin D is likely to be different for each of us. One of the things we have learned in recent years is that there are significant differences in the efficiency with which we convert vitamin D from diet and/or sun exposure into the active form of vitamin D in our cells. Fortunately, the blood test for 25-hydroxyvitamin D is readily available and is widely considered to be an excellent measure of our vitamin D status.

I recommend that you have your blood level of 25-hydroxyvitamin D tested on an annual basis. Based on the best currently available data, I recommend you aim for >20 ng/ml (50 nmol/L) if you wish to minimize your risk of heart disease and >30 ng/ml (75 nmol/L) if you wish to minimize your risk of cancer. If you can achieve those levels through diet and a multivitamin supplement, that is great. If not, I would recommend adding a vitamin D supplement until those levels are achieved.

Finally, you shouldn’t think of vitamin D as a magic bullet. If you are a couch potato and eat sodas and junk food, don’t expect vitamin D to protect you from cancer and heart disease. You should think of maintaining adequate 25-hydroxyvitamin D levels as just one component of a holistic approach to healthy, disease-free living.

 

The Bottom Line

 

There is a lot of confusion around the question of whether vitamin D reduces the risk of cancer and heart disease. A major clinical study has just been published that sheds light on these important questions. It reported:

  • Vitamin D did not decrease the risk of developing cancer during the 5.3-year study duration. The authors pointed out that cancer takes 20-30 years to develop, which means their study was probably too short to detect an effect of vitamin D on the risk of developing cancer.
  • Vitamin D did decrease the risk of dying from cancer, and the longer people were supplementing with vitamin D the bigger the protective effect of vitamin D was.
  • Vitamin D did not decrease the risk of heart disease. However, most study participants had a level of 25-hydroxyvitamin D that was optimal for reducing the risk of heart disease at the beginning of the study. There was no reason to expect that extra vitamin D would provide additional benefit.
  • With respect to both cancer and heart disease the best advice is to:
    • Get your 25-hydroxyvitamin D levels tested on an annual basis and supplement, if necessary, to keep your 25-hydroxyvitamin D levels in what the NIH considers to be an adequate range (20-50 ng/ml).
    • We do not have good dose response data for the beneficial effects of vitamin D on heart disease and cancer. However, according to this article, previous studies suggest you may want to am for 25-hydroxyvitamin D levels above 20 ng/ml to reduce the risk of heart disease and above 30 ng/ml to reduce your risk of cancer.
    • Consider vitamin D as just one component of a holistic approach to healthy, disease-free living.

For more details about the interpretation of these studies and what they mean for you, 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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