Best Way To Reduce Risk Of Breast Cancer

What Does The American Cancer Society Say About Reducing Breast Cancer Risk? 

Author: Dr. Stephen Chaney

breast cancerBreast cancer is a scary disease. The American Cancer Society tells us:

  • 281,000 women will be diagnosed with invasive breast cancer in 2021.
  • 43,000 women will die from breast cancer in 2021.
  • The good news is that both prevention and treatment of breast cancer have gotten much better:
    • The 5-year survival rate is 90%.
    • The 10-year survival rate is 84%.
    • For women over 50 the death rate has decreased by 1%/year between 2013 and 2018 (mainly due to recognition that hormone replacement therapy is a risk factor for breast cancer).
  • The bad news is:
    • The cost of breast cancer treatment can range from $50,000 to over $180,000.
    • The side effects of breast cancer treatment can be brutal.
      • For example, there is an effective treatment to prevent breast cancer recurrence for some forms of breast cancer, but many women discontinue the treatment after a few years because of the side effects.

So, wouldn’t it be wonderful if there were some simple changes you could make that would dramatically reduce your risk of developing breast cancer in the first place? There are lots of options for reducing your risk of developing breast cancer, but which one(s) should you choose?

  • Dr. Strangelove and his friends are only too happy to recommend their favorite potion, food, or diet.
  • There are long lists of foods you should avoid if you want to reduce your risk of breast cancer.
  • There are also lists of harmful chemicals in cleaners and other household products that you should avoid.

It can become confusing. It can become overwhelming. It would be easy to just throw up your hands and say, “I give up. I don’t know what to do.”

You may be thinking, “Why doesn’t someone simplify things by identifying the top few lifestyle changes that are most effective for reducing my risk of developing breast cancer?”

It turns out someone has. Today I will share two recent studies that have identified the top 6 strategies for reducing your risk of breast cancer, and I have ranked them from 1 to 6 in order of effectiveness.

What Is The Best Way To Reduce Risk Of Breast Cancer?

AwardThe first study (RM Tamimi et al, American Journal of Epidemiology, 184: 884-893, 2016 was designed to identify the major modifiable risk factors for invasive, postmenopausal breast cancer (The term “modifiable risk factors” refers to those risk factors that are under your control.

The study utilized data collected from the Nurses’ Health Study between 1980 and 2010. During that time 8,421 cases of invasive breast cancer were diagnosed in 121,700 postmenopausal women in the study. The study looked at the effect of nonmodifiable and modifiable risk factors on the development of invasive breast cancer in these women.

  • Nonmodifiable risk factors included current age, age at which menstruation began, height, age of first birth, number of births, weight at age 18, family history of breast cancer, and prior benign breast disease.
  • Modifiable risk factors included weight change since age 18, alcohol consumption, physical activity level, breastfeeding, and postmenopausal hormone therapy use.

Here were the results from the study:

  • All the risk factors included in this study accounted for 70% of the risk of developing invasive breast cancer in postmenopausal women.
  • Modifiable risk factors accounted for 34.6% of the risk of developing invasive breast cancer in postmenopausal women.

When they analyzed the effect of modifiable risk factors on the risk of developing invasive breast cancer separately:

  • 44 pounds of weight gain since age 18 increased the risk by 50%.
  • Postmenopausal hormone replacement use increased the risk by 35%.
  • More than one alcoholic beverage/day increased the risk by 32%.
  • Low physical activity increased the risk by 7%.
  • Lack of breastfeeding increased the risk by 5%.

What About The Effect Of Diet On Breast Cancer Risk?

You may be wondering, “What about the effect of a healthy diet on my risk developing invasive breast cancer?” Unfortunately, the study I described above completely disregarded the effect of diet on breast cancer risk.

However, the second study (MS Farvid et al, International Journal of Cancer, 144: 1496-1510, 2019) I will discuss today partially addresses this issue. It uses the same database as the first study and looks at the effect of fruit and vegetable consumption on the risk of developing invasive breast cancer.

When this study compared high versus low intake of fresh fruits and vegetable on the risk of developing invasive breast cancer:

  • Women eating >5.5 servings/day of fruits and vegetables had a 11% lower risk than women consuming ≤2.5 servings/day.
  • Women consuming >2.5 servings/day of fruit had a 9% lower risk than women consuming ≤0.5 servings/day.
  • Women consuming >4.5 servings/day of vegetables had a 9% lower risk than women consuming ≤0.5 servings/day.

While all fresh fruits and vegetables contributed to this effect:

  • The most protective fruits were berries and cantaloupe & melons.
  • The most protective vegetables were yams & sweet potatoes, green leafy vegetables (such as kale, mustard greens, and chard), and cruciferous vegetables (such as Brussels sprouts).

The authors concluded, “Our findings support that higher intake of fruits and vegetables, and specifically cruciferous and yellow/orange vegetables, may reduce the risk of breast cancer, especially those that are more likely to be aggressive tumors.”

Now we are ready to answer your question, “Which lifestyle changes are most effective for reducing your risk of developing breast cancer?” If we combine the two studies and rank order the modifiable risk factors, it would look like this.

#1: Minimize weight gain during your adult years.

#2: Don’t use postmenopausal hormone replacement therapy unless absolutely necessary.

#3: Drink little or no alcohol.

#4: Eat a healthy diet with lots of fresh fruits and vegetables.

#5: Be physically active.

#6: Breastfeed when possible.

What Does The American Cancer Society Say About Reducing The Risk Of Breast Cancer?

American Cancer SocietyThe advice of the American Cancer Society is remarkably similar. Here are their recommendations:

  1. Get to and stay at a healthy weight.

After menopause, most of your estrogen comes from fat tissue. Having more fat tissue increases the amount of estrogen your body makes, raising your risk of breast cancer. Also, women who are overweight tend to have higher levels of insulin. Higher insulin levels have also been linked to breast cancer.

If you are already at a healthy weight, stay there. If you are carrying extra pounds, try to lose some. Losing even a small amount of weight can also have other health benefits and is a good place to start.

3) Be physically active and avoid time spent sitting.

Current recommendations are to get at least 150-300 minutes of moderate intensity or 75-150 minutes of vigorous intensity activity each week. Getting to or exceeding 300 minutes is ideal.

In addition, you should limit sedentary behavior such as sitting, lying down, watching TV, and other forms of screen-based entertainment. This is especially important if you spend most of your working day sitting.

3) Follow a healthy eating plan.

A healthy eating pattern includes a variety of vegetables, fiber-rich legumes (beans and peas), fruits in a variety of colors, and whole grains. It is best to avoid or limit red and processed meats, sugar-sweetened beverages, highly processed foods, and refined grain products. This will provide you with key nutrients in amounts that help you get to and stay at a healthy weight.

4) It is best not to drink alcohol.

Research has shown that drinking any alcohol increases the risk of breast cancer. If you choose to drink alcohol, the American Cancer Society recommends that women have no more than 1 alcoholic drink on any given day. A drink is 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of hard liquor.

5) Think carefully about using hormone replacement therapy.

Studies show that HRT using a combination of estrogen and progestin increases the risk of breast cancer. This combination can also lead to increased breast density making it harder to find breast cancer on mammogram.

Talk with your doctor about all the options to control your menopause symptoms, including the risks and benefits of each. If you decide to try HRT, it is best to use it at the lowest dose that works for you and for as short a time as possible.

The Bottom Line

Breast cancer is a scary disease. The good news is that detection and treatment of breast cancer has improved over the past decade. The bad news is that treatment is expensive, and the side effects can be brutal.

There are lots of options for reducing your risk of developing breast cancer, but which one(s) should you choose?

  • Strangelove and his friends are only too happy to recommend their favorite potion, food, or diet.
  • There are long lists of foods you should avoid if you want to reduce your risk of breast cancer.
  • There are also lists of harmful chemicals in cleaners and other household products that you should avoid.

It can become confusing. It can become overwhelming. It would be easy to just throw up your hands and say, “I give up. I don’t know what to do.”

You may be thinking, “Why doesn’t someone simplify things by identifying the top few lifestyle changes that are most effective for reducing my risk of developing breast cancer?”

It turns out someone has. Today I will share two recent studies that have identified the top 6 strategies for reducing your risk of breast cancer, and I have ranked them from 1 to 6 in order of effectiveness in the article above.

For more details about these studies, my ranking of the top 6 strategies for reducing your risk of breast cancer, and the American Cancer Society recommendations, 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.

Does Fiber Reduce Breast Cancer Risk?

Start Young And Finish Strong

Vegan FoodsThe idea that dietary fiber reduces the risk of breast cancer has been around for a long time. But it is controversial. It has been difficult to prove.

Part of the difficulty arises from what scientists call confounding variables. What do I mean by confounding variables? Let me explain.

A high fiber diet is usually a primarily plant-based diet. Plant foods contain much more than just fiber. They are full of antioxidants and phytonutrients. A primarily plant-based diet is, by definition, low in refined grains. It is usually low in sugar and saturated fat as well.

People who eat primarily plant-based diets are often health conscious. They tend to exercise more, weigh less, and smoke less than the general public.

Each of these things are confounding variables. They could reduce the risk of breast cancer on their own. That confounds (makes it more difficult to interpret) the data. Was the reduction in breast cancer risk due to the high fiber diet or to these factors that go along with a high fiber diet?

It is possible to correct for these confounding variables statistically, but that requires a very large study (a large population group) for the correction to be accurate. Large studies are expensive. Thus, you tend to end up with lots of small studies. And once they have been corrected for confounding variables, small studies give conflicting results. Some show a benefit of fiber. Some do not.

That is why this study (MS Farvid et al, Cancer, DOI: 10.1002/cncr.32816) is important. It is a meta-analysis of 20 clinical studies with almost 2 million women.

How Was The Study Done?

Clinical StudyThe meta-analysis combined data from 20 clinical studies with 1,994,910 women. Fiber intake was calculated from a food frequency questionnaire administered at the beginning of the study for all except one study that used 24-hour dietary records administered at the beginning of the study.

  • Study duration ranged from 2 to 20 years. Nine of the studies (1.37 million women) lasted for 10 years or more.
  • Four studies reported results for premenopausal breast cancer, fifteen studies reported results for postmenopausal breast cancer, and one study reported results for both.

Does Fiber Reduce Breast Cancer Risk?

breast cancerAfter correcting for confounding variables, the results of the study were as follows:

  • When comparing the highest intake with the lowest intake, total fiber consumption was associated with an 8% lower risk of breast cancer.
  • The effect was stronger for premenopausal breast cancer (18%) than for postmenopausal breast cancer (9%).
  • The effect was greater with soluble fiber (10% decreased risk) than for insoluble fiber (7% decreased risk).
    • Note: All plant foods contain a mixture of soluble fiber and insoluble fiber. However, the common foods richest in soluble fiber are fruits, oatmeal, nuts, beans, peas, and lentils.

The authors concluded, “A random-effects meta-analysis of prospective observational studies demonstrated that high total fiber consumption was associated with a reduced risk of breast cancer. This finding was consistent for soluble fiber as well as for women with premenopausal and postmenopausal cancer.”

Start Young And Finish Strong

Mother & Daughter Eating ApplesAn 8% risk reduction doesn’t seem like very much, but the 18% risk reduction in premenopausal breast cancer caught my eye. With a little digging I found a study (MS Farvid et al, Pediatrics 137, March 2016: e20151226) that focused on the effect of fiber intake in young women on their subsequent risk developing both premenopausal and postmenopausal breast cancer. This was, in fact, one of the studies included in the meta-analysis I described above.

This study followed 90,534 women (mean age 36 years) for 20 years. The women competed a food frequency questionnaire at enrollment and every four years thereafter. They also completed a questionnaire about their diet during their teenage years.

When comparing the highest versus the lowest fiber intake:

  • High fiber intake reduced total breast cancer risk by 19%.
    • Postmenopausal breast cancer risk was reduced by 13%.
    • Premenopausal breast cancer risk was reduced by 23%.

Interestingly, only 34% of women who consumed high fiber diets during their teenage years continued to consume high fiber diets as young adults. However, high fiber diets in the teenage years were important. When they looked at teenage diets:

  • High fiber intake reduced total breast cancer risk by 16%.
    • Postmenopausal breast cancer risk was reduced by 15%.
    • Premenopausal breast cancer risk was reduced by 25%.

Other important observations from this study were:

  • There was a 13% decrease in breast cancer risk for every 10 gram increase in fiber intake.
    • 10 grams of fiber is equivalent to one apple plus two slices of 100% whole wheat toast or half a cup of cooked kidney beans plus half a cup of cooked cauliflower or squash.
  • Both soluble fiber (14% decreased risk) and insoluble fiber (20% decreased risk) were effective.
    • In terms of foods, the most significant effects were seen with fruits and vegetables.

The authors concluded, “Our findings support the hypothesis that higher fiber intakes reduce breast cancer risk and suggest that intake during adolescence and early adulthood may be particularly important.”

What Does This Mean For You?

Questioning WomanAs I said before, an 8% decrease in breast cancer risk may not sound like much. You might be tempted to say, “Why bother? Why should I give up my favorite processed and convenience foods and switch to a more whole food, plant-based diet?”

Here are some thoughts to consider:

1) As I mentioned above, there are side benefits to a plant-based diet.

    • Plant based diets have a lower caloric density, so you are less likely to be overweight.
    • Your intake of antioxidants and phytonutrients is increased.
    • Plant foods feed beneficial gut bacteria.
    • Your diet is likely to be lower in sugar, highly processed foods, and saturated fat.

All these factors decrease your risk of developing breast cancer, but they were statistically factored out in calculating the 8% reduction in risk. In other words, the 8% reduction in risk was based on fiber intake only. When you consider all the beneficial effects that accompany a high fiber diet, your actual reduction in risk is likely to be substantially more than 8%.

2) When you consume a high fiber diet, your risk of developing premenopausal breast cancer is decreased by 18%. That is twice the risk reduction seen for postmenopausal breast cancer. This is consistent with several other studies showing the premenopausal breast cancer is more influenced by diet than postmenopausal breast cancer. There are a couple of likely explanations for this.

    • By the time they reach menopause women are more likely to be overweight and some of those fat calls accumulate in breast tissue. Those fat cells continue to produce estrogen after menopause. Even worse, that estrogen is produced right next to the breast cells, where it can do the maximum damage.
    • Mutations accumulate in breast tissue as we age, and some of those mutations increase the risk of breast cancer.

3) When you start consuming a healthy, high fiber diet early in life your risk reduction is much greater (a 13-15% decreased risk of developing postmenopausal breast cancer and a 23-25% decreased risk of developing premenopausal breast cancer). Now, we are talking about numbers that should get your attention!

Plus, these numbers are based on fiber intake only. Once again, when you consider all the other benefits of a high fiber diet, your real risk reduction is likely to be much greater.

In closing I should mention that none of the studies were done with fiber supplements. A fiber supplement may help you be more regular, but there is no evidence that a fiber supplement will reduce your risk of breast cancer.

The Bottom Line

Two recent studies have looked at the effect of fiber intake on the risk of developing breast cancer.

The first study showed that:

  • High fiber diets decreased the overall risk of breast cancer by 8% and the risk of premenopausal breast cancer by 18%.
  • As I describe in the article above, these reductions in risk were based on fiber intake only. If you consider all the side benefits of a high fiber diet, the actual risk reduction is likely to be much greater.

The second study looked at fiber intake during adolescence and early adulthood. It found that when high fiber diets were started early in life:

  • High fiber diets decreased the overall risk of breast cancer by 13-15% and the risk of premenopausal breast cancer by 23-25%.
  • Once again, if you consider all the side benefits of a high fiber diet, the actual risk reduction is likely to be much greater.

The authors of both studies concluded that high fiber diets reduce the risk of developing breast cancer. The risk reduction is greater for premenopausal breast cancer than for postmenopausal breast cancer. Finally, the risk reduction is greatest when high fiber diets are started early in life.

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.

Do Organic Foods Decrease Cancer Risk?

Is Eating Organic Worth The Cost?

Author: Dr. Stephen Chaney

 

organic foods decrease cancer riskMillions of Americans choose organic foods whenever possible. However, organic foods are expensive, and some experts claim they are a waste of money. That is why recent headlines claiming that eating organic foods decrease cancer risk have created such a stir. I will look at the study behind the headlines below, but first let me summarize what we do know about organic foods.

I discussed a study comparing organic and conventionally-grown produce in a recent issue, Organic Foods Healthier, of “Health Tips From the Professor”. It was a major study that combined the results from 343 of the best-designed previous studies. The study found that pesticide and herbicide residues were 4-fold lower in organically-raised produce than in conventionally-raised produce. It also found that the polyphenol content of organically-raised produce was slightly higher than in conventionally-raised produce.

Neither of these findings automatically mean that eating organic produce will improve your health. However, there is increasing evidence that pesticide exposure is linked to increased risk of cancer. Thus, it seems logical that eating organic might decrease cancer risk. It is that hypothesis that the current study (J Baudry et al, JAMA Internal Medicine, doi: 10.1001/jamainternmed.2018.4357 ) was designed to test.

 

How Was The Study Designed?

stethoscopeThis study is part of a major French study called NutriNet-Santé that was launched in 2009. The NutriNet-Santé study is web-based study designed to investigate associations between nutrition and health.Volunteers with access to the internet were recruited from the general population. After agreeing to participate in the study, the volunteers were asked to complete a battery of online assessment forms.

The baseline data for the NutriNet-Santé study included age, sex, occupational status, education level, marital status, income, number of children, smoking status, physical activity, and diet. Dietary intake was assessed using three 24-hour dietary recalls collected over a 2-week period. Two of the 24-hour dietary recalls were on weekdays and one was on a weekend.

The dietary recalls were used to create a “score” of diet quality. Without going into detail, diets that favored animal protein, animal fats, sweets, and highly processed foods were considered “poor quality diets.” Diets that favored plant proteins, vegetable oils & and omega-3 fats, fruits, vegetables, and whole grains were considered “good quality diets.”

This portion of the NutriNet-Santé was designed to measure the correlation between organic food consumption and cancer risk. Two months after enrollment in the study, the participants were asked to provide information on the frequency with which they chose the organic version of 16 different types of food. From this information each participant was assigned an “organic food score” ranging from 0 to 32 points.

The participants in this study were also asked to complete a yearly health status questionnaire online. If they reported a cancer diagnosis, they were asked to provide their medical records, and the study physicians contacted the patient’s physician to confirm details of the diagnosis.

A total of 68,946 French adults completed the study (78% female, mean age 44.2 years). They were followed for an average of 4.56 years. During this time period there were 1340 new cancer diagnoses in this population.

 

Do Organic Foods Decrease Cancer Risk?

 

organic foods decrease cancer risk chartThe participants were divided into four groups based on their organic food score. When participants with the highest organic food score were compared to those with the lowest organic food score there was a:

  • 25% reduction in total cancer risk.
  • 86% reduction in non-Hodgkin lymphoma risk. This is not a novel finding. A previous study has also suggested eating organic might reduce the risk of non-Hodgkin lymphoma.
  • 76% reduction in all lymphoma risk.
  • 34% reduction in postmenopausal breast cancer risk.

The authors concluded “A higher frequency of organic food consumption was associated with a reduced risk of cancer. Although the study findings need to be confirmed, promoting organic food consumption in the general population could be a promising preventive strategy against cancer.”

These are the results and conclusions that made the headlines. However, the scientists who designed the study were aware of previous data showing that people who eat organic are also more likely to eat a healthy diet and follow a healthy lifestyle. Thus, their statistical analysis of the data considered all factors that might influence cancer risk. This analysis provided a much more nuanced interpretation of the data. They found that the association between increased organic food consumption and decreased cancer risk:

  • Was significant for women, older adults, individuals with a family history of cancer, individuals who had a poor diet, and former smokers.
  • Was seen for people of all weights but was greatest for individuals who were obese.
  • Was non-significant for men, younger adults, individuals with no family history of cancer, individuals who had a good diet, never-smokers, and current smokers.
  • Was non-significant for other types of cancer.

You are probably wondering “Does this mean organic foods are beneficial for some people, but not for others?” A superficial interpretation of these data might lead to that conclusion, but let’s dig a little deeper.

 

What Does This Study Mean For You?

organic foods decrease cancer risk women ponderingIn interpreting a study of this type, it is important to ask whether enough people will develop cancer during the study for the results to be statistically significant. That depends on 3 factors:

  • The number of people enrolled in the study.
  • The duration of the study.
  • The probability that participants will develop cancer during the duration of the study.

When you look at the whole study population, all three criteria have been met. There were 68,949 participants who were followed for 4.56 years. During that time 1340 of them developed cancer, of which 459 were breast cancer, 47 were non-Hodgkin lymphomas, and 15 were other lymphomas. A higher frequency of organic food consumption was associated with a decreased in the risk of all these cancers, and that decreased risk was statistically significant. This is the main take-home lesson of the study.

However, when you start to break the study down into subgroups, the number of people in each subgroup and the duration of the study become limiting factors. For example:

  • We don’t really know whether eating organic foods are unimportant for men or whether there were too few men in the study for any benefit to be statistically significant.
  • Colon cancer and many other cancers develop gradually over a 10 to 20-year period. We don’t know whether choosing organic foods is unimportant for these cancers or whether 4.56 years is too short a time to show a significant benefit.
  • The same is true for several of the other variables in this study. For example, if you are an older adult, have a family history of cancer, have a bad diet, and/or have smoked in the recent past, your probability of developing cancer over a 4.56-year time period is relatively high. On the other hand, if you are younger, have no family history of cancer, have a good diet, and have never smoked, your probability of developing cancer during that same time period is very low.

So, how do we interpret the data with these subgroups? We could conclude that eating organic foods in unimportant for people who are young, have no family history of cancer, have a good diet, and have never smoked. A more likely interpretation, however, is that people in these groups have such a low risk of cancer that 4.56 years is too short to demonstrate a benefit of organic foods. It might require a 10, 20, or 30-year study to show benefit of organic foods for these people.

Let me close with three important observations:

  • People often say too me: “I can’t afford organic fruits and vegetables, but I am concerned about pesticide exposure. Does that mean I should avoid fruits and vegetables?” The data from this study provide a clear answer. Eating lots of fruits and vegetables is beneficial even if you can’t afford organic.

[I also let them know about “The Dirty Dozen” ( Rank Produce Items By Pesticide Level ). This is a list of the fruits and vegetables most likely to be contaminated with pesticides. If your budget for organic foods is limited, these are the most important fruits and vegetables to spend it on.]

  • I find it ironic that people who consume a poor diet are the ones most likely to experience an immediate benefit from choosing organic foods. This is, of course, the group that is least likely to eat organic.
  • If you smoke, eating organic probably isn’t going to help you much. Your best bet is to stop smoking.

 

The Bottom Line

 

A recent study looked at the association between organic food consumption and cancer risk. When participants who consumed organic foods frequently were compared to those who almost never consumed organic foods there was a:

  • 25% reduction in total cancer risk.
  • 86% reduction in non-Hodgkin lymphoma risk. This is not novel. A previous study has also suggested eating organic might reduce the risk of non-Hodgkin lymphoma.
  • 76% reduction in all lymphoma risk.
  • 34% reduction in postmenopausal breast cancer risk.

The authors concluded “A higher frequency of organic food consumption was associated with a reduced risk of cancer. Although the study findings need to be confirmed, promoting organic food consumption in the general population could be a promising preventive strategy against cancer.”

These are the results and conclusions that you have seen in the headlines. However, the scientists who designed the study were aware of previous data showing that people who eat organic are also more likely to eat a healthy diet and follow a healthy lifestyle. Thus, their statistical analysis of the data considered all factors that might influence cancer risk. This analysis provided a much more nuanced interpretation of the data, which I have discussed in the article above.

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.

Health Tips From The Professor