clinical trials

Which Vitamins Reduce Breast Cancer Risk?

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How Can You Reduce Your Risk Of Breast Cancer?

Author: Dr. Stephen Chaney 

Breast cancer is scary. The good news is that treatment has gotten much better. Breast cancer is no longer a death sentence. But most women would prefer to avoid breast cancer surgery, radiation, and/or chemotherapy if they could.

Could something as simple as supplementation reduce your risk of developing breast cancer? If so, which vitamins should you be taking? Or, put another way, which vitamins reduce breast cancer risk?

If you ask your doctor, they will tell you, “Supplementation is a waste of money. Vitamins don’t reduce your risk of getting cancer.” And they will be correct! That’s because these are the wrong questions.

Let me explain. These are “one size fits all” questions. Studies to answer these questions start with healthy women and asks if vitamin supplementation reduces breast cancer risk for all of them. The answer to that question is, “No”. Multiple studies have confirmed this.

But the truth is more complicated. We should be asking, “Who benefits from vitamin supplementation”, instead of, “Does everyone benefit from supplementation?”Supplementation Perspective

I have summed up this concept with the Venn diagram on the right. Every woman does not need supplementation. But those with poor diet, increased need, genetic predisposition, and/or certain diseases may benefit from supplementation. That is why we should be asking, “Who needs supplementation?”.

Unfortunately, while this concept of individualized treatment has led to dramatic advances for cancer drug development, it has been virtually ignored for studies on supplementation and breast cancer risk.

The current study (H Song et al., Nutrients, 14: 2644, 2022) is an exception. It asks whether obese women who wish to reduce their risk of breast may benefit more from certain micronutrients than women of normal weight.

How Was This Study Done?

Clinical StudyThe data for this analysis came from the KoGES study. This was a study administered by the Korea Agency for Disease Control and Prevention between 2004 and 2016. It was designed to provide a scientific basis for personalized prevention of chronic diseases in the Korean population.

Of the 211,721 participants enrolled in the original KoGES study, this study included data from 41,593 women who:

  • Underwent a health examination at 38 health examination centers upon enrollment between 2004 and 2013 and a follow up health examination between 2012 and 2016. The average follow-up period was 4.9 years.
  • Were cancer-free when they enrolled in the study and developed breast cancer prior to their follow-up health examination.
  • Had reliable diet data.

Dietary intake was based on a food frequency questionnaire administered during their initial health screening. Dietary intake of 15 micronutrients (calcium, phosphorous, iron, potassium, vitamin A, sodium, vitamin B1, vitamin B2, vitamin B6, niacin, folic acid, vitamin C, vitamin E, zinc, and cholesterol) and 4 macronutrients (energy, protein, fat, and carbohydrate) was determined from the food frequency data and compared to the Korean Dietary Reference Intakes (KDRIs). [Note: The Korean DRIs are slightly different than US standards.]

  • The women were then divided into two groups based on whether they consumed more or less than the Korean DRIs for each nutrient.

Which Vitamins Reduce Breast Cancer Risk?

Vitamin SupplementsThere were two major findings from this study.

1) When the investigators grouped all the women in the study together:

    • none of the 15 micronutrients and 4 macronutrients analyzed in this study influenced breast cancer risk.
    • This confirms most previous studies that have been designed as a “one size fits all” study. So, if your doctor was relying on this kind of study, they were technically correct in saying that vitamin supplements don’t appear to reduce breast cancer risk.

2) But when the investigators separated the women by weight, an interesting dichotomy was observed:

    • For obese women (BMI ≥ 25 kg/m2):
      • Vitamin C intake above the recommended Korean DRI (100 mg/day) reduced the risk of breast cancer by 46%.
      • Vitamin B6 intake above the recommended Korean DRI (1.4 mg/day) reduced the risk of breast cancer by 52%.
    • For women of normal weight (BMI < 25 kg/m2) neither vitamin C nor vitamin B6 had any effect on breast cancer risk.

The authors concluded, “In obese women, exceeding the recommended daily intake levels of vitamin C and vitamin B6 was associated with a lower risk of breast cancer. However, other micronutrients were not associated with breast cancer risk in these women.” [Note: Supplement use was not included in the diet survey, so above recommended intake of C and B6 was from foods consumed, not from supplements.]

What Does This Study Mean For You?

Questioning WomanThis study is a perfect example of why we should be asking, “Who benefits from vitamin supplementation”, instead of, “Does everyone benefit from supplementation?”

In terms of the Venn diagram I introduced above, some people consider obesity a disease.

But whether you consider obesity a disease or not, it does increase the need for many nutrients. So, it is conceivable that extra vitamins C and B6 might provide benefits in obese women that are not seen in non-obese women.

This is, of course, a ground-breaking study. It is the first study of its kind and deserves to be followed by other studies to confirm this observation. Ideally, these studies would test whether the same effect is seen in other population groups and determine the optimal dose of vitamin C and B6 to reduce breast cancer risk.

However, I am not optimistic that these studies will be done. It is easy to get funding for the “do vitamin supplements benefit everyone?” studies that confirm the existing prejudice against vitamin supplementation.

It is much harder to obtain funding for “who benefits from vitamin supplementation?” studies that challenge the existing paradigm. But these are the kind of studies that are needed most.

How Can You Reduce Your Risk Of Breast Cancer?

As I said, this is the first study of its kind, so you could consider the results as preliminary. However, assuming it might be true:

  • I do not recommend megadoses of vitamins C and B6. The above average intake of C and B6 in this study came from food alone. And we do not have any dose response studies that might define an optimal dose of C and B6.
  • I do recommend balance. Based on this study, multivitamins should provide enough C and B6 to have a meaningful effect on breast cancer risk. And multivitamins are inexpensive and risk-free.

In addition, there are things you can do that are proven to reduce breast cancer risk. Here is what the American Cancer Society recommends:

  • Get to and stay at a healthy weight.
  • Be physically active and avoid time sitting.
  • Follow a healthy eating plan.
  • It is best not to drink alcohol.
  • Think carefully about using hormone replacement therapy.

I provide more detail about each of these recommendations in a recent article in “Health Tips From the Professor”.

The Bottom Line 

Most doctors will tell you that supplementation does not reduce your risk of breast cancer. And that opinion is backed up by multiple published clinical studies.

But the problem is that these studies are all asking the wrong question. They are asking, “Does supplementation reduce the risk of breast cancer for all women?”. A better question would be, “Which women benefit from supplementation?”

A recent study asked both of those questions. They looked at the effect of 15 micronutrients on breast cancer risk.

  1. When the investigators grouped all the women in the study together:
    • None of the 15 micronutrients influenced breast cancer risk.

2) But when the investigators separated the women by weight, an interesting dichotomy was observed:

    • For obese women (BMI ≥ 25 kg/m2):
      • Vitamin C intake above the recommended intake reduced the risk of breast cancer by 46%.
      • Vitamin B6 intake above the recommended intake reduced the risk of breast cancer by 52%.
    • For women of normal weight (BMI < 25 kg/m2) neither vitamin C nor vitamin B6 had any effect on breast cancer risk.

The authors concluded, “In obese women, exceeding the recommended daily intake levels of vitamin C and vitamin B6 was associated with a lower risk of breast cancer. However, other micronutrients were not associated with breast cancer risk in these women.”

For more information on this study, what it means for you, and proven methods for reducing breast cancer risk 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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My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

 

Are Clinical Trials Misleading?

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Is Most Of What You’ve Been Told About Vitamins Wrong?

Author: Dr. Stephen Chaney

 

man searching with magnifying glassI am a scientist and a professor. I taught medical students for 40 years. I believe in evidence based medicine. Why would I tell you that many of the clinical trials about the impact of individual nutrients on your health are misleading?

Let me start by sharing a story that I used to tell every new graduate student in my lab. The story goes like this: There is this drunk on the sidewalk, on his hands and knees under a lamppost, just groping around. A policeman comes up to him and says, “What are you doing?” The drunk says, “I’m looking for my housekeys.” The policeman gets down on his hands and knees and he looks too, and finally he says, “I can’t find them anywhere. Are you sure you lost them here?” To which the drunk relies, “Nope, I lost them over there, but the light’s better here.”

The point I was trying to make is that we can only do experiments where the light is good. But the questions we sometimes want to ask are over in the corner, where we can’t really shine the light on it directly. It’s often difficult to look in the right place and/or to ask the right questions.

That’s particularly the case with holistic approaches because holistic approaches, by their very nature, are multi-factorial. You have multiple variables that you’re trying to change at one time. For example, you might want to optimize weight, exercise, vitamins, minerals, and essential fatty acids if you’re trying to look at a healthy lifestyle.

But, in the 21st-century, studies generally focus on individual nutrients or individual drugs in an intervention, placebo-controlled trial. This is considered the “Gold Standard” for evidence based medicine. However, it’s very difficult to evaluate holistic approaches with that kind of study.

 

The Whole Is Greater Than The Parts

internationally renowned expert sessionOne of the examples that I love to use, because it really made an impression on me as a young scientist, occurred at an International Cancer Symposium I attended more than 30 years ago.

I attended a session in which an internationally renowned expert was giving his talk on colon cancer. He said, “I can show you, unequivocally, that colon cancer risk is significantly decreased by a lifestyle that includes a high-fiber diet, a low-fat diet, adequate calcium, adequate B-vitamins, exercise and weight control. But I can’t show you that any one of them, by themselves, is effective.”

The question that came to me as I heard him speak was: “What’s the message that a responsible scientist or responsible health professional should be giving to their patients or the people that they’re advising?” You’ve heard experts saying: “Don’t worry about the fat” “Don’t worry about calcium.” “Don’t worry about B-vitamins.” “Don’t worry about fiber.” “None of them can be shown to decrease the risk of colon cancer.”

Is that the message that we should be giving people? Or should we really be saying what that doctor said many years ago – that a lifestyle that includes all those things significantly decreases the risk of colon cancer?

 

Are Clinical Trials Misleading?

 

clinical trialsA recent paper about how to best evaluate the relationships between nutrition and disease (Shao et al, European Journal of Nutrition, DOI: 10.1007/s00394-017-1460-9) caught my attention. This paper, written by a team of 10 international experts, was a summary of key findings from a recent international meeting of the Council for Responsible Nutrition.

The paper started out by reviewing the strengths of clinical studies in which the effect of a single intervention on a health outcome is evaluated in a double-blind, placebo controlled clinical study; something they referred to as a reductionist approach.

  • A reductionist approach is ideal for evaluating the effect of drug candidates on disease outcomes. That is because:
    • Everyone in the study already has the disease.
    • The drug is meant to be used by itself.
    • It is easy to measure outcomes. The drug either has an effect on the disease, or it doesn’t.
  • A reductionist approach has also been valuable in defining the role of nutrients in preventing deficiency diseases. That is because, in the words of the authors:
    • “A simple cause-effect relationship exists between a particular nutrient and a specific deficiency disease.
    • Symptoms of a specific nutrient deficiency can be explained in terms of the role played by the respective nutrient.
    • Providing the nutrient in the diet can prevent, and in many cases, reverse, the deficiency disease.”

However, the authors went on to say that the use of the reductionist approach to study effect of nutrients on optimal health or holistic approaches to health often has led to misleading results. They characterized these studies as often “leading down a rabbit hole.”

For example, the authors said: “In an effort to uncover the magic bullet, scientists inappropriately studied nutrients in a drug-like context. Unlike drugs, nutrients do not function in isolation and have beneficial effects on multiple tissues and organ systems.”

The authors concluded by saying that if we want to truly understand the role of nutrients on health outcomes, we need to focus on holistic studies in which the effect of multiple nutrients on multiple health outcomes are evaluated.

 

Clinical Trials That Have Mislead Us

 

I realize that the report I just described is conceptual. It’s difficult to wrap your mind around. To better understand how clinical trials employing a reductionist approach can often mislead us, let’s look at some specific examples comparing holistic studies to reductionist studies.

dash dietHealthy diets: Healthy diets have a significant impact on health, but it is not possible to show that individual components of those diets are beneficial: In previous issues of “Health Tips From the Professor,” I have discussed the Mediterranean and DASH diets. I have shared studies showing that the Mediterranean diet dramatically reduces the risk of heart disease, diabetes, cognitive decline, and some forms of cancer. However, you would be hard pressed to show that individual components of the Mediterranean diet have a significant impact on these health outcomes.

Similarly, the DASH diet is as effective as drugs at controlling blood pressure (Moore et al, Hypertension, 38: 155-158, 2001 ). Other than sodium restriction, you would also be hard pressed to show that the individual components of the DASH diet exert a significant effect on blood pressure.

Supplements That Are Going to Kill You: Individual nutrients can sometimes have adverse effects on your health. Those reports generate a lot of negative press, but the adverse effects usually disappear when those nutrients are consumed along with nutrients that complement their effect on whole body metabolism.

Here are two examples of the negative press that you may have heard about the dangers of supplementation, but what the studies actually showed is that a holistic approach to supplementation was superior to supplementation with individual supplements.

For example, there was something called the Iowa Women’s Health Study that got some negative press in 2011 (Mursu et al, Archives of Internal Medicine, 171:1625-1633, 2011). This is one of those studies that led to headlines saying: “Vitamins can kill you.”

The study did show a slight increase in mortality in people who consumed high-dose vitamin B6 or high-dose folic acid by themselves. But in that same study, people who were taking high-dose B complex containing both B6 and folic acid in balance had no increase in mortality.

Another example is vitamin E and prostate cancer. You probably saw the headlines, which said: “Vitamin E increases the risk of prostate cancer.” Those headlines were based on a study published in the Journal of American Medical Association in 2011 (J Klein et al, Journal of the American Medical Association, 306: 1549-1556, 2011). However, in that same study the people who were taking vitamin E and selenium (two nutrients that work together synergistically) had no increase in cancer risk.

There is a good biochemical rationale for those results. Vitamin E converts some reactive oxygen species to peroxides, which are quite dangerous themselves. Selenium is part of an enzyme that converts peroxides to water. Together, vitamin E and selenium convert reactive oxygen species (free radicals) to something that is completely harmless. By itself, vitamin E does only half the job.

Holistic Approaches to Supplementation: The same appears to be true if you look at holistic approaches to supplementation rather than holistic approach to supplementationsupplementing with individual nutrients. A study done by Dr. Gladys Block and published in Nutrition Journal in 2007 (Block et al, Nutrition Journal 2007,6:30 doi: 10.1186/1475-2891-6-30) looked at a holistic approach to supplementation for the very first time.

She compared people who were taking multiple supplements, typically a multivitamin, extra antioxidants, extra B vitamins, carotenoids, fish oil and probiotics; people who were taking only a multivitamin; and people who were using no supplements whatsoever over a 20-year period.

The results were dramatic. The holistic supplement users had one-third the prevalence of angina, heart attacks and congestive heart failure and one-quarter the prevalence of diabetes compared to the other two groups. In contrast, reductionist studies looking at the effect of those nutrients individually have generally been inconclusive.

So just like a holistic approach to health, a holistic approach to supplementation appears to be superior to using individual supplements. This is a small study, but it is an example of the kinds of studies that need to be done in the future, if we are to truly understand the role of holistic approaches for optimizing our health.

 

The Bottom Line

Studies in which the effect of a single intervention on health outcomes is evaluated in a double-blind, placebo-controlled clinical study is considered the “Gold Standard” for evidence based medicine. A recent report has questioned the value of this kind of study in defining the impact of holistic approaches on health outcomes.

  • The authors concluded that the “Gold Standard” of clinical studies, which they referred to as a reductionist approach:
    • Was ideal for evaluating the effect of drugs on preventing or treating diseases.
    • Has been well suited for evaluating the role of individual nutrients in preventing deficiency diseases.
    • Was not well suited for evaluating the role of holistic approaches on health outcomes.
    • Was not well suited for evaluating the role of nutrients for promoting optimal health.
  • The authors concluded by saying that if we want to truly understand the role of nutrients on health outcomes, we need to focus on holistic studies in which the effect of multiple nutrients on multiple health outcomes are evaluated.
  • I shared three examples illustrating cases in which holistic approaches were more accurate than reductionist studies:
    • Healthy diets have a significant impact on health, but it is not possible to show that that individual components of those diets are beneficial.
    • Individual nutrients can sometimes have adverse effects on your health, but the adverse effects disappear when those nutrients are consumed along with nutrients that complement their effect(s) on whole body metabolism.
    • A holistic approach to supplementation can have a significant, beneficial effect on health outcomes, but it is difficult to show any benefit from individual nutrients included in that holistic approach to supplementation.
  • 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