Eat Green & Wear Pink

by kwolosz on October 23, 2012

“Let food be thy medicine and medicine be thy food” – Hippocrates

Image courtesy of Hard Rock philanthropy

Perhaps it is no coincidence that October honors both National Breast Cancer Awareness Month and National Vegetarian Awareness Month.

Despite widespread research and treatment options, cancer remains a leading cause of death worldwide. Cancer is still considered a largely preventable disease with estimates of 90-95% of the risk rooted in environmental and lifestyle factors (Cancer Management and Research, 2011).

  • Dietary factors are estimated to be responsible for 30-35% of all cancers in the US.
  • Diet is linked to as many as 50% of breast cancer cases.

At the 2012 American Association for Cancer Research’s (AACR) annual meeting, researchers from the Vanderbilt Epidemiology Center and Shanghai Centers for Disease Control and Prevention presented data from more than 4,800 female breast cancer survivors in China. They had been diagnosed with breast cancer, ranging from stage 1 to stage 4, between 2002 and 2006.

They found that higher consumption of cruciferous vegetables (broccoli, cauliflower, brussels spouts, kale and cabbage) during the first 36 months of diagnosis was associated with a reduced risk for total mortality, breast cancer-specific mortality and the recurrence of breast cancer.

Cruciferous vegetable consumption was measured in quartiles. There was an inverse relationship between women who ate more cruciferous vegetables with a decreased risk for mortality (non- and breast cancer-specific) and recurrence. Women that ate the most reduced their risk by 62% for both overall mortality and breast cancer-specific mortality, while 35% reduced their risk of breast cancer recurrence.

Overall, this study points to the positive role that all cruciferous vegetables can play in preventing (to a degree) and improving survival and recurrence rates associated with breast cancer. Limitations include an understanding of the chemical properties of cruciferous vegetables that protect from breast cancer development, but also the relative quantities in which these beneficial effects are derived.

Image courtesy of Health Media

Researchers at the Sprecher Institute for Comparative Cancer Research at Cornell University have identified and isolated many natural chemicals (phytochemicals) in fruits and vegetables that affect cancer risk and survival. Many other cancer preventing properties of these fruit and vegetable-derived chemicals are preliminary, but include:

  • Isothiocyanates and thiocyanates (brussels sprouts)
  • Flavonoids (berries)
  • Coumarins (citrus fruits)
  • Phenols (almost all fruits and vegetables)
  • Protease inhibitors (legumes)
  • Plant sterols (vegetables)
  • Isoflavones, saponins, inositol hexaphophate (soybeans)
  • Allium compounds (garlic)
  • Limonene (citrus fruit oils)
  • Resveratrol (grapes- aka: WINE!)

The Sprecher Institute at Cornell has a specific program that focuses their research on breast cancer and environmental risk factors. They have defined some of the mechanisms by which the natural chemicals in fruits and vegetables might biologically help reduce the risk of breast cancer and other cancers. These include:

  • Stimulate cell differentiation and stop cell proliferation
    • Cancer occurs more frequently from proliferating cells that are not differentiated. Fruit and vegetable compounds promote cell differentiation and potentially protect from cancer cell formation.
  • Act as antioxidants
    • Fruits and vegetables contain many antioxidants that reduce the oxidation of DNA leading to potential cancer cell formation.
  • Increase activity of protective detoxifying enzymes
    • Toxins in the body can be deactivated and eliminated by protective enzyme systems, a property of many fruits and vegetables, especially broccoli.
  • Enhance immune function
    • Fruits and vegetables strengthen the body’s defense against cancer and other diseases.
  • Alter estrogen level
    • Higher lifetime exposure to estrogen is related to a higher risk of breast cancer. Compounds in fruits and vegetables, especially broccoli, help the body increase the metabolism of estrogen into weaker forms.

Admittedly, the current evidence regarding the actual significance of the relationship between vegetarian eating patterns and the incidence of specific types of cancers are weak. However, a broad body of evidence does link specific plant foods such as fruits and vegetables, plant constituents such as antioxidants and fiber, and achieving and maintaining a healthy weight, as preventative methods to reduce the risk of cancer diagnosis and recurrence.

In the meantime, following a vegetarian diet naturally increases consumption of these beneficial plant constituents. Abiding by a plant-based lifestyle will aid in achieving and maintaining a healthy weight, which is currently the strongest evidence for primary prevention and for improving outcomes after a cancer diagnosis. In fact, vegetarians on average weigh 3-20% less and have lower rates of obesity than omnivores (Cancer Management and Research, 2011). Adopting a low-fat vegetarian diet and regular physical activity will likely lead to a healthy weight and therefore a reduced risk for cancer.

            

                   Bottom line: Eat your broccoli, just like mom said!

 

 

Sources:

Lanou, A., Svenson, B. (2010). Reduced cancer risk in vegetarians: an analysis of recent reports. Cancer Management and Research, 3, 1-8. doi: 10.2147/CMR.S6910

Liu, X., & Lv, K. (2012). Cruciferous vegetables intake is inversely associated with risk of breast cancer: A meta-analysis. The Breast.

Ginny Kendall October 24, 2012 at 10:08 am

This is a very well-written article. The only question I was left with after reading it is, “how much of this vegetables is needed to obtain the protective benefits”? One serving a day of cruciferous veggies? Three?
I successfully battled breast cancer a few years ago, but there is little doubt that mine was caused by 10 years of hormone replacement therapy drugs. It was then believed that, in addition to lessening the effects of menopause, the drugs also protected against heart disease and bone loss. Turns out it did neither, and I ended up with a scary case of breast cancer. So, no amount of vegetables would have helped me. I loved your opening statement from Hippocrates. You tied your beginning and ending together nicely, and you gave just enough technical reference to inform.

kwolosz October 24, 2012 at 10:53 am

Ginny,

Thank you for the kind comments! I really enjoyed writing this post!

With regards to the servings required per day to reach these potential cancer-related risk reductions, I made sure I stated that current research is limited and weak. These studies merely point out the overall benefit of a plant-based diet for improved health and wellness. Future implications suggest that more research is needed to understand the quantity of vegetables required to derive this beneficial effect.

Congratulations on beating breast cancer — I love to hear success stories.

Gaythia Weis October 29, 2012 at 7:24 pm

I agree that this is a well written and informative post. I do hope that more detailed scientific research is done on dietary impacts on health. While I am an omnivore, I do try to include a large variety of vegetables and fruits in my diet. I would like to see more societal support for including fruits and vegetables. That needs to include better access for all. School programs are important.

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