NMU 44 – Nutrition and Lifestyle Practices Shown to Reduce Breast Cancer Recurrence, Metastasis, and Mortality
Nutrition / Natural Medicine Update No. 44 (February 28, 2017)
with Dr. James Meschino
Research Topic: Nutrition and Lifestyle Practices Shown to Reduce Breast Cancer Recurrence, Metastasis, and Mortality
Source: Candian Medical Association Journal (February 21, 2017)
The research I am citing today was published in the Canadian Medical Association Journal on February 21, 2017. The review paper examined whether or not lifestyle modification has an impact on the recurrence of breast cancer and overall survival rates of women who have been treated for breast cancer. The results are quite encouraging and empowering, and very much reinforce many of the diet and lifestyle practices I emphasize within the Meschino Wellness Program. The researchers begin by noting that although more than 90% of patients with breast cancer have early stage disease at diagnosis, about 25% will eventually die of distant metastasis. Many patients with breast cancer seek information about things they can do to help prevent breast cancer recurrence or future metastasis, including looking for any nutrition or lifestyle advice of value.
Here is what the evidence shows so far:
Women who gain weight during or after treatment of breast cancer have been consistently shown to be at higher risk of breast cancer–related death. Also, women who are overweight or obese at the time of diagnosis have a poorer prognosis. Being overweight likely increases risk of metastasis and mortality by increasing blood levels of insulin, insulin-like growth factors, estrogen levels, and pro-inflammatory cytokines, all of which tend to promote the cell division rate of breast cancer cells and breast cells in general. Remaining at an ideal weight is therefore highly recommended.
With respect to physical activity, a recent review showed that physical activity has the most robust effect of all lifestyle factors in reducing breast cancer recurrence. Lowered hormone levels, reduction of inflammation, and reversal of insulin resistance, have all been hypothesized to mediate the effects of exercise on the prevention of breast cancer recurrence and metastasis. The Canadian Cancer Society and the American Cancer Society endorse the following recommendations for breast cancer survivors: “Patients should be encouraged to engage in at least 30 minutes of moderate-intensity physical activity at least five days of the week, or 75 minutes of more vigorous exercise, along with two to three weekly strength training sessions, including exercises for major muscle groups”.
With respect to diet, several observational studies have suggested that high consumption of saturated fats and high-fat dairy products may be associated with an increased risk of breast cancer mortality. They also cite the recent studies suggesting that soy products appear to be safe to consume. Many patients are advised by health care professionals (or find information to that effect on the Internet) to avoid soy because it contains estrogens. However, findings from clinical studies do not support this recommendation. Although randomized trials would be necessary to confirm that soy intake truly reduces breast cancer recurrence, there is sufficient evidence to at least conclude that soy products need not be avoided. Some studies show that soy intake is associated with a marked reduction in risk of breast cancer recurrence and mortality in patients who have been treated for breast cancer.
We also see evidence that indicates that women smokers who develop breast cancer have an increased risk of mortality compared with those who never smoked. By the same token, alcohol consumption, overall, appears to be linked to a greater risk of breast cancer recurrence, especially among women with estrogen-receptor-positive breast cancer. Pooled analysis of four cohort studies reported that alcohol intake of more than one drink daily was associated with a 28% increased risk of late recurrence among survivors with estrogen-receptor–positive breast cancer.
With respect to the use of supplements, a recent meta-analysis of 10 prospective observational studies of supplemental and dietary vitamin C intake after breast cancer diagnosis (< 400 mg/d in most studies and no more than 1000 mg), found a 15% reduction in breast cancer mortality in the supplement group, and a 22% reduction for every 100-mg/d increase in dietary vitamin C. Regarding vitamin D, studies suggest that it appears to be advantageous to maintain a blood vitamin D level between (75–200 nmol/L).
More clinical trials are required to confirm the protective effects of soy and vitamin C, and to determine the magnitude by which vitamin D is protective against breast cancer recurrence and metastasis. However, there is substantial evidence to show that breast cancer patients can improve their long-term prognosis and optimize their overall health by adopting the dietary and lifestyle practices outlined in this report. I think it’s important to note that many of the strategies mentioned here have also been shown to be important in preventing breast cancer from developing in the first place, so, all women should pay attention to these lifestyle strategies
I have included a link to the full-text article below if you would like to the read the published article in its entirety.
Hamer, J., and Warner, E., Lifestyle modifications for patients with breast cancer to improve prognosis and optimize overall health. CMAJ. February 21, 2017, vol. 189, no. 7 http://www.cmaj.ca/content/189/7/E268
Eat Smart, Live Well, Look Great!