A study of more than 400 women suggests that losing weight can reduce levels of cancer-promoting proteins in the blood.
Overweight or obese women who lost weight over a 12-month period—through diet alone or both diet and exercise—significantly lowered their levels of proteins that play a role in angiogenesis.
Researchers say this finding suggests that losing weight might help reduce the risk of developing certain cancers.
“We know that being overweight and having a sedentary lifestyle is associated with an increase in risk for developing certain types of cancer,” said Catherine Duggan, PhD, of the Fred Hutchinson Cancer Research Center in Seattle, Washington.
“However, we don’t know exactly why. We wanted to investigate how levels of some biomarkers associated with angiogenesis were altered when overweight, sedentary, postmenopausal women enrolled in a research study lost weight and/or became physically active over the course of a year.”
Dr Duggan and her colleagues described this investigation in Cancer Research.
The team studied 439 women who were postmenopausal and overweight or obese but were otherwise healthy and ranged in age from 50 to 75.
The women were randomized to 1 of 4 study arms:
- A diet arm, in which women restricted their calorie intake to no more than 2000 kcal per day that included less than 30% of fat calories
- An aerobic exercise arm, in which women performed 45 minutes of moderate to vigorous exercise 5 days a week
- A combined diet and exercise arm
- A control arm.
The researchers collected blood samples at baseline and at 12 months, measuring levels of the angiogenesis-related proteins VEGF, PAI-1, and PEDF.
They also measured weight loss at 12 months and found that women in all 3 intervention arms had a significantly higher mean weight loss than women in the control arm.
The mean weight loss was 0.8% of body weight for women in the control arm, 2.4% for women in the exercise arm (P=0.03), 8.5% for women in the diet arm (P<0.001), and 10.8% for women in the diet and exercise arm (P<0.001).
Compared with women in the control arm, those in the diet-only arm and the diet and exercise arm had significantly lower levels of the angiogenesis-related proteins at 12 months. However, such effects were not apparent among women in the exercise-only arm.
Specifically, women in the diet and exercise arm had a significantly greater reduction in PAI-1 at 12 months than women in the control arm (-19.3% and +3.48%, respectively, P<0.0001).
Women in the diet-only arm and the diet and exercise arm had significantly greater reductions in PEDF than controls (-9.20%, -9.90%, and +0.18%, respectively, both P<0.0001).
And women in the diet-only arm (-8.25%, P=0.0005) and the diet and exercise arm (-9.98%, P<0.0001) had significantly greater reductions in VEGF than controls (-1.21%).
The researchers also observed a linear trend in the reductions. So the more weight loss the women experienced, the greater the reduction in angiogenesis-related protein levels.
“Our study shows that weight loss is a safe and effective method of improving the angiogenic profile in healthy individuals,” Dr Duggan said. “We were surprised by the magnitude of change in these biomarkers with weight loss.”
“While we can’t say for certain that reducing the circulating levels of angiogenic factors through weight loss would impact the growth of tumors, it is possible that they might be associated with a less favorable milieu for tumor growth and proliferation.”
Dr Duggan and her colleagues said limitations of this study include the fact that the researchers only measured 3 angiogenic factors and did not measure them in adipose or other tissues.
