Ovarian Cancer: Nutritional Considerations

Epidemiologic investigations have revealed important clues to etiological factors in ovarian cancer. Mortality in both the Mediterranean region⁴ and Asia⁵ is associated with consumption of meat, milk, and animal fat. In contrast, women whose diets are rich in fruits and vegetables appear to have a reduced risk, as described below. These associations have not been tested in randomized clinical trials for ethical and practical reasons. Nonetheless, they suggest important hypotheses regarding means to reduce cancer risk:

Diet and Prevention of Ovarian Cancer

The following factors are under investigation for a possible role in reducing ovarian cancer risk:

Avoiding or reducing meat and saturated fat. A high intake of fat is associated with an increase in risk for ovarian cancer of about 25%, and most of this risk is attributed to saturated fat intake.⁶ Various food sources of saturated fat have been implicated, including meat,^7–8 eggs,⁹ and whole milk.¹⁰ Animal fat and meat influence estrogen activity and increase blood concentrations of insulin–like growth factor–1 (IGF–1),¹¹ a hormone implicated in several cancers, including ovarian cancer.¹²

Avoiding milk. Saturated fat aside, even consumers of skim or low–fat milk in small amounts (one or more servings per day) have a greater risk for ovarian cancer, which has been attributed to galactose–related oocyte toxicity and/or elevation of gonadotropin concentrations.^13,14 Milk consumption also elevates IGF–1 blood concentrations. Some researchers have suggested this is due to the fact that cow’s milk contains IGF–1 that is identical to the growth factor produced by humans.¹⁵ However, milk’s macronutrients also stimulate IGF–1 production within the human body.

Increased fruit and vegetable intake. Some evidence suggests that the benefit of higher fruit and vegetable intake on ovarian cancer risk is evident only in women with higher intake during adolescence.¹⁶ Other studies found that the benefit is limited to women eating 3 or more vegetable servings per day, estimating a 39% lower risk for ovarian cancer compared with women eating 1 or fewer servings per day.¹⁴ This benefit may be attributable to certain carotenoids, such as beta–carotene¹⁷ and lutein.¹⁸ The strong protective effect of green leafy vegetables¹⁹ may be attributable to folate.²⁰

Intake of foods rich in vitamin E. Higher intake of food sources of vitamin E, including whole grains, wheat germ, and nuts, is associated with a 40% lower risk for ovarian cancer.^21,22 Some evidence indicates that supplementary vitamin E (>75 mg/day) is associated with lower risk,²³ although others found that this benefit is evident only with long–term (> 10 years) supplementation.²⁴

Avoidance of obesity. Obesity in adolescence or early adulthood increases later risk for ovarian cancer by 1.5 to 2.0 times that of women with normal body mass index (BMI).^25,26

Moderate alcohol intake. Alcohol–containing beverages do not appear to increase the risk for ovarian cancer.²⁷ Evidence indicates that alcohol intake may even be protective against this cancer, provided that folate intake is fairly high (≥331 μg per day). This statistical association is not a reason to initiate or maintain alcohol consumption, however. Alcohol contributes to risk of breast cancer and other conditions.

Diet and Survival after Ovarian Cancer Diagnosis

The preceding studies relate to risk of developing ovarian cancer. However, some studies also suggest that diet may also play a role after diagnosis. The following foods are under study:

Vegetables. Women with ovarian cancer who consume vegetable–rich diets tend to have enhanced survival. In a population–based, case–controlled study, women who consumed the most vegetables had a 25% lower mortality risk, compared with women consuming the least. A similar association was found in these women for the intake of cruciferous vegetables (including broccoli, cauliflower, and cabbage), and survival was inversely associated with intake of red meat, white meat, and total protein.²⁹

Green tea. Drinking green tea is associated with a lower risk for developing ovarian cancer.³⁰ Drinking 1 cup or more per day was associated with a 57% lower mortality risk in women with ovarian cancer.³¹ Although green tea is known to inhibit cancer growth through a variety of mechanisms in vitroand in vivo,³² further study is needed to assess the benefit of green tea in survival of ovarian cancer.

Orders

See Basic Diet Orders chapter.

Weight loss, as appropriate. See Obesity chapter

Smoking cessation.

What to Tell the Family

Risk of developing ovarian cancer or of succumbing to it may be reduced through healthy diet and lifestyle practices, along with timely screening and early intervention. Family members may support the patient and improve their own health by adopting the same changes. Smoking cessation, maintaining a healthy weight, and breastfeeding all should be encouraged to reduce the risk of ovarian cancer, in addition to their other health benefits.