A woman’s overall diet may be connected with her chances of having cervical cancer, according to a new analysis of U.S. health data.
The study found that women who consumed more antioxidant nutrients through food had a substantially lower prevalence of cervical cancer.
The finding does not mean that certain foods can stop cancer from developing. Instead, it gives researchers another reason to explore how nutrition, the immune system and cervical health may be connected.
Cervical cancer begins in cells of the cervix, the lower part of the uterus. Nearly all cases are linked to persistent infection with high-risk forms of HPV, a widespread virus that is passed mainly through intimate skin-to-skin contact.
Most HPV infections disappear on their own and never cause cancer. Trouble can develop when a high-risk infection remains for a long time and gradually causes cell changes that may eventually become cancer if they are not detected and treated.
This is why HPV vaccination and cervical screening have transformed prevention. Vaccination can prevent infection with the HPV types responsible for most cervical cancers, while screening can find dangerous cell changes before they turn into invasive cancer.
Scientists are also studying factors that might affect what happens after HPV infection. One possibility is nutrition, because the body needs a wide range of nutrients to maintain normal immune defenses and protect cells from damage.
The latest study examined antioxidants in the diet. These are substances that help control harmful chemical reactions that occur naturally inside the body and can increase when cells are under stress.
Antioxidants include several vitamins, minerals and other substances found in ordinary foods. Vegetables, fruit, beans, nuts, seeds and other plant foods can provide many of these nutrients at the same time.
Rather than asking whether one vitamin was linked to cervical cancer, the researchers used a combined measure called the Composite Dietary Antioxidant Index. A higher score represented greater overall intake of selected dietary antioxidants.
The team turned to the National Health and Nutrition Examination Survey, a long-running U.S. research program that combines interviews, health examinations and laboratory testing. They analyzed information collected from 2003 through 2018.
The final study group contained 1,044 women, including 174 women with cervical cancer and 870 women without it. Dietary recall interviews were used to estimate antioxidant intake and calculate each participant’s combined score.
When the researchers compared the women, those with higher antioxidant scores were less likely to have cervical cancer. The statistical analysis also took account of other characteristics that could affect the results.
Each one-unit rise in the combined antioxidant score was associated with an 11.4% lower prevalence of cervical cancer. When the women were divided into three groups, those in the highest group had a 55.8% lower prevalence than those in the lowest group.
The researchers also looked at the shape of the relationship. Their results suggested that cervical cancer prevalence generally became lower as antioxidant intake increased, rather than changing only at extremely high levels.
One possible explanation involves damage caused by an excess of unstable molecules inside cells. If the body’s normal defenses cannot keep these molecules under control, they can damage important parts of cells and contribute to long-term inflammation.
Antioxidant nutrients help the body manage this process, so researchers have long wondered whether diets rich in them could influence cancer risk. Good nutrition may also support the immune system, which is particularly relevant to cervical cancer because clearing HPV depends heavily on an effective immune response.
Yet the study has a major weakness that changes how the numbers should be interpreted. It looked at an association at a particular period rather than proving that women who ate more antioxidants went on to develop less cancer.
In other words, the researchers cannot say that the diet caused the difference. It is possible that a higher antioxidant score was a sign of a generally healthier lifestyle rather than the direct reason for the lower prevalence of cervical cancer.
There are other uncertainties as well. Dietary recall is not perfect, past eating habits may differ from recent ones, and cervical cancer can develop over many years, making it difficult to connect a snapshot of diet with the full history of the disease.
The findings also should not be interpreted as a reason to take large doses of antioxidant supplements. Nutrients from a varied diet are not necessarily equivalent to concentrated supplements, and high doses of some supplements can cause harm.
The research was published in the International Journal of Gynecology & Obstetrics as “Association between composite dietary antioxidant index and cervical cancer: a population-based cross-sectional study.” The authors called for future studies that follow women forward in time to determine whether the association is truly protective.
The study is valuable because it examines overall antioxidant intake rather than placing too much attention on a single nutrient. Its results are strong enough to justify further research, but the design means the reported 55.8% difference should not be read as a promise that an antioxidant-rich diet will cut an individual’s cancer risk by that amount.
For now, eating a varied diet with plenty of fruits, vegetables and other nutritious foods remains sensible for general health. But when it comes specifically to preventing cervical cancer, HPV vaccination and regular screening remain the proven tools, while the possible protective role of antioxidant-rich diets remains an intriguing question rather than a settled answer.
Source: Wiley.
