A new analysis of nearly two decades of U.S. health data is drawing attention to a possible connection between dietary carotenoids and longevity among women. The study, published in BMC Public Health, examined whether consuming higher amounts of five common carotenoids was associated with breast cancer prevalence or with the risk of dying from any cause later in life. The findings offer a mixed picture: carotenoid intake was not consistently related to whether women had breast cancer, but higher consumption of beta-carotene and lutein plus zeaxanthin was associated with substantially lower all-cause mortality. Researchers emphasized that the results are observational and cannot prove that carotenoids themselves extend life or prevent fatal disease.
Carotenoids are naturally occurring pigments responsible for the red, orange, and yellow colors of many fruits and vegetables, as well as the dark green color of leafy plants. They include beta-carotene, alpha-carotene, beta-cryptoxanthin, lutein, zeaxanthin, and lycopene. Some carotenoids, especially beta-carotene and alpha-carotene, can be converted by the body into vitamin A, a nutrient involved in vision, immune function, tissue maintenance, and cellular communication. Others, including lutein and zeaxanthin, accumulate in the retina and are thought to help protect eye tissues from oxidative stress. Lycopene, abundant in tomatoes and certain red fruits, has also been widely studied for possible links with cardiovascular and cancer-related outcomes.
To investigate these compounds in a large population, Jiawei Wang of Sun Yat-sen Memorial Hospital analyzed information from 11,217 female participants in the National Health and Nutrition Examination Survey, or NHANES, covering survey cycles from 2003 through 2018. NHANES combines interviews, physical examinations, laboratory measurements, and dietary assessments to create a nationally representative picture of health in the United States. Participants reported what they ate during two separate 24-hour dietary recalls. From those reports, researchers estimated intake of five major carotenoid groups: alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, and lutein plus zeaxanthin.
The study used two complementary approaches. First, the researchers conducted a cross-sectional analysis to examine whether dietary carotenoid intake differed between women with and without prevalent breast cancer at the time of the survey. This type of analysis can identify statistical associations but cannot establish which event came first. Second, they performed a prospective mortality analysis using records linked to 11,203 eligible participants. These women were followed for a median of 109 months, or a little over nine years, during which 1,074 deaths were recorded. The analysis accounted for the complex design of NHANES, including sampling weights, variance strata, and primary sampling units, allowing the results to better reflect the broader U.S. female population.
For the breast cancer analysis, the results did not reveal a stable or consistent relationship between higher dietary intake of the five carotenoids and prevalent disease after adjustment for other factors. Researchers used survey-weighted logistic regression, a statistical method designed to estimate the probability of an outcome while accounting for variables that could influence the association. These variables can include age, lifestyle, socioeconomic characteristics, and other health-related factors. Although some apparent relationships may emerge before adjustment, they can weaken or disappear once differences between participants are taken into account. The overall conclusion was that the available NHANES data did not support a clear protective association between dietary carotenoids and having breast cancer.
The mortality findings were more pronounced. Compared with women in the lowest quarter of beta-carotene intake, those in the highest quarter had a hazard ratio for all-cause mortality of 0.72, with a 95 percent confidence interval from 0.58 to 0.89. In practical statistical terms, this corresponded to an estimated 28 percent lower rate of death during follow-up, although the result should not be interpreted as proof of a direct life-extending effect. Women in the highest quarter of lutein plus zeaxanthin intake had a hazard ratio of 0.67, with a 95 percent confidence interval from 0.54 to 0.83. That estimate represented an approximately 33 percent lower mortality rate compared with the lowest-intake group. The researchers did not observe similarly robust associations for beta-cryptoxanthin or lycopene, while the findings for alpha-carotene were inconsistent.
The biological explanation remains uncertain. Carotenoids can act as antioxidants in laboratory conditions, meaning they may help neutralize reactive molecules capable of damaging proteins, lipids, and DNA. However, their effects in the human body are considerably more complicated. Carotenoids interact with cell-signaling pathways, immune responses, inflammation, lipid metabolism, and the activity of enzymes involved in vitamin A production. Their absorption also varies according to food preparation, dietary fat, gut health, genetics, and the structure of the particular carotenoid. Lutein and zeaxanthin may have tissue-specific functions that differ from those of carotenoids converted into vitamin A, but the study was not designed to determine which biological mechanism might explain the mortality association.
The researchers also cautioned that dietary intake estimates have inherent limitations. A 24-hour recall captures only a short period of eating and may not represent a person’s usual diet, especially when based on two days of reporting. People may forget foods, misjudge portion sizes, or change what they report because of social expectations. In addition, individuals who consume more carotenoid-rich foods may differ from lower consumers in many other ways. They may exercise more, smoke less, have greater access to health care, follow other healthy dietary patterns, or have different levels of education and income. Even extensive statistical adjustment cannot eliminate every source of confounding, and reverse causation is also possible if existing illness changes dietary habits.
The findings therefore do not suggest that carotenoid supplements should be used to prevent breast cancer or reduce mortality. In nutrition research, results from foods and results from isolated supplements can be very different, and high-dose supplementation may not reproduce the effects of a varied diet. The study instead adds to a growing body of evidence indicating that dietary patterns rich in vegetables and other plant foods may be associated with better long-term health, while also showing why individual nutrients must be interpreted carefully. Larger longitudinal studies, repeated dietary measurements, biomarker data, and research that separates specific causes of death could clarify whether beta-carotene, lutein, and zeaxanthin have independent effects or are markers of broader lifestyle patterns. For now, the most defensible conclusion is that higher intake of certain carotenoids was linked to lower all-cause mortality among U.S. women in this observational dataset, but the relationship does not establish causation and did not translate into a consistent association with prevalent breast cancer.
Subject of Research: Dietary carotenoid intake, prevalent breast cancer, and all-cause mortality among U.S. women
Article Title: Dietary carotenoid intake in relation to prevalent breast cancer and all-cause mortality among U.S. women: cross-sectional and prospective analyses of NHANES 2003–2018
Article References: Wang, J. “Dietary carotenoid intake in relation to prevalent breast cancer and all-cause mortality among U.S. women: cross-sectional and prospective analyses of NHANES 2003–2018.” BMC Public Health (2026).
Image Credits: AI Generated
DOI: 10.1186/s12889-026-29144-9
Keywords: Breast cancer, dietary carotenoids, beta-carotene, lutein, zeaxanthin, NHANES, all-cause mortality, nutrition epidemiology
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