Researchers looked at hundreds of studies about nutrition and cancer care to understand what we know and what we’re still learning. They found 444 studies happening between 2015 and 2024 that looked at how diet affects cancer patients undergoing treatment. Most studies focused on specific vitamins, supplements, preparing the body before surgery, and helping patients feel better during treatment. However, the researchers discovered that less than one-third of completed studies had actually published their results, making it hard for doctors to know what really works. This analysis shows we need bigger, better-designed studies to help create reliable guidelines for what cancer patients should eat.

The Quick Take

  • What they studied: What nutrition research is being done for cancer patients, and whether those studies are actually getting published so doctors can use the findings
  • Who participated: The study looked at 444 different cancer nutrition research projects from 2015-2024 involving patients actively receiving cancer treatment. Most studies were small, with a typical target of 80 participants, though some ranged from just 1 to 10,000 people
  • Key finding: Less than one-third of completed cancer nutrition studies had published their results by early 2025, which means doctors and patients don’t have access to most of the research being done. Most studies (79%) were testing nutrition interventions, and the most common topics were specific nutrients/supplements, preparing the body before surgery, managing side effects, and nutrition counseling
  • What it means for you: If you’re a cancer patient wondering what to eat during treatment, there’s actually more research happening than you might think—but much of it isn’t being shared publicly. This suggests doctors may not have enough solid evidence yet to give clear nutrition guidelines for all cancer types and treatments. Talk to your cancer care team about nutrition, as they can guide you based on current best practices

The Research Details

Researchers searched two major databases of clinical trials (ClinicalTrials.gov and the Australian New Zealand Clinical Trials Registry) in January 2025 to find all cancer nutrition studies that started between 2015 and 2024. They looked for studies involving patients actively receiving cancer treatment that measured either diet quality, nutritional status, or tested a nutrition intervention. Their search found 1,866 studies initially, but after applying strict criteria, 444 studies qualified for their analysis.

They organized all the studies into categories based on what they were studying: specific nutrients or supplements, preparing the body before surgery, managing side effects and quality of life, nutrition counseling and education, and several other topics. They then looked at patterns like study size, who funded the research, and whether results had been published. This type of analysis is called a ’landscape review’—it’s like taking a bird’s-eye view of an entire field of research to see what’s being studied and what gaps exist.

The researchers used statistical software to organize and analyze the data, looking at differences between types of studies and funding sources. This approach allowed them to identify trends in cancer nutrition research without conducting a new experiment themselves.

Understanding what cancer nutrition research is actually happening is important because it shows doctors and patients what evidence exists to guide treatment decisions. By identifying which topics have the most studies and which have few, researchers can spot where more work is needed. This type of analysis also reveals a major problem: if studies aren’t being published, their findings can’t help patients and doctors make better decisions. The analysis shows that most cancer nutrition research is funded by universities and non-profit organizations rather than government or pharmaceutical companies, which affects what topics get studied.

This is a comprehensive review of existing research rather than a new experiment, so it’s limited by the quality and completeness of information in the trial registries. The researchers couldn’t assess the actual quality of each individual study’s design—they only looked at what was registered and published. The fact that less than one-third of completed studies had published results suggests the actual picture of cancer nutrition research may be even more incomplete than what they found. The study is recent (January 2025) and used systematic search methods, which strengthens its reliability for showing current trends in the field

What the Results Show

The researchers identified 444 cancer nutrition studies conducted between 2015 and 2024. The vast majority (352 studies, or 79%) were intervention studies—meaning they tested whether a specific nutrition change or supplement helped cancer patients. Only about 21% were observational studies that simply tracked what patients ate without trying to change their diet.

The most common research topics were: specific nutrients or supplements (173 studies), preparing the body before surgery or during treatment (153 studies), managing side effects and improving quality of life (136 studies), and nutrition counseling and education (100 studies). This shows that researchers are most interested in testing whether specific dietary changes can help cancer patients feel better and handle treatment side effects.

Most studies were relatively small, with a typical target of 80 participants. However, there was huge variation—some studies aimed to enroll just 1 person while others planned for 10,000. The median (middle point) of 80 participants is important because larger studies generally provide more reliable evidence than small ones.

A striking finding was that most research (85.6%) was funded by sources other than government or industry—primarily universities and non-profit organizations. Only 10.8% received government funding and just 3.6% came from pharmaceutical or supplement companies. This funding pattern suggests that cancer nutrition research is driven more by academic interest than by commercial or government priorities.

The researchers found that less than one-third of completed studies had published their findings as of January 2025. This is a significant problem because unpublished research can’t help doctors and patients make informed decisions. The reasons studies don’t get published vary—sometimes researchers are still analyzing data, sometimes results are disappointing and less likely to be submitted, and sometimes there are resource constraints. This ‘publication gap’ means the true state of cancer nutrition evidence is even more limited than what appears in medical literature. The analysis also showed that intervention studies (which test whether something works) were much more common than studies simply measuring what cancer patients eat, suggesting researchers are more focused on testing solutions than understanding current nutrition practices

This research directly addresses a problem that cancer organizations and medical societies have been noting: there isn’t enough high-quality evidence to create strong nutrition guidelines for cancer patients. Previous reviews have mentioned this gap, but this study provides concrete numbers showing how many studies exist, what they’re studying, and how many results are actually being published. The finding that most research is small and unfunded by government or industry aligns with broader concerns in cancer care that nutrition isn’t prioritized as highly as other treatment areas. This study confirms what many suspected: there’s active research happening, but it’s fragmented and not always making it into the medical literature

The study only looked at trials registered in two databases, so some cancer nutrition research might have been missed if it wasn’t registered. The researchers couldn’t evaluate the actual quality of study designs—they only looked at what was registered and whether results were published. Publication status was checked on just one date (January 1, 2025), so some studies may have published shortly after. The study doesn’t explain why studies weren’t published, only that they weren’t. Finally, this analysis describes what research exists but doesn’t evaluate whether the studies that were published actually had good results or reliable findings—it’s a map of the research landscape, not a judgment of research quality

The Bottom Line

Based on this research, cancer patients should work with their medical team (especially registered dietitians) on nutrition during treatment rather than relying on general nutrition advice. The evidence base is still developing, so personalized guidance from your cancer care team is more reliable than following trends. If you’re considering supplements or major dietary changes during cancer treatment, discuss them with your oncologist or nutrition specialist first, as some may interfere with treatment. The confidence level here is moderate—we know research is happening, but we don’t yet have strong evidence for most nutrition interventions in cancer care

Cancer patients currently undergoing treatment should care about this research because it affects what nutrition guidance their doctors can confidently recommend. Cancer researchers and oncologists should care because it shows where evidence gaps exist and where more research is needed. Cancer organizations developing treatment guidelines should use this information to understand why nutrition guidelines are often weaker than guidelines for other aspects of cancer care. Patients considering joining nutrition studies should know that their participation helps fill these evidence gaps. People interested in cancer prevention may find some relevant information, but this study focuses specifically on patients already being treated

Seeing benefits from nutrition changes during cancer treatment can vary widely. Some benefits like reduced nausea or better energy might appear within days to weeks. Other benefits like improved wound healing before surgery or better tolerance of chemotherapy might take several weeks. Long-term benefits like improved survival or reduced cancer recurrence would take months to years to measure. It’s important to have realistic expectations—nutrition is one part of cancer care, not a replacement for medical treatment

Want to Apply This Research?

  • Track daily nutrition intake (protein, calories, specific nutrients your oncologist recommends) and side effects like nausea, appetite changes, or energy levels. Record this alongside your treatment schedule to see if patterns emerge. Use a simple daily log: date, meals eaten, key nutrients, side effects experienced, and energy level (1-10 scale)
  • Work with your cancer care team to identify 1-2 specific nutrition goals during treatment (such as maintaining protein intake, staying hydrated, or managing appetite changes). Use the app to set reminders for meals and track progress toward these personalized goals rather than following generic nutrition advice
  • Weekly review of your nutrition and symptom patterns with your care team. Look for connections between what you eat and how you feel. Adjust your nutrition plan based on what’s working, not on general trends. Share your tracked data with your oncologist or dietitian at each visit to inform treatment decisions

This analysis describes the current state of cancer nutrition research but does not provide medical advice. Cancer patients should not make nutrition changes based on this information alone. All nutrition decisions during cancer treatment should be made in consultation with your oncology team, including your oncologist and registered dietitian. Some supplements and dietary changes can interfere with cancer treatment or medications. Never start, stop, or change supplements without discussing it with your cancer care team first. This research shows that evidence-based nutrition guidelines for cancer are still being developed, which is why personalized guidance from your medical team is essential.