The body of evidence about nuts and cancer continues to grow, with new local and international research papers regularly published.

Key studies: Systematic reviews and meta-analyses

Association between nut consumption and prostate cancer risk in adults: A systematic review and dose-response meta-analysis of observational studies. (Balali et al, 2023)
This systematic review and dose-response meta-analysis found no significant association between nut intake and risk of total, advanced, non-advanced, and fatal prostate cancer. The dose-response analyses showed no evidence of a linear or non-linear association between total nut intake and prostate cancer risk. It included 11 articles (from observational studies) with 287,786 total participants and 32,213 cases of prostate cancer.

Association between nut consumption and cancer risk: A meta-analysis. (Cao et al, 2022).
The meta-analysis pooled the findings of 17 previously-published prospective studies on the relationship between nut intake and cancer risk and mortality. Among the findings, a 10g/day increase in total nut intake was linked with a 4% reduced risk of cancer and a 7% decrease in overall cancer mortality. And a 10g/day increase in tree nut consumption was linked with a 20% decrease in overall cancer mortality.

Association of total nut, tree nut, peanut, and peanut butter consumption with cancer incidence and mortality: A comprehensive systematic review and dose-response meta-analysis of observational studies. (Naghshi et al, 2020).
This newly-published review collated the findings from 52 published papers. It found a protective association between total nut and tree nut intake and the risk of cancer and its mortality. A 5g/day increase in total nut intake was linked with a 3%, 6% and 25% lower risk of overall, pancreatic, and colon cancers, respectively. For cancer mortality, the researchers found an 18% risk reduction with higher intakes of tree nuts. In addition, a 5g/day increase in total nut intake was linked with a 4% lower risk of dying from cancer.

Nuts and legumes consumption and risk of colorectal cancer: A systematic review and meta-analysis. (Jin et al, 2022).
This meta-analysis of observational studies looked into the association between the consumption of nuts (13 studies) and legumes (29 studies) and the risk of colorectal cancer. Those who consumed the most nuts and legumes had a 16% and 10% lower risk of colorectal cancer, respectively – compared with the lowest consumption. Based on the dose–response analysis, a 28g/day increment of nut consumption was linked with a 33% lower risk of colorectal cancer. While promising, the researchers say further well-designed studies are needed in this area.

Nut consumption and risk of cardiovascular disease, total cancer, all-cause and cause-specific mortality: A systematic review and dose-response meta-analysis of prospective studies. (Aune et al, 2016)
Higher nut intake is associated with reduced risk of cardiovascular disease, total cancer and all-cause mortality, and mortality from respiratory disease, diabetes, and infections.

Nut consumption and risk of cancer and type 2 diabetes: A systematic review and meta-analysis. (Wu et al, 2015)
Nut consumption was inversely associated with the risk of total cancer, and with the risk of colorectal cancer, endometrial cancer and pancreatic cancer specifically, but not for other cancer types.

Nut consumption on all-cause, cardiovascular, and cancer mortality risk: A systematic review and meta-analysis of epidemiologic studies. (Grosso et al, 2015)
Nut consumption is associated with lower risk of all-cause, CVD, and cancer mortality, but the presence of confounding factors should be taken into account when considering such findings.

Other evidence

Adherence to the Mediterranean diet and risk of gastric cancer: A systematic review and dose–response meta-analysis. (Zhu et al, 2023).
This systematic review and meta-analysis included 11 observational studies, with a total of 1,366,318 participants and 5,708 cases of gastric cancer. It found that the highest adherence to the Mediterranean diet was linked with a 29% reduced risk of gastric cancer, compared with the lowest. And each 1-score increment in the ‘Mediterranean diet score’ was linked with a 5% lower risk of gastric cancer. The findings add to the current evidence that healthy dietary patterns, like the Mediterranean diet, offer a practical strategy in the prevention of gastric cancer.

Dried fruits, nuts, and cancer risk and survival: A review of the evidence and future research directions. (Bolling, 2023)
This narrative review summarizes the evidence for dried fruits and nuts and cancer incidence, mortality, and survival and their potential anticancer properties. Among the findings, prospective cohort studies suggest a higher consumption of nuts is linked with a reduced risk of several site-specific cancers (including colon, lung, and pancreas). And a daily handful (28g) of nuts has been associated with a 21% reduction in the rate of cancer mortality. There is also some evidence that frequent nut consumption is linked with improved survival among people with some types of cancer.

Nut consumption and urogenital and genital, gastrointestinal and women-related cancers: Assessment and review. (Mohamadi et al, 2023).
This review considered in vitro and in vivo (animal) studies, and observational studies in humans. It found that nuts are potentially able to inhibit the development and progression of some types of cancer, and may reduce the risk of cancer and cancer-related mortality. Nuts contain various compounds with anticarcinogenic properties, such as folate, phytosterols, saponins, phytic acid, isoflavones, ellagic acid, α-tocopherol, quercetin, and resveratrol. The researchers say their findings support dietary recommendations to increase nut consumption.

The role of nut and seed consumption in colorectal cancer: A narrative review. (Roman et al, 2022).
This narrative review offers a broad perspective on the known effects of nut and seed consumption on colorectal cancer. It sums up the findings of eight papers, published between 2019 and 2022. The research is divided between those studies finding no significant link between nut consumption and colorectal cancer protection, and those which have. The authors say further research is needed in this area, including on the mechanisms behind the protective effect found in some studies.

Nut and peanut butter consumption and risk of prostate cancer in the NIH‐AARP diet and health study. (Ton et al, 2022).
This large prospective cohort study followed US-based males (with a median age at baseline of 63.7 years) for a median of 15 years. The average (mean) nut and peanut butter intakes were 3.4 and 3.7 grams/day, respectively. It found total nut consumption (nuts and peanut butter combined) was not associated with prostate cancer risk. However, greater frequency of nut consumption (>3-4 times/week) was associated with significantly reduced risk, compared with the lowest frequency (<1/month).

Nut consumption in association with overall mortality and recurrence/disease-specific mortality among long-term breast cancer survivors. (Wang et al, 2021).
This research looked at the associations of nut consumption (including peanuts and tree nuts) with overall survival (OS) and disease-free survival (DFS) among 3,449 long-term breast cancer survivors from the Shanghai Breast Cancer Survival Study. At 10-years post-diagnosis), regular nut consumers had higher OS (93.7% vs 89.0%) and DFS (94.1% vs 86.2%) rates, compared with those who didn’t eat nuts. The associations didn’t vary by nut type. The researchers concluded that nut consumption was associated with better survival, particularly DFS, among long-term breast cancer survivors.

Association of nut consumption with risk of total cancer and 5 specific cancers: Evidence from 3 large prospective cohort studies. (Fang et al, 2021).
This research looked into the link between nut consumption and cancer risk. The researchers pooled the evidence from three large, US-based prospective cohort studies (the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professionals Follow-up Study). It found that frequent nut consumption (≥5 times/week) was not associated with risk of total cancer and common individual cancers (including lung, colorectal, breast, bladder, and aggressive prostate cancer). 

Adolescent alcohol, nuts, and fibre: Combined effects on benign breast disease risk in young women. (Berkey et al, 2020).
This prospective cohort study followed 9,031 females, aged 9-15 years at baseline (1996-2001), until 2014. The researchers hypothesised that consuming nuts/nut butter may lessen the elevated risk of benign breast disease (BBD) – a risk factor for breast cancer – among adolescents who drink alcohol. They found that that those who consumed both alcohol and nuts had a lower risk (RR = 0.47, 95% CI: 0.24–0.89; p = 0.02), compared to drinkers who didn’t eat nuts. The researchers concluded that for high school females who drink, their BBD risk may be offset by consuming nuts. Future studies are needed in this area.

Meta-analysis of the association between nut consumption and the risks of cancer incidence and cancer-specific mortality (Zhang et al, 2020).
Nut consumption is inversely associated with the risks of cancer incidence and mortality; a higher intake is significantly associated with a lower cancer risk.

Legume and nuts consumption in relation to glioma: A case-control study. (Malmir et al, 2020)
The study aimed to investigate the relation between legume and nuts consumption and glioma in a case-control study in Iranian adults. Individuals in the top category of legume and nuts consumption were 66% less likely to have glioma compared with those in the bottom category. There was an inverse association between legume and nuts consumption and odds of glioma, even after controlling for a wide range of confounders, including age, sex, energy intake, BMI and dietary intakes.

Nut consumption and risk of cancer: A meta-analysis of prospective studies. (Long et al, 2020)
This meta-analysis evaluated the relationship between nut consumption and risk of cancer. Thirty-three studies, that included more than 50,000 cancer cases were analysed. When comparing the highest with the lowest category of nut intake, high consumption of nuts was significantly associated with decreased risk of overall cancer (RR = 0.90; 95% CI, 0.85–0.95). The protective effect of nut consumption was especially apparent against cancers from the digestive system (RR = 0.83; 95% CI, 0.77–0.89). The authors also observed a linear dose–response relationship between nut consumption and cancer. In conclusion, the results offer compelling evidence about the association between nut intake and the risk of cancer; with significant protective effects found at 9g/day and the risk of cancer decreasing by 10% for every 20g/day increase.

Nut and peanut butter consumption and the risk of lung cancer and its subtypes: A prospective cohort study (2019).
Significant associations found with total nut intake and small cell carcinoma in men, and non-significant inverse trends found for other lung cancer subtypes in men, but not in women.

Food groups and risk of colorectal cancer. (2018).
For intake of nuts, a decreased risk was observed for colon cancer only.

Dietary Patterns and Colorectal Cancer Risk: A Review of 17 Years of Evidence 2000-2016. (2017).
A “healthy” pattern, generally characterized by high intake of fruits and vegetables, wholegrains, nuts and legumes, fish and other seafood, milk and other dairy products, was associated with lower CRC risk.

Dietary Protein Sources and Incidence of Breast Cancer: A Dose-Response Meta-Analysis of Prospective Studies. (2016).
There was a null association between poultry, fish, egg, nuts, total milk, and whole milk intake and breast cancer risk. Higher total red meat, fresh red meat, and processed meat intake may be risk factors for breast cancer, whereas higher soy food and skim milk intake may reduce the risk of breast cancer.