Walnuts for Prostate Cancer

Recruiting at 1 trial location

Overseen By Yunhee Choi-Kuaea, MSW

Age: 18+

Sex: Male

Trial Phase: Phase 2

Sponsor: Stephen Freedland

Must not be taking: Hormone therapy, Antiandrogens, 5-alpha reductase inhibitors

Disqualifiers: Nut allergy, Other active malignancy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: Unknown

Duration: 4-10 weeks

50 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores whether eating walnuts can slow prostate cancer progression in men. Participants will either continue their regular diet or add two ounces of walnuts daily for a few weeks. The trial targets men diagnosed with prostate cancer who are preparing for surgery. Participants must be willing to maintain their usual diet with the possible addition of walnuts. Men with biopsy-confirmed prostate cancer and no nut allergies may be suitable candidates. As a Phase 2 trial, this study measures how effectively walnuts slow cancer progression in an initial, smaller group.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications, but you cannot participate if you've used certain prostate medications recently or are on a diet program with omega-3 supplements.

Is there any evidence suggesting that walnut supplementation is likely to be safe for humans?

Research shows that walnuts are generally safe for people and might even help with some health issues. Studies suggest that eating walnuts regularly could help reduce cell damage, which might benefit diseases like cancer.

In animal studies, a diet including walnuts slowed the growth of prostate cancer cells. While encouraging, these results come from animal studies, not human ones.

This trial is in an early stage, indicating that the treatment has shown some safety in humans, but more research is needed to confirm this. Walnuts are a common food, and most people can eat them without problems. However, some people might have allergies or sensitivities. Always consult a doctor if there are any concerns. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising for prostate cancer?

Unlike standard prostate cancer treatments that often involve surgery, radiation, or hormone therapy, this innovative approach adds two ounces of walnuts to a usual diet. Researchers are excited about walnuts because they are packed with omega-3 fatty acids and antioxidants, which may help reduce inflammation and slow cancer growth. This natural and non-invasive option could offer a complementary strategy to support prostate health with minimal side effects.

What evidence suggests that walnut supplementation might be an effective treatment for prostate cancer?

Research suggests that walnuts might help slow the growth of prostate cancer. In one study, mice on a walnut-rich diet had fewer and slower-growing tumors compared to those without walnuts. Another study found that walnuts are high in antioxidants, which may help protect against cancer. Although short-term walnut consumption did not change PSA levels (a test for prostate cancer) in healthy men, walnuts are still thought to have potential cancer-fighting benefits. In this trial, participants will either follow their usual diet or add two ounces of walnuts daily. These findings suggest that adding walnuts to the diet might benefit those with prostate cancer. ^{2 4 6 7 8}

Who Is on the Research Team?

Stephen Freedland, MD

Principal Investigator

Cedars-Sinai Medical Center

Are You a Good Fit for This Trial?

Men over 18 with confirmed prostate cancer (Gleason score ≥7) who read and understand English, are planning to undergo radical prostatectomy, and can eat walnuts. Excluded are those with nut allergies, hormone therapy history, recent use of certain drugs for prostate issues, prior prostate treatments, serious other diseases or conditions affecting protocol adherence.

Inclusion Criteria

Willing to adhere to a usual diet with the possible addition of 2 oz of walnuts per day

My biopsy shows a grade group 2 or higher.

I am planning to have prostate removal surgery.

Exclusion Criteria

I have used 5-alpha reductase inhibitors in the last 6 months.

Individuals with psychological/mental conditions which can affect the consent process and/or their adherence to the protocol

I have had radiation or cryotherapy for prostate cancer.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants are randomized to either continue their usual diets or add 2 ounces of walnuts daily for 4-10 weeks

4-10 weeks

Baseline visit in conjunction with standard of care post-biopsy, final visit prior to RP

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Walnuts

Trial Overview

The trial is examining if eating walnuts affects the progression of prostate cancer in men awaiting surgery. Participants will either continue their normal diet or add 2 oz of walnuts daily for 4-10 weeks before their operation. They'll be randomly assigned to one of these two groups.

How Is the Trial Designed?

Group I: Usual Diet + Walnuts Experimental Treatment 3 Interventions

Usual diet with the addition of two ounces of walnuts daily, phone counseling with dietitian, for 4-10 weeks

Group II: Usual Diet Active Control 1 Intervention

Usual diet for 4-10 weeks

Who Is Running the Clinical Trial?

Stephen Freedland

Lead Sponsor

Trials

2

Recruited

190+

California Walnut Commission

Collaborator

Trials

25

Recruited

36,700+

Published Research Related to This Trial

In a study of 47,299 men over 26 years, nut consumption was not linked to the incidence of prostate cancer (PCa) or PCa-specific mortality.

However, men who ate nuts five or more times a week after being diagnosed with PCa had a 34% lower overall mortality rate compared to those who consumed nuts less than once a month, suggesting potential benefits of nut consumption for overall health post-diagnosis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Nut consumption and prostate cancer risk and mortality. Wang, W., Yang, M., Kenfield, SA., et al.[2019]

In a study of 580 men aged 40 to 79, the prevalence of prostate adenocarcinoma was found to be 16.6%, with no significant differences in prevalence based on race (White, Mulatto, Black).

The study indicated that there was no racial influence on the likelihood of developing prostate cancer, even when considering age groups, suggesting that factors other than race may play a more significant role in prostate cancer risk.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prevalence of prostate adenocarcinoma according to race in an university hospital. Barros, MS., Silva, VR., Santos, GB., et al.[2019]

In a study involving 40 healthy participants aged 50 and older, consuming 43g of walnuts daily for 8 weeks significantly reduced non-HDL cholesterol and apolipoprotein-B levels, which are important markers related to heart disease risk.

Despite these positive changes in cholesterol levels, other factors such as fasting glucose, insulin, and markers of inflammation and endothelial function did not show significant changes, indicating that walnuts may specifically target lipid profiles without affecting other metabolic parameters.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Walnut-enriched diet reduces fasting non-HDL-cholesterol and apolipoprotein B in healthy Caucasian subjects: a randomized controlled cross-over clinical trial. Wu, L., Piotrowski, K., Rau, T., et al.[2022]

In a 12-month randomized crossover study involving 40 middle-aged men, consuming an average of 35 grams of walnuts daily did not significantly change serum prostate-specific antigen (PSA) levels compared to a control diet.

The findings indicate that short-term walnut consumption is unlikely to negatively impact PSA levels, suggesting it is safe for prostate health in otherwise normal men.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Lack of effect of walnuts on serum levels of prostate specific antigen: a brief report. Simon, JA., Tanzman, JS., Sabaté, J.[2019]

Over a decade, the incidence rate of prostate cancer in the Anglian Cancer Network significantly increased, particularly with a three-fold rise in intermediate-risk cancers, indicating a shift in disease profile.

While the overall incidence of prostate cancer rose, the rates of metastasis decreased, suggesting that more localized cases are being diagnosed, which may lead to more patients being eligible for radical treatment options.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Changing presentation of prostate cancer in a UK population--10 year trends in prostate cancer risk profiles in the East of England. Greenberg, DC., Wright, KA., Lophathanon, A., et al.[2021]

In a study of 248 patients in Taiwan undergoing radical cystoprostatectomy for bladder cancer, the incidence of incidental prostate cancer was found to be 4.03%, with most cases being at early stages (T1 or T2).

This rate is lower than what has been reported in similar studies from the USA, suggesting that while the incidence is not high, screening methods like digital rectal exams and PSA tests are still important for older men with bladder cancer.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Synchronous primary carcinomas of the bladder and prostate. Lee, SH., Chang, PL., Chen, SM., et al.[2006]

A study of 1459 men aged 55-74 with newly diagnosed localized prostate cancer from 1983-1987 revealed significant excess mortality and a notable loss of life expectancy during this period.

The routine treatment approach at the time, which primarily involved observation and endocrine therapy only if the cancer progressed, may have contributed to these poor survival outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Localized prostatic cancer. Survival and loss of life expectancy]. Brasso, K., Friis, S., Juel, K., et al.[2006]

In a study of 585 men undergoing radical prostatectomy for prostate cancer, 35% were asymptomatic at diagnosis, while 65% had lower urinary tract symptoms (LUTS).

The study found no significant differences in tumor characteristics or treatment outcomes between symptomatic and asymptomatic patients, but the Gleason score indicated that asymptomatic patients had a worse long-term prognosis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Screening by lower urinary tract symptoms vs asymptomatic prostate-specific antigen levels leading to radical prostatectomy in Danish men: tumour characteristics and treatment outcome. Borre, M.[2009]

Urolithin A (UA), derived from walnuts, significantly alters gene expression in prostate cancer cells, particularly increasing levels of CDKN1A, which is associated with cell cycle regulation and apoptosis.

The study demonstrated that UA treatment leads to increased apoptosis and a shift in the cell cycle towards the G1 phase, suggesting its potential as a chemopreventive agent for prostate cancer.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Urolithin A causes p21 up-regulation in prostate cancer cells. Sánchez-González, C., Ciudad, CJ., Izquierdo-Pulido, M., et al.[2018]

In a study using the TRAMP mouse model, a high-fat diet containing whole walnuts significantly reduced prostate tumor weight and growth rate compared to a high-fat diet with soybean oil, despite both diets having the same total fat content.

The beneficial effects of the walnut diet on prostate cancer are likely due to the complex mixture of compounds in whole walnuts rather than a specific type of fat or tocopherol, indicating that dietary composition matters in cancer progression.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A high-fat diet containing whole walnuts (Juglans regia) reduces tumour size and growth along with plasma insulin-like growth factor 1 in the transgenic adenocarcinoma of the mouse prostate model. Davis, PA., Vasu, VT., Gohil, K., et al.[2022]

A diet supplemented with walnuts significantly reduced the establishment and growth of LNCaP human prostate cancer cells in nude mice, with only 18.7% of walnut-fed mice developing tumors compared to 44.0% in the control group.

The average tumor size in walnut-fed mice was about one-fourth that of the control diet mice, indicating that walnuts may slow tumor growth effectively.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A walnut-enriched diet reduces the growth of LNCaP human prostate cancer xenografts in nude mice. Reiter, RJ., Tan, DX., Manchester, LC., et al.[2021]

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The results obtained herein strongly indicate that walnut tree constitute an excellent source of effective natural antioxidants and chemopreventive agents.

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The walnut-enriched diet reduced the number of tumors and the growth of the LNCaP xenografts; 3 of 16 (18.7%) of the walnut-fed mice developed tumors; ...

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Our results suggest that short-term consumption of walnuts is unlikely to affect PSA levels adversely among otherwise normal men.

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A diet supplemented with walnuts significantly reduced the establishment and growth of LNCaP human prostate cancer cells in nude mice, with only 18.7% of walnut ...

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Natural Products to Fight Cancer: A Focus on Juglans regia

Many studies correlate walnut consumption to beneficial effects towards several chronic diseases, such as cancer, mainly due to the bioactive molecules stored ...