Ornish diet and lifestyle modification programme

Abstract and key points

The Ornish diet and lifestyle modification programme combines a supplemented vegan diet with exercise, stress management, and group support sessions.

The combined diet and lifestyle modification programme is claimed to enable patients with early-stage prostate cancer to delay or avoid conventional treatment and/or improve quality of life. However, only one randomized trial and one pilot study have been published, all using surrogate markers for prostate cancer.

In prostate cancer patients, the programme was found to improve cardiovascular health parameters, which is important as cardiovascular disease is the primary or secondary cause of death in men with prostate cancer.

Trial results to date indicate absence of adverse effects.


Luc Geeraert, CAM Cancer Consortium. Ornish diet and lifestyle modification programme [online document], August 25, 2020.

Document history

Latest update: September 2020

Next update due: September 2023

What is it?


Dean Ornish, M.D., is founder and president of the non-profit Preventive Medicine Research Institute in Sausalito, California, and clinical professor of medicine at the University of California, San Francisco1. In his popular book entitled “The Spectrum”, Ornish provides examples of various individually tailored diet and lifestyle programmes, including one to prevent/reverse certain types of prostate and breast cancer2.


The Ornish diet and lifestyle modification programme combines a supplemented vegan diet with exercise, stress management, smoking cessation, and group support sessions3.

The vegan diet itself is very low in fat (<10%) and in simple carbohydrates, but high in fibre, and includes predominantly fruits, vegetables, whole grains, and legumes, all in their natural unrefined forms3. Meat, plant foods high in fat (e.g., nuts, seeds, and avocados), fat dairy products, and refined carbohydrates are banned. Consumption of minimal amounts of non-fat dairy products such as skimmed milk, non-fat yoghurt, and non-fat cheese is allowed. This diet is supplemented with soy (one serving of tofu plus 58 g of a fortified soy protein powdered beverage per day), fish oil (3 g per day), vitamin E (400 IU per day), selenium (200 µg per day), and vitamin C (2 g per day). Alcohol is allowed in small amounts but not encouraged. The diet is in general concordance with the American Cancer Society guidelines4.

The exercise part consists of moderate aerobic exercise (30 min of walking, 6 days per week)3.

Stress management includes yoga-based stretching, breathing, meditation, imagery, and progressive relaxation (1 hour per day)3.

Group support sessions (1 hour per week) are included to support adherence to lifestyle changes3.


The earlier work of Ornish and colleagues in the 1980s and 1990s demonstrated that diet, lifestyle changes, and smoking cessation could not only halt the progression of ischemic heart disease, but could actually reverse it5-7. Given that cardiovascular disease is the primary or secondary cause of death in men with prostate cancer, and that a large number of epidemiological and laboratory studies suggested that diet and lifestyle may play an important role in the development of prostate cancer, the Ornish group began exploring the possible effects of such an intervention in the late 1990s3,8.

Claims of efficacy

Ornish and colleagues3,8-10, suggest the possibility that some or all aspects of the combined lifestyle changes (diet + exercise + stress management) enable patients with early-stage prostate cancer to delay or avoid conventional treatment and/or improve quality of life.

Mechanism(s) of action

The mechanism of action of the Ornish diet and lifestyle modification programme was examined in only one prospective pilot study that enrolled 31 low-risk prostate cancer patients11-12.

Differences in RNA samples from needle biopsies taken from normal prostate tissue before intervention compared to RNA samples taken after 3 months of intervention indicated that application of the Ornish diet and lifestyle modification programme may modulate gene expression in the prostate11. Pathway analysis identified significant modulation of biological processes playing critical roles in tumorigenesis, including protein metabolism and modification, intracellular protein traffic, and protein phosphorylation.

In peripheral blood mononuclear cells (PBMCs) of the patients, telomerase activity and hence telomere maintenance capacity was significantly increased12,21. Telomeres are protective DNA-protein complexes that promote chromosomal stability, and shortness of telomeres is a prognostic marker of ageing, disease, and premature morbidity.

Alleged indication(s)

The programme is indicated for early-stage prostate cancer patients (biopsy-documented; Gleason score less than 7; serum prostate-specific antigen (PSA) levels of 4-10 ng/ml; Stages T1 and T2) before surgical intervention or hormone-deprivation, i.e. patients on active surveillance (watchful waiting) closely monitoring disease progress11,13-14.

Prevalence of use


Legal issues


Costs and expenditure

The diet itself is inexpensive as it only concerns common food sources and a few inexpensive supplements. The counselling and group sessions connected to the programme result in a cost of around $7,000 per year15.

Does it work?

Only a limited number of studies have been carried out to date, with investigations limited by reliance on surrogate biomarkers (PSA, PSA doubling time, and serum-induced changes in growth and apoptosis of LNCaP prostate cancer cells), sample size, and duration. To determine the clinical relevance of the findings from these studies on disease-specific survival, and to help define optimal dietary patterns and lifestyle factors important for prostate cancer management, larger, well-designed, and longer-term studies are needed.

Clinical trials

The Ornish diet and lifestyle modification programme was tested in a randomized trial in 93 men with early biopsy-proven prostate cancer (PSA 4-10 ng/ml, Gleason scores less than 7) who had chosen not to undergo any conventional treatment3. After 1 year, intensive lifestyle changes resulted in a PSA decrease of 4% and an inhibition of the serum-stimulated growth of LNCaP cells of 70%, compared to a 6% increase of PSA and only 9% LNCaP growth inhibition in the control group (not following the Ornish diet and lifestyle modification programme, but making lifestyle changes as advised by their physician). None of the 44 patients in the treatment group, but 6 of the 49 control patients had to undergo conventional treatment (e.g., radical prostatectomy, radiotherapy, or androgen deprivation therapy) due to an increase in PSA and/or progression of disease on magnetic resonance imaging. After 2 years, 2 of the 43 experimental patients and 13 of the 49 control patients had undergone conventional prostate cancer treatment; at this time point no significant differences in PSA change were found between the experimental and control patients (excluding patients who had undergone conventional treatment), and adherence to the intensive lifestyle changes remained high (95%)10. Experimental patients showed greater improvements in cardiovascular health parameters than did control patients. Patients in the treatment group appeared to experience overall optimism and hope, make gains in their emotional availability, and highly value a peer/staff community experience16. Patients in both the treatment and the control group who improved their lifestyle showed enhanced physical health-related quality of life and decreased perceived stress after 1 year, but no significant differences in quality of life were found between the groups9. All recommended dietary reference intakes were met by the intervention, only vitamin D intake was less than adequate17. After 1 year, the intake of several dietary constituents that may reduce the risk of many chronic diseases was increased, while the intake of constituents implicated with an increased chronic disease risk was decreased in the intervention group compared to controls18. The levels of insulin-like growth factor 1 (IGF-1) increased in both groups over 1 year, whereas an increase in the levels of IGF-1 binding protein (IGFBP-1) and a trend towards lower fasting insulin levels were observed in the experimental group only19.

In an uncontrolled pilot study in 30 men with biopsy-diagnosed low-risk prostate cancer under active surveillance, the Ornish diet and lifestyle modification programme was found to significantly modulate biological processes playing critical roles in tumorigenesis11, and to significantly increase telomerase activity in PBMCs12. Total PSA did not change significantly, although percent free PSA was improved11. Overall, patients were able to adhere closely to the lifestyle modifications, a significant decrease in cardiovascular disease risk factors was found, and patients reported significant reductions in psychological distress associated with prostate cancer. The intervention was safe and no adverse events were observed. From the intervention group, 10 men were enrolled in a follow-up study where they continued the Ornish diet and lifestyle modification programme, and were compared to 25 external controls with biopsy-proven low-risk prostate cancer under active surveillance21. After 5 years, the relative telomere length had increased in the intervention group and decreased in the control group; this difference between both groups was significant. A better adherence to lifestyle changes was significantly associated with more increased relative telomere length.

Is it safe?

For safety issues regarding vitamin E and selenium, see the respective summaries [selenium, vitamin E]. As to vitamin C, oral doses up to 2 g per day are generally considered safe and well-tolerated. The US Institute of Medicine defined the tolerable upper intake level, i.e., the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects in almost all individuals at 2 g per day, based on the possibility of osmotic diarrhoea and gastrointestinal disturbances above this level20.

Adverse events

No adverse effects have been reported in the above-cited studies. Other data are not available.


Food allergies/intolerance to soy, soy products, and fish oils.


No interactions have been reported in pilot studies and randomized clinical trials.


No warnings have been reported in the literature.

  1. Deanornish.com. Dean Ornish, MD, Bio. 2011. [cited 19th December 2016]. Available online.
  2. Ornish D. The Spectrum: A Scientifically Proven Program to Feel Better, Live Longer, Lose Weight, and Gain Health. New York: Ballantine Books, 2007.
  3. Ornish D, Weidner G, Fair WR, Marlin R, Pettengill EB, Raisin CJ, Dunn-Emke S, Crutchfield L, Jacobs FN, Barnard RJ, Aronson WJ, McCormac P, McKnight DJ, Fein JD, Dnistrian AM, Weinstein J, Ngo TH, Mendell NR, Carroll PR. Intensive lifestyle changes may affect the progression of prostate cancer. J. Urol. 2005 September;174(3):1065-1069. Accessed 11th of September 2020.
  4. Rock CL, Doyle C, Demark-Wahnefried W, Meyerhardt J, Courneya KS, Schwartz AL, Bandera EV, Hamilton KK, Grant B, McCullough M, Byers T, Gansler T. Nutrition and physical activity guidelines for cancer survivors. CA Cancer J Clin. 2012 Jul-Aug;62(4):243-74. doi: 10.3322/caac.21142. Accessed 11th of September 2020.
  5. Ornish D. Can life-style changes reverse coronary atherosclerosis? Hosp. Pract. (Off. Ed.). 1991 May 15;26(5):123-126, 129-132. Accessed 11th of September 2020.
  6. Ornish D, Scherwitz LW, Doody RS, Kesten D, McLanahan SM, Brown SE, DePuey E, Sonnemaker R, Haynes C, Lester J, McAllister GK, Hall RJ, Burdine JA, Gotto AM Jr. Effects of stress management training and dietary changes in treating ischemic heart disease. JAMA. 1983 January 7;249(1):54-59. Accessed 11th of September 2020.
  7. Ornish D, Scherwitz LW, Billings JH, Brown SE, Gould KL, Merritt TA, Sparler S, Armstrong WT, Ports TA, Kirkeeide RL, Hogeboom C, Brand RJ. Intensive lifestyle changes for reversal of coronary heart disease. JAMA. 1998 December 16;280(23):2001-2007. Accessed 11th of September 2020.
  8. Ornish DM, Lee KL, Fair WR, Pettengill EB, Carroll PR. Dietary trial in prostate cancer: Early experience and implications for clinical trial design. Urology. 2001 April;57(4 Suppl 1):200-201. Accessed 11th of September 2020.
  9. Daubenmier JJ, Weidner G, Marlin R, Crutchfield L, Dunn-Emke S, Chi C, Gao B, Carroll P, Ornish D. Lifestyle and health-related quality of life of men with prostate cancer managed with active surveillance. Urology. 2006 January;67(1):125-130.  Accessed 11th of September 2020.
  10. Frattaroli J, Weidner G, Dnistrian AM, Kemp C, Daubenmier JJ, Marlin RO, Crutchfield L, Yglecias L, Carroll PR, Ornish D. Clinical events in prostate cancer lifestyle trial: results from two years of follow-up. Urology. 2008 December;72(6):1319-1323. Accessed 11th of September 2020.
  11. Ornish D, Magbanua MJ, Weidner G, Weinberg V, Kemp C, Green C, Mattie MD, Marlin R, Simko J, Shinohara K, Haqq CM, Carroll PR. Changes in prostate gene expression in men undergoing an intensive nutrition and lifestyle intervention. Proc. Natl. Acad. Sci. USA. 2008 Jun 17;105(24):8369-8374. Accessed 11th of September 2020.
  12. Ornish D, Lin J, Daubenmier J, Weidner G, Epel E, Kemp C, Magbanua MJ, Marlin R, Yglecias L, Carroll PR, Blackburn EH. Increased telomerase activity and comprehensive lifestyle changes: a pilot study. Lancet Oncol. 2008 November;9(11):1048-1057. Accessed 11th of September 2020.
  13. Cooperberg MR, Broering JM, Kantoff PW, Carroll PR. Contemporary trends in low risk prostate cancer: risk assessment and treatment. J. Urol. 2007 September;178(3 Pt 2):S14-S19. Accessed 11th of September 2020.
  14. Klotz L. Low-risk prostate cancer can and should often be managed with active surveillance and selective delayed intervention. Nat. Clin. Pract. Urol. 2008 January;5(1):2-3. Accessed 11th of September 2020.
  15. Zeng W, Stason WB, Fournier S, Razavi M, Ritter G, Strickler GK, Bhalotra SM, Shepard DS. Benefits and costs of intensive lifestyle modification programs for symptomatic coronary disease in Medicare beneficiaries. Am Heart J. 2013 May;165(5):785-92. doi: 10.1016/j.ahj.2013.01.018. Accessed 11th of September 2020.
  16. Kronenwetter C, Weidner G, Pettengill E, Marlin R, Crutchfield L, McCormac P, Raisin CJ, Ornish D. A qualitative analysis of interviews of men with early stage prostate cancer: the Prostate Cancer Lifestyle Trial. Cancer Nurs. 2005 Mar-April;28(2):99-107. Accessed 11th of September 2020.
  17. Dunn-Emke SR, Weidner G, Pettengill EB, Marlin RO, Chi C, Ornish DM. Nutrient adequacy of a very low-fat vegan diet. J. Am. Diet Assoc. 2005 September;105(9):1442-1446. Accessed 11th of September 2020.
  18. Dewell A, Weidner G, Sumner MD, Chi CS, Ornish D. A very-low-fat vegan diet increases intake of protective dietary factors and decreases intake of pathogenic dietary factors. J. Am. Diet Assoc. 2008 February;108(2):347-356. Accessed 11th of September 2020.
  19. Dewell A, Weidner G, Sumner MD, Barnard RJ, Marlin RO, Daubenmier JJ, Chi C, Carroll PR, Ornish D. Relationship of dietary protein and soy isoflavones to serum IGF-1 and IGF binding proteins in the Prostate Cancer Lifestyle Trial. Nutr. Cancer. 2007;58(1):35-42.  Accessed 11th of September 2020.
  20. Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes: Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Accessed 11th of September 2020.
  21. Ornish D, Lin J, Chan JM, Epel E, Kemp C, Weidner G, Marlin R, Frenda SJ, Magbanua MJ, Daubenmier J, Estay I, Hills NK, Chainani-Wu N, Carroll PR, Blackburn EH. Effect of comprehensive lifestyle changes on telomerase activity and telomere length in men with biopsy-proven low-risk prostate cancer: 5-year follow-up of a descriptive pilot study. Lancet Oncol. 2013 Oct;14(11):1112-20. doi: 10.1016/S1470-2045(13)70366-8. Accessed 11th of September 2020.

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