Adherence to a low-fat diet in men with prostate cancer

Developing dietary interventions as therapy for cancer

Cancer cells acquire distinct metabolic preferences based on their tissue of origin, genetic alterations and degree of interaction with systemic hormones and metabolites. These adaptations support the increased nutrient demand required for increased growth and proliferation. Diet is the major source of nutrients for tumours, yet dietary interventions lack robust evidence and are rarely prescribed by clinicians for the treatment of cancer. Well-controlled diet studies in patients with cancer are rare, and existing studies have been limited by nonspecific enrolment criteria that inappropriately grouped together subjects with disparate tumour and host metabolic profiles. This imprecision may have masked the efficacy of the intervention for appropriate candidates. Here, we review the metabolic alterations and key vulnerabilities that occur across multiple types of cancer. We describe how these vulnerabilities could potentially be targeted using dietary therapies including energy or macronutrient restriction and intermittent fasting regimens. We also discuss recent trials that highlight how dietary strategies may be combined with pharmacological therapies to treat some cancers, potentially ushering a path towards precision nutrition for cancer.

Interventions for Improving Body Composition in Men with Prostate Cancer: A Systematic Review and Network Meta-analysis

PURPOSE

To perform a systematic review and network meta-analysis to investigate the most effective intervention for improving body composition outcomes in prostate cancer patients during or after treatment.

METHODS

A systematic search was undertaken in multiple databases from inception to December 2020. Randomized clinical trials examining the effects of exercise/physical activity and/or nutrition interventions on body composition and body weight measures in prostate cancer patients were included. The primary endpoints were both whole-body and regional fat mass and lean mass measures, with body weight and BMI as secondary outcomes. A frequentist random-effects network meta-analysis was undertaken to examine the clustering effect of intervention modalities or control groups on the outcomes of interest. The study protocol is publicly available on PROSPERO (CRD42020202339).

RESULTS

Fifty articles describing 47 trials (n = 3207) were included. Resistance training and combined resistance and aerobic exercise were the most effective interventions to reduce body fat percentage (-0.9%; 95% confidence interval [CI], -1.4% to -0.3%) and fat mass (-0.5 kg; 95% CI, -0.9 to -0.1 kg), respectively. For whole-body and regional lean mass, combined resistance and aerobic exercise + healthy diet (0.6 kg; 95% CI, 0.1 to 1.0 kg) and resistance training alone (0.7 kg, 95% CI: 0.4 to 1.0 kg) were the best intervention, respectively. A low-fat diet was the most effective for reducing body weight immediately after or at follow-up, while no intervention promoted significant reductions in BMI.

CONCLUSIONS

These results indicate that a resistance-based exercise program alone or combined with a general healthy diet are the most effective interventions for improving overall body composition in men with prostate cancer.

The effect of dietary and exercise interventions on body weight in prostate cancer patients: a systematic review

Prostate cancer prognosis may therefore be improved by maintaining healthy weight through diet and physical activity. This systematic review looked at the effect of diet and exercise interventions on body weight among men treated for prostate cancer. MEDLINE, EMBASE, CINAHL, and Cochrane Library databases were searched from the earliest record to August 2013. Randomized controlled trials of diet and exercise interventions in prostate cancer patients that reported body weight or body composition changes were included. A total of 20 trials were included in the review. Because of the heterogeneity of intervention components, a narrative review was conducted. Interventions were categorized as diet (n = 6), exercise (n = 8), or a combination of both diet and exercise (n = 6). The sample size ranged from 8 to 155 and the duration from 3 wk to 4 yr. Four diet interventions and 1 combined diet and exercise intervention achieved significant weight loss with mean values ranging from 0.8 kg to 6.1 kg (median 4.5 kg). Exercise alone did not lead to weight loss, though most of these trials aimed to increase fitness and quality of life rather than decrease body weight. Diet intervention, alone or in combination with exercise, can lead to weight loss in men treated for prostate cancer.

Psychosocial and Behavioral Interventions and Cancer Patient Survival Again

Hypotheses. Although there is evidence that psychosocial and behavioral interventions (PBIs) increase well-being, improve coping and adjustment, and reduce distress among cancer patients, findings regarding PBIs as a means for prolonging survival were not convincing. Conflicting findings resulted in tremendous controversies over the efficacy of PBIs. This study aims at estimating the pooled effects of PBIs on survival of cancer patients. Study Design and Methods. Randomized controlled trials (RCTs) testing the effects of any kind of PBIs on the survival of cancer patients included in MEDLINE, EMBASE, Cancer Lit, CINAHL, Cochrane Library, and reference lists of relevant articles were retrieved and reviewed by 2 independent researchers. Data items derived from the articles included time and duration of study, intervention types and doses, and numbers of patients dying and surviving 1, 2, 4, and 6 years after intervention. Estimation of the collective effects of the interventions used meta-analysis via Review Manager (version 5). Results. A total of 15 RCTs met inclusion criteria, involving 2041 subjects (1118 in intervention and 923 in control groups). Inclusive total mean Mantel-Haenszel risk ratios (RRs) ranged from 0.83 to 0.99, and 3 of these effect sizes were statistically nonsignificant. Yet when the RCTs with less than 30 hours of PBIs were excluded, all the RRs decreased to some extent, with the RR for the first 2 years being decreased to 0.69 (95% CI, 0.55-0.87) and 0.82 (95% CI, 0.71-0.95), respectively. Conclusion. PBIs with adequate intervention doses prolong survival at least for some cancer patients in the first 2 years after intervention, although longer term effects need to be determined via more studies.

A novel measure of dietary change in a prostate cancer dietary program incorporating mindfulness training

Diet may represent a modifiable prostate cancer risk factor, but a vegetable-based prostate-healthy diet is a major change for most men. We used a ratio of animal to vegetable proteins (A:V) to evaluate whether a comprehensive dietary change was self-sustaining following completion of 11 weekly dietary and cooking classes that integrated mindfulness training. Thirty-six men with recurring prostate cancer were randomized to the intervention or wait-list control. Assessments were at baseline, 3 months, and 6 months. Of 17 men randomized to the intervention, 14 completed the requirements. Nineteen were randomized to control and 17 completed requirements. Compared with controls, a significant postintervention (3 months) decrease in A:V in the intervention group (P=0.01) was self-maintained 3 months postintervention (P=0.049). At each assessment, A:V was correlated with lycopene, fiber, saturated fat, and dietary cholesterol, four dietary components linked to clinically relevant outcomes in prostate cancer. Change in A:V was also significantly correlated with changes in fiber, saturated fat, and dietary cholesterol intake. Participants reported regular mindfulness training practice, and there was a significant correlation between mindfulness training practice and changes in both initiation and maintenance of the change in A:V. These pilot results provide encouraging evidence for the feasibility of a dietary program that includes mindfulness training in supporting dietary change for men with recurrent prostate cancer and invite further study to explore the possible role of mindfulness training as a means of supporting both initiation of dietary changes and maintenance of those changes over time.

Men, food, and prostate cancer: gender influences on men's diets

Although healthy eating might enhance long-term survival, few men with prostate cancer make diet changes to advance their well-being. Men's typically poor diets and uninterest in self-health may impede nutrition interventions and diet change. Food choice behavior is complex involving many determinants, including gender, which can shape men's health practices, diets, and prostate cancer experiences. Developing men-centered prostate cancer nutrition interventions to engage men (and where appropriate their partners) in promoting healthy diets can afford health benefits. This article presents an overview and synthesis of current knowledge about men's food practices and provides an analysis of diet and diet change behaviors for men with prostate cancer. Masculinity and gender relations theory are discussed in the context of men's food practices, and suggestions for future applications to nutrition and prostate cancer research and diet interventions are made.

Flaxseed supplementation (not dietary fat restriction) reduces prostate cancer proliferation rates in men presurgery

BACKGROUND

Prostate cancer affects one of six men during their lifetime. Dietary factors are postulated to influence the development and progression of prostate cancer. Low-fat diets and flaxseed supplementation may offer potentially protective strategies.

METHODS

We undertook a multisite, randomized controlled trial to test the effects of low-fat and/or flaxseed-supplemented diets on the biology of the prostate and other biomarkers. Prostate cancer patients (n = 161) scheduled at least 21 days before prostatectomy were randomly assigned to one of the following arms: (a) control (usual diet), (b) flaxseed-supplemented diet (30 g/d), (c) low-fat diet (<20% total energy), or (d) flaxseed-supplemented, low-fat diet. Blood was drawn at baseline and before surgery and analyzed for prostate-specific antigen, sex hormone-binding globulin, testosterone, insulin-like growth factor-I and binding protein-3, C-reactive protein, and total and low-density lipoprotein cholesterol. Tumors were assessed for proliferation (Ki-67, the primary endpoint) and apoptosis.

RESULTS

Men were on protocol an average of 30 days. Proliferation rates were significantly lower (P < 0.002) among men assigned to the flaxseed arms. Median Ki-67-positive cells/total nuclei ratios (x100) were 1.66 (flaxseed-supplemented diet) and 1.50 (flaxseed-supplemented, low-fat diet) versus 3.23 (control) and 2.56 (low-fat diet). No differences were observed between arms with regard to side effects, apoptosis, and most serologic endpoints; however, men on low-fat diets experienced significant decreases in serum cholesterol (P = 0.048).

CONCLUSIONS

Findings suggest that flaxseed is safe and associated with biological alterations that may be protective for prostate cancer. Data also further support low-fat diets to manage serum cholesterol.

Comparison between plasma and erythrocyte fatty acid content as biomarkers of fatty acid intake in US women

BACKGROUND

Erythrocyte fatty acids may be superior to plasma fatty acids for reflecting long-term fatty acid intake because of less sensitivity to recent intake and a slower turnover rate.

OBJECTIVE

The objective was to compare the fatty acid content of erythrocytes with that of plasma with respect to their abilities to reflect usual fatty acid intake.

DESIGN

Fatty acids in plasma and erythrocytes were measured by capillary gas-liquid chromatography in 306 US women aged 43-69 y. Fatty acid intake was assessed with a food-frequency questionnaire, which was validated for measuring intakes of various fatty acids.

RESULTS

Docosahexaenoic acid (DHA, 22:6n-3) in erythrocytes and plasma provided the strongest correlations with its intake, but erythrocyte DHA concentrations [Spearman's partial correlation coefficient (r(s))=0.56] were better than plasma DHA concentrations (r(s)=0.48) as a biomarker. Total trans fatty acids (r(s)=0.43) and total 18:1 trans isomers (r(s)=0.42) in erythrocytes were also more strongly correlated with intake than were those in plasma (r(s)=0.30 and r(s)=0.29, respectively). Moderate correlations were observed for linoleic acid (18:2n-6; erythrocytes, r(s)=0.24; plasma, r(s)=0.25), alpha-linolenic acid (18:3n-3; erythrocytes, r(s)=0.18; plasma, r(s)=0.23), and eicosapentaenoic acid (20:5 n-3; erythrocytes, r(s)=0.38; plasma, r(s)=0.21). For polyunsaturated and trans fatty acids, correlations between intakes and biomarkers improved moderately when average intakes over previous years were used.

CONCLUSION

Erythrocyte n-3 fatty acids of marine origin and trans fatty acid content are suitable biomarkers for long-term intake.