Background: The role of low-carbohydrate ketogenic diet (LCKD) as an adjuvant therapy in antitumor treatment is not well established. This systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to investigate the efficacy of LCKD as an adjuvant therapy in antitumor treatment compared to non-ketogenic diet in terms of lipid profile, body weight, fasting glucose level, insulin, and adverse effects; Methods: In this study, databases such as PubMed, Web of Science, Scopus, CINAHL, and Cochrane trials were searched. Only RCTs that involved cancer participants that were assigned to dietary interventions including a LCKD group and a control group (any non-ketogenic dietary intervention) were selected. Three reviewers independently extracted the data, and the meta-analysis was performed using a fixed effects model or random effects model depending on the I2 value or p-value; Results: A total of six articles met the inclusion/exclusion criteria. In the overall analysis, the post-intervention results = standard mean difference, SMD (95% CI) showed total cholesterol (TC) level = 0.25 (−0.17, 0.67), HDL-cholesterol = −0.07 (−0.50, 0.35), LDL-cholesterol = 0.21 (−0.21, 0.63), triglyceride (TG) = 0.09 (−0.33, 0.51), body weight (BW) = −0.34 (−1.33, 0.65), fasting blood glucose (FBG) = −0.40 (−1.23, 0.42) and insulin = 0.11 (−1.33, 1.55). There were three outcomes showing significant results in those in LCKD group: the tumor marker PSA, p = 0.03, the achievement of ketosis p = 0.010, and the level of satisfaction, p = 0.005; Conclusions: There was inadequate evidence to support the beneficial effects of LCKDs on antitumor therapy. More trials comparing LCKD and non-KD with a larger sample size are necessary to give a more conclusive result.

The findings for the roles of dairy products, calcium, and vitamin D on ovarian cancer risk remain controversial. We aimed to assess these associations by using an updated meta-analysis.Five electronic databases (e.g., PubMed and Embase) were searched from inception to December 24, 2019. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated. A total of 29 case-control or cohort studies were included. For comparisons of the highest vs. lowest intakes, higher whole milk intake was associated with increased ovarian cancer risk (RR: 1.35, 95% CI: 1.15, 1.59), whereas decreased risks were observed for higher intakes of low-fat milk (RR: 0.84, 95% CI: 0.73, 0.96), dietary calcium (RR: 0.71, 95% CI: 0.60, 0.84), and dietary vitamin D (RR: 0.80, 95% CI: 0.67, 0.95). Additionally, for every 100-g/d increment, increased ovarian cancer risks were found for total dairy products (RR: 1.03, 95% CI: 1.01, 1.04) and for whole milk (RR: 1.07, 95% CI:1.03, 1.11); however, decreased risks were found for a 100-g/d increased intakes of low-fat milk (RR: 0.95, 95% CI: 0.91, 0.99), cheese (RR: 0.87, 95% CI: 0.76, 0.98), dietary calcium (RR: 0.96, 95% CI: 0.95, 0.98), total calcium (RR: 0.98, 95% CI: 0.97, 0.99), dietary vitamin D (RR: 0.92, 95% CI: 0.87, 0.97), and increased levels of circulating vitamin D (RR: 0.84, 95% CI: 0.72, 0.97). These results show that whole milk intake might contribute to a higher ovarian cancer risk, whereas low-fat milk, dietary calcium, and dietary vitamin D might reduce the risk.Downloaded from https://www.cambridge.org/core. IP address: 44.RR, relative risk; 95% CI, 95% confidence interval; I 2 , variation in estimated attributable to heterogeneity. * P-value of Z-test for the significance of the pool RRs and 95%CIs. † P-value of Q-test for between-study heterogeneity test. ‡ The analyses of circulating vitamin D were based on three nested case-control study.