Nutrition and health

Objectives:
Epidemiological studies that focus on the relationship between dietary isoflavone intake and the risk of breast cancer still lead to inconsistent conclusions. Therefore, this review article has been conducted.

Does a high isoflavone dietary intake reduce risk of breast cancer among women?

Study design:
This review article included 7 cohort studies and 17 case-control studies with a total of 902,438 females.
The verification of breast cancer in these studies was based on either a cancer registry record or a histological diagnosis.
The exposure assessment of all included studies was based on a food frequency questionnaire (FFQ) via either face-to-face interviews or self-administrative questionnaires.

The publication biases were evaluated using Begg’s test and Egger’s test. The shape of the funnel plots showed asymmetry [p = 0.001] and the Egger’s test found virtual publication bias [p 0.001]. However, the trim-and-fill method failed to identify any potentially missing studies, indicating the publication bias did not affect the results.

Results and conclusions:
The investigators found in the meta-analysis a significantly reduced risk of 29% for breast cancer [summary OR = 0.71, 95% CI = 0.72 to 0.81, I2 = 82.6%] when comparing the highest to the lowest isoflavone dietary intake.
The result remained the same in sensitivity analysis.

The investigators found in subgroup analysis a statistically significant protective effect of 38% for isoflavone dietary intake on breast cancer in the case-control studies [OR = 0.62, 95% CI = 0.50 to 0.76], while no such effect was observed in the cohort studies [OR = 0.94, 95% CI = 0.86 to 1.02].

The investigators found in subgroup analysis a statistically significant protective effect of 38% for isoflavone dietary intake on breast cancer in Asian women [OR = 0.62, 95% CI = 0.52 to 0.74], while no such effect was observed in non-Asian women [OR = 0.97, 95% CI = 0.88 to 1.06].

The investigators found when the highest isoflavone dietary intake was lower than 10 mg/d, the negative relationship between isoflavone dietary intake and breast cancer disappeared [OR = 1.01, 95% CI = 0.94 to 1.08], whereas a statistically significant protective effect of 37% [OR = 0.63, 95% CI = 0.53 to 0.75] was found, when the highest isoflavone dietary intake was above 10 mg/d.
However, a statistically significant difference in the protective effect of isoflavone dietary intake on breast cancer was observed regardless of whether the women were pre- or postmenopausal and regardless of whether they were ER positive or negative.

The investigators concluded at least 10 mg/d isoflavone dietary intake is helpful in reducing breast cancer risk, particularly among Asian women.

Original title:
Isoflavone Consumption and Risk of Breast Cancer: An Updated Systematic Review with Meta-Analysis of Observational Studies by Yang J, Shen H,  […], Qin Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10224089/

Additional information of El Mondo:
Find more information/studies on isoflavone and breast cancer right here.

Objectives:
The effect of probiotic/synbiotic supplementation on gestational diabetes mellitus (GDM) is controversial. Therefore, this review article has been conducted.

Do probiotic/synbiotic supplements improve glucose and lipid metabolism in pregnant women with gestational diabetes mellitus?

Study design:
This review article included 11 RCTs with a total of 390 women with gestational diabetes mellitus in probiotics/synbiotics group and 389 women with gestational diabetes mellitus in placebo group.

The mean age of those participants ranged from 26.4 years to 33.5 years.
The duration of intervention ranged from 4 weeks to 8 weeks.

Results and conclusions:
The investigators found compared with the placebo, probiotics/synbiotics supplements were associated with a statistically significant improvement in fasting plasma glucose (FPG) [MD = -2.33, 95% CI = -4.27 to -0.40, p = 0.02, I2 = 74%].  

The investigators found compared with the placebo, probiotics/synbiotics supplements were associated with a statistically significant improvement in the homoeostatic model assessment for insulin resistance (HOMA-IR) [MD = -0.40, 95% CI = -0.74 to -0.06, p = 0.02, I2 = 76%].  

The investigators found compared with the placebo, probiotics/synbiotics supplements were associated with a statistically significant improvement in fasting serum insulin (FSI) [MD = -2.47, 95% CI = -3.82 to -1.12, p = 0.0003, I2 =73%].  

The investigators found compared with the placebo, probiotics/synbiotics supplements were associated with a statistically significant improvement in total cholesterol (TC) [MD = -6.59, 95% CI = -12.23 to -0.95, p = 0.02].  

The investigators found subgroup analysis revealed that the kind of supplement led to heterogeneity for FPG and FSI, while heterogeneity was not found for others.

The investigators concluded probiotic/synbiotic supplements improve glucose and lipid metabolism in pregnant women with gestational diabetes mellitus. The use of specific probiotic supplementations containing Lactobacillus acidophilus and Bifidobacterium bifidum (>1 × 106 CFU/g) may be a promising prevention and therapeutic strategy for gestational diabetes mellitus, as they could directly act on the intestinal mucosal barrier and restore the gut flora balance. However, due to the heterogeneity among existing studies, further studies are warranted to address the limitations of existing evidence and better inform the management of gestational diabetes mellitus.

Original title:
The Effects of Probiotics/Synbiotics on Glucose and Lipid Metabolism in Women with Gestational Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials by Mu J, Xian Guo X, […], Cao G.

Link:
https://www.mdpi.com/2072-6643/15/6/1375

Additional information of El Mondo:
Find more information/studies on probiotic, diabetes mellitus and pregnancy right here.

 

Objectives:
Findings on the association of dietary intake and tissue biomarkers of linoleic acid (LA) with the risk of prostate cancer are conflicting. Also, no meta-analysis summarized available findings in this regard. Therefore, this review article has been conducted.

Do higher tissue levels or higher dietary intakes of linoleic acid reduce prostate cancer risk in men?

Study design:
This review article included 15 prospective cohort studies with 511,622 participants with an age range of ≥18 years.

During the follow-up periods ranging from 5 to 21 years, 39,993 cases of prostate cancer, 5,929 cases of advanced prostate cancer and 1,661 cases of fatal prostate cancer were detected.

Results and conclusions:
The investigators found higher tissue levels of linoleic acid were significantly associated with a reduced risk of 14% for prostate cancer [RR = 0.86, 95% CI = 0.77 to 0.96].   
However, a significant association was not seen for advanced prostate cancer [RR = 0.86, 95% CI = 0.65 to 1.13].

The investigators found in dose-response analysis, each 5% increase in tissue levels of linoleic acid was significantly associated with a 14% lower risk of prostate cancer.

The investigators found no significant association between dietary intake of linoleic acid and risk of total [RR = 1.00, 95% CI = 0.97 to 1.04], advanced [RR = 0.98, 95% CI = 0.90 to 1.07] and fatal prostate cancer [RR = 0.97, 95% CI = 0.83 to 1.13].
Not significant because RR of 1 was found in the 95% CI of 0.83 to 1.13. RR of 1 means no risk/association.

The investigators concluded higher tissue levels of linoleic acid reduce prostate cancer in men.

Original title:
Dietary intake and biomarkers of linoleic acid and risk of prostate cancer in men: A systematic review and dose-response meta-analysis of prospective cohort studies by Yousefi M, Eshaghian N, […], Sadeghi O.

Link:
https://pubmed.ncbi.nlm.nih.gov/37077161/

Additional information of El Mondo:
Find more information/studies on linoleic acid and prostate cancer right here.

Tissue levels of linoleic acid can be increased by eating foods that are high in linoleic acid and/or taking linoleic acid supplements.
 

Sunflower oil, corn oil, soybean oil, rice bran oil, canola (rapeseed) oil are high in linoleic acid.

Objectives:
Does a high dietary intake of vitamin B6 or a high blood PLP levels (vitamin B6 level in blood) reduce the risk of colorectal cancer?

Study design:
This review article included 20 cohort studies and 8 case-control studies.

Results and conclusions:
The investigators found higher dietary intake of vitamin B6 significantly reduced the risk of colorectal cancer with 20% [combined OR = 0.80, 95% CI = 0.68 to 0.94].

The investigators found higher blood PLP level significantly reduced the risk of colorectal cancer with 46% [combined OR = 0.54, 95% CI = 0.35 to 0.84].

The investigators found subgroup analysis revealed that higher dietary intake of vitamin B6 significantly reduced the risk of colorectal cancer in women with 21% [combined OR = 0.79, 95% CI = 0.65 to 0.96].

The investigators found subgroup analysis revealed that higher blood PLP level significantly reduced the risk of colorectal cancer in women with 59% [combined OR = 0.41, 95% CI = 0.30 to 0.57].

The investigators found subgroup analysis revealed that higher dietary intake of vitamin B6 significantly reduced the risk of colon cancer in men and women with 24% [combined OR = 0.76, 95% CI = 0.64 to 0.91].

The investigators found subgroup analysis revealed that higher blood PLP level significantly reduced the risk of colon cancer in men and women with 44% [combined OR = 0.56, 95% CI = 0.42 to 0.73].

The investigators concluded that higher dietary intake of vitamin B6 and higher blood PLP level (vitamin B6 level in blood) reduce colorectal cancer risk, particularly colon cancer.

Original title:
Association Between Vitamin B6 and the Risk of Colorectal Cancer: A Meta-analysis of Observational Studies by Lai J, Guo M, […], Li J.

Link:
https://pubmed.ncbi.nlm.nih.gov/36961108/

Additional information of El Mondo:
Find more information/studies on vitamin B6 and colorectal cancer right here.

Circulating concentration of vitamin B6 in blood can be increased by eating foods that are high in vitamin B6 and/or taking vitamin B6 supplements.
 

Objectives:
Nausea and vomiting during pregnancy (NVP) are common symptoms in pregnancy. Although no definitive treatment option for NVP, pyridoxine (vitamin B6) supplementation has been used widely. Therefore, this review article has been conducted.

Does supplementation of pyridoxine alone as well as combined treatment of pyridoxine with an active ingredient as the intervention reduce nausea and vomiting during pregnancy?

Study design:
This review article included 8 RCTs.

Results and conclusions:
The investigators found 8 studies showed beneficial effects with pyridoxine alone as the supplementation, while 6 others found that the supplementation of pyridoxine in combination with another active substance had favourable effects.

The investigators found supplementation of pyridoxine alone as well as combined treatment of pyridoxine with an active ingredient as the intervention significantly improved the symptoms of nausea according to Rhode's score [0.78, 95% CI= 0.26 to 1.31, p = 0.003, I2 = 57%, p = 0.10] and PUQE score [0.75, 95% CI = 0.28 to 1.22, p = 0.002, I2 = 0%, p = 0.51], respectively.

The investigators concluded supplementation of pyridoxine (vitamin B6) alone as well as combined treatment of pyridoxine with an active ingredient as the intervention reduces nausea and vomiting during pregnancy.

Original title:
The effects of pyridoxine (vitamin B6) supplementation in nausea and vomiting during pregnancy: a systematic review and meta-analysis by Jayawardena R, Majeed S, […], Ranaweera P.

Link:
https://pubmed.ncbi.nlm.nih.gov/36719452/

Additional information of El Mondo:
Find more information/studies on vitamin B6 and pregnancy right here.
 

Objectives:
The associations between dietary intakes and circulating blood levels of methionine, choline or betaine and breast cancer risk remain currently unclear. Therefore, this review article has been conducted.

Do higher dietary intakes and circulating blood levels of methionine, choline or betaine reduce breast cancer risk?

Study design:
This review article included 8 prospective cohort studies and 10 case-control studies.

Results and conclusions:
The investigators found in case-control studies that higher dietary choline intake significantly reduced breast cancer risk with 62% [OR = 0.38, 95% CI = 0.16 to 0.86].
However, this reduced risk was not significant in prospective cohort studies [HR = 1.01, 95% CI = 0.92 to 1.12].

The investigators concluded that higher choline dietary intake may reduce breast cancer risk. May reduce because this reduced risk is not found in cohort studies.

Original title:
The association between dietary intakes of methionine, choline and betaine and breast cancer risk: A systematic review and meta-analysis by Van Puyvelde H, Dimou N, […], De Bacquer D.

Link:
https://pubmed.ncbi.nlm.nih.gov/36701983/

Additional information of El Mondo:
Find more information/studies on cohort studies/significantly, choline and breast cancer right here.