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:
Previous studies have suggested that selenium as a trace element is involved in bone health, but findings related to the specific effect of selenium on bone health remain inconclusive. Therefore, this review article has been conducted.

Do both high dietary selenium intake and high serum selenium levels increase bone density?

Study design:
This review article included 8 cross-sectional studies, 7 case-control studies and 3 prospective cohort studies and 1 RCT with a total of 69,672 subjects.

The number of participants ranged from 60 to 21,939, while the mean age varied from 39.4 to 75.8 years, with mean selenium intake ranging from 41.2 to 154.4 μg/d or mean serum selenium level ranging from 66.7 to 131.1 μg/L.
All the observational studies had a NOS score ≥ 4, namely moderate- to high-quality scores.
There was no publication bias.

Results and conclusions:
The investigators found a significantly positive association between dietary selenium intake [β = 0.04, 95% CI = 0.00 to 0.07, p = 0.029, I2 = 95.91%] as well as serum selenium [β = 0.13, 95% CI = 0.00 to 0.26, p = 0.046, I2 = 86.60%] and bone mineral density.

The investigators found high dietary selenium intake significantly reduced risk of hip fracture with 56% [OR = 0.44, 95% CI = 0.37 to 0.52, p 0.001, I2 = 65.2%].

The investigators found osteoporosis patients had lower serum selenium level than healthy controls [WMD = -2.01, 95% CI = -3.91 to -0.12, p = 0.037, I2 = 0%].

The investigators concluded persons with higher dietary selenium intake and higher serum selenium have higher bone mineral density. Furthermore, high selenium dietary intake reduces hip fracture.

Original title:
The association between selenium and bone health: a meta-analysis by Xie H, Wang N, […], Wang Y.

Link:
https://boneandjoint.org.uk/article/10.1302/2046-3758.127.BJR-2022-0420.R1

Additional information of El Mondo:
Find more information/studies on selenium and preventing fractures right here.

Circulating concentration of selenium in blood (serum selenium level) can be increased by eating foods that are high in selenium and/or taking selenium supplements.

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:
Magnesium, an essential cation for numerous cellular processes, is a major component of bone. However, its relationship with the risk of fractures is still uncertain. Therefore, this review article has been conducted.

Do lower serum magnesium concentrations increase risk of incident fractures?

Study design:
This review article included 3 prospective cohort studies and 1 retrospective cohort study with a total of 119,755 participants and a mean follow-up duration of 79 months.
The mean age was 62 years, with a mean percentage of 33% women.
The analyses were adjusted for a mean of 15 potential confounders.
All 4 studies included in the meta-analysis were of high quality (Newcastle-Ottawa Scale of 9 for all).

Results and conclusions:
The investigators found lower serum magnesium concentrations were associated with a significantly higher risk of 58% for incident fractures [RR = 1.579, 95% CI = 1.216 to 2.051, p = 0.001, I2 = 46.9%].
The results were not affected by any heterogeneity [I2 = 31.2%, p = 0.201] nor publication bias [Egger’s test = 0.94 ± 0.43, p = 0.10]. After trimming, the recalculated effect size was only slightly reduced [RR = 1.25, 95% CI = 1.09 to 1.43].
Significant because RR of 1 was not found in the 95% CI of 1.09 to 1.43. RR of 1 means no risk/association.

The investigators concluded lower serum magnesium concentrations increase risk of incident fractures.

Original title:
Association between Serum Magnesium and Fractures: A Systematic Review and Meta-Analysis of Observational Studies by Dominguez LJ, Rodas-Regalado S, […], Barbagallo M.

Link:
https://www.mdpi.com/2072-6643/15/6/1304

Additional information of El Mondo:
Find more information/studies on magnesium and preventing fractures right here.

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

Objectives:
Given their potent antioxidation properties, carotenoids play a role in delaying and preventing dementia and mild cognitive impairment (MCI). However, observational studies have found inconsistent results regarding the associations between blood carotenoid levels and the risk of dementia and MCI. Therefore, this review article has been conducted.

Is a lower blood carotenoid level (like lycopene, zeaxanthin, lutein) a risk factor for dementia or mild cognitive impairment?

Study design:
This review article included 23 studies with 1,422 patients with dementia, 435 patients with mild cognitive impairment and 4,753 controls (persons without dementia or mild cognitive impairment).

Results and conclusions:
The investigators found meta-analysis showed that patients with dementia had lower blood lycopene [SMD = -0.521, 95% CI = -0.74 to -0.301], α-carotene [SMD = -0.489, 95% CI = -0.697 to -0.281] β-carotene [SMD = -0.476, 95% CI = -0.784 to -0.168], lutein [SMD = -0.516, 95% CI = -0.753 to -0.279], zeaxanthin [SMD = -0.571, 95% CI = -0.910 to -0.232] and β-cryptoxanthin [SMD = -0.617, 95% CI = -0.953 to -0.281] than the controls.

The investigators found owing to insufficient data, no similar and stable relationship between blood carotenoid levels and mild cognitive impairment was observed.

The investigators concluded lower blood carotenoid level is a risk factor for dementia.

Original title:
Low blood carotenoid status in dementia and mild cognitive impairment: A systematic review and meta-analysis by Wang L, Zhao T, […], Jiang Q.

Link:
https://pubmed.ncbi.nlm.nih.gov/36997905/

Additional information of El Mondo:
Find more information/studies on carotenoids and Alzheimer 's disease right here.

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

Objectives:
Does a high antioxidant dietary intake reduce risk of Alzheimer's disease and dementia?

Study design:
This review article included 17 cohort studies with 98,264 participants, of which 7,425 had dementia after 3-23 years of follow-up.

Results and conclusions:
The investigators found a high antioxidant dietary intake significantly reduced the incidence of Alzheimer's disease with 15% [RR = 0.85, 95% CI= 0.79 to 0.92, I2 = 45.5%].
However, this reduced risk was not significant for dementia [RR = 0.84, 95% CI = 0.77 to 1.19, I2 = 54.6%].
Significant because RR of 1 was not found in the 95% CI of 0.79 to 0.92. RR of 1 means no risk/association.

The investigators concluded that a high antioxidant dietary intake reduces Alzheimer's disease.

Original title:
Association of Dietary and Supplement Intake of Antioxidants with Risk of Dementia: A Meta-Analysis of Cohort Studies by Zhao R, Han X, […], You H.

Link:
https://pubmed.ncbi.nlm.nih.gov/36846999/

Additional information of El Mondo:
Find more information/studies on antioxidant and Alzheimer 's disease 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.