Nutritional advice

Objectives:
The etiology of cancer type may vary significantly due to anatomy, embryology and physiology of the cancer site. Although the association between potato consumption and colorectal cancer (CRC) was summarized in a 2018 meta-analysis of 5 cohort studies, however, no meta-analysis has evaluated potato consumption in relation to multiple cancer sites in adults. Therefore, this review article has been conducted.

Do potato intakes increase multiple cancer sites risk?

Study design:
This review article included 20 prospective cohort studies (with a total of 785,348 participants, of which 19,882 incident cases (persons with cancer)) and 36 case-control studies ( with a total of 21,822 cases (persons with cancer) and 66,502 controls (persons without cancer)).

Certainty of the evidence was low for total cancer, colorectal cancer, colon, rectal, renal, pancreatic, breast, prostate and lung cancer and very low for gastric and bladder cancer.

Results and conclusions:
The investigators found among cohort studies, no association between high versus low intake of total potato (white and yellow) consumption and overall cancers [RR = 1.04, 95% CI = 0.96 to 1.11, tau2 = 0.005, n = 18].

The investigators found no relation between total potato consumption (high compared with low intake) and risk of colorectal, pancreatic, colon, gastric, breast, prostate, kidney, lung or bladder cancer in cohort or case-control studies.

The investigators found no association between high versus low consumption of potato preparations (boiled/fried/mashed/roasted/baked) and risk of gastrointestinal-, sex-hormone-, or urinary-related cancers in cohort or case-control studies.

The investigators concluded that potato intakes or potato preparations are not associated with multiple cancer sites when comparing high and low intake categories. This finding is consistent with the findings from the 2018 meta-analysis regarding potato intake and risk of colorectal cancer.

Original title:
Potato Consumption and Risk of Site-Specific Cancers in Adults: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies by Mofrad MD, Mozaffari H, […], Azadbakht L.

Link:
https://pubmed.ncbi.nlm.nih.gov/33861304/

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Objectives:
Do magnesium intakes reduce risk of all-cause, cancer and cardiovascular disease (CVD) mortality?

Study design:
This review article included 19 prospective cohort studies with a total of 1,168,756 participants (52,378 deaths from all causes (all-cause mortality), 23,478 from cardiovascular disease (CVD) and 11,408 from cancer).
The follow-up period was 3.5 to 32 years.

Results and conclusions:
The investigators found dietary magnesium intake was significantly associated with a lower risk of 13% for all-cause mortality [pooled effect size (ES) = 0.87, 95% CI = 0.79 to 0.97, p = 0.009, I2 = 70.7%, p 0.001].

The investigators found dietary magnesium intake was significantly associated with a lower risk of 20% for cancer mortality [pooled ES = 0.80, 95% CI = 0.67 to 0.97, p = 0.023, I2 = 55.7%, p = 0.027].

The investigators found for supplemental and total magnesium intakes, no significant associations with risks of all-cause, cardiovascular disease and cancer mortality.

The investigators found, however, linear dose-response meta-analysis indicated that each additional intake of 100 mg/d of dietary magnesium was significantly associated with a 6% and 5% reduced risk of all-cause and cancer mortality, respectively.

The investigators concluded that higher intake of dietary magnesium (at least 100 mg/d of dietary magnesium) is associated with a reduced risk of all-cause and cancer mortality, but not cardiovascular disease mortality. Supplemental and total magnesium intakes are not associated with the risk of all-cause, cardiovascular disease and cancer mortality. These findings indicate that consumption of magnesium from dietary sources may be beneficial in reducing all-cause and cancer mortality and thus have practical importance for public health.  

Original title:
Total, Dietary, and Supplemental Magnesium Intakes and Risk of All-Cause, Cardiovascular, and Cancer Mortality: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies by Bagheri A, Naghshi S, […], Esmaillzadeh A.

Link:
https://pubmed.ncbi.nlm.nih.gov/33684200/

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Objectives:
Previous population studies on the associations between dietary fatty acids (FAs), plasma FAs levels and the risk of age-related macular degeneration (AMD) have yielded inconclusive results. Therefore, this review article (meta-analysis) has been conducted.

Do higher dietary fatty acids (EPA and DHA) intakes or higher plasma fatty acids levels reduce risk of age-related macular degeneration?

Study design:
This review article included 11 prospective cohort studies with 167,581 participants. During the follow-up periods (ranging from 3 to 28 years), 6,318 cases of age-related macular degeneration were recorded.

Results and conclusions:
The investigators found that each 1 g/day increment of dietary intake of docosahexaenoic acid (DHA) and eicosatetraenoic acid (EPA) combined significantly reduced risk of early age-related macular degeneration with 33% [RR = 0.67, 95% CI = 0.51 to 0.88].
Significantly means that there is an association with a 95% confidence.

The investigators found that each 1 g/day increment of dietary intake of docosahexaenoic acid (DHA) significantly reduced risk of early age-related macular degeneration with 50% [RR = 0.50, 95% CI = 0.32 to 0.78].
Significantly means it can be said with a 95% confidence that each 1 g/day increment of dietary intake of docosahexaenoic acid (DHA) really reduces risk of early age-related macular degeneration with 50%.

The investigators found that each 1 g/day increment of dietary intake of eicosatetraenoic acid (EPA) significantly reduced risk of early age-related macular degeneration with 60% [RR = 0.40, 95% CI = 0.18 to 0.87].
Significantly because RR of 1 was not found in the 95% CI of 0.18 to 0.87. RR of 1 means no risk/association.

The investigators found that higher plasma docosahexaenoic acid (DHA) levels significantly reduced risk of advanced age-related macular degeneration with 28% [RR = 0.72, 95% CI = 0.55 to 0.95].

The investigators found that higher plasma eicosatetraenoic acid (EPA) levels significantly reduced risk of advanced age-related macular degeneration with 43% [RR = 0.57, 95% CI = 0.40 to 0.81].

The investigators concluded that 1 g/day of dietary intake DHA and 1 g/day of dietary intake EPA and higher plasma DHA and EPA levels are associated with a reduced risk of age-related macular degeneration.

Original title:
Dietary fatty acid intake, plasma fatty acid levels, and the risk of age-related macular degeneration (AMD): a dose-response meta-analysis of prospective cohort studies by Zhong Y, Wang K, [...], Yao K.

Link:
https://pubmed.ncbi.nlm.nih.gov/33469697/

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A high plasma EPA and DHA content can be obtained by eating a lot of oily fish and/or by taking EPA and DHA supplements (fish oil supplements).
Oily fish contains more EPA and DHA than non-oily fish.

Early age-related macular degeneration: most people do not experience adverse symptoms or vision loss in the early stage of age-related macular degeneration, but night vision problems are often reported. Though no pigmentary abnormalities are apparent upon examination, medium-sized drusen (>63 μm and ≤125 μm) are present.

Objectives:
Previous studies on the association between alcohol intake and risk of fracture have reached conflicting findings. Therefore, this review article has been conducted.

Does alcohol consumption increase risk of fractures?

Study design:
This review article included 38 prospective cohort studies with a total sample size of 5,053,117 participants and 169,560 cases of fracture.

Results and conclusions:
The investigators found in a random-effects meta-analysis, that alcohol consumption significantly increased risk of total fractures with 35% [RR = 1.35, 95% CI = 1.01 to 1.81] and any fractures with 24% [RR= 1.24, 95% CI = 1.11 to 1.38].
Significant because RR of 1 was not found in the 95% CI of 1.01 to 1.81. RR of 1 means no risk/association.

The investigators found, however, no significant association between alcohol intake and risk of hip fractures [RR = 1.19, 95% CI = 0.96 to 1.48], osteoporotic fractures [RR = 2.01, 95% CI = 0.76 to 5.34], vertebral fractures [RR = 0.98, 95% CI = 0.68 to 1.40] and wrist fractures [RR = 0.99, 95% CI = 0.85 to 1.16].
No significant because RR of 1 was found in the 95% CI of 0.85 to 1.06. RR of 1 means no risk/association.

The investigators concluded that alcohol consumption is positively associated with risk of total fractures and any fractures.

Original title:
A systematic review and meta-analysis of prospective cohort studies on the association between alcohol intake and risk of fracture by Asoudeh F, Salari-Moghaddam A, […], Esmaillzadeh A.

Link:
https://pubmed.ncbi.nlm.nih.gov/33596741/

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Objectives:
Recent evidence suggests that diet can modify the risk of future cognitive impairment and dementia. A biologically plausible rationale and initial clinical data indicate that the antioxidant activities of dietary carotenoids may assist the preservation of cognitive function. Therefore, this review article has been conducted.

Does carotenoid supplementation improve cognitive performance among healthy adults?

Study design:
This review article included 9 RCTs, involving 2,228 subjects in the treated group (group with carotenoid supplementation) and 2,174 subjects in control group (group without carotenoid supplementation).
The age of all participants varied from 45 to 78 years.
The majority of clinical trials assessed the effect of xanthophylls such as lutein, zeaxanthin, and astaxanthin, whereas only 1 study determined the effects of β-carotene.
The duration of carotenoid supplementation ranged from 2 weeks to 12 months.
The dosage of carotenoids administered in the studies ranged from 0.5 mg/d to 50 mg/d.
There was no evidence of publication bias.

Results and conclusions:
The investigators found results of the pooled meta-analysis showed a significant effect of carotenoid intervention on cognitive outcomes [Hedge's g = 0.14, 95% CI = 0.08 to 0.20, p 0.0001, I2 = 0.00%].
The sensitivity analysis did not change the overall findings obtained from the primary analysis.

The investigators concluded that these results highlight the potential role of carotenoids (0.5 mg/d to 50 mg/d) in the protection of mental functions even in subjects (healthy participants aged 45-78 years) without cognitive impairment. This is particularly important because the population is aging and preservation of cognitive function is crucial for individual autonomy and quality of life, even in non-demented subjects. Further well-powered and long-term trials are required to determine treatment duration, type of carotenoid and optimal dosage.

Original title:
Carotenoids and Cognitive Outcomes: A Meta-Analysis of Randomized Intervention Trials by Davinelli S, Ali S, […], Corbi G.

Link:
https://www.mdpi.com/2076-3921/10/2/223/htm

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Objectives:
Does citrus dietary intake reduce the risk of lung cancer?

Study design:
This review article included 21 observational studies.

Results and conclusions:
The investigators found pooled analyses showed that those with the highest citrus fruit dietary intake compared to the lowest intake had a 9% reduction in lung cancer risk [OR = 0.91, 95% CI = 0.84 to 0.98].

The investigators found a nonlinear association between citrus dietary intake and lung cancer risk in the dose-response analysis [p = 0.0054] and that the risk reached the minimum [OR = 0.91] around 60 g/d.
However, no obvious dose-response association was observed with intakes above 80 g/d.

The investigators concluded that citrus fruit dietary intake is negatively associated with the risk of lung cancer. Besides, there is a nonlinear dose-response relationship between citrus fruit dietary intake and lung cancer risk within a certain range (60-80g per day).

Original title:
Citrus fruit intake and lung cancer risk: A meta-analysis of observational studies by Wang J, Gao J, [...], Qian BY.

Link:
https://pubmed.ncbi.nlm.nih.gov/33529754/

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Citrus fruits include oranges, lemons, limes and grapefruits.

Objectives:
Increasing macular pigment optical density (MPOD) as a result of increased macular concentration of lutein and zeaxanthin may reduce the risk of age-related macular degeneration (AMD). Therefore, this review article has been conducted.

Have daily egg consumption beneficial effects on macular pigment optical density and serum lutein levels?

Study design:
This review article included 5 RCTs with a total of 296 participants.
There was no heterogeneity between studies.

Results and conclusions:
The investigators found that egg consumption significantly increased macular pigment optical density [WMD = +0.037, 95% CI = 0.004 to 0.069, p = 0.027] and serum lutein levels [WMD = +0.150 μmol/L, 95% CI = 0.037 to 0.263, p = 0.009].

The investigators found subgroup analyses showed that egg consumption had a larger effect on macular pigment optical density in studies with a parallel design and increased serum lutein levels to a greater extent in a healthy population.

The investigators concluded daily egg consumption have beneficial effects on macular pigment optical density and serum lutein level is inversely associated with reduced age-related macular degeneration progression. Further clinical trials are required to confirm the results of this review article.

Original title:
A positive effect of egg consumption on macular pigment and healthy vision: a systematic review and meta-analysis of clinical trials by Sikaroudi MK, Saraf-Bank S, […], Soltani S.

Link:
https://pubmed.ncbi.nlm.nih.gov/33491232/

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Objetivos:
¿Aumenta un nivel bajo de selenio en los tejidos humanos el riesgo de cáncer de mama?

Diseño del estudio:
Este artículo de revisión incluyó 18 estudios de casos y controles con 3,374 mujeres diagnosticadas con cáncer de mama (grupo de casos) y 3,582 controles sanos (mujeres sin cáncer de mama).

Resultados y conclusiones:
Los investigadores encontraron que el nivel de selenio de grupo de casos (grupo con mujeres diagnosticadas con cáncer de mama) fue significativamente menor que grupo de control (grupo con mujeres sin cáncer de mama) [-0.53 μg/L, 95% IC = -0.72 a -0.34, p 0.001].

Los investigadores encontraron en el análisis de subgrupos que el nivel de selenio sérico de grupo de casos fue significativamente más bajo que grupo de control [-1.14 μg/L, 95% IC = -1.70 a -0.58, p 0.001].

Los investigadores encontraron en el análisis de subgrupos que el nivel de selenio en plasma de grupo de casos fue significativamente más bajo que grupo de control [-0.21 μg/L, 95% IC = -0.37 a -0.04, p 0.014].

Los investigadores encontraron en el análisis de subgrupos que el nivel de selenio de la uña del pie de grupo de casos fue significativamente más bajo que grupo de control [-0.21 μg/L, 95% IC = -0.38 a -0.03, p 0.021].

Los investigadores concluyeron que un nivel bajo de selenio en los tejidos humanos aumenta el riesgo de cáncer de mama, lo que puede mejorar la comprensión de los efectos del selenio en la salud humana.

Título original:
Relationship Between Selenium in Human Tissues and Breast Cancer: a Meta-analysis Based on Case-Control Studies by Zhu X, Pan D, […], Sun G.

Enlace:
https://pubmed.ncbi.nlm.nih.gov/33420696/

Información adicional de El Mondo:
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Objectives:
Does a low selenium level in human tissues increase the risk of breast cancer?

Study design:
This review article included 18 case-control studies with 3,374 women diagnosed with breast cancer (case group) and 3,582 healthy controls (women without breast cancer).

Results and conclusions:
The investigators found selenium level of the case group (group with women diagnosed with breast cancer) was significantly lower than the control group (group with women without breast cancer) [-0.53 μg/L, 95% CI = -0.72 to -0.34, p 0.001].

The investigators found in subgroup analysis that serum selenium level of the case group was significantly lower than the control group [-1.14 μg/L, 95% CI = -1.70 to -0.58, p 0.001].

The investigators found in subgroup analysis that plasma selenium level of the case group was significantly lower than the control group [-0.21 μg/L, 95% CI = -0.37 to -0.04, p 0.014].

The investigators found in subgroup analysis that selenium level of toenail of the case group was significantly lower than the control group [-0.21 μg/L, 95% CI = -0.38 to -0.03, p 0.021].

The investigators concluded that a low selenium level in human tissues increases the risk of breast cancer, which may improve the understanding of the effects of selenium on human health.

Original title:
Relationship Between Selenium in Human Tissues and Breast Cancer: a Meta-analysis Based on Case-Control Studies by Zhu X, Pan D, […], Sun G.

Link:
https://pubmed.ncbi.nlm.nih.gov/33420696/

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Objectives:
Does a high dietary intake of β-cryptoxanthin reduce the risk of osteoporosis and hip fracture?

Study design:
This review article included 7 cohort studies, 4 case-control studies and 4 cross-sectional studies with a total of 100,496 individuals.
The methodological qualities of all studies were rated as “fair” to “good”.
The number of populations in each study ranged from 59 to 25,566.

Results and conclusions:
The investigators found that a high dietary intake of β-cryptoxanthin significantly reduced risk of osteoporosis with 24% [OR = 0.76, 95% CI = 0.66 to 0.88, p = 0.0002, I2 = 36%, p = 0.11].

The investigators found in subgroup analysis that a high dietary intake of β-cryptoxanthin significantly reduced risk of osteoporosis with 28% [OR = 0.72, 95% CI = 0.58 to 0.91, p = 0.005, I2 = 59%] among women.

The investigators found in subgroup analysis that a high dietary intake of β-cryptoxanthin significantly reduced risk of osteoporosis with 20% [OR = 0.80, 95% CI = 0.65 to 1.00, p = 0.005, I2 = 11%] among men.

The investigators found that a high dietary intake of β-cryptoxanthin significantly reduced risk of hip fracture with 28% [OR = 0.72, 95% CI = 0.60 to 0.87, p = 0.0008, I2 = 55%].

The investigators found in subgroup analysis that a high dietary intake of β-cryptoxanthin significantly reduced risk of hip fracture with 29% [OR = 0.71, 95% CI = 0.54 to 0.94, p = 0.02, I2 = 71%] among women. 

The investigators concluded that a high dietary intake of β-cryptoxanthin reduces the risk of osteoporosis and hip fracture. Further longitudinal studies are needed to validate the causality of current findings.

Original title:
Effects of β-Cryptoxanthin on Improvement in Osteoporosis Risk: A Systematic Review and Meta-Analysis of Observational Studies by Kim SJ, Anh NH, […], Kwon SW.

Link:
https://www.mdpi.com/2304-8158/10/2/296/htm

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Objectives:
Although several epidemiological studies have investigated associations between poultry and fish consumption and pancreatic cancer (PC) risk, these findings have been inconsistent. Therefore, this review article has been conducted.

Do high dietary poultry or fish intakes increase risk of pancreatic cancer?

Study design:
This review article included 25 studies (cohort studies and case-control studies).

Results and conclusions:
The investigators found for the highest vs. lowest poultry intake category a significantly increased risk of 14% for pancreatic cancer [pooled RR = 1.14, 95% CI = 1.02 to 1.26] in cohort studies.
Significant because RR of 1 was not found in the 95% CI of 1.02 to 1.26. RR of 1 means no risk/association.

The investigators found there was no association between fish intake and pancreatic cancer risk [RR = 1.00, 95% CI = 0.93 to 1.07].
No association because RR of 1 was found in the 95% CI of 0.93 to 1.07. RR of 1 means no risk/association.

The investigators concluded that large amount of poultry intake increases pancreatic cancer risk, while fish intake is unlikely to be linked to pancreatic cancer risk. These findings require further investigation, particularly between poultry and pancreatic cancer.

Original title:
Poultry and Fish Intake and Pancreatic Cancer Risk: A Systematic Review and Meta-Analysis by Gao Y, Ma Y, […], Wang X.

Link:
https://pubmed.ncbi.nlm.nih.gov/33432844/

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Objectives:
Does dietary acrylamide intake increase risk of breast, endometrial and ovarian cancer?

Study design:
This review article included 14 prospective cohort studies.

Results and conclusions:
The investigators found no significant association between dietary acrylamide intake and the risk of breast [RR = 0.95, 95% CI = 0.90 to 1.01], endometrial [RR = 1.03, 95% CI = 0.89 to 1.19] and ovarian cancers [RR = 1.02, 95% CI = 0.84 to 1.24].
In addition, no significant association between dietary acrylamide intake and the risk of breast, endometrial and ovarian cancers in different subgroup analyses by smoking status, menopausal status, BMI status and different types of breast cancer.

The investigators concluded there is no significant association between dietary acrylamide intake and the risk of breast, endometrial and ovarian cancers.

Original title:
Dietary acrylamide intake and risk of women's cancers: a systematic review and meta-analysis of prospective cohort studies by Benisi-Kohansal S, Salari-Moghaddam A, […], Esmaillzadeh A.

Link:
https://pubmed.ncbi.nlm.nih.gov/33413725/

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Acrylamide is a chemical that naturally forms in starchy food products during high-temperature cooking processes, such as frying, roasting and baking. Acrylamide in food forms from sugars and an amino acid that are naturally present in food.
 

Objetivos:
¿Reduce el consumo de frutas y verduras el riesgo de cáncer del conducto biliar?

Diseño del estudio:
Este artículo de revisión incluyó 14 estudios.

No hubo sesgo de publicación entre los estudios [p Begg = 0.53, p Egger = 0.84 para hortalizas y p Begg = 0.95, p Egger = 0.64 para frutas].

Resultados y conclusiones:
Los investigadores encontraron para el consumo más alto en comparación con más bajo, un riesgo significativamente reducido del 52% para el cáncer del conducto biliar [RR resumido = 0.48, 95% IC = 0.22 a 0.74, I2 = 86.8%, p 0.001, n = 10] para el consumo de verduras.

Los investigadores encontraron para el consumo más alto en comparación con más bajo, un riesgo significativamente reducido del 53% para el cáncer del conducto biliar [RR resumido = 0.47, 95% IC = 0.32 a 0.61, I2 = 63.3%, p = 0.001, n = 13] para el consumo de fruta.

Los investigadores encontraron por cada incremento de 100 gramos/día de consumo de verduras, un riesgo significativamente reducido del 69% para el cáncer del conducto biliar [RR = 0.31, 95% IC = 0.20 a 0.47, I2 = 63.3, n = 8].

Los investigadores concluyeron que el consumo de frutas y verduras reduce el riesgo de cáncer del conducto biliar. Se necesitan más estudios prospectivos bien diseñados para confirmar estos hallazgos.

Título original:
Vegetable, Fruit Consumption and Risk of Biliary Cancer: Evidence from a Meta-Analysis by Huai J and Xiaohua Ye X.

Enlace:
https://pubmed.ncbi.nlm.nih.gov/32731775/

Información adicional de El Mondo:
Encontrar aquí más información/estudios sobre significativamente/estudios de cohorte, el consumo de frutas y verduras y el cáncer.

Objectives:
Data on the association of nut intake with risk of cancer and its mortality are conflicting. Although previous meta-analyses summarized available findings in this regard, some limitations may distort their findings. Moreover, none of these meta-analyses examined the dose-response associations of total nut intake with the risk of specific cancers as well as associations between specific types of nuts and cancer mortality. Therefore, this review article (meta-analysis) has been conducted.

Do higher nut dietary intakes reduce risk of cancer incidence and mortality?

Study design:
This review article included in total 43 articles (observational studies) on cancer risk and 9 articles (observational studies) on cancer mortality.

Results and conclusions:
The investigators found when comparing the highest with lowest intakes of total nuts, the highest intakes of total nuts (tree nuts and peanuts), significantly reduced risk of cancer with 16% [summary effect size = 0.86, 95% CI = 0.81 to 0.92, p 0.001, I2 = 58.1%, p 0.01].

The investigators found when comparing the highest with lowest intakes of tree nuts, the highest intakes of tree nuts significantly reduced risk of cancer with 13% [pooled effect size = 0.87, 95% CI = 0.78 to 0.96, p 0.01, I2 = 15.8%, p = 0.28].

The investigators found based on the dose-response analysis, a 5-g/d increase in total nut intake was associated with 3%, 6% and 25% lower risks of overall, pancreatic and colon cancers, respectively.  

The investigators found in terms of cancer mortality, 13%, 18% and 8% risk reductions with higher intakes of total nuts, tree nuts and peanuts, respectively.

The investigators found, in addition, a 5-g/d increase in total nut intake was associated with a 4% lower risk of cancer mortality.

The investigators concluded there is a protective association between total nut and tree nut intake and the risk of cancer and its mortality.

Original title:
Association of Total Nut, Tree Nut, Peanut, and Peanut Butter Consumption with Cancer Incidence and Mortality: A Comprehensive Systematic Review and Dose-Response Meta-Analysis of Observational Studies by Naghshi S, Sadeghian M, […], Sadeghi O.

Link:
https://pubmed.ncbi.nlm.nih.gov/33307550/

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Tree nuts in this review article are walnuts, pistachios, macadamia nuts, pecans, cashews, almonds, hazelnuts and Brazil nuts.

Objectives:
Do omega-3 fatty acid supplements (EPA and DHA) improve sarcopenia-related performances among the elderly?

Study design:
This review article included 10 RCTs with 552 participants.
The number of study participants ranged from 24 to 126 and the durations of the interventions spanned 10 to 24 weeks.
The doses ranged from 0.16 to 2.6 g/day of EPA and from 0 to 1.8 g/day of DHA.
The mean ages of the participants across the RCTs ranged from 63 to 75 years old.

Results and conclusions:
The investigators found in subgroup analyses that omega-3 fatty acid supplements (EPA and DHA) at more than 2 g/day significantly increased muscle mass among the elderly [SMD = 0.67 kg, 95% CI = 0.16 to 1.18, p 0.05].

The investigators found in subgroup analyses that omega-3 fatty acid supplements (EPA and DHA) during more than 6 months significantly improved walking speed among the elderly [SMD = 1.78 m/sec, 95% CI = 1.38 to 2.17, p 0.05].

The investigators concluded that taking at least 2 grams of omega-3 supplements (EPA and DHA) per day increases muscle mass among the elderly, while taking omega-3 supplements for at least 6 months increases walking speed among the elderly.

Original title:
Effects of Omega-3 Fatty Acids on Muscle Mass, Muscle Strength and Muscle Performance among the Elderly: A Meta-Analysis by Huang YH, Chiu WC, […], Wang YH.

Link:
https://www.mdpi.com/2072-6643/12/12/3739/htm

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EPA and DHA are present in fish.
 

Objectives:
Does calcium combined with vitamin D supplementation reduce risk of osteoporosis in postmenopausal women?

Study design:
This review article included 10 RCTs.

Results and conclusions:
The investigators found calcium combined with vitamin D supplementation significantly increased total bone mineral density [SMD = 0.537, 95% CI = 0.227 to 0.847] in postmenopausal women.

The investigators found calcium combined with vitamin D supplementation significantly increased lumbar spine bone mineral density [SMD = 0.233, 95% CI = 0.073 to 0.392, p 0.001] in postmenopausal women.

The investigators found calcium combined with vitamin D supplementation significantly increased arms bone mineral density [SMD = 0.464, 95% CI = 0.186 to 0.741] in postmenopausal women.

The investigators found calcium combined with vitamin D supplementation significantly increased femoral neck bone mineral density [SMD = 0.187, 95% CI = 0.010 to 0.364] in postmenopausal women.

The investigators found calcium combined with vitamin D supplementation significantly reduced risk of hip fracture with 13.6% [RR = 0.864, 95% CI = 0.763 to 0.979] in postmenopausal women.

The investigators found in subgroup analysis that calcium combined with 400 IU/d (10 mcg/d) vitamin D supplementation significantly increased femoral neck bone mineral density [SMD = 0.335, 95% CI = 0.113 to 0.558] in postmenopausal women.

The investigators found in subgroup analysis that dairy products fortified with calcium and vitamin D significantly increased total bone mineral density [SMD = 0.784, 95% CI = 0.322 to 1.247] in postmenopausal women.

The investigators found in subgroup analysis that dairy products fortified with calcium and vitamin D significantly increased lumbar spine bone mineral density [SMD = 0.320, 95% CI = 0.146 to 0.494] in postmenopausal women.

The investigators concluded that dairy products fortified with calcium and vitamin D have a favourable effect on bone mineral density. Furthermore, calcium combined with vitamin D supplementation could prevent osteoporosis hip fracture in postmenopausal women.

Original title:
Effects of combined calcium and vitamin D supplementation on osteoporosis in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials by Liu C, Kuang X […], Li D.

Link:
https://pubmed.ncbi.nlm.nih.gov/33237064/

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Objectives:
Epidemiological studies showing the correlation between folate (folic acid) and the breast cancer risk have revealed inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Do higher folate dietary intakes or plasma folate levels reduce risk of breast cancer?

Study design:
This review article included 39 studies on folate dietary intake (19 were prospective cohort studies, which included 37,917 cases (persons with breast cancer) and 20 were case-control studies, which included 13,074 cases and 17,497 controls (persons without breast cancer)) and 12 studies on plasma folate level (10 were case-control studies, consisting of 7,850 cases and 8,898 controls and 2 cohort studies, consisting of 815 incident cases).

Results and conclusions:
The investigators found when compared to the lowest folate dietary intake, the highest folate dietary intake significantly reduced risk of breast cancer with 15% [combined OR = 0.85, 95% CI = 0.79 to 0.92, I2 = 75.2%, p 0.001].
This reduced risk was not significant for cohort studies [OR = 0.97, 95% CI = 0.91 to 1.03, I2 = 53.3%, p = 0.316].

The investigators found for every 100-μg/day increase in folate dieatary intake, a significantly reduced risk of 2% for breast cancer [combined OR = 0.98, 95% CI = 0.97 to 0.99, I2 = 72.8%, p = 0.002].
This reduced risk was also significantly in cohort studies [summary OR = 0.99, 95% CI = 0.98 to 1.00]. 
Significant means that there is an association with a 95% confidence.

The investigators found stratification by menopausal status showed that a higher folate dietary intake significantly reduced risk of breast cancer in premenopausal women with 20% [OR = 0.80, 95% CI = 0.66 to 0.97, p = 0.022] but not in postmenopausal women [OR = 0.94, 95% CI = 0.83 to 1.06, p = 0.320].
Significant because OR of 1 was not found in the 95% CI of 0.66 to 0.97. OR of 1 means no risk.

The investigators found the highest versus lowest plasma folate levels had no correlation with the risk of breast cancer [combined OR = 0.98, 95% CI = 0.82 to 1.17, I2 = 63.0%, p = 0.822].

The investigators concluded there is a negative correlation between folate dieatary intake, at least 100-μg/day and the risk of breast cancer. However, plasma folate levels have no correlation with the risk of breast cancer. Therefore, whether folate dietary intake has practical clinical significance requires further study and the use of additional folate supplements should be carefully considered.

Original title:
Association of folate intake and plasma folate level with the risk of breast cancer: a dose-response meta-analysis of observational studies by Ren X, Xu P, [...], Dai Z.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7695428/

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The plasma folate level can be increased by taking folate-rich foods and/or folate supplements.

Objectives:
The association between vitamin C intake and breast cancer is unclear. Therefore, this review article (meta-analysis) has been conducted.

Does a higher vitamin C intake reduce risk of breast cancer incidence, mortality and recurrence?

Study design:
This review article included 24 cohort studies and 30 case-control studies.

Results and conclusions:
The investigators found pooled results suggested that the highest versus lowest vitamin C intake was significantly associated with a 14% lower risk of breast cancer incidence [relative risk = 0.86, 95% = 0.81 to 0.92, I2 = 78.7%, p 0.00].
Sensitivity analysis indicated that the overall results remained consistent even after excluding studies individually.

The investigators found the use of random-effects model indicated that a 100-mg/day increment in vitamin C intake had no significant effect on breast cancer risk.

The investigators found stratification by study design showed a 26% lower risk of breast cancer incidence for vitamin C intake in case-control studies [RR = 0.74, 95% CI = 0.65 to 0.84, p 0.001]. However, a non-significant inverse association was found in cohort studies [RR = 0.96, 95% CI = 0.89 to 1.04, p = 0.295].

The investigators found when the studies were stratified by the source of vitamin C, a 11% lower risk of breast cancer incidence with dietary intake [RR = 0.89, 95% CI = 0.82 to 0.96, p = 0.004] but not with supplements [RR = 1.02, 95% CI = 0.94 to 1.10, p = 0.678].

The investigators found that the highest versus lowest vitamin C intake was significantly associated with a 22% lower risk of breast cancer mortality [HR = 0.78, 95% CI = 0.69 to 0.88, I2 = 2.6%].

The investigators found that the highest versus lowest vitamin C intake was significantly associated with a 19% lower risk of breast cancer recurrence [HR = 0.81, 95% CI = 0.67 to 0.99, p = 0.043, I2 = 0.0%].

The investigators concluded that higher vitamin C dietary intake is significantly associated with a reduced risk of breast cancer incidence, mortality and recurrence.

Original title:
Association of vitamin C intake with breast cancer risk and mortality: a meta-analysis of observational studies by Zhang D, Xu P, [...], Dai Z.

Link:
https://www.aging-us.com/article/103769/text

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Objectives:
Heated debates have been on-going about tea consumption and the incidence of cancer, especially in head and neck cancer types. Therefore, this review article (meta-analysis) has been conducted.

Does habitual tea consumption reduce risk of nasopharyngeal cancer?

Study design:
This review article included 6 articles.

Results and conclusions:
The investigators found that habitual tea consumption significantly reduced risk of nasopharyngeal cancer with 13.5% [OR = 0.865, 95% CI = 0.806 to 0.929].

The investigators concluded that habitual tea consumption is associated with prevention of nasopharyngeal cancer development. Additional studies are needed to further understand the molecular role of bioactive compound and potential health benefit of tea consumption in nasopharyngeal cancer prevention.

Original title:
The Association between Tea Consumption and Nasopharyngeal Cancer: A Systematic Review and Meta-Analysis by Okekpa SI, Basria R, […], Musa MY.

Link:
https://pubmed.ncbi.nlm.nih.gov/32856842/

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

Objectives:
The number of cancer survivors is growing rapidly worldwide, especially long-term survivors. Although a healthy diet with a high vegetable and fruit consumption is a key factor in primary cancer prevention, there is a lack of specific dietary recommendations for cancer survivors, except in the case of breast cancer [World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) report]. Therefore, this review article (meta-analysis) has been conducted.

Does the general recommendation to consume ≥5 servings of vegetables and fruit per day (400 g/d) meet the needs of cancer survivors?

Study design:
This review article included 28 cohort studies.

Results and conclusions:
The investigators found a high vegetable intake before diagnosis significantly reduced overall mortality in survivors of head and neck cancer with 25% [HR = 0.75, 95% CI = 0.65 to 0.87].  

The investigators found a high vegetable intake before diagnosis significantly reduced overall mortality in survivors of ovarian cancer with 22% [HR = 0.78, 95% CI = 0.66 to 0.91].  

The investigators found a high fruit intake before diagnosis significantly reduced overall mortality in survivors of ovarian cancer with 18% [HR = 0.82, 95% CI = 0.70 to 0.96].  

The investigators found the evidence was insufficient for survivors of other cancers, although these associations generally tended to be protective. Therefore, more studies are needed to clarify the association between vegetable and fruit consumption and the prognosis of these different types of cancer.

The investigators concluded the general recommendation to consume ≥5 servings of vegetables and fruit per day (400 g/d) could underestimate the needs of cancer survivors, particularly those with ovarian tumors, in which the recommendation could increase to 600 g/d (i.e., 300 g/d of vegetables and 300 g/d of fruit).

Original title:
Vegetable and Fruit Consumption and Prognosis Among Cancer Survivors: A Systematic Review and Meta-Analysis of Cohort Studies by Hurtado-Barroso S, Trius-Soler M, […], Zamora-Ros R.

Link:
https://pubmed.ncbi.nlm.nih.gov/32717747/

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

Objectives:
Isoflavones have a structure similar to 17β-estradiol, so they may be useful to postmenopausal women in preventing bone loss related to estrogen deficiency. Therefore, this review article has been conducted.

Do isoflavone supplements increase bone mineral density (BMD) in postmenopausal women?

Study design:
This review article included 63 RCTs, involving 6,427 postmenopausal women.

Isoflavone interventions were generally safe and well tolerated.

Results and conclusions:
The investigators found statistically significant differences in bone mineral density at the last follow-up visit between the two groups (isoflavones vs. control) at the lumbar spine [MD = 21.34 mg/cm², 95% CI = 8.21 to 34.47 mg/cm², p = 0.001], the femoral neck [MD = 28.88 mg/cm², 95% CI = 15.05 to 42.71 mg/cm², p 0.0001] and the distal radius [MD = 19.27 mg/cm², 95% CI = 5.65 to 32.89 mg/cm², p = 0.006].
This improved bone mineral density was found for genistein 54 mg/day and ipriflavone (a synthetic isoflavone) 600 mg/day.

The investigators concluded isoflavone interventions, genistein (54 mg/day) and ipriflavone (600 mg/day) in particular, have beneficial effects on bone mineral density outcomes and are safe in postmenopausal women. They may be considered as a complementary or alternative option in the prevention and treatment of menopause-related osteoporosis.

Original title:
Effects of Isoflavone Interventions on Bone Mineral Density in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Sansai K, Takuathung MN, [...], Koonrungsesomboon N.

Link:
https://pubmed.ncbi.nlm.nih.gov/32524173/

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Find more information/studies on isoflavones and elderly right here.

Objectives:
It is unclear how dietary intake influences the ovarian cancer. Therefore, this review article (meta-analysis) has been conducted.

Is there a relationship between dietary intake of different nutrients/food groups and ovarian cancer risk?

Study design:
This review article included 97 cohort studies.

Results and conclusions:
The investigators found no significant association between dietary intake and risk of ovarian cancer.

The investigators found in subgroup analyses that dietary intake of green leafy vegetables significantly reduced risk of ovarian cancer with 9% [RR = 0.91, 95% CI = 0.85 to 0.98].

The investigators found in subgroup analyses that dietary intake of allium vegetables significantly reduced risk of ovarian cancer with 21% [RR = 0.79, 95% CI = 0.64 to 0.96].

The investigators found in subgroup analyses that dietary intake of fiber significantly reduced risk of ovarian cancer with 11% [RR = 0.89, 95% CI = 0.81 to 0.98].

The investigators found in subgroup analyses that dietary intake of flavonoids significantly reduced risk of ovarian cancer with 17% [RR = 0.83, 95% CI = 0.78 to 0.89].

The investigators found in subgroup analyses that dietary intake of green tea significantly reduced risk of ovarian cancer with 39% [RR = 0.61, 95% CI = 0.49 to 0.76].

The investigators found in subgroup analyses that dietary intake of tota fat significantly increased risk of ovarian cancer with 10% [RR = 1.10, 95% CI = 1.02 to 1.18].

The investigators found in subgroup analyses that dietary intake of saturated fat significantly increased risk of ovarian cancer with 11% [RR = 1.11, 95% CI = 1.01 to 1.22].

The investigators found in subgroup analyses that dietary intake of saturated fatty acid significantly increased risk of ovarian cancer with 19% [RR = 1.19, 95% CI = 1.04 to 1.36].

The investigators found in subgroup analyses that dietary intake of cholesterol significantly increased risk of ovarian cancer with 13% [RR = 1.13, 95% CI = 1.04 to 1.22].

The investigators found in subgroup analyses that dietary intake of retinol (vitamin A) significantly increased risk of ovarian cancer with 14% [RR = 1.14, 95% CI = 1.00 to 1.30].

The investigators found, in addition, acrylamide, nitrate, water disinfectants and polychlorinated biphenyls were significantly associated with an increased risk of ovarian cancer.

The investigators concluded that dietary intakes of green leafy vegetables, allium vegetables, fiber, flavonoids and green tea reduce ovarian cancer.

Original title:
Association between dietary intake and risk of ovarian cancer: a systematic review and meta-analysis by Khodavandi A, Alizadeh F and Razis AFA.

Link:
https://pubmed.ncbi.nlm.nih.gov/32661683/

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Find more information/studies on different food groups and cancer right here.

Objectives:
Some evidence indicates that carotenoids may reduce the risk of bladder cancer (BC), but the association is unclear. Therefore, this review article (meta-analysis) has been conducted.

Do dietary carotenoid (β-cryptoxanthin, α-carotene, β-carotene and lutein and zeaxanthin) intakes or circulating carotenoid concentrations reduce bladder cancer risk in men and women?

Study design:
This review article included 22 studies (case-control and cohort studies), involving 516,740 adults.

Results and conclusions:
The investigators found no association for the highest compared with the lowest category of carotenoid dietary intake and reduced risk of bladder cancer [RR = 0.88, 95% CI = 0.76 to 1.03].
No association because RR of 1 was found in the 95% CI of 0.76 to 1.03. RR of 1 means no risk/association.

The investigators found no association for the highest compared with the lowest category of circulating carotenoid concentrations and reduced risk of bladder cancer [RR = 0.36, 95% CI = 0.12 to 1.07].

The investigators found for the highest compared with the lowest category of circulating lutein and zeaxanthin concentrations a significantly reduced risk of 47% for bladder cancer [RR = 0.53, 95% CI = 0.33 to 0.84].
Significant because RR of 1 was not found in the 95% CI of 0.33 to 0.84. RR of 1 means no risk/association.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 42% [RR = 0.58, 95% CI = 0.36 to 0.94] for every 1 mg increase in daily dietary β-cryptoxanthin intake.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 76% [RR = 0.24, 95% CI = 0.08 to 0.67] for every 1 μmol/L increase in circulating concentration of α-carotene.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 27% [RR = 0.73, 95% CI = 0.57 to 0.94] for every 1 μmol/L increase in circulating concentration of β-carotene.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 56% [RR = 0.44, 95% CI = 0.28 to 0.67] for every 1 μmol/L increase in circulating concentrations of lutein and zeaxanthin.

The investigators concluded dietary β-cryptoxanthin intake and circulating concentrations of α-carotene, β-carotene and lutein and zeaxanthin reduce risk of bladder cancer.

Original title:
Carotenoid Intake and Circulating Carotenoids Are Inversely Associated With the Risk of Bladder Cancer: A Dose-Response Meta-analysis by Wu S, Liu Y, […], Ramirez AG.

Link:
https://pubmed.ncbi.nlm.nih.gov/31800007/

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Find more information/studies on carotenoids and cancer right here.

Objectives:
A growing number of epidemiological studies have suggested a possible association between long-chain omega-3 polyunsaturated fatty acid (PUFA) intake and the risk of cancers, but the results have been inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does dietary intake of omega-3 PUFAs reduce digestive system cancers?

Study design:
This review article included 8 case-control studies and 17 cohort studies, involving 1,247,271 participants and 23,173 patients with digestive system cancers.

Visual inspection of funnel plots and the Begg's and Egger's tests revealed no evidence of publication bias.

Results and conclusions:
The investigators found the risk of digestive system cancers significantly decreased by 17% in individuals who consumed omega-3 PUFAs [RR = 0.83, 95% CI = 0.76 to 0.91].

The investigators found the risk estimates of digestive system cancers varied by cancer sites, study location, study design, type of omega-3 PUFAs and other confounders (smoking, alcohol consumption, body mass index and physical activity).

The investigators concluded omega-3 PUFA is a healthy dietary component for the prevention of digestive system cancers. Cancer incidence decreases with increasing omega-3 PUFAs intake for most digestive system cancer sites. The relation between omega-3 PUFAs and digestive system cancers RR is similar among different populations.

Original title:
Omega-3 PUFA Intake and the Risk of Digestive System Cancers: A Meta-Analysis of Observational Studies by Jian J, Zhang and Zhao L.

Link:
https://pubmed.ncbi.nlm.nih.gov/32384489/

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Objectives:
Has oral supplementation of vitamin B (vitamins B1, B6, B12 and folic acid alone or combined) preventive effect on cognitive decline in cognitively unimpaired individuals?

Study design:
This review article included 20 RCTs, ranging from 23 to 2,919 participants per study, with a total of 12,697 participants.
8 of these 20 RCTs were deemed appropriate for the meta-analysis.

Results and conclusions:
The investigators found meta-analysis did not yield a significant overall effect of supplementation with vitamin B on cognitive function [SMD = 0.02, 95% CI = -0.034 to 0.08]. A sensitivity analysis focusing on specific risk factors did not alter this result.
Some studies reported isolated significant effects of the intervention on secondary outcomes. However, these findings were outnumbered by the number of cognitive tests that did not yield significant effects.

The investigators concluded there is no overall evidence that oral vitamin B supplementation prevent cognitive decline in cognitively unimpaired individuals. The results of this review do not provide evidence that population groups with certain risk factors would profit more from the intervention than others.

Original title:
Vitamin B-Can It Prevent Cognitive Decline? A Systematic Review and Meta-Analysis by Behrens A, Graessel E, [...], Donath C.

Link:
https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-020-01378-7

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