Nutrition and health

Objectives:
Evidence suggests that vitamin C supplementation could be a potential therapy in type 2 diabetes. However, its effectiveness and evidence quality require further evaluation. Therefore, this review article has been conducted.

Does oral vitamin C supplementation improve glycemic control, cardiovascular risk factors and oxidative stress in people with type 2 diabetes?

Study design:
This review article included 28 RCTs with in totaal 1,574 participants.
RCTs were predominantly short term (6 months) with a small number of participants (n 100).

Results and conclusions:
The investigators found that oral vitamin C supplementation significantly reduced systolic blood pressure [mean difference = -6.27, 95% CI = -9.60 to -2.96 mmHg, p = 0.0002, with moderate evidence certainty].

The investigators found that oral vitamin C supplementation significantly reduced HbA1c levels [mean difference = -0.54%, 95% CI = -0.90 to -0.17, p = 0.004, with very low evidence certainty].

The investigators found that oral vitamin C supplementation significantly reduced diastolic blood pressure [mean difference = -3.77, 95% CI = -6.13 to -1.42 mmHg, p = 0.002, with very low evidence certainty].

The investigators concluded evidence from short-term RCTs suggests that oral vitamin C supplementation may improve glycemic control and blood pressure in people with type 2 diabetes. However, vitamin C supplementation cannot currently be recommended as a therapy until larger, long-term and high-quality trials confirm these findings.

Original title:
Effects of Vitamin C Supplementation on Glycemic Control and Cardiovascular Risk Factors in People With Type 2 Diabetes: A GRADE-Assessed Systematic Review and Meta-analysis of Randomized Controlled Trials by Mason SA, Keske MA and Wadley GD.

Link:
https://pubmed.ncbi.nlm.nih.gov/33472962/

Additional information of El Mondo:
Find more information/studies on vitamin C, reducing blood pressure and diabetes right here.
 

Objectives:
Is fish or omega-3 fatty acids consumption associated with a lower risk of venous thromboembolism (VTE)?

Study design:
This review article included 8 prospective cohort studies.
The follow-up duration ranged from 0.5 to 19 years.
The sample size ranged from 595 to 80,263.
The fish and omega-3 fatty acids consumption was assessed by food-frequency questionnaire (FFQ) in all studies.
The diagnosis of venous thromboembolism was obtained in registered medical record (imaging or autopsy) and food was considered as the source of omega-3 fatty acids in all included studies.
Begg's rank-correlation test showed no evidence of publication bias.

Results and conclusions:
The investigators found the overall multi-variable adjusted RR showed no significant relationship between fish consumption and the risk of venous thromboembolism [RR = 1.02, 95% CI = 0.93 to 1.11, p = 0.709, I2 = 33%, p = 0.176].
The sensitivity analysis showed only minimal changes in magnitude of the pooled RR when any study was excluded from the meta-analysis, suggesting that no individual study had excessive influence on these robust aggregate results.

The investigators found the overall multi-variable adjusted RR showed that omega-3 fatty acids consumption was associated with a lower risk of 11% for venous thromboembolism [RR = 0.89, 95% CI = 0.80 to 0.98, p = 0.024, I2 = 0%, p = 0.469].
The sensitivity analysis showed only minimal changes in magnitude of the pooled RR when any study was excluded from the meta-analysis, suggesting that no individual study had excessive influence on these robust aggregate results.

The investigators found the overall multi-variable adjusted RR showed that omega-3 fatty acids consumption was associated with a lower risk of 55% for recurrent venous thromboembolism [RR = 0.45, 95% CI = 0.25 to 0.81, p = 0.008, I2 = 26.4%, p = 0.244].
Significant because RR of 1 was not found in the 95% CI of 0.25 to 0.81. RR of 1 means no risk/association.

The investigators concluded omega-3 fatty acids consumption is associated with a lower risk of both venous thromboembolism and recurrent venous thromboembolism.

Original title:
Associations of Fish and Omega-3 Fatty Acids Consumption With the Risk of Venous Thromboembolism. A Meta-Analysis of Prospective Cohort Studies by Zhang Y, Ding J, [...],Li Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7793732/

Additional information of El Mondo:
Find more information/studies on omega-3 and fish consumption and cardiovascular diseases right here.

Venous thromboembolism (VTE) is a condition in which a blood clot forms most often in the deep veins of the leg, groin or arm (known as deep vein thrombosis, DVT) and travels in the circulation, lodging in the lungs (known as pulmonary embolism, PE).

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/

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

Objectives:
Many studies have investigated the association between dietary iron intake and death due to cardiovascular disease (CVD), but the results were inconsistent. Therefore, this review article has been conducted.

Does dietary iron intake increase risk of death due to cardiovascular disease (cardiovascular disease mortality)?

Study design:
This review article included 19 prospective cohort studies including 720,427 participants (46,045 deaths due to cardiovascular disease).

Results and conclusions:
The investigators found when comparing the highest versus lowest level, the highest level of dietary heme iron intake significantly increased risk of death due to cardiovascular disease with 19% [pooled RR = 1.19, 95% CI = 1.01-1.39].

The investigators found every 1-mg/day increase in dietary heme iron intake significantly increased risk of death due to cardiovascular disease with 25% [pooled RR = 1.25, 95% CI = 1.17-1.33].

The investigators found every 1-mg/day increase in dietary heme iron intake significantly increased risk of death due to stroke with 17% [pooled RR = 1.17, 95% CI = 1.04-1.32].

The investigators found the association between dietary iron intake and cardiovascular disease mortality was linear [p nonlinearity > 0.05].

The investigators concluded higher dietary intake of heme iron (at least 1-mg/day) is associated with a greater risk of cardiovascular disease mortality. Therefore, reducing consumption of heme iron may help to prevent premature death due to cardiovascular disease.

Original title:
Dietary iron intake and risk of death due to cardiovascular diseases: A systematic review and dose-response meta-analysis of prospective cohort studies by Han M, Guan L, […], Lu J.

Link:
https://pubmed.ncbi.nlm.nih.gov/32674239/

Additional information of El Mondo:
Find more information/studies on significant/cohort studies, iron consumption and cardiovascular disease right here.

Food items of heme iron are:

• Beef or chicken liver
• Beef
• Canned light tuna
• Canned sardines
• Organ meats
• Oysters, clams, mussels
• Poultry

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/

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

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.
 

Objectives:
Previous studies lack consistent conclusions as to whether astaxanthin is actually linked to various health benefits as claimed. Therefore, this review article has been conducted.

Is there a causal relationship between astaxanthin consumption and improvements in risk factors for diabetes or cardiovascular disease?

Study design:
This review article included 14 RCTs.

Results and conclusions:
The investigators found that astaxanthin consumption was not associated with FBS, HbA1c, TC, LDL-C, TG, BMI, BW, DBP and SBP.

The investigators found that astaxanthin consumption was associated with an increase in HDL cholesterol levels [WMD = 1.473 mg/dL, 95% CI = 0.319 to 2.627, p = 0.012].

The investigators found that astaxanthin consumption during ≥12 weeks was associated with a decrease in CRP levels [WMD = -0.528 mg/L, 95% CI = -0.990 to -0.066].

The investigators found that >12 mg/day astaxanthin consumption was associated with a decrease in CRP levels [WMD = -0.389 mg/dL, 95% CI = -0.596 to -0.183].

The investigators concluded that astaxanthin consumption is causally associated with an increase in HDL cholesterol levels (good cholesterol) and a decrease in CRP levels for >12 mg/day astaxanthin consumption during ≥12 weeks. Significant associations are not observed for other outcomes.

Original title:
The effects of astaxanthin supplementation on obesity, blood pressure, CRP, glycemic biomarkers, and lipid profile: A meta-analysis of randomized controlled trials by Xia W, Tang N, [...], Zhu Y.

Link:
https://pubmed.ncbi.nlm.nih.gov/32755613/

Additional information of El Mondo:
Find here more information/studies about astaxanthin consumption and cholestrerol.

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/

Additional information of El Mondo:
Find more information/studies on significant/cohort studies, nuts consumption and cancer right here.

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

Objectives:
Dyslipidemia is a common metabolic disease worldwide and also an important predisposing factor for cardiovascular diseases (CVDs). Coffee is loved by people all over the world; however, the association between coffee consumption and blood lipids has yielded inconsistent results. Therefore, this review article has been conducted.

Is there a causal relationship between coffee consumption and dyslipidemia?

Study design:
This review article included 12 RCTs.

Results and conclusions:
The investigators found pooled results showed that coffee consumption significantly increased total cholesterol (TC) levels [WMD = 0.21 mmol/L, 95% CI = 0.04 to 0.39, p = 0.017].  
Significant means that there is an association with a 95% confidence.

The investigators found pooled results showed that coffee consumption significantly increased triglyceride (TG) levels [WMD = 0.12 mmol/L, 95% CI = 0.03 to 0.20, p = 0.006].  
Significant because the calculated p-value of 0.006 was less than the p-value of 0.05.

The investigators found pooled results showed that coffee consumption significantly increased LDL cholesterol (bad cholesterol) levels [WMD = 0.14 mmol/L, 95% CI = 0.05 to 0.24, p = 0.003].  

The investigators found pooled results showed that coffee consumption had no significant effect on HDL cholesterol (good cholesterol) levels [WMD = -0.01 mmol/L, 95% CI = -0.06 to 0.04, p = 0.707].
No significant means that there is no association with a 95% confidence.

The investigators found dose-response analysis results revealed significant positive nonlinear associations between coffee consumption and the increase in total cholesterol, LDL cholesterol and triglyceride levels.

The investigators concluded that coffee consumption is associated with an elevated risk for dyslipidemia and cardiovascular diseases. So a reasonable habit of coffee consumption (3 cups/d) is essential for the prevention of dyslipidemia.  

Original title:
Effect of coffee consumption on dyslipidemia: A meta-analysis of randomized controlled trials by Du Y, Lv Y, […], Luo Q.

Link:
https://pubmed.ncbi.nlm.nih.gov/33239163/

Additional information of El Mondo:
Find more information/studies on significant/RCTs/causal relationship, coffee consumption, lowering cholesterol levels and cardiovascular disease right here.

Dyslipidemia is elevation of plasma cholesterol, triglycerides (TGs), or both, or a low HDL cholesterol (good cholesterol) level that contributes to the development of atherosclerosis. Atherosclerosis is the main underlying cause of cardiovascular disease (CVD).

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/

Additional information of El Mondo:
Find more information/studies on significant/cohot studies, folate (folic acid) consumption and breast cancer right here.

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

Additional information of El Mondo:
Find more information/studies on significant/cohot studies, vitamin C consumption and cancer right here.
 

Objectives:
Dietary sodium intake has received considerable attention as a potential risk factor of cardiovascular disease. However, evidence on the dose-response association between dietary sodium intake and cardiovascular disease risk is unclear. Therefore, this review article has been conducted.

Is there a dose-response association between dietary sodium intake and cardiovascular disease (CVD) risk?

Study design:
This review article included 36 cohort studies with a total of 616,905 participants.
The duration of follow-up ranged from 2.7 years to 29 years.

For dietary sodium intake assessment, 18 of the studies were based on twenty-four urinary excretion, 7 used food frequency questionnaires, 8 used 24 h dietary recall, 2 used dietary records; 1 used a self-administered questionnaire and 1 used single spot urine sodium excretion.
The daily dietary sodium intake ranged from 1.0 to 7.5 g.

The mean score (± standard deviation) for the quality of the included studies was 8.0 ± 1.0 according to the Newcastle-Ottawa Scale.

Results and conclusions:
The investigators found compared with individuals with low sodium intake, individuals with high sodium intake had an 19%-higher adjusted risk of cardiovascular disease [rate ratio = 1.19, 95% CI = 1.08 to 1.30].

The investigators found in dose-response meta-analysis that the risk of cardiovascular disease significantly increased by 6% when 1 g dose of sodium was ingested [rate ratio = 1.06, 95% CI = 1.01 to 1.11].

The investigators concluded that high sodium intake is an important risk factor of cardiovascular disease (CVD) and in dose-response meta-analysis, every 1 g of dietary sodium intake increases the risk of cardiovascular disease by 6%.

Original title:
Dietary Sodium Intake and Risk of Cardiovascular Disease: A Systematic Review and Dose-Response Meta-Analysis by Wang YJ, Yeh TL, [...], Chien KL.

Link:
https://www.mdpi.com/2072-6643/12/10/2934/htm

Additional information of El Mondo:
Find more information/studies on salt consumption and cardiovascular disease right here.

1 gram salt (sodium chloride) = 0.4 gram sodium.

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:
Epidemiological studies on the impact of fish consumption on coronary heart disease (CHD) incidence have shown inconsistent results. Therefore, this review article has been conducted.

Does dietary intake of fish reduce coronary heart disease incidence and mortality?

Study design:
This review article included 40 prospective cohort studies (22 studies investigated the association between fish consumption and coronary heart disease incidence (28,261 persons with coronary heart disease and 918,783 participants) and 27 studies investigated the association between fish consumption and coronary heart disease mortality (10,568 events and 1,139,553 participants)).

No evidence of publication bias was found.

Results and conclusions:
The investigators found higher fish consumption was significantly associated with a 9%-lower coronary heart disease risk [RR = 0.91, 95% CI = 0.84 to 0.97, I2 = 47.4%].

The investigators found a significant correlation between fish consumption and coronary heart disease risk in the female subgroup [RR = 0.85, 95% CI = 0.78 to 0.92, I2 = 5.6%], the subgroup with a follow-up period of ≥10 years [RR = 0.91, 95% CI = 0.84 to 0.99, I2 = 51.5%] and the subgroup with an article quality of ≥7 points [RR = 0.90, 95% CI = 0.83 to 0.98, I2 = 50.6%].
However, it was not found in the male subgroup, the subgroup with a follow-up period of 10 years and the subgroup with an article quality of 7 points.

The investigators found higher fish intake was significantly associated with a 15%-lower coronary heart disease mortality risk [RR = 0.85, 95% CI = 0.77 to 0.94, I2 = 51.3%].

The investigators found the summary results did not change significantly in sensitivity analysis.

The investigators found dose-response analysis showed that the coronary heart disease incidence and mortality were reduced by 4%, respectively, with a 20 g/day increment in fish consumption.

The investigators concluded that a higher dietary intake of fish reduces coronary heart disease incidence and mortality. This finding has important public health implications in terms of the prevention of coronary heart disease. Since most of the research was conducted in male groups and Western countries, further research needs to be performed in female groups and other regions.

Original title:
Fish Consumption and Coronary Heart Disease: A Meta-Analysis by Zhang B, Xiong K, […], Ma A.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7468748

Additional information of El Mondo:
Find more information/studies/nutritional advices on fish consumption and coronary heart disease right here.

In practice, higher fish consumption means at least twice a week of fish consumption (150 grams of fish at a time).

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:
Observational studies regarding the putative associations between dietary intake of homocysteine metabolism-related B-vitamins (vitamin B6, folate and vitamin B12) and stroke risk have yielded inconsistent results. Therefore, this review article has been conducted.

Does dietary intake of vitamin B6, folate or vitamin B12 reduce stroke risk?

Study design:
This review article included 1 nested case-control study and 11 prospective cohort studies comprising 389,938 participants and 10,749 cases (persons with stroke).

The studies were published from 2002 through to 2019 and the follow-up period ranged from 4.2 to 19 years.

All 12 studies provided risk estimates adjusted for cigarette smoking and most studies also adjusted for other conventional risk factors, including BMI, energy intake, alcohol consumption, hypertension and/or physical activity.

Study quality scores ranged from 5 to 9; the mean quality score was 7.4.

There was no evidence of publication bias.

Results and conclusions:
The investigators found for the highest versus the lowest category of dietary vitamin B6 intake, a significantly reduced risk of 16% for stroke [RR = 0.84, 95% CI = 0.73 to 0.97, I2 = 48.8%].

The investigators found in dose-response analysis that each 0.5 mg/d increment in vitamin B6 dietary intake was associated with a 6% reduction in the risk of stroke [RR = 0.94, 95% CI = 0.89 to 0.99, I2 = 77.0%].

The investigators found for the highest versus the lowest category of dietary folate intake, a significantly reduced risk of 15% for stroke [RR = 0.85, 95% CI = 0.78 to 0.94, I2 = 11.5%].

The investigators found in dose-response analysis that each 100 μg/d increase in dietary folate intake was associated with a 6% reduction in the risk of stroke [RR = 0.94, 95% CI = 0.90 to 0.98, I2 = 46.8%].

The investigators found, in contrast, no significant association between dietary vitamin B12 intake and the risk of stroke, with an RR of 1.01 [95% CI = 0.97 to 1.06] per 3 μg/d increase.

The investigators concluded increased dietary intake of vitamin B6 (at least 0.5 mg/d) and dietary folate intake (at least 100 μg/d) is associated with a reduced risk of stroke, supporting the notion that increasing habitual folate and vitamin B6 intake may provide a small but beneficial effect with respect to stroke.

Original title:
Dietary Intake of Homocysteine Metabolism-Related B-Vitamins and the Risk of Stroke: A Dose-Response Meta-Analysis of Prospective Studies by Chen L, Li Q, [...], Wang F.

Link:
https://academic.oup.com/advances/advance-article/doi/10.1093/advances/nmaa061/5854025

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Objectives:
Hypertension is regarded as a major and independent risk factor of cardiovascular diseases and numerous studies observed an inverse correlation between vitamin C intake and blood pressure. Therefore, this review article has been conducted.

Does a high serum vitamin C reduce blood pressure?

Study design:
This review article included 11 cross-sectional studies and 7 case-control studies. These studies comprised 22,200 observational subjects and were conducted from the year 1990 to 2017. Of the 18 articles, 14 were published in the English language and 4 were in Chinese.

Assessed with NOS, all the case-control studies yield a high quality averaging with 7.143 scores. And the result of AHRQ indicates a moderate quality with all cross-sectional studies scoring between 4 and 7.

Results and conclusions:
The investigators found random-effects model showed serum level of vitamin C of hypertensive subjects was 15.13 μmol/L lower than the normotensives [MD = -15.13, 95% CI = -24.19 to -6.06, p = 0.001, I2 = 98%].

The investigators found subgroup analysis showed that hypertensive subjects who took antihypertensive drugs had a 15.97 μmol/L lower serum vitamin C compared with normotensive ones.

The investigators found serum vitamin C had a significant inverse relation with both systolic blood pressure [Fisher′s Z = -0.17, 95% CI = -0.20 to -0.15, p 0.00001] and diastolic blood pressure [Fisher′s Z = -0.15, 95% CI = -0.20 to -0.10, p 0.00001].

The investigators concluded people with hypertension have a relatively low serum vitamin C and vitamin C is inversely associated with both systolic blood pressure and diastolic blood pressure.

Original title:
Association between Serum Vitamin C and the Blood Pressure: A Systematic Review and Meta-Analysis of Observational Studies by Ran L, Zhao W, […], Bu H.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211237/

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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/

Additional information of El Mondo:
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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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Objectives:
Is there a causal relationship between black or green tea consumption and lowering blood pressure in subjects with elevated blood pressure (BP) or hypertension?
 
Study design:
This review article included 5 RCTs with 408 individuals.

None of the studies reported any side effects.

Results and conclusions:
The investigators found regular tea consumption significantly reduced systolic blood pressure [WMD = -4.81 mmHg, 95% CI = -8.40 to -1.58, p = 0.004] in subjects with elevated blood pressure (BP) or hypertension.

The investigators found regular tea consumption significantly reduced diastolic blood pressure [WMD = -1.98 mmHg, 95% CI = -3.77 to -0.20, p = 0.029] in subjects with elevated blood pressure (BP) or hypertension.

The investigators found, however, excluding the most heterogeneous trials showed that regular tea intake significantly reduced systolic blood pressure and diastolic blood pressure by about -3.53 and -0.99 mmHg, respectively.

The investigators found based on meta-regression findings, the longer the duration of tea intake (≥3 months), the higher the decrease in both systolic blood pressure and diastolic blood pressure.

The investigators found categorized studies, according to the tea type, revealed that the hypotensive effects of green tea were more pronounced compared to black tea.

The investigators concluded regular tea consumption, particularly green tea during ≥3 months reduces systolic blood pressure and diastolic blood pressure in subjects with elevated blood pressure (BP) or hypertension. Hence, it may be applicable to physicians, health care providers and particularly hypertension patients.

Original title:
The Effects of Regular Consumption of Green or Black Tea Beverage on Blood Pressure in Those With Elevated Blood Pressure or Hypertension: A Systematic Review and Meta-Analysis by Mahdavi-Roshan M, Salari A, […], Ashouri A.

Link:
https://www.sciencedirect.com/science/article/abs/pii/S0965229919316899?via%3Dihub

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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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Find more information/studies on omega-3 PUFAs and cancer right here.

Objectives:
Epidemiologic studies, including trials, suggest an association between potassium intake and blood pressure (BP). However, the strength and shape of this relationship is uncertain. Therefore, this review article has been conducted.

What is the strength and shape of the relationship between potassium intake and blood pressure (BP)?
 
Study design:
This review article included 32 RCTs with a duration ≥4 weeks using the recently developed 1‐stage cubic spline regression model. This model allows use of trials with at least 2 exposure categories.
Most trials were conducted in adults with hypertension using a crossover design and potassium supplementation doses that ranged from 30 to 140 mmol (1173 and 5474 mg) per day.

Results and conclusions:
The investigators found a U‐shaped relationship between 24‐hour active and control arm differences in potassium excretion and blood pressure (BP) levels, with weakening of the blood pressure reduction effect above differences of 30 mmol/d and a blood pressure increase above differences ≈80 mmol/d.

The investigators found achieved potassium excretion analysis also identified a U‐shaped relationship. The blood pressure lowering effects of potassium supplementation were stronger in participants with hypertension and at higher levels of sodium intake.

The investigators found blood pressure increased with high potassium excretion in participants with antihypertensive drug‐treated hypertension but not in their untreated counterparts.

The investigators concluded that an adequate intake of potassium (≤30 mmol (1173 mg) per day) is desirable to achieve a lower blood pressure level but excessive potassium supplementation (>80 mmol (3128 mg) per day) should be avoided, particularly in specific subgroups.

Original title:
Potassium Intake and Blood Pressure: A Dose‐Response Meta‐Analysis of Randomized Controlled Trials by Filippini T, Naska A, […], Whelton PK.

Link:
https://www.ahajournals.org/doi/full/10.1161/JAHA.119.015719?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed&

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Objectives:
An increased risk of gastric cancer for pickled vegetable and salted fish intake has been suggested, yet the lack of a dose-response association warrants a quantitative analysis. Therefore, this review article (meta-analysis) has been conducted.

Do pickled vegetable and salted fish intakes increase risk of gastric cancer?

Study design:
This review article included 21 cohort studies with a total of 195,624 participants for the analysis of pickled vegetable intake and 16 cohort studies with a total of

196,384 participants for the analysis of salted fish intake.

Results and conclusions:
The investigators found in a dose-response meta-analysis of 6 studies, a significantly increased risk of 15% [combined RR = 1.15, 95% CI = 1.07 to 1.23, p for heterogeneity = 0.14] for gastric cancer incidence for a 40 g/day increment in pickled vegetable intake.

The investigators found in the categorical meta-analysis of 6 studies, a marginally significant increase in the risk of gastric cancer incidence, comparing the highest to the lowest intake of salted fish [RR = 1.17, 95% CI = 0.99 to 1.38, p for heterogeneity = 0.26].

The investigators concluded intake of 40 g/day of pickled vegetable increases risk of gastric cancer incidence.

Original title:
Pickled Vegetable and Salted Fish Intake and the Risk of Gastric Cancer: Two Prospective Cohort Studies and a Meta-Analysis by Yoo JY, Cho HJ, […], Park SK.

Link:
https://www.mdpi.com/2072-6694/12/4/996/htm

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Objectives:
Is there a causal relationship between tomato consumption and lowering effects on cholesterol, triglycerides or fasting blood sugar levels?
 
Study design:
This review article included 6 RCTs.

Results and conclusions:
The investigators found tomato consumption significantly reduced total plasma cholesterol levels [WMD = -4.39 mg/dL, 95% CI = -7.09 to -1.68, I2 = 48%, p = 0.05].

The investigators found tomato consumption significantly reduced plasma triglyceride (TG) levels [WMD = -3.94 mg/dL, 95% CI = -7.67 to -0.21, I2 = 90%, p = 0.001].
A higher reduction effect was found on younger participants.

The investigators found tomato consumption significantly reduced plasma LDL cholesterol (bad cholesterol) levels [WMD = -2.09 mg/dL, 95% CI = -3.73 to -0.81, I2 = 78%, p = 0.001].
A higher reduction effect was found on younger participants.

The investigators found tomato consumption significantly increased plasma HDL cholesterol (good cholesterol) levels [WMD = 2.25 mg/dL, 95% CI = 0.41 to 4.10, I2 = 97%, p = 0.001].

The investigators found tomato consumption had no significant effect on plasma fasting blood sugar levels [WMD = 0.59 mg/dL, 95% CI = -0.28 to 1.46, I2 = 95%, p = 0.001].

The investigators concluded that tomato consumption increases plasma HDL cholesterol (good cholesterol) levels and decreases plasma total cholesterol, LDL cholesterol (bad cholesterol) and triglyceride levels.

Original title:
Effect of Tomato Consumption on Fasting Blood Glucose and Lipid Profiles: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Li H, Chen, A, [...],Yin X.

Link:
https://pubmed.ncbi.nlm.nih.gov/32243013/

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Patients with heart disease often have high LDL cholesterol, low HDL cholesterol and high triglycerides levels.

Objectives:
Do dietary calcium intakes or calcium supplements increase risk of cardiovascular disease?
 
Study design:
This review article included 26 prospective cohort studies and 16 RCTs.

Results and conclusions:
The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of cardiovascular disease [relative risk = 0.96, 95% CI = 0.87 to 1.05].

The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of coronary heart disease [relative risk = 0.98, 95% CI = 0.88 to 1.08].

The investigators found in cohort studies that dietary calcium intakes ranging from 200 to 1500 mg/d did not affect the risk of stroke [relative risk = 0.94, 95% CI = 0.85 to 1.04].

The investigators found in RCTs that calcium supplements significantly increased risk of coronary heart disease with 20% [relative risk = 1.20, 95% CI = 1.08 to 1.33, I2 = 0.0%].

The investigators found in RCTs that calcium supplements significantly increased risk of myocardial infarction with 21% [relative risk = 1.21, 95% CI = 1.08 to 1.35, I2 = 0.0%].

The investigators concluded that 200-1500 mg/d calcium intake from dietary sources do not increase the risk of cardiovascular disease, including coronary heart disease and stroke, while calcium supplements increase coronary heart disease risk, especially myocardial infarction.

Original title:
The Evidence and Controversy Between Dietary Calcium Intake and Calcium Supplementation and the Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Cohort Studies and Randomized Controlled Trials by Yang C, Shi X, […], Sun G.

Link:
https://pubmed.ncbi.nlm.nih.gov/31625814/

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