Nutrition and health

Objectives:
Previous studies suggest that dietary vitamin C is inversely associated with gastric cancer (GC), but most of them did not consider intake of fruit and vegetables. Therefore, this review article has been conducted.

Do higher dietary vitamin C intakes reduce gastric cancer risk after adjusting for intake of fruit and vegetables?

Study design:
This review article included 14 case-control studies with in total 5,362 cases (persons with gastric cancer) and 11,497 controls (persons without gastric cancer).

More cases were male (61.88% vs. 54.64%), older than 60 years (63.37% vs. 57.87%) and had low socioeconomic status (57.29% vs. 45.66%) compared with controls. 
In addition, a higher proportion of cases than controls were obese (21.34% vs. 19.06%), current smokers (26.58% vs. 24.14%) and ever drinkers (64.85 vs. 63.29%). 
Similarly, H. pylori seropositivity (63.82% vs. 61.86%) was more common among cases than among controls when considering only participants from the 7 studies with available information. 
A larger proportion of controls reported high intake of fruit and vegetables compared with cases. 
Most cases were of noncardia (57.03%) and intestinal type gastric cancer (33.01%). 
Cases had a lower median intake of vitamin C and fewer of them were in the highest quartiles of intake compared with controls.

Results and conclusions:
The investigators found individuals in the highest quartile of dietary vitamin C intake had a significantly reduced risk of 36% for gastric cancer compared with those in the lowest quartile [OR = 0.64, 95% CI = 0.58 to 0.72]. 

The investigators found, however, when additionally adjusting for BMI and intake of fruit and vegetables, the observed association was attenuated and the OR for the highest versus lowest quartile of dietary vitamin C was 0.85 [95% CI = 0.73 to 0.98].

The investigators found a significant inverse association for noncardia gastric cancer, as well as for both intestinal and diffuse types of the disease. 

The investigators found dose-response analysis showed decreasing ORs of gastric cancer up to 150-200 mg/day of vitamin C [OR = 0.54, 95% CI = 0.41 to 0.71], whereas ORs for higher intakes were close to 1.0. 

The investigators concluded that consumption of 150-200 mg/day of vitamin C reduce gastric cancer risk. However, further well-designed prospective studies, aimed at disentangling the complex relationships between intake of fruit and vegetables, vitamins and other antioxidants and gastric cancer, are warranted to prove causality of the observed relationship between vitamin C and gastric cancer.

Original title: 
Dietary intake of vitamin C and gastric cancer: a pooled analysis within the Stomach cancer Pooling (StoP) Project by Sassano M, Seyyedsalehi  MS, […], Boffetta P. 

 

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11016516/

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Find more information/studies on cohort studies/significantly, viamin C and cancer right here. 

Objectives:
The association between soy product consumption and cancer risk varies among studies. Therefore, this review article has been conducted.

Do higher soy product consumption reduce cancer risk?

Study design:
This review article included 17 cohort studies and 35 case-control studies with a total of 861,372 participants and 44,932 cases (persons with cancer). 

Regarding quality assessment, the case-control studies achieved an average score of 6.7. The mean score of the cohort study was 7.2, which satisfied the criterion of high quality. 
All analyses adjusted for age and most studies adjusted for smoking status (n = 38), drinking status (n = 29), total energy intake (n = 27), BMI (n = 26) and education level (n = 26). 

Results and conclusions:
The investigators found in pooled analysis of cohort studies and case-control studies that higher consumption of total soy products significantly reduced risk of cancer with 31% [RR = 0.69, 95% CI = 0.60 to 0.80, I2 = 82.7%, p < 0.001]. 
However, this reduced risk was not significant in cohort studies (RR = 0.90, 95% CI = 0.80 to 1.01].

The investigators found higher tofu consumption significantly reduced cancer risk in both men and women.

The investigators found higher consumption of total soy products significantly reduced risk of cancer amond women with 24% [RR = 0.76, 95% CI = 0.65 to 0.89].

The investigators found in subgroup analysis that higher consumption of total soy products was significantly associated with a reduced risk for gastrointestinal cancer [RR = 0.74, 95% CI = 0.61 to 0.89], prostate cancer [RR = 0.47, 95% CI = 0.31 to 0.71], lung cancer [RR = 0.67, 95% CI = 0.52 to 0.86], upper aerodigestive tract cancer [RR = 0.33, 95% CI = 0.22 to 0.49] and multiple myeloma [RR = 0.10, 95% CI = 0.01 to 0.97], but not in bladder or liver cancer.

The investigators found in pooled analysis of cohort studies and case-control studies that higher consumption of tofu significantly reduced risk of cancer with 22% [RR = 0.78, 95% CI = 0.70 to 0.86, I2 = 47.9%, p = 0.004]. 
However, this reduced risk was not significant in cohort studies [RR = 0.89, 95% CI = 0.78 to 1.01, p = 0.186].

The investigators found in pooled analysis of cohort studies and case-control studies that higher consumption of soymilk significantly reduced risk of cancer with 25% [RR = 0.75, 95% CI = 0.60 to 0.86, I2 = 47.9%, p = 0.004]. 
However, this reduced risk was not significant in cohort studies [RR = 1.10, 95% CI = 0.76 to 1.58].

The investigators found a 54g per day increment of total soy products significantly reduced cancer risk by 11%, a 61g per day increment of tofu significantly reduced cancer risk by 12%, and a 23g per day increment of soymilk significantly reduced cancer risk by 28%, while none of the other soy products were associated with cancer risk. 

The investigators concluded that daily consumption of 54g total soy products, 61g tofu or 23g soymilk is associated with a lower cancer risk. More prospective cohort studies are still needed to confirm the causal relationship between soy product consumption and cancer risk.

Original title: 
Soy Product Consumption and the Risk of Cancer: A Systematic Review and Meta-Analysis of Observational Studies by Wang C, Ding K, […], Hong H. 

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11013307/

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Find more information/studies on cohort studies/significantly, soy and cancer right here. 

Objectives:
Carotenoids appear to have anticancer effects. Prospective evidence for the relation between serum carotenoids and breast cancer is controversial. Therefore, this review article has been conducted.

Do higher carotenoids levels (likes, α-carotene, β-carotene, β-cryptoxanthin, lycopene, zeaxanthin and lutein) reduce breast cancer risk among women?

Study design:
This review article included 17 nested case-control studies and 1 cohort study, published between 1984 and 2016 with a total of 20,188 participants. 
Median follow-up ranged from 8 months to 21 years during which 7,608 breast cancer cases were reported. 
All studies assessed circulating carotenoids using high-performance liquid chromatography. The majority of studies carried out on circulating carotenoids and the risk of breast cancer were adjusted for the following variables: BMI (n = 9), dietary variables (n = 8), age (n = 9), alcohol (n = 6), age at menarche (n = 6) and age at first birth (n = 8). 
According to the quality assessment, except for 2 studies, other publications had high quality. 

There was no publication bias. 

Results and conclusions:
The investigators found that the highest levels of total carotenoids compared to the lowest were significantly related to a 24% lower risk of breast cancer [relative risk (RR) = 0.76, 95% CI = 0.62 to 0.93, I2 = 45.6%, p = 0.075]. 
According to the sensitivity analysis, no study affected the overall RR. 

The investigators found according to linear dose-response analysis, the risk of breast cancer decreased by 2% for every 10 μg/dL of total carotenoids [RR = 0.98, 95% CI = 0.97 to 0.99]. A steady drop in the risk of breast cancer was observed for total carotenoid concentrations <1200 μg/dL followed by a plateau. The level of evidence was graded as low.

The investigators found that the highest levels of α-carotene compared to the lowest were significantly related to a 23% lower risk of breast cancer [relative risk (RR) = 0.77, 95% CI = 0.68 to 0.87, I2 = 0.0%, p = 0.48]. 
According to the sensitivity analysis, no study affected the overall RR. 

The investigators found according to linear dose-response analysis, the risk of breast cancer decreased by 22% for every 10 μg/dL of α-carotene [RR = 0.78, 95% CI = 0.66 to 0.93]. 
No evidence for nonlinear association was found. The level of evidence was graded as low. 

The investigators found that the highest levels of β-carotene compared to the lowest were significantly related to a 20% lower risk of breast cancer [relative risk (RR) = 0.80, 95% CI = 0.65 to 0.98, I2 = 56.5%, p = 0.004]. 
According to the sensitivity analysis, no study affected the overall RR. 

The investigators found according to linear dose-response analysis, the risk of breast cancer decreased by 4% for every 10 μg/dL of β-carotene [RR = 0.96, 95% CI = 0.93 to 0.99]. No evidence for nonlinear association was found. The level of evidence was graded as low. 

The investigators found that the highest levels of β-cryptoxanthin compared to the lowest were significantly related to a 15% lower risk of breast cancer [relative risk (RR) = 0.85, 95% CI = 0.74 to 0.96, I2 = 0.0%, p = 0.80]. 
According to the sensitivity analysis, no study affected the overall RR. 

The investigators found according to linear dose-response analysis, the risk of breast cancer decreased by 10% for every 10 μg/dL of β-cryptoxanthin [RR = 0.90, 95% CI = 0.82 to 0.99]. 

The investigators found that the highest levels of lycopene compared to the lowest were significantly related to a 14% lower risk of breast cancer [relative risk (RR) = 0.86, 95% CI = 0.76 to 0.98, I2 = 0.0%, p = 0.46]. 
According to the sensitivity analysis, no study affected the overall RR. 

The investigators found that the highest levels of lutein compared to the lowest were significantly related to a 30% lower risk of breast cancer [relative risk (RR) = 0.70, 95% CI = 0.52 to 0.93, I2 = 17.1%, p = 0.30]. 
According to the sensitivity analysis, no study affected the overall RR. 

The investigators concluded that higher levels of carotenoids, α-carotene, β-carotene, β-cryptoxanthin, lycopene and lutein are related to a decreased risk of breast cancer. Additionally, each 10 μg/dL of total carotenoids, α-carotene, β-carotene and β-cryptoxanthin reduce breast cancer risk with 2%, 22%, 4% and 10%, respectively. 

Original title: 
The Association between Circulating Carotenoids and Risk of Breast Cancer: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies by Dehnavi MK, Ebrahimpour-Koujan S, […], Azadbakht L.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10694674/ 

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