Yogurt

ImportanceSeveral meta-analyses have summarized evidence for the association between dietary factors and the incidence of colorectal cancer (CRC). However, to date, there has been little synthesis of the strength, precision, and quality of this evidence in aggregate.ObjectiveTo grade the evidence from published meta-analyses of prospective observational studies that assessed the association of dietary patterns, specific foods, food groups, beverages (including alcohol), macronutrients, and micronutrients with the incidence of CRC.Data sourcesMEDLINE, Embase, and the Cochrane Library were searched from database inception to September 2019.Evidence reviewOnly meta-analyses of prospective observational studies with a cohort study design were eligible. Evidence of association was graded according to established criteria as follows: convincing, highly suggestive, suggestive, weak, or not significant.ResultsFrom 9954 publications, 222 full-text articles (2.2%) were evaluated for eligibility, and 45 meta-analyses (20.3%) that described 109 associations between dietary factors and CRC incidence were selected. Overall, 35 of the 109 associations (32.1%) were nominally statistically significant using random-effects meta-analysis models; 17 associations (15.6%) demonstrated large heterogeneity between studies (I2 > 50%), whereas small-study effects were found for 11 associations (10.1%). Excess significance bias was not detected for any association between diet and CRC. The primary analysis identified 5 (4.6%) convincing, 2 (1.8%) highly suggestive, 10 (9.2%) suggestive, and 18 (16.5%) weak associations between diet and CRC, while there was no evidence for 74 (67.9%) associations. There was convincing evidence of an association of intake of red meat (high vs low) and alcohol (≥4 drinks/d vs 0 or occasional drinks) with the incidence of CRC and an inverse association of higher vs lower intakes of dietary fiber, calcium, and yogurt with CRC risk. The evidence for convincing associations remained robust following sensitivity analyses.Conclusions and relevanceThis umbrella review found convincing evidence of an association between lower CRC risk and higher intakes of dietary fiber, dietary calcium, and yogurt and lower intakes of alcohol and red meat. More research is needed on specific foods for which evidence remains suggestive, including other dairy products, whole grains, processed meat, and specific dietary patterns.

The main objective of this experiment was to determine the effects of yogurt supplementation on fat deposition, oxidative stress, inflammation and fibrosis in the liver of rats with high-fat (HF) diet-induced obesity. Male Wistar rats were used in this study and were separated into the following four different groups: the control, control + yogurt, high fat and high fat+ yogurt groups. The high fat groups received a HF diet for eight weeks. A 5% yogurt (w/w) supplement was also provided to rats fed the HF diet. Yogurt supplementation prevented glucose intolerance and normalized liver-specific enzyme activities in the HF diet-fed rats. Yogurt supplementation also significantly reduced the levels of oxidative stress markers in the plasma and liver of HF diet-fed rats. Moreover, inflammatory cell infiltration, collagen deposition and fibrosis in the liver of HF diet-fed rats were also prevented by yogurt supplementation. Furthermore, yogurt supplementation normalized the intestinal lining and brush border in HF diet-fed rats. This study suggests that yogurt supplementation potentially represents an alternative therapy for the prevention of metabolic syndrome in HF diet-fed rats.

The aim of this study was to investigate the impact of consuming dairy yogurt containing Lactobacillus paracasei ssp. paracasei (L. paracasei), Bifidobacterium animalis ssp. lactis (B. lactis) and heat-treated Lactobacillus plantarum (L. plantarum) on immune function. A randomized, open-label, placebo-controlled study was conducted on 200 nondiabetic subjects. Over a twelve-week period, the test group consumed dairy yogurt containing probiotics each day, whereas the placebo group consumed milk. Natural killer (NK) cell activity, interleukin (IL)-12 and immunoglobulin (Ig) G1 levels were significantly increased in the test group at twelve weeks compared to baseline. Additionally, the test group had significantly greater increases in serum NK cell activity and interferon (IFN)-γ and IgG1 than placebo group. Daily consumption of dairy yogurt containing L. paracasei, B. lactis and heat-treated L. plantarum could be an effective option to improve immune function by enhancing NK cell function and IFN-γ concentration (ClinicalTrials.gov: NCT03051425).

The consumption of milk can contribute to the consumers` exposure to aflatoxin as aflatoxin M1 (AFM1), a hydroxylated metabolite of aflatoxin B1 (AFB1), is transferred into the milk of AFB1 exposed dairy cows. As mitigation measures against AFB1 presence in cattle feed, fungal biocontrol strains are applied on plant materials to reduce toxigenic A. flavus growth. The present study investigates the impact of applying two biocontrol strains (Trichoderma afroharzianum and non-toxigenic Aspergillus flavus) compared with a toxigenic A. flavus strain on the mycotoxin transfer from maize into milk and milk products in a “farm to fork” approach. Firstly, in a feeding study three groups of high yielding dairy cows are exposed to different maize flours infested with biocontrol or AFB1-foming fungal strains for 14 days to monitor a potential toxin transfer from feed to milk. In the milk of cows exposed to AFB1, AFM1 was detected with a mean value of (95.6 ng/kg ± 13.7 ng/kg) while the mean transfer rates (3.8% ± 0.9%) were slightly higher than published in previous studies. Neither AFM1 nor cyclopiazonic acid could be detected in milk from the cows exposed to the two biocontrol strains. The data show, that the AFM1 limit of 50 ng/kg in milk can be exceeded when cattle feed is contaminated with AFB1 within the legal limit. Consequently, the use of cattle feed within the current European legal limits does not necessarily guarantee for obtaining milk compliant with European maximum levels. In the second part, AFM1 containing raw milk from the experimental cows was processed further into yoghurt to investigate the fate of the toxin under acidic fermentation conditions. No AFM1 degradation was found during authentic yoghurt making, albeit in a model experiment the hydration of AFM1 in presence of citric acid was shown. Further studies are necessary to investigate the exact conditions suitable for reducing the AFM1 content of contaminated milk during the processing of dairy products