Fatty acid modifications and cholesterol oxidation in pork loin during frying at different temperatures

Fried-food consumption and risk of cardiovascular disease and all-cause mortality: a meta-analysis of observational studies

OBJECTIVE

We performed a meta-analysis, including dose-response analysis, to quantitatively determine the association of fried-food consumption and risk of cardiovascular disease and all-cause mortality in the general adult population.

METHODS

We searched PubMed, EMBASE and Web of Science for all articles before 11 April 2020. Random-effects models were used to estimate the summary relative risks (RRs) and 95% CIs.

RESULTS

In comparing the highest with lowest fried-food intake, summary RRs (95% CIs) were 1.28 (1.15 to 1.43; n=17, I²=82.0%) for major cardiovascular events (prospective: 1.24 (1.12 to 1.38), n=13, I²=75.7%; case-control: 1.91 (1.15 to 3.17), n=4, I²=92.1%); 1.22 (1.07 to 1.40; n=11, I²=77.9%) for coronary heart disease (prospective: 1.16 (1.05 to 1.29), n=8, I²=44.6%; case-control: 1.91 (1.05 to 3.47), n=3, I²=93.9%); 1.37 (0.97 to 1.94; n=4, I²=80.7%) for stroke (cohort: 1.21 (0.87 to 1.69), n=3, I²=77.3%; case-control: 2.01 (1.27 to 3.19), n=1); 1.37 (1.07 to 1.75; n=4, I²=80.0%) for heart failure; 1.02 (0.93 to 1.14; n=3, I²=27.3%) for cardiovascular mortality; and 1.03 (95% CI 0.96 to 1.12; n=6, I²=38.0%) for all-cause mortality. The association was linear for major cardiovascular events, coronary heart disease and heart failure.

CONCLUSIONS

Fried-food consumption may increase the risk of cardiovascular disease and presents a linear dose-response relation. However, the high heterogeneity and potential recall and misclassification biases for fried-food consumption from the original studies should be considered.

Fried food intake and risk of nonfatal acute myocardial infarction in the Costa Rica Heart Study

Economic development in middle-income countries has led to a noticeable rise in the availability of commercial deep fried foods and lifestyles that require eating meals “on the go” and outside of the home. Yet, data from these countries where fried foods were traditionally prepared at home are scarce, despite several studies showing the potential adverse effects of fried food consumption on risk for heart disease. We aimed to examine whether consumption of fried foods inside or outside of the home is associated with an increased risk of myocardial infarction (MI) among Hispanic/Latinos living in Costa Rica. Participants were incident cases of a first acute MI (n = 2,154) and randomly selected controls matched for age, sex, and residence (n = 2,154). After adjustment for traditional cardiovascular risk factors, including history of diabetes, history of hypertension, smoking, abdominal obesity, income, educational years, occupation, alcohol intake, dietary intakes of saturated fatty acid, fiber intake, and total energy intake, the multivariable-adjusted odds ratio (OR, 95% CI) for risk of MI were 1.00 (reference), 1.02 (0.86–1.21), 1.26 (0.81–1.95), and 1.58 (1.08–2.30) for intake of fried foods outside of the home <1/week, 1-3/week, 4-6/week, and 1/day, respectively (P trend = 0.02); and 1.00, 0.81 (0.65–1.00), 0.81 (0.61–1.09), and 0.93 (0.72–1.19), respectively (P for trend = 0.65) for intake of fried foods inside the home. The data suggest that consumption of fried foods outside of the home, a practice that has been associated with economic development, could have adverse effects on cardiovascular disease.

Consumption of fried foods and risk of heart failure in the physicians' health study

BACKGROUND

Consumption of fried foods is highly prevalent in the Western dietary pattern. Though limited studies have reported a positive association between frequency of fried food intake and risk of coronary artery disease, diabetes, or hypertension, other investigators failed to report such an association. It is unclear whether intake of fried foods is associated with a higher risk of heart failure (HF). Hence, we sought to examine the association between the frequency of fried food consumption and the risk of HF.

METHODS AND RESULTS

This was a prospective cohort study of 15 362 participants from the Physicians' Health Study. Fried food intake frequency was assessed by a food frequency questionnaire (1997-2001), and incident HF was captured by annual questionnaires. We used Cox regression to calculate hazard ratios (HRs) of HF. After an average follow-up of 9.6 ± 2.4 years, a total of 632 new HF cases occurred in this cohort. Compared to subjects who reported fried food consumption of <1 per week, HRs (95% CI) for HF were 1.24 (1.04 to 1.48), 1.28 (1.00 to 1.63), and 2.03 (1.37 to 3.02) for fried food intake of 1 to 3/week, 4 to 6/week, and 7+/week, respectively, after adjustment for age, energy intake, alcohol use, exercise, smoking, and overall diet score (P linear trend, 0.0002). Similar results were obtained for intake of fried foods at home or away from home and among subjects with higher dietary score or HF without antecedent myocardial infarction.

CONCLUSIONS

Our data are consistent with a positive association of fried food intake frequency with incident HF in male physicians.

Fried-food consumption and risk of type 2 diabetes and coronary artery disease: a prospective study in 2 cohorts of US women and men

BACKGROUND

Through the processes of oxidation, polymerization, and hydrogenation, the cooking method of frying modifies both foods and their frying medium. However, it remains unknown whether the frequent consumption of fried foods is related to long-term cardiometabolic health.

OBJECTIVE

We examined fried-food consumption and risk of developing incident type 2 diabetes (T2D) or coronary artery disease (CAD).

DESIGN

Fried-food consumption was assessed by using a questionnaire in 70,842 women from the Nurses' Health Study (1984-2010) and 40,789 men from the Health Professionals Follow-Up Study (1986-2010) who were free of diabetes, cardiovascular disease, and cancer at baseline. Time-dependent Cox proportional hazards models were used to estimate RRs and 95% CIs for T2D and CAD adjusted for demographic, diet, lifestyle, and other cardiometabolic risk factors. Results were pooled by using an inverse variance-weighted random-effects meta-analysis.

RESULTS

We documented 10,323 incident T2D cases and 5778 incident CAD cases. Multivariate-adjusted RRs (95% CIs) for individuals who consumed fried foods <1, 1-3, 4-6, or ≥7 times/wk were 1.00 (reference), 1.15 (0.97, 1.35), 1.39 (1.30, 1.49), and 1.55 (1.32, 1.83), respectively, for T2D and 1.00 (reference), 1.06 (0.98, 1.15), 1.23 (1.14, 1.33), and 1.21 (1.06, 1.39), respectively, for CAD. Associations were largely attenuated when we further controlled for biennially updated hypertension, hypercholesterolemia, and body mass index.

CONCLUSIONS

Frequent fried-food consumption was significantly associated with risk of incident T2D and moderately with incident CAD, and these associations were largely mediated by body weight and comorbid hypertension and hypercholesterolemia.

Consumption of fried foods and risk of coronary heart disease: Spanish cohort of the European Prospective Investigation into Cancer and Nutrition study

OBJECTIVE

To assess the association between consumption of fried foods and risk of coronary heart disease.

DESIGN

Prospective cohort study.

SETTING

Spanish cohort of the European Prospective Investigation into Cancer and Nutrition.

PARTICIPANTS

40 757 adults aged 29-69 and free of coronary heart disease at baseline (1992-6), followed up until 2004.

MAIN OUTCOME MEASURES

Coronary heart disease events and vital status identified by record linkage with hospital discharge registers, population based registers of myocardial infarction, and mortality registers.

RESULTS

During a median follow-up of 11 years, 606 coronary heart disease events and 1135 deaths from all causes occurred. Compared with being in the first (lowest) quarter of fried food consumption, the multivariate hazard ratio of coronary heart disease in the second quarter was 1.15 (95% confidence interval 0.91 to 1.45), in the third quarter was 1.07 (0.83 to 1.38), and in the fourth quarter was 1.08 (0.82 to 1.43; P for trend 0.74). The results did not vary between those who used olive oil for frying and those who used sunflower oil. Likewise, no association was observed between fried food consumption and all cause mortality: multivariate hazard ratio for the highest versus the lowest quarter of fried food consumption was 0.93 (95% confidence interval 0.77 to 1.14; P for trend 0.98).

CONCLUSION

In Spain, a Mediterranean country where olive or sunflower oil is used for frying, the consumption of fried foods was not associated with coronary heart disease or with all cause mortality.

Dietary intake of different types and characteristics of processed meat which might be associated with cancer risk – results from the 24-hour diet recalls in the European Prospective Investigation into Cancer and Nutrition (EPIC)

Objective

There is increasing evidence for a significant effect of processed meat (PM) intake on cancer risk. However, refined knowledge on how components of this heterogeneous food group are associated with cancer risk is still missing. Here, actual data on the intake of PM subcategories is given; within a food-based approach we considered preservation methods, cooking methods and nutrient content for stratification, in order to address most of the aetiologically relevant hypotheses.

Design and setting

Standardised computerised 24-hour diet recall interviews were collected within the framework of the European Prospective Investigation into Cancer and Nutrition (EPIC), a prospective cohort study in 27 centres across 10 European countries.

Subjects

Subjects were 22 924 women and 13 031 men aged 35–74 years.

Results

Except for the so-called ‘health-conscious’ cohort in the UK, energy-adjusted total PM intake ranged between 11.1 and 47.9 g day−1 in women and 18.8 and 88.5 g day−1 in men. Ham, salami-type sausages and heated sausages contributed most to the overall PM intake. The intake of cured (addition of nitrate/nitrite) PM was highest in the German, Dutch and northern European EPIC centres, with up to 68.8 g day−1 in men. The same was true for smoked PM (up to 51.8 g day−1). However, due to the different manufacturing practice, the highest average intake of NaNO2 through PM consumption was found for the Spanish centres (5.4 mg day−1 in men) as compared with German and British centres. Spanish centres also showed the highest intake of NaCl-rich types of PM; most cholesterol- and iron-rich PM was consumed in central and northern European centres. Possibly hazardous cooking methods were more often used for PM preparation in central and northern European centres.

Conclusions

We applied a food-based categorisation of PM that addresses aetiologically relevant mechanisms for cancer development and found distinct differences in dietary intake of these categories of PM across European cohorts. This predisposes EPIC to further investigate the role of PM in cancer aetiology.

Postprandial lipid oxidation and cardiovascular disease risk

A mild pro-oxidative state accompanies meal ingestion, which results in an increase in biomarkers of inflammation, adhesion, and endothelial dysfunction, all of which are factors in the development of cardiovascular disease. Both fat and carbohydrate can cause the effect, which is additive and exacerbated by diabetes. The presence of lipid, glucose, and cholesterol oxidation products of dietary or endogenous origin may contribute to postprandial oxidative stress. However, the generation of excess superoxide due to abundant energy substrate after the meal may be a predominate factor resulting in oxidative stress and a decrease in nitric oxide, which is important to endothelial function. Remediation of postprandial oxidative stress through direct reduction of superoxide generation and simultaneous consumption of antioxidants with each meal should be a focus of future research.

Consequences of microwave heating and frying on the lipid fraction of chicken and beef patties

Two types of commercial meat patties were analyzed to evaluate the effect of two applied cooking methods on the lipid fraction and the cholesterol oxidation process during heating. Microwave heating hardly modified the fatty acid profiles of both chicken and beef patties, whereas frying in olive oil increased oleic and eicosapentaenoic acids and decreased linoleic and docosahexaenoic acids in both types of products. Frying improved the omega6/omega3 fatty acids ratio in beef patties from 10.67 (raw) to 5.37 (fried). Total cholesterol oxidation product (COP) increments were 5.3-6.1-fold with microwave heating and 1.5-2.6-fold with frying. Chicken patties, raw and cooked, had a COP content twice as high as the corresponding beef ones.

Combined effect of cooking (grilling and roasting) and chilling storage (with and without air) on lipid and cholesterol oxidation in chicken breast

The oxidation of the lipid fraction and cholesterol in raw and cooked chicken breast samples stored for 0 and 6 days at 4 degrees C under aerobic conditions and in vacuum packaging was studied. The multivariate statistical analysis showed significant effects of both culinary process and storage conditions on the lipid and cholesterol oxidation process, with a significant interaction between the two variables. Aerobic storage increased thiobarbituric acid reactive substances (TBA) from 0.04 to 0.06 ppm for raw samples, from 0.21 to 1.20 ppm for grilled samples, and from 0.24 to 1.62 ppm for roasted samples. During vacuum storage, only roasted samples showed significant increases in TBA. Levels of total cholesterol oxidation products (COP) remained low (2.88 to 4.35 microg/g of lipid) for all raw samples. Cooking increased COP levels to 12.85 and 11.54 microg/ g of lipid for grilled and roasted samples, respectively. Total COP and all individual COP except for cholestanetriol were significantly correlated with TBA and the peroxide index. However, the most extensive effect was attributable to the aerobic storage of cooked samples, which led to COP levels of 92.35 and 88.60 microg/g of lipid in grilled and roasted samples, respectively. Vacuum packaging did not increase COP levels for cooked samples.