Saturated fat -a never ending story?

A Newly Developed Indicator of Overeating Saturated Fat Based on Serum Fatty Acids and Amino Acids and Its Association With Incidence of Type 2 Diabetes: Evidence From Two Randomized Controlled Feeding Trials and a Prospective Study

Objective

Hyper-caloric intake of saturated fatty acids (SFAs) is common in modern societies, probably contributing to the epidemic of type 2 diabetes mellitus (T2DM). This study conducted two randomized controlled trials (RCTs) for developing a new indicator that can assess the nutritional status and examined its association with incidence of T2DM.

Methods

In RCT 1, healthy participants were randomly assigned into three groups, namely, control group (n = 40), overfeeding group 1 (100 g butter per day, n = 37), and overfeeding group 2 (120 g butter per day, n = 37). In RCT 2, healthy subjects were randomly assigned into two groups, namely, control group (n = 52) and high-fat group (300-extra kcal/day from diet that was designed by high-fat diet, n = 58). In the prospective cohort, 4,057 participants aged 20–74 years were enrolled and followed up over 5.3 years. Serum profiles of fatty acids and amino acids were measured.

Results

In RCT 1, serum fatty acids, including C14:0 and C18:0, increased, whereas C18:2, C20:4, C22:5, and C22:6 decreased; serum amino acids, including tyrosine, alanine, and aminobutyric acid, increased, whereas histidine and glycine decreased (p < 0.05). Among these serum fatty acids and amino acids, changes in C14:0, C20:4, tyrosine, histidine, and glycine were also observed in RCT 2. An indicator was developed based on the five fatty acids and amino acids, namely, C14:0 × tyrosine × 1,000/[C20:4 × (glycine + histidine)], and it significantly identified participants in the intervention group with area under the curve (AUC) (95% CI) being 0.85 (0.77–0.92). The indicator was significantly associated with incidence of T2DM in the prospective cohort with HRs (95% CIs) from bottom quartile to top quartile being 1,1.21 (0.82–1.77), 1.60 (1.12–2.30), 2.04 (1.42–2.94).

Conclusion

The newly developed indicator in RCTs can be used in assessing the nutritional status of hypercaloric intake of SFA and predicting the development of T2DM.

The use and meaning of the parachute metaphor in biomedicine: a citation analysis of a systematic review and a randomized trial of the parachute for freefall

Background: Numerous authors have used the 'parachute' analogy to comment on the importance of and need for randomized, controlled trials (RCTs) in the hierarchy of medical evidence. Methods: The authors completed a retrospective literature analysis examining publications citing the 2003 parachute paper by Smith and Pell and a 2018 RCT of a parachute by Yeh et al. For all of the articles that directly analogized a medical intervention to a parachute, the authors identified the desired outcome of the practice and searched PubMed for relevant RCTs. Results: Authors citing the parachute analogy are often critical of RCTs and often draw comparisons to interventions that are not parachutes.

The impact of a community-based food education programme on dietary pattern in patients with type 2 diabetes: Results of a pilot randomised controlled trial in Portugal

The purpose of this study was to analyse the effects of a food education programme, with easy-to-implement strategies integrated in a community-based exercise programme, on dietary pattern of patients with type 2 diabetes (T2D). Thirty-three patients (65.4 ± 5.9 years old) were engaged in a 9-month randomised controlled trial: a supervised exercise programme (control group [CON]; n = 15; combined exercise; three sessions per week; 75 min per session) or the same exercise programme plus a concomitant 16-week food education programme (experimental group [EXP]; n = 18; 15-min. group classes and dual-task strategies during exercise). Dietary pattern was assessed using a 3-day food record at baseline and at 9 months. The intake of total fat, polyunsaturated fat, and the daily servings of vegetables significantly increased in EXP compared with the CON group. Retention and adherence to the programme were 54% and 49.5 ± 27.2%, respectively. This food education programme improved dietary pattern of patients with T2D. Special attention should be given to strategies that support participants' attendance.

Liver tumorigenesis is promoted by a high saturated fat diet specifically in male mice and is associated with hepatic expression of the proto-oncogene Agap2 and enrichment of the intestinal microbiome with Coprococcus

Liver cancer results in a high degree of mortality, especially among men. As fatty liver disease is a risk factor for development of hepatocellular carcinoma, we investigated the role of dietary fat type in tumor promotion by high-fat diets in mice after initiation with the chemical carcinogen diethyl nitrosamine. Tumor incidence and multiplicity were significantly greater in males than those in females. In males, fat type had complex effects on tumorigenesis. Preneoplastic foci were most prevalent in mice fed a polyunsaturated fat diet enriched in docosahexaenoic acid, whereas carcinomas and large visible liver tumors were significantly greater in mice fed a saturated fat diet made with cocoa butter relative to mice fed mono- or polyunsaturated fats. Different mechanisms thus seemed involved in early and late tumor promotion. The hepatic transcriptome and gut microbiome were assessed for traits associated with tumorigenesis. Hepatic expression of more than 20% of all genes was affected by sex, whereas fat type affected fewer genes. In males, the saturated fat diet induced expression of the proto-oncogene Agap2 and affected the expression of several cytochrome P450 genes, and genes involved in lipid, bile acid and fatty acid metabolism. The gut microbiome had a higher level of genus Akkermansia and a lower level of Firmicutes in females than in males. Males fed saturated fat had an altered microbiome, including an enrichment of the genus Coprococcus. In conclusion, sex and the dietary fat type affect the gut microbiome, the hepatic transcriptome and ultimately hepatic tumor growth.

Why Do Mice Overeat High-Fat Diets? How High-Fat Diet Alters the Regulation of Daily Caloric Intake in Mice

OBJECTIVE

Ad libitum high-fat diets (HFDs) spontaneously increase caloric intake in rodents, which correlates positively with weight gain. However, it remains unclear why rodents overeat HFDs. This paper investigated how changing the proportion of diet that came from HFDs might alter daily caloric intake in mice.

METHODS

Mice were given 25%, 50%, or 90% of their daily caloric need from an HFD, along with ad libitum access to a low-fat rodent chow diet. Food intake was measured daily to determine how these HFD supplements impacted total daily caloric intake. Follow-up experiments addressed the timing of HFD feeding.

RESULTS

HFD supplements did not alter total caloric intake or body weight. In a follow-up experiment, mice consumed approximately 50% of their daily caloric need from an HFD in 30 minutes during the light cycle, a time when mice do not normally consume food.

CONCLUSIONS

An HFD did not disrupt regulation of total daily caloric intake, even when up to 90% of total calories came from the HFD. However, HFDs increased daily caloric intake when provided ad libitum and were readily consumed by mice outside of their normal feeding cycle. Ad libitum HFDs appear to induce overconsumption beyond the mechanisms that regulate daily caloric intake.

Fats in Foods: Current Evidence for Dietary Advice

Current discussion of the importance of food fats in the risk of coronary heart disease (CHD) often suffers from preconceptions, misunderstandings, insufficient knowledge, and selective reasoning. As a result, the sustained controversy about dietary fat recommendations can be contradictory and confusing. To clarify some of these issues, the International Expert Movement to Improve Dietary Fat Quality in cooperation with the International Union of Nutritional Sciences (IUNS) organized a symposium at the 21st meeting of the IUNS, October 17, 2017, Buenos Aires, Argentina, to summarize the key scientific evidence underlying the controversy on the relationship between the saturated and unsaturated fat consumption and CHD risk. Presenters also discussed, using examples, the rationale for and implications of the partial replacement of foods rich in saturated fats by those rich in unsaturated fats. Presentations included strategies to fit healthier fats into meals. This report summarizes the symposium presentations.