The association of energy and macronutrient intake with all-cause mortality, cardiovascular disease and dementia: findings from 120 963 women and men in the UK Biobank

Sexual dimorphism in the context of nutrition and health

Diets and dietary constituents that we consume have a considerable impact on disease risk. Intriguingly these effects may be modulated to some extent by sex. Lack of female representation in nutritional studies as well as a lack of stratification by sex has and continues to limit our understanding of these sex × diet interactions. Here we provide an overview of the current and available literature describing how exposure to certain dietary patterns (Western-style diet, Mediterranean diet, vegetarian/vegan, ketogenic diet) and dietary constituents (dietary fibre, PUFA and plant bioactive) influences disease risk in a sex-specific manner. Interestingly, these sex differences appear to be highly disease-specific. The identification of such sex differences in response to diet stresses the importance of sex stratification in nutritional research.

Associations of Diet with Health Outcomes in the UK Biobank: A Systematic Review

The UK Biobank is a cohort study that collects data on diet, lifestyle, biomarkers, and health to examine diet-disease associations. Based on the UK Biobank, we reviewed 36 studies on diet and three health conditions: type 2 diabetes (T2DM), cardiovascular disease (CVD), and cancer. Most studies used one-time dietary data instead of repeated 24 h recalls, which may lead to measurement errors and bias in estimating diet-disease associations. We also found that most studies focused on single food groups or macronutrients, while few studies adopted a dietary pattern approach. Several studies consistently showed that eating more red and processed meat led to a higher risk of lung and colorectal cancer. The results suggest that high adherence to "healthy" dietary patterns (consuming various food types, with at least three servings/day of whole grain, fruits, and vegetables, and meat and processed meat less than twice a week) slightly lowers the risk of T2DM, CVD, and colorectal cancer. Future research should use multi-omics data and machine learning models to account for the complexity and interactions of dietary components and their effects on disease risk.

Low-carbohydrate diet and risk of cardiovascular disease, cardiovascular and all-cause mortality: a systematic review and meta-analysis of cohort studies

Background: Evidence for the long-term health effect of low-carbohydrate diets (LCDs) is inconsistent. Herein, we aimed to examine the associations of LCDs with cardiovascular disease (CVD) and all-cause and cause-specific mortality. Methods: We searched PubMed, EMBASE, and the Web of Science up to 26 July 2023 for eligible publications. Random-effect models were used to pool the summary relative risks (RRs) and 95% confidence intervals (CIs). Results: A total of 44 studies (17 articles) were included in the systematic review and 38 in the meta-analysis, including 223 657 all-cause deaths (771 609 participants), 14 046 cardiovascular deaths (274 807 participants), 18 264 CVD cases (405 631 participants), and 3634 coronary heart disease (CHD) cases (151 023 participants). Subsequently, the highest LCD score was compared with the lowest one and the pooled RRs (95% CIs) were 1.05 (0.96, 1.14; I2 = 65.1%; n = 13) for CVD, 1.43 (1.18, 1.72; I2 = 25.4%; n = 3) for CHD, 0.93 (0.81, 1.06; I2 = 0.0%; n = 2) for stroke, 1.03 (0.96, 1.10; I2 = 86.6%; n = 13) for all-cause mortality and 1.09 (0.99, 1.19; I2 = 65.1%; n = 10) for cardiovascular mortality. Conclusion: Our analysis showed positive associations of LCDs with CHD. Thus, vigilance is recommended for long-term adherence to this dietary pattern.

The Dietary Carbohydrate/Fat-Ratio and Cognitive Performance: Panel Analyses in Older Adults at Risk for Dementia

Background

Roughly 80% of total energy intake (TEI) in most human diets originates from digestible carbohydrates (eCarb) and fat (eFat), but the impact of their proportions on cognitive performance is poorly understood.

Objectives

Our primary aim was to investigate estimates of global cognition in relation to macronutrient intake, with the log-ratio eCarb/eFat (CFr) as the primary predictor variable of interest. Secondary predictors were protein and the saturated/total fat ratio. Exploratory comparisons of CFr with eCarb and eFat as separate predictors were an additional aim.

Methods

The observations were made on panel data (years 0, 1, 2) from the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability, n = 1251; age 60-77 y; 47% females; selected by risk factors for dementia. Self-reported diet was assessed by 3-d food records. Global cognition was measured using a modified Neuropsychological Test Battery. A mixed linear regression model was used, adjusted for age, sex, education, body-mass index, cholesterol-lowering drugs, TEI, time, time × intervention/control group, with study site and subject as random factors. Estimates were standardized (mean = 0; SD = 1) with 95% CI.

Results

CFr had a negative estimate to global cognition (β = -0.022, CI: -0.039, -0.005; P = 0.011). The point estimate for protein was β = 0.013 (P = 0.41), and for the saturated/total fat ratio, associations with cognition were nonlinear. CFr correlated highly with eCarb (Pearson's r = 0.92) and eFat (r = -0.94). The point estimate for CFr fell between eCarb (β = -0.026, P < 0.001) and (inversely) eFat (β = 0.017, P = 0.090).

Conclusions

A lower CFr was associated with better global cognition among older adults at risk for dementia. Because this is an important target group for preventive interventions, clinical trials are warranted to further investigate the impact of macronutritional composition on cognitive health. The potential role of CFr as a predictor for cognitive health should be further studied.

Carbohydrate Intake and Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Prospective Studies

The purpose of this study is to understand the conflicting results from previous studies on the association between carbohydrate intake and cardiovascular disease (CVD) by conducting a systematic review and meta-analysis to summarize the most recent scientific evidence. A systematic review used three electronic databases to gather literature on the association between carbohydrate intake and CVD. Considering the discrepancies, either fixed or random effect models were chosen to determine the effect size, and sensitivity analysis results, as well as publication bias, were also presented. The meta-analysis found that individuals with the highest carbohydrate intake had a 1.15-fold increased risk of CVD compared to those with the lowest intake (hazard ratio, HR: 1.15, 95% confidence interval, CI: 1.07-1.23). Further subgroup analysis revealed that this association was only present in Asia, with a 1.52-fold increased risk (HR: 1.52, 95% CI: 1.17-1.97), while no associations were seen in the Americas, Europe, and Oceania. The relationship between carbohydrate intake and CVD was non-linear, with a marked escalation beyond 60% of total energy from carbohydrates. Our findings suggest that a high-carbohydrate diet may raise the risk of CVD, particularly in Asian populations. This association may be due to the higher carbohydrate consumption and genetic variations found in Asia.

The Impact of High Protein Diets on Cardiovascular Outcomes: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

High protein diets have gained increased popularity as a means of losing weight, increasing muscle mass and strength, and improving cardiometabolic parameters. Only a few meta-analyses have addressed their impact on cardiovascular morbidity and mortality and failed to show any significant associations without applying strict values to define high protein intake. Due to the conflicting research background, we conducted a meta-analysis to assess the impact of high protein diets compared to normal protein consumption on cardiovascular outcomes in adults without established cardiovascular disease. Fourteen prospective cohort studies were included. A total of 6 studies, including 221,583 participants, reported data about cardiovascular death, without showing a statistically significant difference in the random effect model (odds ratio: 0.94; confidence interval: 0.60-1.46; I2 = 98%; p = 0.77). Analysis of three studies, which included 90,231 participants showed that a high protein diet was not associated with a lower risk of stroke (odds ratio: 1.02; confidence interval: 0.94-1.10; I2 = 0%; p = 0.66). Regarding the secondary outcome of non-fatal myocardial infarction, stroke, or cardiovascular death, 13 studies that included 525,047 participants showed no statistically significant difference (odds ratio; 0.87; confidence interval: 0.70-1.07; I2 = 97%; p = 0.19). In conclusion, according to our study results, high protein consumption does not affect cardiovascular prognosis.

Multi-Nutrient Analysis of Dietary Macronutrients with All-Cause, Cardiovascular, and Cancer Mortality: Data from NHANES 1999-2014

Macronutrients are a major component of the human diet. However, few studies have assessed their collective association with mortality. We sought to evaluate the associations of macronutrient intake with all-cause, cardiovascular, and cancer mortality in US adults using a multi-nutrient approach. This prospective cohort analysis used data from the National Health and Nutrition Examination Survey from the years 1999 to 2014. The participants included 33,681 US adults aged 20−85 years (52.5% female). The maximum follow-up time was 16.8 years, with a total of 4398 total deaths, including 772 cardiovascular deaths and 952 cancer deaths. The associations between mortality and dietary macronutrients were explored using three-dimensional generalized additive models, allowing for visual and statistical inference of complex nonlinear associations. Absolute macronutrient intake demonstrated a three-way interactive association with all-cause mortality (p < 0.001), cardiovascular mortality (p = 0.02), and cancer mortality (p = 0.05), adjusted for age, sex, ethnicity, socioeconomic status, dietary quality, and lifestyle. Compositionally, a high caloric diet composed of moderately high protein (20%), moderate fat (30%), and moderate carbohydrate (50%) levels was associated with the highest mortality risk. Across the total energy intake levels, lower mortality risk was observed in two separate regions consisting of higher protein (30%), higher carbohydrate (60%), and lower fat levels (10%) or lower protein (10%), moderate carbohydrate (45%), and higher fat levels (45%). These findings highlight a complex nonlinear and interactive association between macronutrients and all-cause mortality such that several distinct dietary compositions are associated with similarly high or low risk. Future research is needed to explore the drivers of these associations and whether they differ across varying dietary patterns and populations.

Adherence to dietary guidelines and risk of dementia: a prospective cohort study of 94 184 individuals

AIMS

Recent estimates suggest that 40% of dementia cases could be avoided by treating recognised cardiovascular risk factors such as hypertension, diabetes, smoking and physical inactivity. Whether diet is associated with dementia remains largely unknown. We tested if low adherence to established dietary guidelines is associated with elevated lipids and lipoproteins and with increased risk of Alzheimer's disease and non-Alzheimer's dementia – a dementia subtype with a high frequency of cardiovascular risk factors.

METHODS

We used the prospective Copenhagen General Population Study including 94 184 individuals with dietary information and free of dementia at baseline. Mean age at study entry was 58 years, and 55% (N = 51 720) were women and 45% (N = 42 464) were men. Adherence to dietary guidelines was grouped into low, intermediate and high adherence based on food frequency questionnaires. Main outcomes were non-Alzheimer's dementia and Alzheimer's disease.

RESULTS

Low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol and plasma triglyceride levels were higher in individuals with intermediate and low adherence to dietary guidelines compared with individuals with high adherence (all p for trends <0.001). Age and sex-adjusted hazard ratios (HRs) for non-Alzheimer's dementia v. individuals with high adherence were 1.19 (95% confidence interval 0.97–1.46) for intermediate adherence, and 1.54 (1.18–2.00) for low adherence. Corresponding HRs in multivariable-adjusted models including APOE genotype were 1.14 (0.92–1.40) and 1.35 (1.03–1.79). These relationships were not observed in individuals on lipid-lowering therapy.

CONCLUSIONS

Low adherence to national dietary guidelines is associated with an atherogenic lipid profile and with increased risk of non-Alzheimer's dementia – the subtype of dementia with a high frequency of vascular risk factors. This study suggests that implementation of dietary guidelines associated with an anti-atherogenic lipid profile could be important for prevention of non-Alzheimer's dementia.