Abstracts - Nutrition

Meat products provide essential nutrients including high-quality proteins, iron, zinc and vitamins. Their nutritional contribution depends on meat matrix effect: its composition, processing conditions and dietary context. This review highlights the mechanisms influencing nutrient bioavailability and related nutritional challenges.

Modelling approaches help clarify how the structural organization of meat influences digestion, nutrient release and overall nutritional quality. Statistical and machine-learning tools support the prediction of key matrix-related traits such as composition, texture or digestibility, by capturing complex relationships within experimental datasets. In parallel, mechanistic models provide a more detailed representation of heat and mass transfer phenomena and digestive processes, integrating the heterogeneous structure of meat particles with the dynamic conditions of the gastrointestinal environment.

Bioavailability - the proportion of a nutrient that is absorbed and used by the body - varies considerably depending on whether foods are of animal or plant origin. This review summarises data from Chungchunlam and Moughan (2024) on the bioavailability of thirteen vitamins and choline, an essential nutrient related to the B vitamins, in major food sources. Animal-sourced foods are the almost exclusive sources of preformed vitamin A (retinol and retinyl esters, 74% bioavailable) and vitamin B12 (65%), and provide all B vitamins with high bioavailability (biotin: 89%; vitamin B6: 83%; thiamin: 82%; pantothenic acid: 80%; folate and niacin: 67%). Plant-based foods are the main sources of vitamin C (76%) and provitamin A carotenoids (β-carotene, 16%). These data show that animal-sourced foods - particularly offal and red meat - provide vitamins with, for the most part, generally high bioavailability. They also confirm the value of a diversified diet, supported by a nutritional complementarity already demonstrated by modelling: to meet all nutrient-based recommendations, the contribution of animal protein to total protein intake must represent at least 45 to 60% depending on age and sex.

Few studies have examined dietary protein intake and sources, in combination with longitudinal changes in brain structure markers. Our study aimed to examine the association between dietary protein intake and different sources of dietary protein, with the longitudinal rate of change in brain structural markers. A total of 2723 and 2679 participants from the UK Biobank were separately included in the analysis. The relative and absolute amounts of dietary protein intake were calculated using a 24 h dietary recall questionnaire. The longitudinal change rates of brain structural biomarkers were computed using two waves of brain imaging data. The average interval between the assessments was three years. We utilized multiple linear regression to examine the association between dietary protein and different sources and the longitudinal changes in brain structural biomarkers. Restrictive cubic splines were used to explore nonlinear relationships, and stratified and sensitivity analyses were conducted. Increasing the proportion of animal protein in dietary protein intake was associated with a slower reduction in the total hippocampus volume (THV, β: 0.02524, p < 0.05), left hippocampus volume (LHV, β: 0.02435, p < 0.01) and right hippocampus volume (RHV, β: 0.02544, p < 0.05). A higher intake of animal protein relative to plant protein was linked to a lower atrophy rate in the THV (β: 0.01249, p < 0.05) and LHV (β: 0.01173, p < 0.05) and RHV (β: 0.01193, p < 0.05). Individuals with a higher intake of seafood exhibited a higher longitudinal rate of change in the HV compared to those that did not consume seafood (THV, β: 0.004514; p < 0.05; RHV, β: 0.005527, p < 0.05). In the subgroup and sensitivity analyses, there were no significant alterations. A moderate increase in an individual’s intake and the proportion of animal protein in their diet, especially from seafood, is associated with a lower atrophy rate in the hippocampus volume.

Currently, some consumers are reducing or even eliminating their consumption of red meat for environmental, ethical, or financial reasons. Beyond the well-established nutritional benefits of red meat, particularly in terms of protein quality and micronutrient content, this study aimed to assess the influence of its presence in a complete couscous-type meal on the overall nutritional quality of the meal. In vivo digestibility measurements were used to collect data on the bioavailability of nutrients in meals with and without meat, highlighting the importance of meat products in meeting nutritional needs depending on the type of meal.

Results from observational studies suggest associations of red meat intake with increased risk of cardiovascular disease (CVD); however, Randomized Controlled Trials (RCT) have not clearly demonstrated a link between red meat consumption and CVD risk factors. Further, the specific effects of beef, the most consumed red meat in the United States, have not been extensively investigated. This study aimed to perform a systematic review and meta-analysis of Randomized Controlled Trials data evaluating the effects of minimally or un- processed beef intake on CVD risk factors in adults. A search of the literature was conducted using PubMed and CENTRAL databases. Randomized Controlled Trials in adults that provided diets with fresh or minimally processed beef were included. Data were extracted, and pooled estimates from random-effects models were expressed as standardized mean differences (SMDs) between the beef intervention and comparator intervention with less or no beef. Sensitivity and subgroup analyses were also performed. Twenty relevant Randomized Controlled Trials that met the criteria were included. Beef intake did not impact blood pressure or most lipoprotein-related variables, including total cholesterol, HDL-cholesterol, triglycerides, non–HDL-cholesterol, apolipoprotein A or B, and VLDL-cholesterol. Beef consumption had a small but significant effect on LDL-cholesterol, corresponding to ~2.7 mg/dL higher LDL-cholesterol in diets containing more beef than that in low-beef or -o beef comparator diets. Sensitivity analyses show this effect was lost when 1 influential study was removed. Daily unprocessed beef intake does not significantly affect most blood lipids, apolipoproteins, or blood pressures, except for a small increase in LDL-cholesterol compared with diets with less or no beef. Thus, there may be other factors influencing the association of red meat and beef on CVD risk that deserve further investigation.
This study was registered at INPLASY as 202420013.