Recent findings suggest that the distribution of protein intake throughout the day has an impact on various health outcomes in older adults, independently of the amount consumed. We evaluated the association between the distribution of dietary protein intake across meals and all-cause mortality in community-dwelling older adults. Data from 3225 older adults aged ≥ 60 years from the Seniors-ENRICA-1 cohort were examined. Habitual dietary protein consumption was collected in 2008–2010 and in 2012 through a validated diet history. Protein distribution across meals was calculated for each participant as the coefficient of variation (CV) of protein intake per meal, in sex-specific tertiles. Vital status was obtained from the National Death Index up to 30 January 2020. Cox proportional hazards regression was performed to determine the hazard ratios (HR) and their 95 % CI for the association between the distribution of daily protein intake across meals and all-cause mortality. Over a median follow-up of 10·6 years, 591 deaths occurred. After adjustment for potential confounders, the CV of total protein intake was not associated with all-cause mortality (HR and 95 % CI in the second and third tertile v. the lowest tertile: 0·94 (0·77, 1·15) and 0·88 (0·72, 1·08); Ptrend = 0·22). Similarly, the HR of all-cause mortality when comparing extreme tertiles of CV for types of protein were 0·89 (0·73, 1·10) for animal-protein intake and 1·02 (0·82, 1·25) for plant-protein intake. Dietary protein distribution across meals was not associated with all-cause mortality, regardless of protein source and amount, among older adults. Further studies should investigate whether this picture holds for specific causes of death.

Although a decrease in carbohydrate intake and an increase in fat intake among Koreans have been reported, investigations of changes in protein intake have been limited. Thus, this study aimed to explore trends in the dietary intake of total, plant and animal proteins overall and by socio-demographic subgroups in Korea over the past two decades. A total of 78 716 Korean adults aged ≥ 19 years who participated in the seven survey cycles of the Korea National Health and Nutrition Examination Survey 1998–2018 were included. Dietary protein intake, overall and by source, was calculated using a single 24-h dietary recall data. Changes in dietary protein over 20 years were estimated using multiple linear regression analysis after adjusting for potential covariates. For total protein intake, a significant decrease was reported from 1998 to 2016–2018 (P for trendlinearity < 0·001), whereas an increasing trend was observed from 2007–2009 to 2016–2018 (P for trendlinearity < 0·001). In terms of protein intake by source, plant protein intake decreased while animal protein intake increased over the past two decades, indicating steeper trends during the recent decade (P for trendlinearity < 0·001). These trends were more pronounced among younger adults and those with higher household income and education levels. These findings suggest that continuous monitoring of dietary protein intake overall and by source (plant v. animal) across socio-demographic group is needed.

The roles of different dietary proteins in the aetiology of type 2 diabetes (T2D) remain unclear. We investigated the associations of dietary proteins with the risk of incident T2D in Finnish men from the prospective Kuopio Ischaemic Heart Disease Risk Factor Study. The study included 2332 men aged 42–60 years at the baseline examinations in 1984–1989. Protein intakes were calculated from 4-d dietary records. Incident T2D was determined by self-administered questionnaires, fasting blood glucose measurements, 2-h oral glucose tolerance tests, and with national registers. The multivariable-adjusted risk of T2D on the basis of protein intakes was compared by the Cox proportional hazard ratios (HR). During the mean follow-up of 19·3 years, 432 incident T2D cases were identified. Total, animal, meat or dairy product protein intakes were not associated with risk of T2D when the potential confounders were accounted for. Plant (multivariable-adjusted extreme-quartile HR 0·65; 95 % CI 0·42, 1·00; Ptrend 0·04) and egg (HR 0·67; 95 % CI 0·44, 1·00; Ptrend 0·03) protein intakes were associated with a decreased risk of T2D. Adjustments for BMI, plasma glucose and serum insulin slightly attenuated associations. Replacing 1 % energy from carbohydrates with energy from protein was associated with a 5 % (95 % CI 0, 11) increased risk of T2D, but adjustment for fibre intake attenuated the association. Replacing 1 % of energy from animal protein with energy from plant protein was associated with 18 % (95 % CI 0, 32) decreased risk of T2D. This association remained after adjusting for BMI. In conclusion, favouring plant and egg proteins appeared to be beneficial in preventing T2D.

Low protein intake can lead to declined lean mass (LM) in elderly. We examined the associations of total protein (TP), animal protein (AP) and plant protein (PP) intakes with LM. The association of TP intake with LM change was further evaluated according to weight change status. This cross-sectional and prospective cohort study included 554 women aged 68 (sd 1·9) years from the Osteoporosis Risk Factor and Prevention – Fracture Prevention Study (OSTPRE-FPS). The intervention group (n 270) received daily cholecalciferol (800 IU; 20 μg) and Ca (1000 mg) for 3 years while the control group received neither supplementation nor placebo (n 282). Participants filled out a questionnaire on lifestyle factors and a 3-d food record in 2002 and underwent dual-energy X-ray absorptiometry for body composition measurements at baseline and 3 years. Multiple linear regressions evaluated the association between protein intake and LM, adjusting for relevant covariates. At the baseline TP and AP intakes were positively associated with LM and trunk LM, TP was associated also with appendicular LM (aLM). Follow-up results showed that in the total population and the intervention group, higher TP and AP were associated with increased LM and aLM (P ≤ 0·050). No such associations were observed in the control group. PP intake was also associated with aLM change in the total population. Overall, the associations were independent of fat mass. Further, among weight maintainers, TP intake was positively associated with LM, aLM and trunk LM changes (P ≤ 0·020). In conclusion, dietary TP, especially AP, intake may be a modifiable risk factor for sarcopenia by preserving LM in the elderly.

Adequate dietary iodine intake in children is essential for optimal physical and neurological development. Whether lower dietary animal food and salt intake may adversely affect iodine status is under discussion. We examined the association between dietary animal:plant protein ratio with 24-h urinary iodine excretion (24-h UI, μg/d), and whether this is modified by salt intake. A 24-h UI was measured in 1959 24-h urine samples from 516 6- to 12-year-old participants of the Dortmund Nutritional and Anthropometric Longitudinally Designed Study. Parallel 3 d weighed food records were used to estimate dietary intakes. Protein sources were classified as dairy, animal and plant. A repeated-measures regression model (PROC MIXED) was used to analyse the effect of animal:plant protein ratios on 24-h UI. Animal:plant protein ratios ranged from 0·5 (95 % CI 0·4, 0·6) to 1·6 (95 % CI 1·4, 1·9) (lowest and highest quartile). After adjustment for total energy intake, main dietary iodine sources (dairy and salt intake), and further covariates, the inter-individual variation in animal:plant protein ratio was significantly associated with variation in 24-h UI. One unit higher animal:plant protein ratio predicted 6 μg/d higher 24-h UI (P= 0·002) in boys and 5 μg/d (P= 0·03) in girls. This relationship was partially mediated by a higher salt intake at higher animal:plant protein ratios. These results suggest that lower consumption of animal protein is associated with a small decline in iodine excretion, partially mediated by decreased salt intake. Because limited salt and increased intake of plant-based foods are part of a preferable healthy food pattern, effective nutrition political strategies will be required in the future to ensure appropriate iodine nutrition in adherent populations.

The objective of the present study was to assess animal and plant protein intakes in the Belgian population and to examine their relationship with overweight and obesity (OB). The subjects participated in the Belgian National Food Consumption Survey conducted in 2004. Food consumption was assessed by using two non-consecutive 24 h dietary recalls. About 3083 participants ( ≥ 15 years of age; 1546 males, 1537 females) provided completed dietary information. Animal protein intake (47 g/d) contributed more to total protein intakes of 72 g/d than plant protein intake, which accounted for 25 g/d. Meat and meat products were the main contributors to total animal protein intakes (53 %), whereas cereals and cereal products contributed most to plant protein intake (54 %). Males had higher animal and plant protein intakes than females (P < 0·001). Legume and soya protein intakes were low in the whole population (0·101 and 0·174 g/d, respectively). In males, animal protein intake was positively associated with BMI (β = 0·013; P = 0·001) and waist circumference (WC; β = 0·041; P = 0·002). Both in males and females, plant protein intake was inversely associated with BMI (males: β = − 0·036; P < 0·001; females: β = − 0·046; P = 0·001) and WC (male: β = − 0·137; P < 0·001; female: β = − 0·096; P = 0·024). In conclusion, plant protein intakes were lower than animal protein intakes among a representative sample of the Belgian population and decreased with age. Associations with anthropometric data indicated that plant proteins could offer a protective effect in the prevention of overweight and OB in the Belgian population.

Global poverty and food insecurity continue to remain critical issues, especially in rural areas. Developing and fostering agricultural systems that not only require low to moderate amounts of economic capital and few external inputs but also maintain and enhance the resource base of production are key features of sustainable agricultural development. Sustainable agricultural development, including diversifying smallholder production to include livestock, is a pragmatic approach to address both rural poverty and food insecurity. Livestock play important roles in the lives of humans as converters, recyclers and banks of nutrients. Smallholders raise a diversity of livestock species and often raise multiple species simultaneously. High fecundity, diet flexibility and adaptability to a wide range of housing and management approaches are critical traits of livestock species well suited for producing meat for home consumption and marketing in the context of rural smallholders. Swine (Sus scrofa) and chicken (Gallus domesticus) meet many of these criteria and are well known livestock species. This paper examines the potential for a less common species of livestock, guinea pig (Cavia porcellus) to enhance food security and increase household income of rural smallholders. Although cultural acceptance of guinea pig as a source of nutrition and income is less ubiquitous than that of swine, chicken and other species, the biological, ecological and economic advantages of guinea pig deserve further examination by those working to alleviate global poverty and food insecurity.

The objective of the study was to investigate the ability of an NMR-based metabonomic approach, applied to biofluids, to explore and identify overall exogenous and endogenous biochemical effects of a short-time high intake of milk protein or meat protein given to prepubertal children, the aim being to compare relative differences and not an absolute quantification. A total of twenty-four 8-year-old boys were asked to take 53 g protein as milk (n 12) or meat daily (n 12). At baseline and after 7 d, urine and serum samples were collected and high-resolution 1H NMR spectra were acquired on these using a 800 MHz spectrometer. The milk diet reduced the urinary excretion of hippurate, while the meat diet increased the urinary excretion of creatine, histidine and urea. The NMR measurements on serum revealed minor changes in the lipid profile, which most probably should be ascribed to an increase in the content of SCFA in the blood after consumption of the milk diet. The meat diet had no effect on the metabolic profile of serum. The study for the first time demonstrates the capability of proton NMR-based metabonomics to identify the overall biochemical effects of consumption of different animal proteins. The urine metabolite profile is more susceptible to perturbations as a result of short diet interventions than the serum metabolite profile. The milk diet-induced reduction in urinary excretion of hippurate suggests alterations in gut microflora, which may be useful information for further studies elucidating the effects of bioactive components in milk.

Most protein in sub-Saharan Africa comes from animal sources, a significant proportion of this from wild species or bushmeat. Availability of protein sources to human populations in Africa has not been studied before, perhaps because most population centres are too large for data collection to be practicable. Assessment of the availability and consumption of animal protein within the city of Malabo (c. 60 000 inhabitants), Bioko Island, Equatorial Guinea, included estimation of the annual animal protein supply to the city from daily counts of small livestock meats (goat, pork, lamb, duck, chicken), beef, fish and bushmeat (December 2003–March 2004) in the city's central market and other selling points, and the animal protein consumption per adult male equivalent (AME) derived from a sample of around 200 households to explore influence of household income on consumption of different protein sources. Current animal protein production (bushmeat, small livestock meats, beef and fish) in Bioko, and potential production needed to supply adequate amounts of protein to the people of Malabo in the future were calculated. Annually around 2100 t of meat/fish (460 t of animal protein) was available, of which only 7% was produced on the island. Consumption patterns indicated that larger-sized households purchased more meat, but protein intake per AME fell significantly with household size. Income was positively correlated with volume of small livestock meats consumed per household, but negatively related with bushmeat eaten. Income did not influence beef or fish consumption per household. Although the island is capable of producing more alternative meats, it cannot sustain itself on local production and will therefore continue to be dependent on importing a large proportion of meat (and protein). There is no dependency on bushmeat species, but current rates of wild species use can still have a dramatic impact on wildlife populations on the island if left unabated. Alternative ways of ensuring sufficient protein supply for the Malabo population are crucial for wildlife conservation, and curbing consumption of bushmeat species is of highest conservation priority now.

Fish meal is the most widely used protein source in commercial eel foods and information on the nutritive value of more economical protein sources is needed in order to improve cost-effectiveness of diets. This investigation was conducted to determine apparent digestibility coefficients of available plant and animal meals for juvenile Australian short-finned eel (Anguilla australis australis, Richardson). The suitability of a modified Guelph-type settlement faecal collector in eel digestibility studies was assessed. Animal by-product (spray-dried meat solubles; blood meal; high fat poultry meal) and plant protein (soya bean; canola; maize gluten; lupin; field pea) meals were mixed with a reference diet and marker (0·3: 0·69: 0·01) and the resultant test diets given to the juvenile eels (3·15 (s.e. 0·42) g) at 0·05 live weight per day. The reference diet and all the test diets were well accepted by the fish. Apparent digestibility coefficients for crude protein (ADCCP) for maize gluten meal (MGM), lupin meal (LM) and blood meal (BM) were found to be 0·97, 0·96 and 0·96 respectively and they were significantly (P < 0·001) higher than that for the other ingredients. However, apparent digestibilities for dry matter (ADCDM) and energy (ADCkJ) were significantly (P < 0·0001) higher for animal by-products than for plant proteins except for maize gluten meal. This was explained by the higher content of nitrogen free extractives in the former plant proteins. There was a strong positive correlation between ADCDM and ADCkJ for all ingredients (P < 0·01). Weaker positive correlations were also found between ADCCP and ADCDM and between ADCCP and ADCkJ. Similar results obtained for warm water species using similar faecal collection techniques and over limited eel digestibility data support the suitability of the modified Guelph-type settlement collector system in digestibility studies with juvenile eels.