Although the prevalence of malnutrition in the old age is increasing worldwide a synthetic understanding of the impact of aging on the intake, digestion, and absorption of nutrients is still lacking. This review article aims at filling the gap in knowledge between the functional decline of the aging gastrointestinal tract (GIT) and the consequences of malnutrition on the health status of elderly. Changes in the aging GIT include the mechanical disintegration of food, gastrointestinal motor function, food transit, chemical food digestion, and functionality of the intestinal wall. These alterations progressively decrease the ability of the GIT to provide the aging organism with adequate levels of nutrients, what contributes to the development of malnutrition. Malnutrition, in turn, increases the risks for the development of a range of pathologies associated with most organ systems, in particular the nervous-, muscoskeletal-, cardiovascular-, immune-, and skin systems. In addition to psychological, economics, and societal factors, dietary solutions preventing malnutrition should thus propose dietary guidelines and food products that integrate knowledge on the functionality of the aging GIT and the nutritional status of the elderly. Achieving this goal will request the identification, validation, and correlative analysis of biomarkers of food intake, nutrient bioavailability, and malnutrition.

Inflammation is a major biological process regulating the interaction between organisms and the environment, including the diet. Because of the increase in chronic inflammatory diseases, and in light of the immune-regulatory properties of breastfeeding, the ability of dairy products to modulate inflammatory processes in humans is an important but unresolved issue. Here, we report a systematic review of 52 clinical trials investigating inflammatory markers in relation to the consumption of dairy products. An inflammatory score (IS) was defined to quantitatively evaluate this interaction. The IS was significantly positive for the entire data set, indicating an anti-inflammatory activity in humans. When the subjects were stratified according to their health status, the IS was strongly indicative of an antiinflammatory activity in subjects with metabolic disorders and of a pro-inflammatory activity in subjects allergic to bovine milk. Stratifying the data by product categories associated both low-fat and high-fat products, as well as fermented products, with an anti-inflammatory activity. Remarkably, the literature is characterized by a large gap in knowledge on bioavailability of bioactive nutrients. Future research should thus better combine food and nutritional sciences to adequately follow the fate of these nutrients along the gastrointestinal and metabolic axes.

Vitamin B12 is synthesized exclusively by microorganisms; therefore, humans must absorb it from food. Excellent sources of B12 are foods of ruminant origin, so dairy and meat products play an important role in efforts to meet the official daily B12 intake recommendation of 3.0 μg. Concentrations of the vitamin vary within foods of ruminant origin, with the highest concentrations found in offal such as liver and kidney. In comparison, dairy products have much lower quantities of the vitamin. In bovine milk, the B12 concentration is stable with regard to breed, feed, season, and stage of lactation, but in ruminant meat, the amount of B12 can vary based on the feeding and husbandry of the animal as well as the cut of meat chosen and its preparation. Processing of ruminant food, including thermal treatment, usually diminishes the vitamin B12 concentration. This review summarizes the vitamin B12 content of foods and discusses the impact of food processing on vitamin content. The contribution of ruminant food sources to B12 intake is specifically evaluated, with its bioavailability taken into account.