The Food Matrix: Understanding Food and Nutrition

THE FOOD MATRIX SC/NATS1560 UNDERSTANDING FOOD  THE REDUCTIONIST PARADIGM Analysis = decomposition of a whole into simpler parts Reductionism = the whole is nothing more than the sum of its parts Ac...

THE FOOD MATRIX SC/NATS1560 UNDERSTANDING FOOD  THE REDUCTIONIST PARADIGM Analysis = decomposition of a whole into simpler parts Reductionism = the whole is nothing more than the sum of its parts According to the scientific paradigm of reductionism − in principle, any complex system can be decomposed— conceptually, materially, or both— into simpler parts without destroying or losing anything significant − the system can then be reconstructed by adding the parts back together − such decomposition and reconstruction process—whether conceptual, material, or both—is the only way to scientifically understand complex wholes − the properties of a whole can be predicted from the properties of its isolated components − the process through which the system is produced is irrelevant to the properties of the whole − a system can be conceptually or materially simplified by disregarding or discarding the components judged to be irrelevant for a given purpose − systems can be improved by replacing one or more of their elementary components − new systems can be invented by assembling elementary components in new ways 2 REDUCTIONISM APPLIED TO FOODS Diet = sum Viewing diets as of single nothing more than foods sums of single foods Single food = sum of and foods as nothing chemical substances, more than sums of vehicle for nutrients chemical substances and calories Viewing foods fractionation, refinement, exclusively as purification, chemical analysis vehicles for Nutrients: selected nutrients and pure substances, calories Focusing on isolated or molecules nutrients Disregarding non- Nutritional profile: nutrients, structures, quantities of calories, and synergies macronutrients and between micronutrients components  FROM REDUCTIONISM TO HOLISM Historically, the scientific understanding of the relationship between diet and health has advanced using the reductionist paradigm 19th and 20th-century nutrition science: ‒ built upon the atomic theory of matter, organic chemistry, biochemistry, and molecular biology ‒ focused on the biological effects of isolated Reductionism: the whole is nutrients nothing more than the sum of ‒ isolating biological effects from its parts psychological, cultural, and ecological aspects of food and eating A growing body of evidence indicates that food health effects depend not only on quantities of individual nutrients but also on molecule-embedding structures and interactions Holism: the whole is 21st-century nutrition science: increasingly shifting more than the sum of focus from reductionist, nutrient-driven approaches to its parts more holistic views of diet-health relation  THE FOOD MATRIX Food matrix: chemical components and physical structures in which they are embedded ‒ how molecules are organized in 3d at different scales ‒ how molecules interact Whole foods: intact matrix Food matrix effect (FM effect): the food matrix plays a crucial role in food processing, eating, digestion, absorption, and overall health effects of food ‒ bioaccessibility: fraction of ingested nutrients that is released in the GI tract during digestion ‒ bioavailability: fraction of nutrients that is absorbed Processed foods: and reaches systemic circulation disrupted matrix ‒ satiation, satiety, and appetite control  PLANT CELLS In plant tissue, cells are enclosed within thick cell walls made of indigestible polysaccharides Bioavailability of nutrients from plant cells depends on Light micrograph (about 250x) of a potato, disrupting the cell walls showing starch granules inside cell walls. Source: Quinn 2022 E.g., metabolizable energy of whole raw, roasted, and chopped almonds is significantly lower than estimated from modified Atwater values Almonds consumed in different forms promote the growth of different species Source: Gebauer et al. 2016, 4236 of gut bacteria  MILK In our diet after infancy, mostly from cows but also from goats, sheep, buffalos, etc. Complex mixture of over 100 different substances, affected by mammal’s breed and diet Composition of cow milk by weight : 87-88% water 4.8-5% sugar (lactose and some oligosaccharides) 3.4-3.8% fat (milkfat) 3.3-3.5% proteins (casein and whey protein) vitamins (mainly A, B1, B2, and B12 ) minerals (mainly calcium, magnesium, potassium, selenium, and zinc) enzymes many other molecules, including flavour compounds Cow milkfat: 98.3% triglycerides (long and short fatty acids, 70% saturated and 30% unsaturated, with 5% of the unsaturated being trans), mono- and diglycerides, free fatty acids, phospholipids, and cholesterol Flavour compounds: alcohols, aldehydes, ketones, acids, esters, lactones, phenols, ethers, sulfur-containing compounds, terpenes, and other organic compounds Other milks have similar composition  WHOLE MILK MATRIX Whole milk is a heterogeneous mixture, with different microscopic and sub-microscopic structures coexisting at different scales Microscopic scale: oil-in-water emulsion of milkfat globules (fat droplets), Colloidal scale: Suspension of casein micelles (aggregates of molecules) in water Sub-colloidal and molecular scale: whey proteins, lactose, minerals, enzymes, and other molecules dispersed in water  FAT GLOBULES Confocal laser scanning Models of a milkfat globule and of the milk fat globule image of a large fat membrane. Source: arlafoodsingredients.com/early-life-nutrition/our-ingredients/milk-fat- globule. globule-membrane/ © 2010 American Chemical Society. Source: Everett 2025, doi.org/10.3168/jds.2024-25682  CASEIN MICELLES Micrograph of a large casein Casein micelle model showing different micelle taken by field-emission types of casein molecules (red, green, and scanning electron microscope. blue) and calcium phosphate nanoclusters Source: Everett 2025, doi.org/10.3168/jds.2024- (gray). 25682 Source: Everett 2025, doi.org/10.3168/jds.2024-25682  PROCESSING MILK Creaming: separation of concentrated fat (cream), forming a thick layer at the top Homogenization: breaking up and reduction in size of fat globules, and formation of a recombined membrane, preventing creaming Fat destabilization or fat agglomeration: clustering and clumping (coalescence, flocculation, partial coalescence) of the fat globules, forming a continuous internal fat network, as needed for making butter or whipping cream, or ice cream  CONCLUSIONS* “The dairy food matrix contains structural components on length-scales ranging from nanometers to micrometers. The digestibility and absorption of nutrients is largely dictated by the matrix components and interactions between these, indicating that nutrient quality is more than the sum of individual components in isolation. Dairy processing steps in the manufacture of milk products alters the structure, and this requires understanding of the impact on nutritional delivery for human health. Clinical studies have reported health outcomes from consumption of dairy foods that do not reflect the outcomes of consumption of milk components in a different food matrix, or in isolation. This apparent paradox requires a fuller understanding of the structural chemistry and biochemistry of milk under digestive conditions. The challenge in the future is to develop in vitro digestion models that closely mimic human digestion.” * From (Everett 2025)  SOURCES David W. Everett, “Invited Review: The Impact of the Dairy Food Matrix on Digestion and Absorption”, Journal of Dairy Science, in press, available online 7 January 2025, doi.org/10.3168/jds.2024-25682 Sarah K. Gebauer et al., “Food processing and structure impact the metabolizable energy of almonds”, Food & Function 7, 2016, 4231-4238, DOI: 10.1039/c6fo01076h Hannah D. Holscher et al., “Almond Consumption and Processing Affects the Composition of the Gastrointestinal Microbiota of Healthy Adult Men and Women: A Randomized Controlled Trial”, Nutrients 10, 2018, 126. DOI:10.3390/nu10020126 Sue Quinn, “Why are scientists so intrigued by the food matrix?”, BBC Food, January 2022