The physical structure of food matters more than nutrition labels suggest. When product developers add nutrients to packaged goods, they often focus on what nutrients go in and miss how food structure affects whether your body can actually absorb them.
Bioavailability measures the proportion of a nutrient that your intestinal wall absorbs and uses for normal body functions. The food matrix describes that physical structure and how nutrients sit within it. These two forces interact in ways that govern nutrient absorption.
In a dense food matrix, enzymes in your digestive tract cannot easily release trapped nutrients. According to Marion Nestle, a nutrition professor at New York University, "If the structure of a food is tight, enzymes in the digestive tract can't release nutrients. Sugars are easy for enzymes to get to; the fats in almonds are not."
The tightness matters because nutrients can be physically inaccessible. A study cited in the article suggests that meat nutrients are more bioavailable than plant nutrients because certain vitamins in plants bind to the food matrix and do not fully release. Niacin in grains, for example, can link to carbohydrates or peptides and stay trapped.
Other compounds make the problem worse. Phytic acid and similar inhibitors can bind to nutrients and reduce absorption even when the structure is not tight. Conversely, some foods contain natural enhancers that boost absorption, such as vitamin C alongside iron from meat.
Ultra-processed foods flip this dynamic. Because manufacturing breaks apart food structure before you eat it, Nestle says that ultra-processed foods have "an essentially pre-digested matrix." This makes nutrients easier to absorb. One review article proposes that this rapid absorption may suppress satiety hormones like GLP-1, which could contribute to overeating.
The supplement question complicates the picture. Nutrients in pills are not inherently less bioavailable than those in whole foods. Nestle notes that while some foods contain components that enhance absorption, others do not. The difference between food and supplement benefits may stem from the fact that foods contain multiple interacting nutrients whereas supplements deliver isolated compounds.
Industry should rethink how it fortifies food. Simply adding more nutrients does not guarantee absorption if the food matrix traps them. As food design evolves, companies must balance nutrient content with the physical structure that determines whether consumers can actually use those nutrients.