When we consume food, our attention typically centers on what is presented on our plate. We look forward to the flavor, the texture, and the aroma of certain foods or a beloved dish. Our food choices are also influenced by their nutritional value.
Nevertheless, there is a critical process that takes place between consumption and nutrient absorption, which supplies us with the necessary nutrients we require to support our overall health and wellbeing.
In this article, we explore the basics of digestion, which includes the process of nutrient absorption, as well as factors that may influence how nutrients are absorbed.
What Is Nutrient Absorption?
Nutrient absorption is a complex process that is essential for our health because it allows the body to utilize essential vitamins, minerals, and other nutrients from the food we eat. In fact, the extent to which a nutrient can be absorbed is known as bioavailability. Bioavailability is an important factor in this process, because it helps us to understand and determine how much your body will absorb a nutrient or nutrients, to help support cellular processes.1,2
Let’s look ahead at the digestion and absorption processes to find out more about what factors may affect nutrient absorption.
Digestion and Absorption — Oh My!
When we consume food, we rarely pause to think about the digestion process, unless, of course, we experience some gastrointestinal discomfort or have particular dietary issues. And thankfully, our bodies manage the digestion process for us.
So let’s start with simply defining digestion, which is the process of breaking down food into smaller molecules that the body can use. This intricate process consists of two primary components: mechanical digestion, which involves physical action or movements like chewing and churning of food, and chemical digestion, where enzymes facilitate the breakdown of food substances. These two mechanisms operate together to ensure that essential nutrients are rendered accessible for absorption and utilization by the body.1,2
Here is a snapshot of the digestion process, starting with both the mechanical and chemical breakdown of food.1,2,3
Mouth. Chewing starts the process of physically breaking down the food into smaller pieces, mixes with saliva, and forms a bolus. Enzymes in your saliva also begin digesting carbohydrates. Initiating a swallow helps to move the bolus down the esophagus into the stomach through wave-like movement of the muscles that line your GI tract. This is called peristalsis.4
Stomach. Stomach acid and digestive enzymes break down proteins and churn food into a paste called chyme. Peristalsis continues to move this into the intestines now.
Small Intestine. There’s a lot going on here in the small intestine. This is the starting point for nutrient absorption. Tiny finger-like structures called villi and microvilli line the intestinal wall. These provide a good surface area so nutrients can be absorbed efficiently.
Large Intestine. Water, electrolytes, like sodium and potassium, and a few vitamins made by gut bacteria are absorbed here. Anything that is not needed by our body is excreted as waste.
Nutrient Interactions 101
Are you aware that specific nutrients can work well together to enhance absorption, while others may actually hinder nutrient absorption if paired together? The way in which you mix foods or supplements can greatly influence how efficiently your body assimilates vital nutrients. Here are some examples that illustrate both the synergistic mechanisms of nutrients as well as those that may interfere with absorption.
Nutrients That Enhance Absorption
Vitamin D and calcium. Vitamin D boosts the absorption of calcium in your intestines. Without enough vitamin D, your body may not use calcium efficiently, even if you’re getting enough in your diet.5
Vitamin C and non-heme iron. Vitamin C helps your body absorb non-heme iron (the type of iron found in plant foods like beans, spinach, and tofu). Adding citrus fruits or vegetables like tomatoes or bell peppers to iron-rich meals can enhance iron absorption6.
Fat-soluble vitamins and healthy fats. Vitamins A, D, E, and K are fat-soluble, meaning they require dietary fat for optimal absorption. Pairing vegetables with some olive oil may support nutrient absorption of these vitamins.
Magnesium and vitamin D. Magnesium helps activate vitamin D in the body, supporting its role in calcium regulation and bone health.7
Nutrients That Can Interfere With Absorption
Calcium and iron. These two minerals can compete for absorption in the small intestine, especially in supplement form. To get the most out of both, take them at different times of day.
Zinc and copper. Too much zinc can reduce copper absorption and cause a deficiency over time. Look for balanced supplements or talk to your doctor.
Fiber and some dietary minerals. While fiber supports gut health, large amounts (particularly from bran or fiber supplements) may bind minerals like iron, magnesium, and zinc, making them harder to absorb.2
Tannins and iron. You probably know that some beverages like tea, coffee, and some red wines contain tannins, which are naturally occurring phenolic compounds — and that’s a good thing. However, tannins can block the absorption of non-heme iron, making iron less bioavailable. Try drinking those beverages between meals rather than with iron-rich foods.8
Takeaway
Maintaining a healthy diet is just one aspect of overall wellness. It is equally important to ensure that your body effectively absorbs the nutrients from the foods you eat. If you have any questions, it is advisable to consult with your healthcare provider. They can help address any questions or concerns about your digestion and overall health. They can also provide a referral to a Registered Dietitian, who can collaborate with both you and your healthcare professional to facilitate your health journey.
Disclaimer: This blog contains promotional content about our products. The information provided in this blog is for educational and informational purposes only and should not be construed as medical advice. While the nutritional information and health tips shared here are based on published studies and expert insights, they should not replace advice and treatment from a healthcare professional. Always consult a qualified healthcare provider with any questions you may have regarding a medical condition or health objectives.
References
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). “Your Digestive System & How It Works.” National Institutes of Health, https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works . Accessed 25 June 2025
- Sterling, Lydia. “Factors Affecting Nutrient Absorption: Dietary, Genetic, and Environmental Influences on Optimal Nutrition.” Archives in Food and Nutrition, vol. 7, no. 4, 2024, https://www.alliedacademies.org/articles/factors-affecting-nutrient-absorption-dietary-genetic-and-environmental-influences-on-optimal-nutrition-30095.html. Accessed 25 June 2025.
- Wakim, Suzanne, and Mandeep Grewal. “18.3: Digestion and Absorption.” Biology LibreTexts, bio.libretexts.org/Bookshelves/Human_Biology/Human_Biology_(Wakim_and_Grewal)/18%3A_Digestive_System/18.3%3A_Digestion_and_Absorption. https://bio.libretexts.org/Bookshelves/Human_Biology/Human_Biology_(Wakim_and_Grewal)/18%3A_Digestive_System/18.3%3A_Digestion_and_Absorption. Accessed 25 June 2025.
- Cleveland Clinic. “Peristalsis: Definition, Function & Problems.” Cleveland Clinic, 28 Apr. 2022, my.clevelandclinic.org/health/body/22892-peristalsis. https://my.clevelandclinic.org/health/body/22892-peristalsis. Accessed 25 June 2025.
- National Institutes of Health Office of Dietary Supplements. “Calcium: Fact Sheet for Health Professionals.” NIH ODS, https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/. Accessed 25 June 2025.
- Office of Dietary Supplements. “Iron.” National Institutes of Health, https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/. Accessed 25 June 2025.
- Uwitonze, Anne Marie, and Mohammed S. Razzaque. “Role of Magnesium in Vitamin D Activation and Function.” The Journal of the American Osteopathic Association, vol. 118, no. 3, 1 Mar. 2018, p. 181, https://doi.org/10.7556/jaoa.2018.037. https://pubmed.ncbi.nlm.nih.gov/29480918/ . Accessed 25 June 2025.
- Ojo, Moses Ayodele. “Tannins in Foods: Nutritional Implications and Processing Effects of Hydrothermal Techniques on Underutilized Hard-to-Cook Legume Seeds-A Review.” Preventive nutrition and food science vol. 27,1 (2022): 14-19. doi:10.3746/pnf.2022.27.1.14. https://pmc.ncbi.nlm.nih.gov/articles/PMC9007702/
