What factors affect absorption?
• Interaction of Nutrients: Vitamin C increases iron absorption, while tannins in tea/coffee decrease iron absorption.
• Physical and Chemical Structure of the Food: Cooking methods and degree of grinding affect absorption. For example, protein absorption from boiled eggs is higher than from raw eggs.
• Gut Health: Celiac disease, Crohn's disease, ulcerative colitis, irritable bowel syndrome (IBS), leaky gut syndrome, and the balance of the gut flora (microbiota) directly affect absorption.
• Age: As we age, the production of digestive enzymes and stomach acid may decrease, which can negatively affect absorption.
• Individual Metabolism and Genetic Factors: Each individual's digestive and absorption capacity may vary.
• Meal Size: Very large portions may slightly reduce absorption efficiency.
Conclusion
According to research, to give a general estimate, more than 90-95% of an average nutrient (in terms of macronutrients) is absorbed in a healthy individual. However, it should be noted that this does not mean that "90% of the food consumed is absorbed by mass." A significant portion of the food consumed (fiber, water, indigestible components) is not absorbed and is excreted through stool. This process is vital for the body to obtain the energy and building blocks it needs while removing the indigestible parts.
Absorption rates should be examined in detail when dealing with a specific nutrient or health condition.
It is absorbed at a high rate of 98-99%.
• Absorbable carbohydrates, such as starches and sugars, are almost completely broken down and absorbed.
Carbohydrates
Proteins: 92-98% are absorbed.
• Once proteins are broken down into amino acids and small peptides, they are absorbed very efficiently in the small intestine.
• Absorption rate may vary slightly depending on the source of the protein (animal vs. plant-based) and the cooking method.
Proteins
In the digestive system, approximately 90-95% of the energy and nutrients from ingested food are absorbed.
However, this ratio varies greatly depending on the type of food, the health of the digestive system, the individual's metabolism, and many other factors.
Let's examine this in detail:
Overall Absorption Rates (Based on Macronutrients)
Absorption rates vary greatly. For example: • Fat-soluble vitamins (A, D, E, K): Around 70-90% can be absorbed because it occurs along with fat absorption. • Water-soluble vitamins (B group, C): Absorption rates are variable. For example, vitamin B12 requires a special carrier protein.
Vitamins
Their absorption is largely influenced by their interactions with each other and with other nutrients.
• Calcium: Approximately 25-30% is absorbed.
• Iron: Hem iron (animal source) is absorbed at a rate of 15-35%, while non-heme iron (plant source) is absorbed at a rate of 2-20%. Consuming it with vitamin C increases absorption.
• Zinc: Approximately 15-35% is absorbed.