Eating well but still deficient? Doctors explain why your body may not be absorbing nutrients properly and how to fix it

A balanced plate does not always guarantee a nourished body. Many people today eat home-cooked meals, include fruits and vegetables, and still feel tired, weak, or “off.” Blood tests often reveal low levels of iron, vitamin B12, or vitamin D despite a seemingly good diet.Doctors say this is more common than it appears. The issue is not always what goes on the plate, but what happens after the first bite. Digestion, absorption, and how the body uses nutrients all matter. When any of these steps falter, the body quietly slips into deficiency. Food must first be broken down before the body can use it. This process begins in the stomach and continues through the intestines.Dr Harshavardhan Rao B explains it clearly, “When we eat food, it's not just about what kind of food we eat, it is about the form in which we take the food, the quantity, as well as other medications that we might be on, which can affect the way the food is being handled by the gastrointestinal tract.”If stomach acid is low or digestive enzymes are weak, food does not break into absorbable parts. This condition, known as maldigestion, often leads to hidden deficiencies even when meals are adequate.When a key gene fails: What a new leukemia study is telling us about treatmentThe small intestine plays a crucial role. It contains tiny structures called villi that absorb nutrients into the bloodstream. When these are damaged, the body loses its ability to absorb essential vitamins and minerals.Dr Simna L notes that conditions like chronic inflammation or intestinal disorders reduce this surface area. As a result, nutrients like iron, calcium, and vitamin B12 fail to enter the bloodstream efficiently.Diseases such as celiac disease or inflammatory bowel conditions often go unnoticed for years. Meanwhile, the body continues to lose nutrients silently. Even with a balanced diet, the nutritional value of food has changed over time. Soil depletion and modern farming methods have reduced the mineral content in crops.A Indian Council of Agricultural Researchreport has highlighted concerns about declining micronutrients in soil, which directly affects food quality.At the same time, processed foods add calories without adding real nourishment. This creates a gap where people feel full but remain undernourished.Nutritional needs are not fixed. They change with stress, illness, age, and lifestyle.Someone dealing with chronic stress or long work hours may require higher levels of magnesium and B vitamins. Pregnant women, athletes, and people recovering from illness also need more nutrients than usual.A National Institute of Nutrition report outlines varying dietary requirements across age and lifestyle groups.So even a “normal” diet may fall short for someone with higher demands.Some daily habits interfere with nutrient uptake more than expected.High caffeine intake can reduce iron absorption. Excess alcohol affects vitamin storage and gut health. Long-term use of certain medicines can also interfere.Dr Simna L highlights that medications like antacids, antibiotics, and metformin can alter gut bacteria and reduce nutrient absorption over time.These factors often go unnoticed because they feel routine, not harmful. Nutrient deficiencies rarely appear overnight. They build slowly and show up in small ways.Fatigue that does not improve with rest. Hair thinning. Frequent infections. Poor focus. These are often dismissed as stress or lifestyle issues.Correcting deficiencies requires a deeper approach than simply eating more.Start with gut health. Include fermented foods like curd or buttermilk. Eat fiber-rich foods to support healthy bacteria.Pay attention to meal timing and combinations. For example, pairing vitamin C with iron-rich foods improves absorption.Reduce excess caffeine and alcohol. Review long-term medications with a doctor if deficiencies persist.Most importantly, do not self-medicate with supplements. Blood tests and professional guidance are essential to target the right deficiency. Medical experts consultedThis article includes expert inputs shared with TOI Health by:Dr Simna L, Consultant, Department of Gastroenterology, KIMSHEALTH, Thiruvananthapuram.Dr Harshavardhan Rao B, HOD & Consultant, Department of Medical Gastroenterology, Ramaiah Memorial Hospital, Bengaluru.Inputs were used to explain why nutrient deficiencies can occur despite a healthy diet and how proper diagnosis and targeted interventions can help improve absorption.