A young patient of mine, a busy professional, decided to clean up her life so that she could keep all her health parameters in check. She started eating better, ramped up workouts, swapped processed foods for whole meals and increased her sleep time. But with these changes she began to feel even worse. Her energy plummeted, her skin flared up, her digestion went haywire. Why was her body spinning out of control? I carefully listened to her habits, one by one. Then something struck me. Since she was a busy professional, she would prepare meals in bulk, storing leftovers in the fridge. She would then reheat and have them as per convenience. There lay her problem. Refrigerated food was triggering her intolerance to histamine, which is a natural substance made by the body and plays a big role in immune defence, digestion and nerve communication. What is histamine? Histamine is a chemical compound that acts as a signalling molecule in the body, playing a crucial role in various physiological processes, including inflammation, immune responses and regulating sleep-wake cycles. In the right amount, it’s helpful in fighting off infection. But when levels rise too high, or the body struggles to clear it, histamine becomes our foe. The immune system overreacts to harmless substances, not just bugs. Common triggers include peanuts, pollen, animal dander and mostly food. What are the symptoms? Other than the symptoms mentioned above, what I see are leaky vessels causing the eyes to tear up, congestion in the nose, hives and swelling anywhere. Histamine works with nerves to produce itching. In food allergies, it can cause vomitting and diarrhoea. And it constricts muscles in the lungs, making it harder to breathe. Most worrisome is when histamine causes anaphylaxis, a severe reaction to an allergen or any substance the body perceives as enemy, that is potentially fatal. Here swollen airways can prevent breathing, and a rapid drop in blood pressure could starve organs of vital blood. Histamine intolerance often goes unnoticed because its symptoms mirror many everyday health complaints. Some may develop facial flushing, blocked sinuses, dizziness or a quickened pulse after meals. Others experience recurring headaches or digestive discomfort, such as bloating or abdominal cramps, without an obvious cause. Some may also experience irregular menstrual cycles or feel unusually sensitive to temperature changes — signs that often slip under the radar. Foods that are enemies of histamine Ironically, many foods considered healthy can add to the body’s histamine burden. Fermented foods, including yogurt, kombucha and pickles are often added to diets in the name of gut health. But these same foods, along with aged cheeses, spinach, avocados, tomatoes, and certain fish, are known to raise histamine levels. Leftovers stored in the fridge for too long or reheated multiple times can also be culprits. You may also react when you let foods — especially meats — sit out too long. Canned and processed foods may also trigger histamine intolerance. Add vigorous workouts — especially in the heat — and the body may find itself unable to cope. It all begins in the gut Diamine oxidase (DAO) is an enzyme which helps the body break down histamine, with much of that work happening in the digestive tract. Now this activity drops when the number of certain bacteria in the gut, which produce histamine as a byproduct of their metabolism, increases. A kind of bacteria found in patients of Irritable Bowel Syndrome (IBS), have been found as a significant histamine producer. What about managing the condition? Managing histamine intolerance isn’t about fear or drastic restriction. It begins with observation. A food and symptom journal can be a helpful tool in understanding what sets off a response. For some, a temporary low-histamine diet helps quiet symptoms and offers clarity. Working with a doctor can make a crucial difference. Sometimes, doctors may suggest specific enzymes or supplements, but only when truly needed. The encouraging part is that histamine intolerance doesn’t always last. With the right care and by addressing what’s causing the imbalance, the body often regains its ability to tolerate foods that once caused trouble. When the body responds unpredictably during a wellness push, it’s not necessarily a sign of failure. Sometimes, it’s a clue. The solution isn’t to stop, but to listen — and adjust with care. (The author is Associate Clinical Director and Head of Department, General Medicine, CARE Hospitals, Banjara Hills, Hyderabad)
