Metabolism

HbA1c

Hemoglobin A1c (HbA1c) measures average blood sugar levels over the past three months, making it a key indicator of diabetes risk and glucose control.

What it is

Hemoglobin A1c (HbA1c) measures average blood sugar levels over the past three months, making it a key indicator of diabetes risk and glucose control. High HbA1c suggests poor blood sugar regulation, increasing the risk of diabetes, nerve damage, and cardiovascular disease. Low HbA1c, though less common, may indicate insulin overproduction or hypoglycemia. Monitoring HbA1c helps track metabolic health, guiding lifestyle adjustments to prevent long-term complications related to blood sugar imbalances.

What affects your levels

High HbA1c is caused by chronic high blood sugar due to poor diet, insulin resistance, stress, or lack of physical activity. Metabolic syndrome, obesity, and genetic factors also contribute. Low HbA1c can result from excessive insulin production, fasting, malnutrition, or adrenal insufficiency. Certain medications and medical conditions affecting blood sugar regulation may influence levels. Identifying these factors helps optimize long-term glucose control.

Signs and symptoms

High HbA1c may cause fatigue, excessive thirst, frequent urination, blurred vision, and slow wound healing. If left unchecked, it increases the risk of nerve damage, kidney disease, and cardiovascular complications. Low HbA1c may lead to dizziness, confusion, or fainting due to unstable blood sugar. Regular glucose monitoring, exercise, and a balanced diet help maintain optimal HbA1c levels, reducing the risk of metabolic disorders and long-term health complications.

Foods that help

Low-glycemic foods like whole grains, lentils, and non-starchy vegetables help stabilize blood sugar. Healthy fats from nuts, seeds, and avocados slow glucose absorption. Lean proteins, including fish, eggs, and legumes, prevent blood sugar spikes. Fiber-rich foods such as berries, flaxseeds, and chia seeds improve insulin sensitivity. Maintaining a nutrient-dense diet focused on whole, unprocessed foods supports better blood sugar management and reduces diabetes risk.

Foods to limit

Refined carbohydrates, sugary drinks, and high-sugar snacks can raise HbA1c levels, worsening insulin resistance. Processed foods, trans fats, and excessive alcohol contribute to blood sugar fluctuations. Reducing white bread, pastries, and ultra-processed snacks while focusing on balanced meals with fiber and protein helps maintain stable blood sugar. Limiting hidden sugars in sauces and packaged foods also supports healthy glucose metabolism and HbA1c control.

Educational information only — not a diagnosis. Every Pheno result is interpreted in context and reviewed by a physician.

See all 119 markers we test →