What Controls Metabolism?

• There are many factors that control metabolism.
• Each person’s metabolism is influenced by their genes, age, illness, medications and stress.
• Metabolism is the process by which our body converts the food and drink we consume into energy.
• Metabolism is controlled by our endocrine system, which produces and releases hormones.
• Imbalances in hypothalamic and pancreatic regulation of metabolism can lead to increased risk for metabolic disorders such as diabetes type 2.

It’s tempting to dismiss or blame metabolism as being about fast or slow, weight gain or loss. The truth is metabolism lies at the core of our body’s healthy functioning. Our bodies need metabolic processes to sustain life. Metabolism keeps us alive.

What is metabolism?

Metabolism is the internal process by which our body converts the food and drink we consume into energy. This energy is stored and released as needed for use in cells. Metabolism is at the root of all work in our cells and enables other essential chemical reactions to happen. Without these chemical processes we can’t breathe, circulate blood, build and repair cells and everything else our bodies require to survive.

So how does metabolism work? 

Metabolism is a balancing act between anabolism and catabolism. Our digestive enzymes turn carbohydrates into simple sugars like glucose, fats into fatty acids, and proteins into amino acids. These nutrients are absorbed in the blood and carried through our body to cells, where they are metabolized in two finely balanced chemical processes. Catabolism is the breakdown of nutrients and the release of energy. Anabolism uses that energy for bodily processes, growth and maintenance. 

What controls metabolism? 

The whole process of metabolism is controlled by our endocrine system, a network of glands all over the body which produce and release hormones. Those hormones in turn manage most functions in our bodies, including our metabolism, reproduction, growth and development, energy levels, emotions, response to injury, stress, sexual function, and sleep.

It’s a finely tuned process. Sometimes glands produce too much or not enough of a hormone. This can lead to imbalance and health problems such as weight gain, high blood pressure, changes in mood and sleep. Many external and internal factors affect how our bodies create and release hormones. Age, medications, illness and stress can all cause hormonal imbalance. 

The hormones that regulate your metabolism, your body’s ability to break down food and create energy, are produced by your thyroid, adrenal gland, hypothalamus and pancreas. Each plays a different and complementary role in controlling and influencing your body’s metabolic health.

How is the thyroid important for metabolism?

The Thyroid is vital in regulating the metabolic processes needed for healthy growth and development, as well as regulating the body’s metabolism. The thyroid uses iodine from the food you consume to produce its two primary hormones thyroxine (T4) and triiodothyronine (T3). These are stored and secreted as needed. The link between a healthy functioning thyroid, body weight and energy expenditure is well established.

Hypothyroidism (underactive thyroid) is when the thyroid gland doesn’t release enough hormones and metabolism slows down, affecting the entire body. This is often linked with autoimmune condition Hashimoto’s disease which is an inflammation of the thyroid gland. Symptoms of hyperthyroidism in women include unusual weight gain, muscle weakness and pain, fatigue, thinning hair and constipation.

In hyperthyroidism (overactive thyroid) overproduction of hormones can lead to accelerated metabolism causing unintentional weight loss, changes in menstrual patterns, more frequent bowel movements, sweating, tachycardia (rapid heartbeat), arrhythmia (irregular heartbeat), anxiety, hair thinning and can cause Grave’s disease.

How does the adrenal gland regulate metabolism?

Adrenal or suprarenal glands sit on top of your kidneys. Adrenals produce and release cortisol (steroid) hormones and epinephrine (adrenaline) that help regulate your metabolism, immune system, blood pressure and maintain your response to stress. 

Among other important functions, cortisol helps control the body’s use of fats, proteins and carbohydrates, regulates blood pressure and increases blood sugar. Disorders related to the adrenal glands not functioning properly include Cushing syndrome, Addison’s disease, Congenital adrenal hyperplasia and Conn’s syndrome. 

Hypothalamic regulation of metabolism

Studies are increasingly demonstrating that the hypothalamus is critical in coordinating metabolism and central to energy balance. The hypothalamus region of the brain regulates metabolism by controlling food intake, energy storage and release “through the ability of neurons to sense, integrate, and respond to numerous metabolic signals.”

How does the pancreas control metabolism?

The two glands in the pancreas are crucial to metabolism regulation, playing a key role in nutrient digestion and blood sugar control. The endocrine gland makes hormones that manage blood sugar levels; insulin lowers blood sugar and glucagon raises blood sugar levels. The exocrine gland secretes digestive enzymes crucial for breaking down carbohydrates, fats, proteins and acids in the duodenum.  

Imbalances in both hypothalamic and pancreatic regulation of metabolism can lead to increased risk for metabolic disorders such as diabetes type 2.

What are inherited metabolic disorders?

Inherited metabolic disorders are rare genetic conditions that cause a person’s metabolism to not work properly from birth. Typically caused by a family history of inherited genetic disorders or by gene changes causing a deficiency in hormones or enzymes needed for the digestion process. These deficiencies cause abnormal chemical reactions that keep the body’s metabolism from working properly, with the processes that convert food into energy and remove waste and toxins from the body compromised. Doctors have identified many different and rare disorders, each of which has varying symptoms and treatment options. 

Why is it important to understand metabolism?

Knowing how metabolism is controlled by your body’s endocrine system, and that each person’s metabolism is also influenced by their genes, age, illness, medications and stress, can help you have a better understanding of your body. 

Whenever you have weight changes (gain or loss) you can’t explain you should talk to your doctor, especially if accompanied by other possible symptoms of metabolism imbalance. 

Your doctor will run tests and advise you of treatment options and medications are available to regulate hormones. And a healthy lifestyle – staying active, eating a healthy diet and getting lots of sleep – will always have a positive impact on weight and energy levels.

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If you are concerned you may have issues with your metabolism, get tested in the privacy of your own home by ordering a blood test here.

Nabta is reshaping women’s healthcare. We support women with their personal health journeys, from everyday wellbeing to the uniquely female experiences of fertility, pregnancy, and menopause. You can track your menstrual cycle and get personalised support by using the Nabta app.

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