Constantly Tired? Doctors Warn of Nutrient Deficiency
Chronic fatigue can be a sign of vitamin and mineral deficiency, with doctors particularly highlighting iron and vitamin B12, and recommending a blood test before taking supplements.
Chronic fatigue can be a sign of vitamin and mineral deficiency, with doctors particularly highlighting iron and vitamin B12, and recommending a blood test before taking supplements.
Many attribute persistent exhaustion to a fast-paced lifestyle or stress, but medical experts warn that chronic fatigue can hide a deficiency in key vitamins and minerals. For a large number of people, daily lack of energy becomes so common that they stop perceiving it as a health signal. However, doctors emphasize that fatigue lasting for days and weeks is not a condition that should be accepted as normal.
There are, of course, life periods when exhaustion is expected, for example, in the first months after a child is born or during exam seasons. However, when waking up without energy in the morning turns into a long-term pattern, it may signal a deeper problem in the body.
Dr. Michael Billington, Chief Scientific Officer at PrimaryMD, notes that assessing such complaints begins with ruling out more severe conditions. As he explained, there are clear signs that require urgent medical attention.
"In people who have unexplained weight loss, fever, night sweats, shortness of breath, chest pain, unusual bleeding, including heavy menstrual periods or blood in the stool, as well as enlarged lymph nodes, it is necessary to undergo detailed examinations as soon as possible," he explains.
The good news is that in most situations, exhaustion does not have such a serious cause. Three general practitioners, who spoke with Parade magazine, point out that very often the underlying issue is indeed a deficiency of certain nutrients.
Dr. Alexander Acosta, a general practitioner at SonderCare Health Center, emphasizes that fatigue can accompany a wide range of conditions, which is why he never draws conclusions before a thorough conversation with the patient. He always first checks sleep patterns, as lack of sleep is one of the leading reasons for exhaustion. Then he analyzes dietary habits and stress levels, which also strongly affect vitality.
All agree that a laboratory blood test, which includes basic biochemical parameters and levels of vitamins and minerals, is the most reliable way to uncover the true cause. The experience of these doctors shows that patients very often are found to have iron or vitamin B12 deficiency. Dr. Alexa Mieses Malchuk, a family medicine specialist at Geisinger Health System, notes that in the United States, the most common deficiencies are iron, vitamin D, vitamin B12, folate, and magnesium.
She also notes that vegetarians and vegans are more prone to iron and B12 deficiency, while menstruating women are at increased risk of low iron levels. Dr. Acosta adds that it is not uncommon for someone to have low levels of iron, B12, and vitamin D simultaneously, which together can significantly contribute to chronic exhaustion.
This vitamin has an indispensable function in the production of red blood cells, which deliver oxygen to all tissues.
"If there is not enough vitamin B12, the body gets less oxygen, which can cause fatigue, difficulty concentrating, and muscle weakness. This vitamin is also important for preserving the protective sheath of nerves, so a long-term deficiency can lead to more serious problems with the nervous system, not just fatigue," explains Dr. Acosta.
A 2022 scientific paper confirmed that even B12 levels at the lower threshold of normal can be associated with feelings of exhaustion and a drop in energy. A similar pattern applies to iron, numerous studies confirm that its deficiency not only causes fatigue but also impairs concentration.
Once test results confirm a deficiency, the next step is to increase intake through food. Dr. Billington explains that vitamin B12 is produced exclusively by bacteria, so it is almost entirely found in animal-derived foods. To replenish iron and B12, he recommends more regular consumption of eggs, shellfish such as mussels and oysters, as well as fatty fish, salmon, mackerel, and sardines. Beef is also a good source of these nutrients.
For vegetarians and vegans, he advises fortified products, such as certain breakfast cereals, soy or almond plant-based drinks, meat substitutes, and nutritional yeast with added vitamins. At the same time, he warns that fermented foods, tempeh, miso, kimchi, sauerkraut, do not contain sufficient amounts of B12 to significantly improve status. The same applies to spirulina, despite frequent marketing claims. For those on a strictly plant-based diet, he advises consuming more dark leafy greens, beans, lentils, and tomatoes to increase iron intake.
Dr. Acosta notes that in cases of severe deficiency, diet alone often cannot compensate for the deficit.
"In people who already have very low levels of a particular nutrient, food alone is often not enough. In such cases, supplements can be a more practical solution," he says.
Dr. Billington adds that some people simply cannot properly absorb B12, regardless of the amount they consume through food. This especially applies to patients who have undergone stomach surgery or suffer from autoimmune diseases. All doctors share the view that vegetarians and vegans with confirmed deficiency should consider iron and B12 supplementation, as it is difficult to get enough without animal products.
Dr. Billington also warns that long-term use of certain medications, metformin, proton pump inhibitors, H2 blockers, can increase the risk of B12 deficiency. Colchicine, cholestyramine, and oral contraceptives can have a similar effect. People using GLP-1 medications for weight loss or diabetes treatment are also at increased risk due to reduced appetite.
According to Dr. Acosta, people over 50 often have impaired B12 absorption due to reduced stomach acid secretion. In such circumstances, sublingual tablets or injections may be more effective than standard oral preparations.
Dr. Malchuk reminds that iron and B12 supplements are not subject to the same strict regulations as medications, so she advises choosing products that have undergone independent quality testing. This reduces the possibility of incorrect dosage or the presence of undesirable substances.
Dr. Billington is clear, people without a confirmed deficiency will not get more energy just because they started taking supplements.
"Supplements only make sense in people who have actually been confirmed to have a deficiency," he says.
The doctors conclude that daily fatigue should not be ignored. Dr. Acosta emphasizes that many people, for months or even years, accept exhaustion as a normal state, attributing it to stress or age, without thinking about checking their vitamin and mineral levels. That is why it is crucial to first do a blood test, because other conditions can hide behind fatigue, and self-initiated supplement use can temporarily mask the real problem.
"Many people, for months or even years, accept fatigue as something normal. They think it is stress or aging and do not even think about checking their vitamin and mineral levels. That is why it is important to first do blood tests, because other health conditions can be behind fatigue, and self-supplementation can temporarily hide the real problem," concludes Dr. Acosta.
Sometimes, a simple blood test is the first step toward discovering why you feel without energy every day.
