Symptoms such as constant exhaustion, mental fog, and occasional tingling in the hands or feet are often dismissed as stress or simply getting older. However, these signs can point to underlying nutrient deficiencies, including vitamin B12, iron, and folate (vitamin B9). These nutrients play a crucial role in brain health, nerve function, and carrying oxygen around the body.Lack Of This Vitamin Deficiency Can Lead To ExhaustionWhen ignored, these symptoms can quietly worsen. They are often your body’s way of signalling problems with nerve health, oxygen supply, and overall energy levels, which can make even simple daily activities feel harder than they should. According to the Daily Mail, around 15 per cent of people aged 15 to 29, and about 20 per cent of those over 60, have vitamin levels that are not low enough to be classed as a deficiency but are still insufficient to cause noticeable symptoms.What Is Vitamin B12?Vitamin B12 allows the brain to transmit signals properly and helps protect the nerves. When levels drop, people may notice memory lapses, poor concentration, or balance problems. In older adults, this can raise the risk of falls. Some individuals sit in a borderline range, where levels are not low enough to be diagnosed as deficient but are still enough to cause symptoms.Certain people face a higher risk. Vegans are vulnerable because B12 is found mainly in animal products such as milk, meat, eggs, and fish. As people age, their ability to absorb B12 often declines due to lower stomach acid. Long-term use of acid-suppressing drugs, including proton pump inhibitors, can further reduce absorption, meaning supplements or injections may be needed.Iron Is Important Iron is essential for making haemoglobin, the substance in red blood cells that carries oxygen through the body. When iron levels are low, oxygen transport is reduced, and tissues with high energy needs, such as the brain and nerves, are affected first. This can lead to dizziness, weakness, and cold hands and feet.Iron works closely with folate and vitamin B12 to support red blood cell production. A shortage of any one of these nutrients can limit how well oxygen is delivered, making tasks like climbing stairs or keeping warm feel far more draining. In the UK, iron deficiency affects around 3 per cent of men and 8 per cent of women.FolateFolate is important for cell development and the production of red blood cells. Levels have been falling in recent years, with teenagers showing particularly high rates of deficiency. Women of reproductive age are especially at risk, as low folate levels early in pregnancy can raise the chance of neural tube defects.To address this, the UK government plans to add folic acid to white flour by the end of 2026, covering common foods such as bread and baked goods. Folate can also be found naturally in leafy green vegetables, beans, and citrus fruits.Blood tests are the most reliable way to confirm whether a deficiency is present. Iron levels can be difficult to correct through diet alone because the body tightly controls absorption, so supplements are often needed, particularly for people with heavy periods or digestive problems. Folate deficiency is usually easier to correct with dietary changes or supplements.Boosting vitamin B12 depends on the cause. Vegans often need supplements, while older adults or people taking acid-reducing medication long term may need higher doses or injections.Leaving deficiencies untreated can allow symptoms to linger and, in some cases, lead to lasting nerve damage. The positive news is that once a deficiency is identified and treated, many people begin to feel better within weeks. Energy, focus, and overall well-being often return quickly, bringing noticeable improvements to everyday life.