Vitamin D, B12 and Iron: What UK Women Should Know

Tiredness, low energy and difficulty concentrating can have many causes. Vitamin or mineral deficiency is one possibility, but symptoms alone cannot tell you which nutrient is involved.

Three nutrients that often raise questions for women in the UK are vitamin D, vitamin B12 and iron. Here is what the NHS advises, who may be at greater risk, and when a blood test is more useful than guessing.

Vitamin D

Vitamin D helps regulate calcium and phosphate and supports healthy bones, teeth and muscles. In the UK, sunlight is not strong enough for most people to make sufficient vitamin D between October and early March.

The NHS says adults and children over four should consider a daily supplement containing 10 micrograms (400 IU) during autumn and winter. Some people should consider 10 micrograms throughout the year, including those who are rarely outdoors, usually cover most of their skin outdoors, or have dark skin.

More is not automatically better. The NHS advises adults not to take more than 100 micrograms (4,000 IU) of vitamin D a day unless a clinician has recommended a different amount.

Read the full NHS vitamin D guidance.

Vitamin B12

Vitamin B12 helps keep the nervous system healthy and is involved in making red blood cells. A deficiency can cause extreme tiredness, low energy, pins and needles, a sore red tongue, mouth ulcers, muscle weakness and problems with memory or judgement.

These symptoms can have other causes. The NHS advises seeing a GP if you think you may have a B12 or folate deficiency, as diagnosis normally considers symptoms and a blood test.

Risk can be influenced by diet, absorption problems and some medicines. People following a vegan diet need reliable B12 from fortified foods or supplements, but diet is not the only possible cause.

Read the NHS guide to vitamin B12 and folate deficiency anaemia.

Iron

Iron deficiency anaemia can cause tiredness, lack of energy, shortness of breath, noticeable heartbeats, paler skin and headaches. Heavy periods and pregnancy are common causes, but blood loss from the stomach or bowel can also be involved.

Because the cause matters, iron is not a supplement to take blindly. If you think you may have iron deficiency anaemia, the NHS advises seeing a GP. A full blood count can help identify anaemia, and further checks may be needed to understand why it has developed.

If iron tablets are recommended, follow your clinician's advice. Iron supplements can cause side effects, and an overdose can be dangerous, particularly for young children.

Read the NHS iron deficiency anaemia guidance.

Should You Get Tested?

If symptoms persist, are severe, or affect daily life, speak to your GP rather than building a large supplement routine around a guess. A clinician can consider other explanations and decide whether blood tests are appropriate.

Seek medical advice promptly if you have symptoms such as chest pain, severe shortness of breath, fainting, unexplained bleeding, or rapidly worsening weakness.

Choosing Supplements Sensibly

• Check the amount per daily serving, not just the number printed on the front.
• Avoid combining several products that contain the same nutrient.
• Tell your pharmacist or clinician about medicines and other supplements you take.
• Follow the label and keep iron-containing products away from children.
• Use supplements to complement a varied, balanced diet, not replace it.

You can browse the SlimPulse Wellness Essentials collection for everyday vitamin and mineral products. Product pages include serving information and important warnings so you can compare options clearly.

This article is for general information and is not medical advice. Supplements are not intended to diagnose, treat or prevent disease. Speak to an appropriate healthcare professional if you have symptoms, take medicines, are pregnant or breastfeeding, or have been advised to restrict a nutrient.