Ferritin
Ferritin is a protein that stores iron inside your cells, acting as your body's iron reserve. Unlike a standard blood count, which measures iron currently circulating in your blood, ferritin tells us how much iron your body actually has in storage- a more complete picture of your iron status. Iron is essential for making haemoglobin, the protein in red blood cells that carries oxygen from your lungs to the rest of your body. Ferritin levels can be influenced by diet, exercise, age, and your body's current demands.
Vitamin B12
A vitamin that your body cannot produce on its own, it must come entirely from diet or supplementation. It plays an important role in energy production, healthy nerve function, and the formation of red blood cells. B12 is found naturally in animal products including meat, fish, eggs, and dairy, and is also available in fortified foods. Levels can be affected by dietary choices, age, and how well your digestive system absorbs nutrients.
Folate
Folate plays a key role in producing and repairing DNA, forming healthy red blood cells, and supporting normal brain function. It works closely alongside vitamin B12, and the two are often measured together. Folate is found naturally in dark leafy greens, lentils, beans, and eggs. Levels can be influenced by diet, alcohol consumption, and how efficiently the body absorbs and uses nutrients. Folate is particularly important during pregnancy for healthy foetal development.
Iron
Iron is a mineral that helps your body produce haemoglobin - the protein in red blood cells that carries oxygen from your lungs to the rest of your body. Iron levels can fluctuate depending on diet, absorption, and your body’s needs.
Vitamin D
Vitamin D is produced naturally when sunlight hits the skin and also obtained in small amounts through food sources such as oily fish, eggs, and fortified products. Despite behaving more like a hormone, it's referred to as a vitamin and plays a role in calcium absorption, bone strength, immune function, and muscle health. In the UK, sunlight levels between October and April are generally not sufficient for the body to produce adequate vitamin D, making this one of the most commonly measured markers in routine health screening.
Magnesium
Magnesium is a mineral involved in energy production, muscle and nerve function, and blood sugar regulation to name a few. It is found in a wide range of foods including nuts, seeds, dark leafy greens, legumes, and wholegrains. The majority of the body's magnesium is stored in bones and cells rather than in the blood, which means blood levels alone don't always reflect total body stores. Magnesium levels can be influenced by diet, stress, exercise, and certain medications.
