Vitamins and Minerals: Frequently Asked Questions

Vitamins and minerals are both essential micronutrients, but they have different origins and functions. Vitamins are organic compounds made by plants or animals, and they can be broken down by heat, air, or acid. Minerals are inorganic substances that come from soil and water, and they retain their chemical structure throughout processing and digestion.

The body needs vitamins to support immune function, energy production, and tissue repair. Minerals help build bones, regulate muscle contractions, and maintain proper fluid balance. While both are vital for health, they work in different ways and require different sources in your diet.

Fat-soluble vitamins—A, D, E, and K—dissolve in dietary fats and are stored in body tissues, particularly the liver and fatty tissue. This means your body can draw on these reserves when needed, though excessive intake can lead to accumulation. These vitamins are best absorbed when eaten with dietary fats like olive oil or nuts.

Water-soluble vitamins, including the B complex (B1, B2, B3, B5, B6, B7, B9, B12) and vitamin C, dissolve in water and are not stored in the body. Excess amounts are excreted through urine, so you need a regular dietary supply. They are found in lean meats, whole grains, leafy greens, and citrus fruits.

The recommended dietary allowance (RDA) for vitamin D is 600 to 800 IU (15 to 20 micrograms) per day for adults aged 19 to 70 years. However, individual needs vary based on factors like sun exposure, skin tone, age, and geographic location. Some experts and health organisations recommend higher intakes for optimal levels.

The best sources of vitamin D include fatty fish (salmon, mackerel, sardines), egg yolks, and fortified milk products. Your skin also produces vitamin D when exposed to sunlight, though the amount depends on latitude, season, and time of day. A simple blood test can determine your current vitamin D levels.

Iron is a crucial mineral that carries oxygen throughout the body as part of haemoglobin in red blood cells. It also plays an important role in energy production and supports immune function. The body recycles iron efficiently, but some is lost through bleeding, sweat, and other means, making dietary intake essential.

There are two types of iron in food: haem iron (from animal sources like red meat, poultry, and fish) and non-haem iron (from plant sources like beans, lentils, and fortified cereals). Haem iron is better absorbed by the body, while non-haem iron absorption improves when paired with vitamin C-rich foods. Recommended daily intakes are 8 mg for adult men and 18 mg for women aged 19 to 50.

While calcium is famous for building and maintaining strong bones, it has many other vital functions. Calcium plays a key role in muscle contractions, nerve signal transmission, enzyme activation, and hormone regulation. The body maintains tight control of blood calcium levels, drawing from bone reserves when dietary intake is insufficient.

The recommended intake for adults is 1,000 mg per day, increasing to 1,200 mg for women over 50 and men over 70. Dairy products like milk, yoghurt, and cheese are rich sources, but calcium is also found in leafy greens, fortified plant-based milks, almonds, and tinned fish with bones. Adequate vitamin D, magnesium, and regular weight-bearing exercise enhance calcium absorption and utilisation.

Vitamin B12 is essential for red blood cell formation, nervous system function, and DNA synthesis. It supports energy metabolism and helps maintain healthy nerve cells and myelin—the protective coating around nerves. Unlike most other vitamins, B12 is not naturally found in plant foods, making dietary sources challenging for vegetarians and vegans.

Deficiency risk is highest among vegetarians, vegans, older adults with reduced stomach acid, people with digestive disorders, and those taking certain medications. Animal products like meat, fish, eggs, and dairy are the primary sources of B12. Vegetarians and vegans should seek fortified foods or B12 supplements, as the recommended daily intake is just 2.4 micrograms. Your healthcare provider can test B12 levels if you experience fatigue or neurological symptoms.

Vitamins C and E function as antioxidants, neutralising free radicals—unstable molecules created during normal metabolism and by environmental stressors. Free radicals can damage cell membranes, DNA, and proteins, contributing to cellular ageing and various health concerns. Antioxidant vitamins donate electrons to stabilise free radicals, reducing oxidative stress.

Vitamin C is found abundantly in citrus fruits, berries, bell peppers, and leafy greens, with a recommended daily intake of 75 to 90 mg. Vitamin E is present in nuts, seeds, vegetable oils, and whole grains, with an RDA of 15 mg daily. These vitamins work best as part of a broader antioxidant system that includes minerals like selenium and zinc, plus phytonutrients from colourful plant foods.

Magnesium is a mineral involved in over 300 enzymatic reactions in the body. It supports muscle and nerve function, maintains heart rhythm, regulates blood sugar levels, and aids in energy production and protein synthesis. Magnesium also plays a role in bone health and interacts closely with calcium and vitamin D for optimal skeletal function.

The recommended daily intake is 400 to 420 mg for adult men and 310 to 320 mg for adult women. Rich dietary sources include leafy green vegetables (spinach, kale), nuts and seeds (almonds, pumpkin seeds), whole grains, legumes, and fish. Some people find that adequate magnesium supports healthy sleep patterns and muscle relaxation, though individual responses vary. If you suspect deficiency, consult with a healthcare provider for personalised guidance.

Folate is the naturally occurring form of vitamin B9 found in foods, while folic acid is the synthetic version used in supplements and fortified foods. Both are essential for DNA synthesis, cell division, and healthy red blood cells. During pregnancy, adequate folate is particularly important as it supports proper foetal development and reduces the risk of certain neural tube defects.

Natural sources of folate include leafy greens, legumes, asparagus, Brussels sprouts, and avocados. The recommended daily intake for adults is 400 micrograms. Women of childbearing age who are planning pregnancy or could become pregnant should ensure adequate folate intake through diet and, if advised, supplemental folic acid. Some people metabolise folic acid differently due to genetic variations, making natural food sources particularly valuable.

Food is generally the preferred source of vitamins and minerals because it provides not only the nutrients themselves but also dietary fibre, phytonutrients, and other beneficial compounds that work synergistically. A varied, balanced diet rich in fruits, vegetables, whole grains, legumes, and lean proteins can meet the needs of most healthy individuals. Food also naturally regulates intake, making excessive consumption unlikely.

Supplements can be valuable for addressing specific deficiencies, supporting special diets (such as veganism), or providing extra support during certain life stages. However, some nutrients are better absorbed from food, and high-dose supplements can sometimes interfere with medications or create imbalances. Before starting any supplement regimen, it is wise to assess your current diet and consult with a healthcare provider or registered dietitian to identify any actual gaps and determine whether supplementation is appropriate.

Zinc is a trace mineral that plays a crucial role in immune function, supporting the development and activation of immune cells. It is also essential for wound healing, protein synthesis, DNA formation, and maintaining the sense of taste and smell. Zinc helps regulate inflammatory responses and supports the skin barrier, which is an important line of defence against pathogens.

The recommended daily intake is 11 mg for adult men and 8 mg for adult women. Excellent dietary sources include shellfish (oysters, crab), red meat, poultry, beans, nuts, seeds, and whole grains. Zinc absorption can be impaired by excessive fibre or phytates (found in some plant foods), so eating zinc-rich foods with adequate protein and some fat enhances uptake. If you suspect zinc deficiency, a healthcare provider can perform a test and recommend appropriate strategies.

A practical first step is to evaluate your diet honestly, noting the variety of foods you consume. A diverse diet including multiple servings of colourful fruits and vegetables, whole grains, lean proteins, and healthy fats typically provides adequate micronutrients for most people. Online dietary assessment tools or a food diary can help identify potential gaps, though professional guidance is more reliable.

A registered dietitian or nutritionist can review your individual diet and identify specific deficiencies based on your age, sex, health status, and lifestyle. Blood tests can measure levels of vitamins like B12, folate, vitamin D, and minerals like iron and zinc. If you experience persistent fatigue, poor wound healing, or other symptoms that might suggest micronutrient deficiency, discussing these concerns with your healthcare provider is advisable. Regular monitoring ensures you maintain optimal nutrient status.