The A-Z of vitamins and minerals

The A-Z of vitamins and minerals

( 26 January 2022 )

You can’t make vitamins or minerals in your body so you have to get them through diet and supplements - but what should you take and how much?

You only need small amounts of each supplement but you need to get them regularly

When it comes to vitamins and minerals, to be healthy you only need small amounts of each one but you need to get them regularly - ideally, every day. Deficiency diseases caused by inadequate intakes are rare, but not unknown, in the UK.

Among other things, vitamins help drive biological processes, they help absorb other essential nutrients such as minerals, they protect us from free radical damage, are involved in hormone production and help release energy from food.

Minerals are involved in a wide range of crucial functions throughout the body. They are a necessary part of over 600 enzymes, and are involved in every tissue. Some are needed in amounts of more than 100 mg a day, and these are called macro-minerals. Others are needed in much smaller quantities and these are called micro-minerals.

As we grow older, our body becomes less efficient at extracting nutrients from our food and absorbing them into the blood. It becomes more important to top up our reserves as time goes on.

Vitamins are either fat-soluble (A, D, E and K) or water-soluble (the Bs and C). Fat-soluble vitamins are stored in the body, so we need less, but they can also build up if we take too much. Water-soluble vitamins pass through easily, so we need daily top-ups. They are washed out of foods during preparation and cooking.

Minerals come from the soil and are absorbed by plants that we eat or are eaten by animals. The mineral content of food depends on where the plants grow and on what the animals are fed. Modern farming methods produce large amounts of food, but a lot of it does not have the nutrients of the equivalent organic crop or traditionally farmed version.

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Dietary vitamins and minerals

Fresh food, destined for the supermarket and stored in chilled containers, can travel hundreds or even thousands of miles and take several days to get to and from distribution centres.

Processing removes most of the nutrients. White flour, white rice and refined white sugar contain no vitamins at all and only 10% of the minerals they originally had. Manufacturers compensate by adding back some, but not all, of the nutrients removed or destroyed – the “fortified” foods. Cereals, margarines, bread, milk and orange juice have added vitamins B1, B2, B6, C and D and also minerals such as iron and calcium.

Many fruits and vegetables contain a lot less of some nutrients now compared to 40 years ago. For instance broccoli and pineapples now have less than half the calcium; the vitamin C in cauliflower is 40% less and 30% less in sweet peppers; watercress has 80% less iron, and some oranges have no vitamin C at all.

Specialist diets such as low-protein, low-carbohydrate, vegetarian and the like may mean you get less of the essential vitamins or minerals that you need. Research shows that most of us don’t come anywhere near to reaching the daily requirement of vitamins and minerals, and suffer from minor deficiency symptoms as a result.

Choosing vitamin and mineral supplements

Supplements are a simple way to compensate for the falling standards of our food and the modern lifestyle. True deficiency diseases are uncommon, but this does not mean we don’t need supplements to help our health.

Supplements can’t compensate for poor food choices, and they don’t replace missed meals. Buy the best supplement you can afford. Cheap does not necessarily mean poor quality, but may come with fewer ingredients. Check the label for ingredient range. Including herbs or cod liver oil is not necessarily a good plan as there needs to be reasonable amounts of such "extras" to have any positive effect.

Liquids or granules get into the blood stream quickly and efficiently. They are the best but also the most expensive. Tablets are less costly and less efficient at delivering the goods. Capsules are in between – a bit more expensive than tablets, but gentler on sensitive stomachs and release the nutrients quicker. Prolonged action or time-release tablets and capsules tend to pass through the gut too quickly to dissolve properly.

Consider the physical size of the tablet or capsule. Swallowing an enormous bomb of a capsule puts some people off. Make sure you are capable of getting it down.

How much?

The supplement label lists ingredients in grams (o), milligrams (mg), micrograms (mcg) or international unit (iu) then gives this amount as a percentage of the RDA - the Recommended Daily Allowance. This is a measure of the minimum amount of a vitamin or mineral the body needs to avoid a deficiency disease. Please remember it’s not the ideal, nor the optimum but the absolute minimum. The better supplements give you 100% of the RDA in each dose.

Side effects

Stop taking the supplement if you feel worse or have unexpected allergic reactions and side effects. Tell your doctor or health professional and ask for advice.

There is a wide safety margin between what most supplements deliver and what would be required to cause side effects or toxic reactions. As an example, it would take at least 100 times the RDA of vitamin D to cause a possible toxic effect. However, taking excessive amounts of vitamins is not recommended. Some vitamins can become toxic, such as vitamin A, or cause problems when taken in large quantities over a long duration, such as overdoing vitamin c causing kidney stones. Speak to your doctor if you plan on supplementing above the recommended dose.

Minerals can and do cause more toxicity problems than vitamins. But, a multi-mineral supplement is unlikely to cause such problems since they contain only small amounts of each mineral.

Single mineral supplements can be helpful if a particular mineral is extremely deficient, e.g. iron in anaemia. But if they are not needed they can give sudden excesses that unbalance other vitamin levels and could cause more problems than they solve.