Do healthy adults need to take vitamin/mineral supplements?

As featured on ITV’s “Save Money: Good Health” series 1, episode 4 with Sian Williams


During the TV experiment with Sian Williams and our lovely volunteers in Eastbourne on ITV’s “Save Money: Good Health” show, we looked at whether healthy older adults should spend money on vitamin/mineral supplements.

Half our volunteers were already taking a variety of supplements (with strong beliefs that they were needed for good health) whilst the other half did not take any (with equally strong beliefs that they were unnecessary).

What did the pre-experiment blood tests tell us?... Most vitamin/mineral status results were within the normal healthy ranges, however some supplementers had levels higher than the normal healthy ranges. For our short snap-shot study, we asked our original supplementers to stop their supplements and our original non-supplementers to start taking supplements.

After six weeks, we retested bloods again… and found that everyone’s results were in the normal healthy ranges. The pre-experiment high supplemented levels had returned to normal healthy ranges, as the supplements had stopped. As our volunteers were healthy and eating regularly, including a variety of foods, they did not need supplements; their diets were meeting their nutritional requirements.

Food First…

Vitamins, minerals and trace elements are essential nutrients that are needed by your body in small amounts. The amount needed will vary… depending on your age, gender and for women whether you are pregnant or breast-feeding.

We know that the body absorbs nutrients better in food form rather than in tablet/pill supplement form. It’s better to have a “little and often top up dose” achieved by eating a variety of different foods throughout the day, rather than an “all in one dose” capsule.

As some nutrients use the same processing pathways in the body, taking the full day intake in one capsule could lead to competition between the nutrients and therefore you may not absorb the full dose of nutrient.

More Is Not Better…

There are two types of vitamins: fat-soluble (vitamins A, D, E, K) and water-soluble (the B group vitamins, vitamin C).

The body stores fat-soluble vitamins (in our body fat) so excessively high intakes could be harmful, as the body has no pathway to get rid of the excess. Excessive vitamin A supplementation (>1500mcg/d over a prolonged period of time) could result in skin/eye problems, hair loss, bone density loss, joint pain, chronic headaches and liver damage. Pregnant women (or those planning a pregnancy) should not supplement with vitamin A, as high intakes are harmful to embryo and foetus. Excessive vitamin D supplementation (>45mcg/d over a prolonged period of time) could result in bone resorption and demineralisation and irreversible renal/cardiovascular toxicity.

Water-soluble vitamins are not stored in the body, so sources need to be included in your diet every day. Excesses of water-soluble vitamins are unlikely to cause harm, but you will be creating expensive wee!

There is no evidence to show that vitamin C supplements prevent colds in us mere mortals (there is some evidence to show benefits in cold prevention for elite endurance athletes), but be mindful that high doses in excess of 1000mg/day may cause gastrointestinal upset (stomach pain and diarrhoea)… I think I’d rather have a cold!

Double Dosing…

If you’re taking a range of supplements (e.g.: one for heart health, plus another for immune system boosting, plus another for eyesight, plus cod liver oil, plus a one-a-day multivitamin-mineral, etc.), there’s a real risk of double dosing… so read the labels to ensure that you’re not taking amounts in excess of the RNI (reference nutrient intake), particularly for the fat-soluble vitamins (A, D, E, K) that are stored in the body.

An excess of one nutrient can prevent your body absorbing enough of another nutrient; so taking excessive supplements could upset your body’s natural balance. Excessively high doses of folic acid (vitamin B9) could mask a vitamin B12 deficiency.

Most healthy adults who are not planning a pregnancy, pregnant or breast-feeding do not need to take any supplements… with one seasonal exception.

The Exception…

Current advice in the UK is that we should all consider taking a 10-microgram vitamin D supplement each day, during the autumn/winter months (October to March). This is because there’s not enough sunshine for us to generate vitamin D from the sunlight effect on our exposed skin, and it’s hard to get enough vitamin D from our diets.

Vitamin D is found naturally in oily fish and eggs, and may be added to some yoghurts and spreadable fats. However, you’d need to eat a salmon fillet every day to meet that 10-microgram intake… now I like salmon, but I don’t want to eat it EVERY day!

Buy an own brand supermarket or high street chemist vitamin D3 supplement, as they are cheaper than and absorbed just as effectively as the more expensive options.

Take your vitamin D3 supplement with your main meal, rather than your breakfast… as your main meal is likely to contain more fat which will aid better absorption of the vitamin D.

As they are excluding meat, fish and dairy (food sources of B12), vegans should consider taking a B12 supplement.

Interactions with medications…

Before taking any vitamin/mineral supplements, check that they won’t interact with any prescribed medications… as our GPs are very busy, your pharmacist or dietitian can advise.

Take Home Message…

Most healthy adults (who are not planning a pregnancy, are not pregnant or breastfeeding) can get all the vitamins, minerals and trace elements needed from a varied and balanced diet… without the need for additional supplements.

A balanced diet includes plenty of fruits, vegetables and starchy wholegrain carbohydrates, some protein and dairy, with a little added unsaturated fat.

If you’re concerned that your diet is not varied enough, or if you need nutritional advice about a specific medical condition, make an appointment to see a dietitian. See the link below for more information about my services.

Read what some of my dietitian colleagues have to say about supplements: