Do we need Nutritional Supplements?

Updated: Aug 21, 2019

For most of us, eating a balanced and healthy diet which is rich in wholegrains, fruits and vegetables, lean protein and healthy fats will provide us with all the vitamins and minerals that our bodies require. That said, there are some instances when your doctor or dietitian may recommend a nutritional supplement. Some of these situations are discussed below.

The One Supplement We Should all be Taking:

It’s vitamin D! Vitamin D is needed in the diet to help our bodies to regulate the amount of calcium and phosphate in our bone, teeth and muscles. You can get vitamin D through three ways: the food we eat, the action of sunlight exposure and supplements. Our main source of vitamin D in the UK is from the action of sunlight on our skin.

Back in 2016 the UK Scientific Advisory Committee on Nutrition (SACN) reviewed the evidence on vitamin D and health to see if the UK dietary recommendations from 1991 were still appropriate. One of their new recommendations was that everyone (excluding babies receiving more than 500ml infant formula per day) should consume a daily 10 microgram vitamin D supplement, particularly during autumn and winter months. This is to protect our bone and muscle health.

People who are at higher risk of vitamin D deficiency include those with limited exposure to sunlight or people who cover their skin when outside. These people are advised to take a vitamin D supplement every day of the year.

Whilst you can get vitamin D through the diet by eating foods which are rich in vitamin D such as oily fish (i.e. salmon), eggs and fortified spreads, it’s difficult to get enough vitamin D from food alone. Vitamin D supplements are widely available from supermarkets and pharmacies. You don’t need to buy an expensive supplement, so long as the supplement contains 10 micrograms of vitamin D.

Supplements during Pregnancy:

Eating a healthy and balanced diet provides most of the vitamins and minerals required during pregnancy.

Folate is a B vitamin which plays an important role in DNA synthesis, red blood cell production and the growth and development of the foetus. The synthetic form of folate is known as folic acid, and it is commonly found in nutritional supplements for pregnancy.

It's recommended that women trying to get pregnancy take a daily 400-microgram folic acid supplement from pre-conception up until 12 weeks pregnant. This is to prevent neural tube defects, including spina bifida.

Pregnant women should also take a daily vitamin D supplement to support normal growth and development of their baby. Some women choose to take a multivitamin supplement during pregnancy to support the increased micronutrient requirements. If you do decide to take a pregnancy multivitamin, make sure that your supplement doesn’t contain vitamin A, as too much can be harmful to the foetus.

Omega 3 Fish Oil Supplements:

Oily fish is an important part of a healthy diet, and it contributes to heart health and overall health. Current UK recommendations are to have at least two portions a week, including at least one of oily fish.

Omega-3 refers to fatty acids found in fish and some plants. There have been claims that taking omega-3 supplements can reduce the risk of a range of conditions, such as heart disease and stroke. However, a major systematic review (the best that has been done to date) looked at the effects of omega 3 supplements on heart health in humans. It found moderate to high-quality evidence that omega-3 has little or no effect on mortality and heart health.

There are currently no UK recommendations for omega 3 fish oil supplements. It is best to try and get omega 3 from foods. Despite this, the global market for omega-3 supplements is now estimated to be a multi-billion-pound industry.

Current NICE guidelines recommend that people with or at high risk of cardiovascular disease (CVD) consume at least two portions of fish a week, including one oily fish. However, it advises against omega-3 fatty acid supplements for primary or secondary prevention of CVD.

They also advise that healthcare professionals tell people that there is no evidence that omega-3 fatty acid compounds help to prevent CVD. The same goes for patients who have had a heart attack or those with familial hypercholesterolemia.

Vegans and Supplements:

A healthy and balanced vegan diet provides almost all the nutrients that you need. However, if your diet isn’t well planned you could miss out on essential nutrients such as vitamin B12, calcium and vitamin D. Many vegans take nutritional supplements, although this is down to personal choice.

Calcium is required for strong bones. Vegan sources of calcium include: fortified soya, rice and oat milk, leafy green vegetables, dried fruit and pulses. Adults need 700 micrograms a day so make sure you are plenty of calcium-rich foods throughout the day.

Vitamin D is required to help our bodies absorb calcium. As mentioned earlier, everyone over one year should consider taking a daily supplement in the UK. Other dietary sources of vitamin D include fortified spreads and cereals plus action from sunlight exposure.

Vitamin B12 is only found naturally in animal products. Vegans can consume fortified products which contain B12 such as yeast extract (i.e. Marmite), fortified breakfast cereals and fortified soya products. Adults need 1.5 micrograms a day and a deficiency in B12 can lead to vitamin B12 deficiency anaemia, whereby the body produces abnormally large red blood cells which cannot function properly.

Finally, women in particular are at risk of iron deficiency, including those on a vegetarian or vegan diet. Women aged 19-50 years need 14.8 micrograms of iron a day, and slightly less after the menopause. Adult men require 8.7 micrograms per day.

The iron in meat (heme) is better absorbed compared with the iron in plant sources (non-heme). Vegan sources of iron include pulses, nuts, dried fruit, dark green vegetables, fortified cereals and wholemeal bread. Vitamin C has been shown to enhance the absorption of non-heme iron. Try having a glass of orange juice or a piece of fruit which is rich in vitamin C such as a kiwi during your meal to increase iron absorption.

If your doctor is concerned by your iron levels and/or you experience symptoms of iron deficiency anaemia such as tiredness and pale skin, they may recommend an iron supplement.


Whilst the exact mechanism is unknown, probiotics are thought to help restore the natural balance of our gut bacteria.

It certainly appears probiotics can help manage certain medical conditions, but it depends on the strains, mixtures and dosages. Much the same with antibiotics, different types are needed for different scenarios, and not everyone responds the same.

Most of the research looking at safety and efficacy of probiotics comes from studies of Lactobacillus and Bifidobacterium; less is known about other types of bacteria.

Different probiotic supplements have different effects on the body, and little is known about which the best types are. If you wish to try a probiotic supplement, select one product at a time and monitor its effects. Try it for a minimum of four weeks at the recommended dose by the manufacturer.


Always speak to your doctor before starting a nutritional supplement. It’s worth remembering that a healthy and balanced diet can often provide your body with enough vitamins and minerals. However, if you do require a supplement, supermarket own brand supplements are usually sufficient and will save you a lot of money. Some vitamins and minerals can be toxic or harmful in high amounts so always stick to the recommended manufacturer’s dose.