Supplements – who needs them and when?

The dietary supplement industry worldwide is huge. According to a recent Mintel report, Brits alone spend around £500 million on vitamins and supplements each year [1] – with an estimated $30 billion per year being spent in the US! One study also found that as much as 70% of US adults over the age of 60 take at least one dietary supplement [2].

It's clear dietary supplements are popular, but is this popularity well-merited? Supplements were originally created for those people who had a medical need for them, but they have grown to be an essential item in most health-conscious people's toolkits! Concerns around supplement use range from them simply being a waste of money, to over-use actually being harmful in some cases.

Here's the lowdown on supplements to help you make a choice on what your personal needs might be.

Do supplements work?

Many people report taking vitamins and other supplements because they believe they will improve their health and protect them from illness [3]. While some observational studies do show that people who take regular supplements have less incidence of certain illnesses such as cancer and heart disease – other more robust research methods do not support this relationship [4]. It seems more likely that people who are health conscious are more inclined to eat a balanced diet, be a healthy weight and take regular exercise – and also be the people who take dietary supplements. Therefore, protection from disease is more likely from their general healthy lifestyle, as opposed to the supplements alone.

On the flipside, there are known groups of people who may be more at risk of nutritional deficiencies. For these groups, supplementation can help to bridge the gap. Examples could be some people in low-income countries, who may not have the diet diversity they need for health. Or someone suffering with iron-deficiency anaemia can benefit from taking a daily iron supplement to help build up their iron levels.

Are supplements safe to use?

The safety question really depends on the type of supplement being taken. Certain water-soluble vitamins such as vitamin C or B vitamins aren't stored in our body, so excess intakes of these will essentially just result in expensive wee! That said, there are some reported side effects such as gastrointestinal discomfort with excessive vitamin C intakes – while not hugely harmful, it's not pleasant.

Fat-soluble vitamins however, such as vitamin A, D and E are stored in our body. This means excessive intakes can lead to a build-up in our bodies, which may be harmful. As an example, some research has found that excessive intakes of vitamin A can affect bone formation [5]. This is when supplementation can be a risk, when people are taking unnecessarily high doses, alongside healthy levels already present in their diet, leading to harmfully high intakes overall.

In most cases, if supplements are taken as instructed, they are unlikely to cause significant harm – but they may not do all that much good either. Before going down this route, it's important to identify what, if any, supplementation you would benefit from personally. The belief that a daily multivitamin in isolation is going to keep you healthy is simply misled.

Who should take supplements?

As mentioned, there are some groups of people who would benefit from taking certain supplements. In terms of general advice, official NHS recommendations in the UK are:

• Vitamin D – for everyone. Recommendation is for us all to consider taking a vitamin D supplement in the autumn and winter months, when our bodies can't make enough from sunlight. Vitamin D is important for bone health and immunity.
• Folate – for women trying to get pregnant. Recommendation is to take a folic acid supplement prior to becoming pregnant and for the first 12 weeks of pregnancy. Folic acid can help prevent neural tube defects in developing babies.

What about people following certain diets?

With a varied diet, everyone should be able to get the nutrients their bodies need from food alone – especially as many products are fortified with nutrients now too. However, there are some diets where certain nutrients need special attention. A vegan diet is one example as all animal-based foods are removed from the diet. As animal foods are good natural sources of many important nutrients, some supplementation may be recommended to be on the safe side.

Vitamin B12 for example, which is only naturally present in animal foods. Certain foods such as breakfast cereals and dairy-free milk alternatives are often fortified with vitamin B12 – but if these aren't eaten regularly, a supplement would be helpful for vegans.

Do I need to supplement on a low-calorie diet?

Understandably it can be a concern when you're eating less food, about whether you will still be able to get the right level of important nutrients to stay healthy. The short answer is yes – if you make the right food choices. Many of the important vitamins and minerals we need come from fruits and vegetables – and these should feature highly in any low-calorie diet.

As well as this, choosing wholegrain carbs such as oats, wholemeal bread and wholegrain rice; lean protein such as fish, skinless chicken, eggs, pulses; and including 3 portions of low-fat dairy, or calcium-fortified dairy-alternatives in your diet each day, will ensure a great mix of nutrients. The amount of food you can eat on a 1,200-1,400 calorie diet is still adequate to meet your body's requirements – it just means there's not as much room for the less nutritious stuff.

Bottom line...

While some supplements have a value, in many cases people are taking them unnecessarily. Most people taking supplements say they do so to improve their health, but it's important to note that nothing is a substitute for a healthy diet. One study found that adequate intakes of several nutrients was associated with reduced risk of disease, but this was only the case when the nutrients were provided from food – not supplements [6]. This highlights the importance of a varied and natural healthy diet above all else.

For some people, illness or dietary restrictions can lead to nutritional deficiencies. In this case it's important to consult your doctor to discuss your personal needs. If your doctor recommends you take a supplement, it's important you follow their advice and do so.