Live chat

My Basket

One-time purchases


${line.quantity} Quantity
Subscribe and save


${line.quantity} pack every ${line.frequency} ${line.frequencyUnits}
No items were added
Subtotal ${model.subTotal.label}
Discount ${model.discountTotal.label}
Order total ${}
Fruit and juices

Our 101 guide to vitamins and supplements

"In an ideal world we would get all the nutrients we need from a healthy diet, we would exercise regularly and get at least eight hours' sleep a night; we wouldn't smoke, drink or get stressed out. Back in the real world, however, things are very different," says Healthspan's Dr Sarah Brewer.

"But, with as many different dietary supplements available as there are conflicting messages about them, it can be hard to know what is best for you. There are also questions of how best to take them, when to take them, how much is too much and other important considerations," she says.

With this in mind and with the help of Dr Sarah, we have put together a comprehensive guide on how to make the most out of your vitamins and minerals. 

Blue alarm clock

First things first: find a routine

So that your body can make the most out of the supplements you take, it's important to take them regularly and at the right time of day. It's so important, in fact, that we've dedicated an article to supplement routines.

See When's the best time to take my supplements? for more information.

What's the difference between vitamins and supplements?

Vitamins are nutrients needed by the body in very small amounts to make its processes work correctly. For example, vitamin C is vital to produce collagen, which binds structures in the body together, while vitamin D is needed for the production of proteins that are needed in the immune system.

Vitamin deficiency can lead to a number of health problems, from lowered immunity to fatigue and weakened bones. There are also minerals that are vital for health, such as magnesium for energy, bones and teeth, and zinc for immunity and healthy hair, skin and nails.

It may not always be possible to get all the vitamins and minerals we need from our diet, due to life pressures and dietary preferences or requirements. What's more, some vitamins, such as vitamin D, are mainly made in the skin on exposure to sunlight, and this can be difficult in cloudy countries such as the UK.

This is where supplements come in. Supplements are a way of complementing the vitamins and minerals you gain from your diet through tablets or capsules, thereby helping to make sure any gaps are filled.

There are vitamins A, B, C, D, E, and K...
...but what happened to vitamins F, G, H, I, and J?

Vitamin F

Reissued as an Essential Fatty Acid (EFA) a long time ago – think omega-3 and omega-6.

Vitamin G

Previously this was the American name for vitamin B2. Now known as 'riboflavin' in both the US and UK.

Vitamins H and I

You'll probably know vitamin I from its colloquial form 'ibuprofen'. Vitamin H, more commonly known as biotin, is part of the B complex group of vitamins.

Vitamin J

Vitamin J was once identified as choline, which was also formerly considered to be a B vitamin (vitamin B4).

Choline is one of the missing B numbers, along with inositol (vitamin B8) and para amino benzoic acid (PABA), which is sometimes referred to as vitamin B10.

Supplement Safety

What are RNIs and NRVs?

RNIs (Reference Nutrient Intakes) are the levels of intake of essential nutrients that are considered to meet the known needs of most healthy people. When it comes to the labelling on supplements, you should pay attention to the Nutrient Reference Value, or NRV.

The NRV shows the percentage of an adult's daily nutrient requirement that a supplement meets; for example, a 10mcg vitamin D supplement would meet 200% of an adult's vitamin D NRV.

Some supplements do contain more than the NRV, but there are good health reasons for this; for more information see Why supplements don't always contain the recommended intake. It's also not a problem as long as you abide by Safe Upper Limits (see below).

Occasionally higher doses of vitamins may cause side effects such as indigestion; vitamin C is an example. To avoid this, try a gentle form of vitamin C.

Safe Upper Limits

Nutritional scientists have identified upper tolerable levels for the long-term use of vitamin and mineral supplements. These reflect the doses that most people can take every day without a risk to health, and are known as Safe Upper Limits (SUL).

In many cases, these doses are a lot higher than the NRV in your supplement. For a few supplements, however, the upper safe level is close to the recommended daily amount (e.g. for iron and magnesium).

Combining supplements

If you are combining supplements that might contain the same vitamins or minerals, check the combined doses carefully to ensure you do not breach upper safe levels except under medical advice (e.g. to treat iron-deficiency anaemia).

Red telephone

Supplement tips

● If you order from Healthspan's call centre, their Nutritional Advisors will let you know if you are likely to go above upper safe limits based on the supplements you purchase.

● If you have a medical condition and are thinking about taking supplements, always check with your doctor or pharmacist first. This is especially important if you are taking prescribed medicines or over-the-counter remedies. Many drugs are known to interact with foods or supplements, so always check for potential interactions before you take them.

● Keep your supplements in a dry, dark place, and check the expiry dates. Spring-cleaning is a good opportunity to go through your supplements cupboard and get rid of anything out of date. Expired tablets and capsules can be popped out of the packets into your food waste bin.

To make sure you don't buy too many supplements and to avoid them going out of date, consider subscribing to your favourite Healthspan products. This means that packs will arrive at a frequency you choose, so you won't receive too many and you'll never run out.

Why do some supplements that already combine vitamins and minerals?

Some supplements have a synergistic effect when used together, which is why glucosamine and chondroitin is one of the most popular combined supplements. Calcium and vitamin D are also often used together, as vitamin D enhances the absorption of calcium from the intestines.

Similarly, vitamin C boosts the uptake of dietary iron. One of the most popular combinations for many people is a multivitamin and mineral plus an omega-3 fish oil, as this provides a good foundation for nutritional health.

Water-soluble versus fat-soluble

Vitamins fall into one of two categories based on their solubility. Water-soluble vitamins dissolve in water and are readily lost from the body via the kidneys. A regular, daily intake is therefore important to avoid deficiencies. By contrast, fat-soluble vitamins are more readily stored in liver and fat cells, so it takes longer for low dietary intakes to lead to a deficiency.

Examples of water-soluble vitamins

  • Vitamins B1, B2, B3, B5, B6, B12, folate, biotin, C.
  • Vitamin B12 is unusual as, although it is water-soluble, the liver can store significant amounts.

Examples of fat-soluble vitamins

  • Vitamins A, D, E and K

How to get the most out of your supplements

Tablets with tick and cross on yellow background

From what to eat with your supplements to what to do if you miss a dose: find out the dos and don'ts of taking supplements.

Find out more

Dr Sarah Brewer is Healthspan's Medical Director and holds degrees in Natural Sciences, Surgery and Medicine from the University of Cambridge. Having worked as a GP and hospital doctor, Dr Sarah now holds an MSc in Nutritional Medicine from the University of Surrey and specialises in nutrition. She is also an award-winning writer and author.

Find out more at Dr. Sarah Brewer's website, or read more about Healthspan's health experts.

Nothing beats a healthy, balanced diet to provide all the nutrients we need. But when this isn't possible, supplements can help. This article isn't intended to replace medical advice. Please consult your healthcare professional before trying supplements or herbal medicines.