Why are vitamins and minerals important?

Dr Zoe Williams: When we're thinking about optimising our diet, increasing nutrients, or being as healthy as possible, a lot of us choose to invest in supplements, so be that vitamin supplements, it could be weight loss supplements; some people use protein shakes to try and gain muscle.

But does the evidence back them up? Are they useful, or should they be avoided?

Well I'm joined today by lead dietitian Niamh Hennessy, who can help shed some light on this really interesting topic.

I think to start us off Niamh, when we're talking about dietary supplements, what do we typically mean?

Niamh Hennessy: When we're looking at dietary supplements, as the title shows, it's a supplement to the diet - it's not instead of food and drinks.

Dr Zoe Williams: Okay. And I think that's really important isn't it, because sometimes people think, oh I don't need to eat that food if I have this supplement, but it should always be nutrition first.

When we're thinking about vitamin supplements, what type of vitamin supplements would you recommend people do take or should they not?

Niamh Hennessy: So in the UK, we do recommend people take some supplements. The key one that most people will be aware of is vitamin D, especially in the months of September through to April, when we don't have the best of sunlight here in the UK during those months.

Other supplements that we find are very popular is the likes of your iron, calcium, looking at vitamin B12 for some people, but everything needs to be tailored to the individual.

Dr Zoe Williams: Okay, so when you say for some people, who should be taking supplements and who perhaps should be avoiding them, and are they a waste of money if you take them when you're already getting those nutrients in your diet?

Niamh Hennessy: It all depends on what your diet is like. If there's an area that you know you're not getting good amounts of foods from, and one of the groups typically would be fish oils - not everyone is keen on fish even though it's very good for you - so taking a fish oil supplement can be beneficial.

Other areas are calcium can be deficient in some areas, so if you're not great at taking the milk and the dairy products it's getting a top up in this area. Iron would be another one or the B vitamin so vitamin B12 if you're following a vegan diet.

Dr Zoe Williams: Okay so it's really about that individual, I guess, making an assessment of their own dietary needs and if they can't get enough from their diet, thinking about taking a supplement.

Can you overdose? Can you take too many, because I know these days I have loads of friends who, some of them might be taking six or seven or eight different supplements in a morning, can that be dangerous?

Niamh Hennessy: It can be harmful, and this is where we get people to really have a look at what they're taking because sometimes you'll have, say, calcium and vitamin D often go together, but you could also find you get vitamin D in some of the fish oils because they're trying to make it easier for people.

So, you want to make sure that you're not overdosing in especially fat-soluble vitamins - so that's A, D, E and K. These can become harmful if taken in very high amounts.

There's one particular group that we are conscious about, and that's any expectant mothers and we don't want to have too much vitamin A because this can be harmful to any potential baby in the future.

Dr Zoe Williams: So if those are the fat-soluble vitamins, what are the water-soluble vitamins and can they build up?

Niamh Hennessy: So water-soluble vitamins are the likes of vitamin C and B vitamins and these don't tend to build up in your system. You need to take them every day. But any excess you end up getting rid of them in your wee.

Dr Zoe Williams: Right. So, if you're taking lots of extra - not harmful, but you're spending a lot of money on making very expensive wee, essentially.

Niamh Hennessy: Yes you are.

Dr Zoe Williams: Okay. And if we're having a balanced diet - so I’ll use myself as an example, I eat some meat some fish, quite a lot of fruit and veg, but my diet is definitely not perfect. Am I wasting my money if I do take a multivitamin?

Niamh Hennessy: I wouldn't say you're wasting your money. Multivitamins nowadays on the market - there's loads of them and they're quite reasonable to buy, especially in the winter months if you're picking up colds and flu, they can be, they may be of help to people.

Sometimes even if it's a placebo effect and you feel better, I wouldn't say it's a waste of money.

One thing you could do is try a couple of weeks without them and see if you feel any different, but it's very down to the individual.

Dr Zoe Williams: There are a lot of newer supplements on the market. I see them all the time on social media and they're making these big, big claims about - means you won't age as quickly and your skin will be better. How much evidence is there to support these sort of newer supplements?

Niamh Hennessy: Unfortunately, the evidence is very weak in this area and we wouldn't normally recommend taking especially the bigger the claim, the more suspicious you should be. Often times with supplements, we can use them a lot more readily when we take them in through our diet. So taking them in a supplement, you often have to have more of that to have a beneficial effect.

That's why unless you're deficient in a particular area, we wouldn't recommend them. Now especially with social media and the Internet, it's a very good point to cover. We need to be very careful because the regulation in supplements isn't as good as what we would like it to be. And especially if you're buying something over the Internet, you've no guarantee on how it's been made, how it's been prepared, that the ingredients on the packet are actually the ingredients that you're taking.

So we would always recommend to get your supplements from your local pharmacy or from a reputable source.

Dr Zoe Williams: You can always have a chat with the pharmacist, can't you.

I think people often don't realise that because it's a food supplement, it's completely different - the way it's tested and regulated is completely different to medicines because medicines are very tightly regulated, they've got to go through certain studies and trials, and then be approved by the MHRA. But for food supplements, they can pretty much say what they want, can't they, and get away with it.

Niamh Hennessy: They can. They can. Now some supplements are very well manufactured, especially the ones we recommend in healthcare, but lots of other supplements on the market, they're not very well regulated at all.

Dr Zoe Williams: There are lots of supplements out there that promise weight loss and it's such a huge market. Everything from skinny teas to skinny lollipops, gummies, all the way through to certain medicines actually that can be bought over the counter. What are your views on these?

Niamh Hennessy: You need to be really, really careful because some of them have the potential of causing a lot of harm. Especially a lot of them work off of malabsorption. So there's a laxative effect and that it can basically – you end up pooing and malabsorbing calories and vitamins and minerals. So if you take them over a long period of time, they can be very harmful.

The other things are not very heavily regulated in that market so you can't really be 100% sure what you're taking. There is no secret to weight loss, there is no quick fixes. It's down to diet and exercise and getting a healthy balanced diet.

Dr Zoe Williams: There are a lot of these meal replacement shakes now where you actually have that instead of a meal and they're even being used in health care, so presumably they can be effective, but what advice would you give to somebody who's thinking about using these to lose weight?

Niamh Hennessy: It's a lot like different tools for weight loss. We use them for people to help kickstart their weight loss journey. They can be really helpful for people to control the calories and making sure that they're getting a nutritionally complete diet. You can use them as a meal replacement or as a supplement, but the key thing here is making sure you're using a reputable brand.

Dr Zoe Williams: A lot of people are trying to build muscle - not just bodybuilders but you know, particularly I think women around the age of menopause as well, we now know that building muscle is a really good thing to try and do, so how do you think that protein shakes and protein bars - do they have a place in our diet?

Niamh Hennessy: I think you can incorporate them as part of a healthy balanced diet, but the key thing is it's part of a balanced diet. They're similar to what you can take in through your diet, but some people find them easier to take and more palatable, so it's better to have something than to have nothing.

Dr Zoe Williams: Is it preferable to have that protein as food though? I guess if you're going to the gym, a protein shake is handy, but you could boil two eggs in the morning and take those with you and have those afterwards instead. What's your view - is a protein shake not as good or is it okay?

Niamh Hennessy: I think they are okay. Obviously, we'd always recommend food first, but sometimes you need to fit into your busy lifestyle and it's really important that golden window, so that hour after exercise, is really key. It's much better for you to have the protein shake than to have nothing. But if you can have the likes of your boiled eggs or you can have some lean protein and some carbohydrates, the key is not to forget the carbohydrates because the protein is really good for growth and repair but we actually store energy in the form of glucose in the muscle, so you need both to get your gains right.

Dr Zoe Williams: That's really, really good to know. A lot of people are on specialist diets now, whether that is vegetarian or vegan or gluten-free or dairy-free. Are there some supplements that would be more beneficial to people in these groups?

Niamh Hennessy: When we're looking at any of the groups and any of the different diets it's really important to have a look and check and see where you're missing. For example, with gluten-free, once you're having a healthy balanced diet and you're managing to remove gluten from it, you can get the variety and the balance in there, but we would only recommend that for coeliacs, we wouldn't recommend it for the general population.

When you're looking at vegan diets, we do know that if you have the balance and you really work hard, you can get a nutritionally complete diet. But not everyone likes all of the different food groups and it's making sure you kind of get the balance in there. So the B12 vitamins is the one that we see or folate quite often in that area. Iodine as well is another one for our vegan group.

Dr Zoe Williams: And I guess it's really important to mention as well anyone who's trying to conceive or who's in the first trimester of pregnancy, folic acid alongside vitamin D is definitely recommended.

Niamh Hennessy: Yeah, we would definitely recommend that for that group.

Dr Zoe Williams: But essentially, don't throw your money away spending a fortune on supplements that aren't going to benefit you as an individual.

Niamh Hennessy: Yeah, it's everything in moderation.

Dr Zoe Williams: Perfect advice. Thank you so much Niamh.

Niamh Hennessy: Thank you.