Most replayed moment: What The Science Says About Supplements | Prof Tim Spector & Prof Sarah Berry

**SPEAKER_1** (0:01)
Hello, and welcome to ZOE Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today, we're talking about supplements. We've all seen them, the multivitamins, the fortified foods, the neatly packaged powders promising improved energy, immunity, and longevity. Supplements boast bold claims. However, it's hard to know if they're genuinely helpful, or just well-marketed. Professor Tim Spector and Professor Sarah Berry, join me to unpack why supplements exist, what the science really says about their benefits and risks, and how to decide if supplements deserve a place in your daily routine.
What exactly are supplements, and why were they created in the first place?

**Tim Spector** (0:51)
There isn't an official definition of supplement as far as I'm aware, but it's usually some chemical that you have as a pill or a liquid or a powder that will replace a deficiency and improve your health.
And this is why we have supplements added to foods all the time routinely. Some of them by law, for example, in breads, when you strip out the normal bit of the wheat, you lose the normal vitamins that are there, the B vitamins. And so by law, you have to supplement that food again with what you're lacking. So that's the general remit, but it's a very broad area. And it's usually taken to be things that are in some chemical form rather than a food form.

**Sarah Berry** (1:41)
And traditionally, when we think about supplements, we think about vitamins and minerals. These are essential for our health. And at a time where there was deficiency, supplements were of value. But we're talking hundreds of years ago, for example, where there was deficiency in vitamin C amongst sailors, which we often talk about in nutrition, that led to something called scurvy.
It's almost eradicated now. As long as you're consuming a reasonably balanced diet, it's very difficult to be deficient in these essential vitamins and essential minerals. There are some people at certain stages in life that may benefit from supplements. For example, eye deficiency and anemia is quite a big problem amongst certain populations. But for the majority of people, we get the vitamins and minerals that we need from our diet.

**SPEAKER_1** (2:33)
A hundred years ago, was this very different? Because you mentioned scurvy, and I do remember this in history, like sailors needing to eat lemons or something. It's not only scurvy that you're talking about in these deficiencies?

**Sarah Berry** (2:46)
Yeah. There were lots of different deficiencies. It depended on where you were living as well. There still are some vitamin and mineral deficiencies in other countries who are typically malnourished. But in well-nourished countries, like the UK, like the US, it's really unusual. But yes, there were deficiencies years ago, not just in vitamin C, but in many other vitamins and minerals as well.

**Tim Spector** (3:08)
For example, all these pictures 100 years ago in Glasgow of kids with bendy joints. This was a vitamin deficiency that now really no longer exists.

**SPEAKER_1** (3:20)
We often talk about how the diets in the past were much healthier. So why was there this concern and actually this occurrence of deficiency?

**Tim Spector** (3:29)
It generally happened during industrialization and the UK was at the forefront of the Industrial Revolution, and people rapidly moved from the country side where they didn't really have these deficiencies to big cities, and the food supply had to be reorganized, and people ended up just, for example, eating bread or just porridge, didn't get any fresh fruits, vegetables, any variety.
As soon as you lose that variety, you go onto these staples, you do risk having some of these vitamin deficiencies. So that was the cause of this, and this actually you see in times of war and displacement of people, that's when you get these vitamin deficiencies in things like thiamine deficiency, vitamin D, vitamin C. All these occur in major catastrophes. So that's why nutrition was actually set up as a science, really because of the two world wars, dealing with nutritional deficiencies at a population level. So that's why we've been obsessed with this idea that supplements are replacing these nutrients that for these geopolitical reasons have been a problem. And this legacy has carried on into the modern day. And we've still got this mindset that we're living in this post-war environment, which no longer is applicable for the vast majority of people.

**Sarah Berry** (4:55)
And I think when we think about supplements, it's thinking about deficiency, which very, very few of us are deficient in most of our essential nutrients, micronutrients.
We also think about insufficiency. So if we think about iron, for example, some people who aren't getting enough iron or aren't absorbing it well might have iron deficiency anemia. There is a place then to supplement with iron. Then there's other people that might have moderately okay iron stores, but might be quite fatigued and may benefit from some additional iron. So that's in a phase of insufficiency, but this whole idea of adding extra nutrients or adding extra chemicals, vitamins, minerals in to then boost your health, I think that's where we start to go into problems. So using iron again as an example, if you have sufficient iron stores, this idea that, oh well, hold on, iron prevents us from feeling fatigued if you have anemia. Let's add more iron in to feel really this great boost of energy. If you've got enough, you don't need to add more and it's not going to make you feel more energetic and if anything, it can actually be harmful.