ZOE Science & Nutrition - Recap: How dairy impacts your health: according to the science | Prof. Tim Spector & Prof. Sarah Berry

Episode Date: August 6, 2024

There seem to be good arguments for and against eating dairy.  But how do we know what to listen to? Well at Zoe, we consult the latest research to draw our conclusions. In this episode, our two resident professors join us to unpack what the science says about dairy and your health.  Learn how your body responds to food 👉 zoe.com/podcast for 10% off 🌱 Try our new plant based wholefood supplement - Daily 30 *Naturally high in copper which contributes to normal energy yielding metabolism and the normal function of the immune system 📚 Books from our ZOE Scientists: Food For Life by Prof. Tim Spector Every Body Should Know This by Dr Federica Amati Free resources from ZOE: Live Healthier: Top 10 Tips From ZOE Science & Nutrition  Gut Guide - for a healthier microbiome in weeks Have feedback or a topic you'd like us to cover? Let us know here Listen to the full episode here

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 discussing how dairy impacts your health. As with many topics, there seem to be good arguments for and against eating dairy. So how do we know what to listen to? Well, at Zoe, we consult the latest research to draw conclusions. In this episode, our two resident professors join us to unpack what the science says about dairy and your health. But first, Tim debunks a common myth about dairy and stronger bones. the latest research shows that milk doesn't actually protect you against osteoporotic

fractures which was one of the osteoporotic fractures other than hard to say bone fragility fractures or you know hip fracture wrist fracture things that tend to become more common as you get brittle bone disease is what it's commonly known as. And it's something that affects about one in three women. So it's incredibly common. Yes. So you start with a wrist fracture in your 60s, then you might get a loss of height due to vertebral fracture. Then in your 80s, you're highly susceptible to hip fractures, which can really end up changing your life. So really important, big epidemic of this. We were telling everyone 10 years ago to drink more milk,

particularly around the menopause. This would protect you. Which is what I thought you were supposed to do. Yes. Well, that was up to very recently, the latest advice. But all the actual evidence now suggests that milk drinkers have no protection against hip fracture compared to non-milk drinkers. And it sort of makes sense because the biggest milk drinkers in the world are the Dutch and the Scandinavians, and they have the highest fracture rates in the world. So all of that calcium is in your milk and it's going to protect you. This is all turns out to be nonsense. Yes. That's what the science is now telling us. And, you know, there's many other sources of calcium.

We always think of milk as the only source of calcium, but actually there's so much in green leafy vegetables, in kale, in broccoli, in nuts, in almonds, all kinds of different areas we can get much more easy access to this calcium. And so I don't think we should be really pushing milk as much as we have been. And is that true for all dairy? So we talked about milk. I think, Jonathan, it's important to pick up on the osteoporosis question here regarding milk, that whether all dairy should be classified as not being helpful in that situation. So there's studies that have taken place in care homes, for example, where they will take a number of different care

homes and some care homes have added to the diet dairy. Now, this isn't just milk, though. This is like adding yogurt, cheese and other dairy and then other care homes that haven't. So it's part of a clinical trial. The care homes that add dairy to the diets of the people that are living there, they do have a reduction in lots of different unfavorable health outcomes, including fractures. Overall, what we know from population studies is people that consume more dairy have lower rates of type 2 diabetes. That's really consistent, the evidence for that. We also know populations that have higher intakes of dairy have lower rates of cardiovascular disease. It's less consistent, but the majority of the data would support that, and we're starting

to understand mechanistically why that is. We also know that people that have higher intakes of dairy tend to have better weight overall and we also know that dairy may be protective against some cancers so there's really consistent evidence that people have higher intakes of dairy have lower risk of colon cancer for. But then we need to look at the different types of dairy to see which types are more protective than other types. And I think the best way we as nutritionists would separate them out is typically the fermented and non-fermented. And then once we look at the fermented, then we'd separate them out according to whether they're like liquid or hard. So when we talk about fermented, we mean cheese, we mean yogurt. When we're talking about the non-fermented, we mean milk and we mean butter. So to make sure I've got that, you're

saying like overall, actually, when you look back at people living their entire lives and what they ate, then actually the people who are eating dairy have tended to look healthier. But within that, it's like there's this mix of different things. And so some of those dairy might be really quite good for you. Some of those dairy might not be very good for you. And you mix it all together. And on average, that might be better than someone who's not eating dairy. And I guess the risk always is, you know, are they drinking Coca-Cola? What are the alternative choices?

So it's quite complex compared to many of these things where maybe it's just sort of clear that if you eat you know a whole grain it's better than a highly refined grain yeah so dairy is a huge food group and so whilst we can say broadly speaking if you consume more dairy you tend to be healthier we need need to look at all of the different components of the food groups. There's also quite a lot of clinical trial data that we can draw on as well to look at whether dairy itself is what's improving health or whether it's all the other factors that normally complicate how we understand a food impacts our health. So is it that people that have higher overall diet quality tend to consume more dairy or is it the dairy itself? And what's the answer?

So my interpretation of the evidence is that for cheese and for yogurt is the dairy itself that's conferring a favorable impact. And we're starting to understand why this is as well. The data, as Sarah is saying, on cheeses and yogurts is actually stronger than for milk. I don't think there's comprehensive data about it being fracture protective, but it's certainly suggested that way, certainly. And I think all the fermented dairies have all these extra advantage of the probiotic microbes in there that we know now from clinical trials are good for the immune system. They have an effect within a few weeks. They do hang around in our gut to energize the other microbes there, have lots of effects. We still don't understand in our body. And I think we should still be pushing those. And all the evidence about yogurt

and cheese is much more positive than for milk alone. That's amazing. Before we dig into the individual things, the number two question that we had from literally like about a thousand people was about full fat versus lower fat dairy. And I guess this can apply right across whether it's milk or if it's cheese. And lots and lots of people saying, well, the government advice makes really clear that I am supposed to swap my full fat milk for low fat milk or my full fat cheese for low fat cheese. And we did our research and both the UK government and the US government are currently saying that. I know that you don't always agree with whatever the existing advice, which we know goes through a process that means sometimes it's a bit out of date.

What's your personal views on this? Well, I think there's no evidence at all that full fat milk is more harmful compared to skimmed or semi-skimmed milk. There's no evidence for any advantage of low fat milks and lots of theoretical reasons why they might be less good for you by skimming off the fat because you're losing a lot of the nutrients. Okay, so the reason that the government have put out these low-fat guidelines, not just in the UK and the US, it's actually if you look at nearly all guidelines across many different countries, they recommend you to have the low-fat

versions of dairy. One is because in most instances, all of the healthy nutrients are maintained. So if you have skim milk versus full-fat milk, you still retain the calcium, the iodine, the potassium, and many of the other really healthy nutrients. But what you also do is by going to low-fat milk is you reduce your saturated fat content. And we've always believed and the evidence would support that increasing saturated fat increases. And we've always believed and the evidence would support that increasing saturated fat intake increases your cholesterol, increases your risk of cardiovascular disease. And this is why the government have recommended us to have low fat, to cut down the saturated fat intake. And what do you believe? But what I believe is that whilst it's very clear that low-fat dairy has a favourable impact on health, it's also

clear that full-fat dairy has some favourable impact on health, but just not quite as favourable as low-fat dairy. My big problem with this is that this was a theoretical argument, and you made the good theoretical case for it, but all the clinical trials have failed to show any real difference between these two arms. And by saying you have to take out the fat by spinning it basically in a centrifuge to get the fat globules off, you take out lots of stuff you may not know about because the milk is incredibly complex. Just to keep it really simple, you know, my dad's listening to this right now, and he would be drinking full fat milk, but the medical advice he's been given is he should swap out the full fat milk for skimmed milk because he's got high cholesterol. How important is that advice for him to follow, do you think, Sarah? so i think based on evidence from observational studies we

know that it's very clear that people that consume more full or low fat dairy have reduced risk of cardiovascular disease and typically lower cholesterol and there's also randomized control trials have looked at this so there's one quite well-known randomized control trial where people were allocated to either follow no dairy diet or for 12 weeks follow a low-fat dairy diet and for 12 weeks follow a high-fat dairy diet. And what they did is they particularly focused on cholesterol and the different types of cholesterol. And what they found interestingly is those following either the no dairy, low-fat dairy, or the full-fat dairy had absolutely no difference in blood

cholesterol levels. And this is not what you'd expect based on a really high saturated fat content of dairy, which is why dairy is so special because we know that there's something more interesting and complicated going on with the food matrix. So I would say to someone, if your doctor says, no, you have to go to low fat or you have to avoid dairy, I would say that it's perfectly healthy and actually beneficial potentially to include cheese and to include yogurt. And I don't see the harm in having skimmed milk or semi-skimmed milk versus whole milk. I'd love to talk about a few of the fermented dairy because I think that lots of people will believe that these are foods they shouldn't eat. And I'd like to share what the

latest data shows. So could we start with, you know, yogurt? How healthy is this? Should we be eating it? So I think yogurt and cheese are a fantastic part of our diet. They're packed full of great nutrients, including calcium, iodine, potassium, fantastic types of proteins. So it's a complete protein. So it provides all of the proteins that our body can't make. And actually, a fortunate part of cheese and yogurt is there seems to be something really special about the matrix of the food structure that means that despite having a high saturated fat content they actually don't increase our cholesterol so that sounds a bit magic because we're just we're talking about milk and sort of saying on balance like it's not terrible for you but it's not a health food either so i've taken the milk i basically left it sitting out there for a long time and now magically you're telling

me it's better for me what's quite interesting is if we do studies where we compare butter versus cheese despite having the same amount of saturated fat cheese does not raise our cholesterol certainly in comparison to butter it lowers our cholesterol it lowers our bad cholesterol despite having the same fats and what this highlights is that we have to really be careful when we're looking at either back-a-pack labeling of taking that really reductionist view of thinking just of the nutrients we have to think of the food could we have some actionable advice let's say you're going to the grocery store to the supermarket you're trying to decide what to eat

can you share some tips small portions little little and often is what you want with fermented dairy. And there's something called kefir, which is fermented milk, which has about seven to ten times the amount of microbes that yogurt does have. And it's like a super yogurt, it's thinner. If you're after something for its health benefits, then switching from yogurt to kefir is really good, and you can make it yourself very cheaply. We've noticed you have to have them at least every day or two. You can't just have a giant dairy binge once a week because it won't be present all the time to have those benefits on your gut microbiome. So small amounts regularly is what we're after. And again, try and move to kefir as well as these cheeses.

Pick, if you can, artisanal cheeses. Avoid highly processed cheeses, which are dead. If you can get raw milk cheeses, and increasingly you can get raw milk cheeses, go for them because they do have a greater variety of microbes, particularly on the rinds, et cetera. And go and enjoy it. But pick the stuff that you enjoy and try and get diversity of your cheese, because the more diverse your cheese is, the more diverse the microbes you're going to be ingesting. In terms of yogurts, as we've discussed before,

it's going for the full-fat, unadulterated, so you know it's not processed if it's full-fat. That's the other really important reason why I really say to people go for full fat you know it hasn't been tampered with and go for ones without vanilla you go ones without additives it's got no fruit and you can add stuff yourself so you know what's in it that's the basic rule all those full fat yogurts will be fine make sure there's no artificial sweeteners, and they haven't done anything to it on the back of the pack, and you'll be fine. Thank you for listening to today's recap episode. I want to take 30 seconds to talk about something that's not talked about enough. Menopause. Over half the people on the planet experience perimenopause and menopause.

Yet symptoms are often misunderstood or dismissed. At Zoe, we're moving menopause research forward. We recently conducted the largest study of menopause and nutrition in the world. And our study showed that two-thirds of perimenopausal women reported experiencing over 12 symptoms. Symptoms like weight gain, memory problems and fatigue. The good news is the results also show that changing our food habits may reduce the chance of having a particular menopause symptom by up to 37% for some women. We know how important it is for you to be able to take control of your own health journey. So we've created the Menoscale Calculator to help you score the frequency take control of your own health journey. So we've created the Menoscale calculator

to help you score the frequency and impact of your menopause symptoms. Go to zoe.com slash Menoscale to get your score. The calculator is free and only takes a couple of minutes. And by the way, we've spoken about perimenopause and menopause many times since starting the Zoe Science and Nutrition podcast. To find these episodes, simply search Zoe Menopause in your favorite podcast player.