Tonight on the Checkup ` Gareth grapples with a gripe affecting one in 10 Kiwi blokes. The prostate is like a doughnut. Sam follows her nose. I have no idea. (WOMAN CHUCKLES) Something sticky? And Jayani beefs up her iron intake. Some foods definitely outweigh others. But first ` how to give your bones the most bang for their exercise buck. (GRUNTS) (GRUNTS) (GRUNTS) I'm an avid fan of regular exercise, but I'm fast approaching the age where my body will start to respond differently to my workouts. For example, from our mid-30s onwards, we lose bone density. But can exercise halt the process or even reverse it? I enjoy tennis. It's a great way to catch up with my family and friends. But is it doing anything for my bones? Associate Professor Thor Besier investigates how different types of exercise can affect the density of our bones. My tennis partner, Suzie, has volunteered to help us out today. The nice thing about Suzie is she's been playing tennis since she was 4. Mm. And so, the bone responds more during growth and adolescence, when you're laying down new bone, as it does after the skeletons mature, so in our 20s, say. So, what we wanna do is look at how the mechanical forces and loads of her tennis playing might impact or influence the shape and size of her bones. And it's a really interesting comparison because we can compare her left and her right arm. Now, I don't know which one is her serving arm or the one that she plays with, but hopefully the bones will tell us that story. Thor is using this state-of-the-art DEXA scanner to measure how dense Suzie's bones are. So, what we can see here are the images from your right and your left arm, and the first thing that strikes me is that this image here seems much brighter. There's a lot more white area here, which is more dense bone, when you compare it to the left side. And this is probably what you'd expect with a tennis player who's more dominantly using one arm versus the other. Yep. So, my guess is that you're a right-handed tennis player. Yes. Yep. That's right. How much is the difference? So, at this part here, your right arm has about 18% more bone mineral density than... Really? in your right. So, almost 20% more bone in your dominant arm. That's a lot. Yeah. The other thing you can pick up here ` on the left-hand side, there's an overlay between the left and the right. And so, you can see the outline of the right bone. Yeah. You can see it's overlaid in, kind of, that pinky colour. Yeah. And you can actually see it's slightly bigger here too. Right. And that bone has been deposited... Mm-hm. ...during your growth in adolescence. Wow. And so that's really fascinating. So because of Suzie playing tennis growing up, she's got both a wider diameter of her bone but it's also more dense. Yeah, exactly. So, this is the take-home message for all of us,... Yeah. Yeah. ...if we're fit and active during growth and adolescence, the bones respond by getting stronger. Yeah. We put down more bone, and we also change the size of our bones. Yeah. And those changes stay with us during our life. When Suzie serves, the weight-bearing bones in her right arm experience resistance. In response, they become denser and bigger. But are all sports equally good for our bones? My turn to be the guinea pig. To find out which activities trigger bone growth, Thor fits me with an accelerometer to measure impact before he puts me through my paces. Keep it up. You're doing good. Awesome. Let's bump it up. (CHUCKLES) All right. (EXCLAIMS) That's it. 17. I think this is my workout for the day. Yeah. That's it. (CHUCKLES) 18 K's. So, do that two hours, and you're a top marathon runner. (CHUCKLES) I'm more of a gentle jogger. We'll bring it down. All right. OK. I'm gonna stop that. Awesome. Well done. (CHUCKLES) How'd I go? Well, here are my two curves. So, we can see a transition as you go from walking into running. And we can see here is your walking phase. Walking, yeah. And then you start running, and then it ramps up a bit. And those top peaks there now are getting probably about three times what they were with your walking. So I'm, basically, going faster and faster, higher and higher, which means harder and harder. Yeah. Exactly. Yep. OK. Next up, the bike. OK. Come on. Dig it in. All right. Let's go. Here we go. (MACHINE BEEPS) (GRUNTS, CHUCKLES) OK, Matt. I think we got it. Yeah? All right. Lucky. You can probably slow down now. Yeah. You're putting me through the ringer. (CHUCKLES) Yeah, it's good. (SIGHS) Good workout. Good workout, yeah. Yeah, mate. Well done. (CHUCKLES) How does it look this time around on the bike? Well, what do you expect? Well, I feel like I'm putting in even more effort, but I'm not actually touching the ground, so, I doubt I'm showing much impact on my bones. Right. Yep. Before when you were walking, you were above 40 for impact. Yep. And the accelerations you get here are all below 40 the whole time, even though you're going super fast. But it looks like I'm doing a lot, but I'm not showing much impact. You're not getting those impacts. (EXCLAIMS) Lastly, an exercise I haven't done for a while. Cool. So, what's your prediction now? Harder impact. Yeah. Sure. (CHUCKLES) Cool. Awesome. We got it. Yeah. Some of these are as high as what you were getting when you were running at 18km an hour. So, the interesting thing is you could go skipping for only two minutes and experience enough load for the bone to say, 'I'm happy. I'm gonna stay strong and fit,' and you'll get a response from the bone. And two minutes of that is probably the same... Yeah. ...as doing an hour on the bike. All right? OK. The short, sharp intensity is really what bone likes. While all forms of exercise are good for us, any that involve impact ` walking, running, racket sports, skipping ` have the added benefit of strengthening and stimulating our bones to stay strong. And if you don't fancy any of those, just try a daily hop. (EASY-GOING MUSIC) (BRIGHT MUSIC) We all know the sensation ` that uncomfortable feeling when you fall asleep on your arm or you've crossed your legs for too long. Its scientific name is paraesthesia, but most of us know that strange, tingling sensation as 'pins and needles'. 'Perhaps because it feels like someone is gently raking your skin 'over and over again with hundreds of tiny little pointy objects.' But why do we get them? And what really is going on under our tingling skin? 'Paraesthesia happens when you interfere with the sensory nerves.' Sensory nerves send information to the spinal cord and up to the brain, allowing you to feel sensations such as if your drink is too hot or too cold; if you're putting too much pressure on something or how fluffy your cat is. When our limbs find themselves in awkward positions, we can prevent the blood supply to those nerves. It's like crimping the garden hose to prevent the flow of water. Without water, the roots of this plant can't feed the stem and leaves. In our body, our nerves need our blood supply to feed them so they are happy, healthy and can function normally. With 'pins and needles' we feel numb as the nerves stop getting the oxygen and energy they need to pass along their sensory messages. When you tell your arm or leg to move, it won't be listening. But when you uncross your leg or shift your arm, the blood vessels supplying those nerves can get back to work, though the nerves may still be misfiring as they reboot. The brain interprets this as tingling, hence the 'pins and needles'. Most 'pins and needles' are harmless and last only a minute or two. If it's frequent and lasts longer, it could be a sign of something more serious, so visit your doctor. And for the rest of us, the best thing to do is shake it out, keep moving, and get back to work. Smell can evoke intense memories, more so than any other sense. The sense of smell is connected to the limbic system, and the limbic system is connected to the memory parts of the brain. (YOWLS) At Specsavers, get standard progressive lenses for free when you buy one style from the $169 range. VOICEOVER: Hey, Auckland, which of the Youi 40 ways to save would work best for where you live? Grey Lynn, close to the city, is where Ava lives, so number 1 of 40 - "Don't drive to work" - could be best for her. Do a car insurance quote at youi.co.nz. * (GROANS) I don't think about smell too much unless I'm putting out the rubbish or emptying the cat litter. The truth is, our sense of smell is nothing short of a superpower ` alerting us to danger; provoking powerful memories; and without it, the fun would go out of our food. Neuroscientist Dr Brigid Ryan is going to show me how much we depend on our nose every time we sit down to eat. Today, we're gonna do a little experiment to see if you can identify some familiar foods with and without your sense of smell. But there's a twist. You're also gonna have a blindfold so that you can't see them. (CHUCKLES) So, I'll get you to put those on first, and then we'll get started. OK. OK, so no cheating. OK. Very good. No cheating. (CHUCKLES) (PLAYFUL PIANO MUSIC) I've never done anything like this before, Brigid. (BOTH CHUCKLE) Even better. I'm sure you'll do fine. (CHUCKLES) OK. OK. I'm gonna hand you the first food now. There you go. (PLAYFUL PIANO MUSIC) What do you think that one is? I have no idea. (CHUCKLES) Something sticky? It takes like play dough. I don't know. (GIGGLES) OK. (CHUCKLES) Here's the next one. Here you go. (PLAYFUL PIANO MUSIC) It tastes sweet, but I can't` I really can't even guess. Some` I don't know. Honey? I don't know. And what about this one? (PLAYFUL PIANO MUSIC) What do you think that one is? I reckon that's pineapple. Pineapple. Of the eight foods I tasted, I correctly guessed only two when my nose was blocked. Now we're gonna try that again, but this time you can take the nose plug off... Oh, good. ...so you can use your sense of smell. OK. I scored six out of eight when my nasal passages were cleared. Oh. It's sweet. Um... But it's complex. It's, um... Is it tomato sauce? It's tomato sauce. Very good. (CHUCKLES) OK. There you go. There's another spoon. OK. Oh. Peanut butter. Very good. Can I take my blindfold off now? You can now take your blindfold off. Wow. That was actually harder than what I thought it was going to be. Yeah. Like, it's much easier when you can smell it. Right. Yeah. Brigid's taste test proved to me how much we depend on our sense of smell to appreciate our food. (BRIGHT MUSIC) But that's by no means all we need our noses for. The smell of PVA glue instantly takes me back to when I was 6 years old, making Christmas decorations with lots of glitter. Smell can evoke intense memories, more so than any other sense. Brigid's colleague, Associate Professor Maurice Curtis explains why. The sense of smell is connected to the limbic system, and the limbic system is connected to the memory parts of the brain. And the two are very closely connected. And so, you've got the area that's generating the memory ` the olfactory system ` connected to the area that's gonna store the memory long-term. And so, when it comes to recalling those stored memories, the olfactory system is very good at being able to pull those memories back, so that the situation when you made that memory ` the smells associated with it ` are brought back to front of mind very quickly. This particular root through the brain is unique to our sense of smell. So, when you smell something burning, it will be your limbic system that gets you motivated to move away from that particular smell. The input to the limbic system is mainly through the olfactory system. Why do humans need a sense of smell? We need a sense of smell for helping us to detect the difference between food that's good and food that's off for understanding what's gonna be good for us to consume and what's not ` that side of things. But I think more generally, humans are constantly using their sense of smell to just alter their thinking subtly. So, when it comes to deciding around friendships, around places that you like, things that you like, the sense of smell just constantly pervades that thinking. Morris and Brigid's research into our sense of smell could have far-reaching consequences. So, one of the things we're really interested in is this idea that changes in your sense of smell might be happening really early on in brain diseases, such as dementias. So, some of the research we're doing here at the University of Auckland is looking at people who are in this very early, pre-clinical phase of dementia, and we're trying to find out if their sense of smell is affected at that really early stage. So, what's the ultimate aim for this research? What we wanna do with this research is to be able to detect Alzheimer's or Parkinson's disease very early so that we can treat the disease much earlier. However, we might also be able to use the loss of the sense of smell and the progression of that loss of the sense of smell, to see whether or not the treatments that we use early on are actually being effective, whether they're stopping that reduction in the sense of smell. (ELEGANT PIANO MUSIC) Our sense of smell is more important than I realised. It could be warning us of more than just rubbish that needs taking out. I'm gonna make more use of my superpower and seek out the smells I love. (ELEGANT PIANO MUSIC) So, do you know why iron's important for the body? It does lots of things. (CHUCKLES) Everything. Skin. It must be good for everything. Issues with our prostate are usually revealed when we pee. * There is debate amongst researchers as to whether or not life is actually busier for us than it was for our ancestors. But I'd just like to say, it certainly feels busy. That's not an issue if you're full of beans, but when the tank is empty, you can end up on Struggle Street. If you're feeling fatigued, grumpy, unable to concentrate or feel cold all the time, you may be suffering from low iron levels. Low iron is the most common dietary deficiency in the world. One in 14 New Zealand women are low in iron and up to 25% of children under 3. The easiest way to increase our intake is through our diet. So, we've got some food here. Yeah. Which of these foods do you think has more iron in it? Um, the red meat. I would say the baked beans. The oysters or the mussels. Probably the meat. The steak? Mm-hm? The steak, yeah. I think the beans have more iron than the meat. If I were to guess, I'd think this one. Mm-hm. Well, the interesting thing is it's a trick question... OK. ...because all of the food here in these quantities have the same amount of iron. Oh, wow. Yeah. Wow. Really? No kidding. Yeah. Yeah. I didn't think that the spinach would have that much. Trick question, Jayani? Yeah. Oh. Trick question. (CHUCKLES) (CHUCKLES) So, do you know why iron's important for the body? Well, I presume it's like vitamins. It's just general all-around health. It helps our heart and our brain and our breathing. It helps with your oxygenation. Good for the bones. Blood. (CHUCKLES) That's right. Yeah, yeah, yeah, yeah. It does lots of things. Everything. Skin. (CHUCKLES) Yeah. It must be good for everything. Iron is essential in the production of red blood cells, which carry oxygen throughout our bodies and are vital in transforming food into energy. The amount we require depends on our age and gender. Women often need the most. For women to get a good daily dose of iron would mean either having this many mussels, this many baked beans, this much meat or this much spinach. Pregnant women need even more and men less than half. This may look a lot, but iron intake for women is based on eating 18mg and hoping at least 3mg will be absorbed. Our body's ability to use and absorb vitamins and minerals is referred to as its 'bioavailability'. When it comes to iron-rich foods, some definitely outweigh others. Haem iron ` the type found in meat and fish ` is absorbed much more efficiently than the non-haem iron found in plant foods. The fascinating thing about iron is that there are some clever tricks to help enhance its absorption. For starters, pair your iron-rich foods with those high in vitamin C. It's a marriage made in heaven for iron absorption. The iron in our vegetables will also be absorbed four times better if we eat meat in the same meal. Furthermore, you can increase the iron absorption in some foods just by cooking it. Lastly, be aware that while some foods increase iron uptake, others undo all the good work. If you like to finish your meal with a tea or coffee, you may wanna think again. Coffee and tea reduce iron absorption, so wait at least half an hour after eating before you boil the jug. To keep on top of the world, we need to keep on top of our iron levels, so make like Popeye and chomp down on that spinach or wrap your laughing gear around a big juicy steak ` the world will be your oyster. (EASY-GOING MUSIC) (PECULIAR MUSIC) Men ` supposedly there's nothing we like better than talking about cars, engines, sports and tools. (DRILL WHIRRS) (BLOWS AIR) All that manly stuff. And there's nothing more manly than our prostate. This walnut-shaped gland, based in our backside, doesn't get a whole lot of airtime around the barbecue, most likely due to the neighbourhood it inhabits. The prostate gland surrounds the neck of the bladder and the beginning of the urethra ` the tube that drains urine from the bladder out through the penis. It's main function is to help produce semen, so it's relatively useful. Issues with our prostate are usually revealed when we pee. A change in frequency, urgency and pressure ` such as low flow or dribbling or the presence of blood in your urine ` can all be warning signs. But rest assured, prostate problems are not always cancer. BPH or benign prostatic hypertrophy is a non-cancerous increase in the size of the prostate. It affects around half of Kiwi men over 50 and is part of the natural ageing process. The prostate is like a doughnut. The tube that we pee out of passes through the centre of it. As we get a little bit older in years, the prostate increases in size, making the central hole smaller. A smaller central hole constricts the tube, hence, our waterwork woes. The symptoms, however, are similar to prostate cancer. So, should you get checked and what does it involve? If you are experiencing any symptoms, you should definitely go see a doctor. He'll start by performing two tests. The first is a PSA blood test. PSA is a protein produced by the prostate gland that can be detected in the blood. The idea of the second test ` a gloved finger up the bottom called a 'digital-rectal exam' ` sounds alarming, but the reality is it's quick, painless and the doctor's seen it all before. If any irregularities are detected during the exam, your doctor may recommend a biopsy. Prostate cancer is the most commonly diagnosed cancer in New Zealand males, affecting around one in 10, though, it's most often found in men over 65. Not everyone with prostate cancer will exhibit symptoms. This can raise a lot of questions. If I don't have symptoms, am I happy and healthy? Is screening the obvious answer? Do I actually need to be tested? The Ministry of Health suggests men discuss screening with their doctor between the ages of 50 and 70 or at the age of 40 if you have a family history. While prostate cancer is common, doctors often describe it as coming in three forms ` the turtle, the bird and the rabbit. The turtle is a slow-growing type of cancer. You'll likely live to a ripe old age and pass away from something else. The bird ` it's nasty. It flits and floats, flies around the body and spreads, and, unfortunately, it doesn't have a very good outcome. The rabbit is in the middle. It sort of hops along. If diagnosed early, there's a good chance of a positive outcome. Depending on the stage of the cancer, your age, symptoms and lifestyle, you and your doctor will weigh up the benefits and risks of the various treatment options. Now, I'm not suggesting we bring up the subject of our prostates at the Christmas dinner table, but we all know that Kiwi males do have a reputation for ignoring their own health. If you do have symptoms, most definitely see a doctor. And if you don't but want to know more about screening, your GP is keen to chat. (BRIGHT MUSIC)