Tonight on The Checkup ` Gareth delivers the good oil on some very fishy supplements,... 90% of them exceeded the limits of oxidation that we tested for. ...Sam finds the apple doesn't fall far from the tree,... Your brother has dimples, and you're the only short one in your family. What's going on? ...and Jayani sets out to answer a burning question. How does running on a treadmill compare to... running outside? Is one better than the other? But first, when it comes to body mass, does one size fit all? (LAID-BACK MUSIC) Some of my friends and family complain about having big thunder thighs, love handles, muffin tops, and they even get asked if they're pregnant. And that's just the blokes. Maintaining a healthy weight can be a challenge. But first things first ` how do you identify what your ideal weight actually is? Most of us rely on what the scale tells us or the body mass index, BMI, which is an indicator of your weight for height. Knowing both your weight and your BMI is a useful way to gauge your health risk, but they are simple tools which don't always tell the whole story. (BEEP!) All right. OK. (LAUGHS) So, it tells me my weight, my height, normal weight range for a man and for a woman. My BMI's 23, which is within the normal range of 20 to 25. To me, that's good news. But neither the scales nor the BMI index distinguish between muscle and fat, and they don't take into account my body shape or how the fat I do have is distributed. Maybe the devil is in the detail ` not just how much fat we're carrying, but precisely where it is being stored. (LAID-BACK MUSIC) I've made some posters that demonstrate four distinct body types. I'm curious to know which shapes people think could carry higher health risks. I reckon C... C? ...and... B. C and B? OK. At risk is, more likely,... C, D. What do you think? C and D. C and D? Yeah. Oh, I feel very mean saying this. Um, C, I guess? D? D. Why do you think that is? Yeah, yeah, C. Because he looks fatter. Uh, C is just... slightly larger than D. This one's got, like, more... I dunno what guys call it. Moobs. Yeah, boobs. (LAUGHS) Do you think it matter where those extra kgs are? I've heard, like, the saying, 'It all goes to my hips,' (CHUCKLES) and all that. Right. Under the arms and, like, the thighs... Really? ...and the glutes. I'm not sure, though. Possibly,... more stomach area would be the most dangerous area. Now, he's got a fair amount, but that guy looks slimmer than him but has got a big gut, and that's actually dangerous, cos he might ignore that. Overall, the majority believed the larger male, Figure C, was most likely to have health risks, but there was also concern about the belly of Figure D. Can looks be deceiving, though? Professor Sally Poppitt at Auckland University's Human Nutrition Unit has learnt not to judge a book by its cover. Sally, so, you see people of all sorts of different shapes and sizes, but I wonder ` are there some types of body shapes that are more at risk than others? Yeah, we definitely think that there are. So, somebody, perhaps, who's got fat on their thighs, or perhaps their upper arms ` probably a little bit safer than if somebody has what we might think of as central fat, so around the stomach, around the organs. We call that visceral fat. You might call that a beer belly, maybe. Don't want a beer belly. And probably worst of all is if you actually have fat inside your organs, so, um... People have often heard of fatty liver and also fatty pancreas. Fat inside the organs can change their structure, size, colour and their ability to function. There's an expression we sometimes use, which is 'TOFI' ` so, 'thin on the outside but fat on the inside'. So somebody who might look quite a lean person might have some, um, fat stored in their organs. The biggest health risk with carrying visceral fat is Type 2 diabetes, which can increase the chance of heart disease and stroke. (BELLY RUMBLES) Unfortunately, just gaining a little bit of weight, for some people ` if it's central, if it's visceral, if it's ectopic ` they may be a classic TOFI person, so their risk will be up, but they may not realise it. Mm. I'm quite a slim guy, but now I'm thinking about where my fat is stored. Sally's organised for me to meet Associate Professor Lindsay Plank at the Body Composition Lab. Hey, Lindsay. Nice to see you again. Sally, nice to see you again. Now, Mat, have you had a DEXA before? No, so I'm really excited about getting one today. Great. OK. Lindsay is going to perform a DEXA scan. (SCANNER BEEPS) ...just down to your elbows. This technology allows researchers to visualise layers deep within the body that we can't see with the naked eye. So, Mat, we've got your results here of the DEXA scan. It's given a breakdown of your body into total body fat, the bone mineral and all the lean soft tissue that's left over. Your total fat content was 9.5kg,... Mm-hm. ...which is 14% of your body weight, so you've come out with a very low body fat percentage,... All right. ...suggesting you're probably heavily into exercise. Yeah, that's what I was aiming for. Right. (ALL CHUCKLE) That's very good. And the amount of that fat that's visceral, that's internal around the organs and in the organs, is 300g, so those are very low figures. Those are very reassuring. There's no magic number we should aim at for visceral fat levels. For most of us, the lower the better. Without undergoing a costly DEXA scan, how do we monitor our visceral fat? Definitely keep an eye on your weight and do something as simple as just a waist circumference measurement. And we would normally say less than 88cm for women, less than 102cm for men. And how much weight should we put on the body mass index? Studies have revealed that when calculating healthy BMI, important factors such as ethnicity need to be taken into account. When you look at the BMI cut-off of 30 for obesity, that's been developed in terms of metabolic risk in European populations. It doesn't really apply to the Asian populations; it doesn't really apply to the Polynesian and Pacific Islanders. So there are different body compositions in these ethnic groups, which really mean that the BMI is not a very satisfactory measure, basically. And this is particularly true for people of Asian ethnicity, who are predisposed to accumulating fat in the central area of the trunk, and so the risk of diabetes and cardiovascular disease in Asian, Indians, accelerates at a BMI of around 25; whereas in a European population, that would occur at a BMI of 30. So one has to be careful about... comparing BMIs and comparing body fat percentages across different ethnic groups. So although there's some issues, or limitations, with the BMI, do you think it still should be used by most people? Yeah, I guess none of us are getting any taller, so if you see your BMI gradually going up and up, then it's... you should probably start to think a little bit about your body weight and, perhaps, your diet and your exercise. Mm. When it comes to our flabby bits, we may not like the way our heavy thighs or wobbly waists look, but it's more than just aesthetics. Even those of us with seemingly lean physiques aren't home free. We all need to be aware, because it really is what's on the inside that counts. Having six fingers is a dominant gene, but we all know what's more common. Do I need to do all of this, or can I just pop one of these? * (BIRDS CHIRP) SAMANTHA: If we think of DNA as a cookbook, our genes are the recipes ` recipes that tell our body's cells how to function, what characteristics you'll inherit and how it's all dished out. Your sister has detached earlobes, your brother has dimples, and you're the only short one in your family. What's going on? We used to believe that for many of our physical traits, we receive two versions of a specific gene ` one from Mum and one from Dad. These genes could either be dominant or recessive, the dominant overriding the recessive gene and determining which trait we inherit. If you're right-handed, have dimples and unattached earlobes, then not so long ago, you would have considered these to be single-gene dominant traits. At school, most of us learnt that it was simply a dominant gene overriding a recessive one that gave us brown eyes over blue or enabled some kids to roll their tongues with glee while most of us watched on with envy. But as scientists discover more about our genes, it seems that with most physical traits, multiple genes play a role in determining which characteristics win out. Now scientists know that more than just one gene influences eye colour. There could be multiple genes in play. That means that predicting a child's eye colour may not be as clear-cut as we first thought. But there are still a few physical traits that are considered to be controlled by one gene ` like freckles. Freckles show a dominant inheritance pattern, so to find out the likelihood of a child having freckles, you can draw up a Punnett square. From each of our parents, we receive two versions of the freckle gene. A recessive trait is represented in small letters, and a dominant trait is represented in capital letters. To have the dominant trait, all you need is one uppercase letter. For the recessive trait, however, you would need both letters to be lowercase. In this instance, your mum's freckle-free complexion won't get passed down, but if your dad has freckles and is a carrier for the no-freckle gene, you still have a 50% chance of being freckle-free. But what if both of your parents have freckles? Is there any chance that you won't have them? If both your parents are carriers for the recessive gene, you might be in with a 25% chance. But just because we have dominant genes like freckles doesn't mean they're more common. Having six fingers is a dominant gene, while having five is recessive, but we all know what's more common. And that's because there's more of the recessive gene in the wider population. So traits determined by a recessive gene can still win out through sheer force of numbers. And, seriously, did we really need that sixth finger? Genes can give us a peek into the future. But a lot of what makes us unique is still up to chance and can be environmentally influenced. Some people still can learn to roll their tongues, and this should help with my freckles. (PLAYFUL MUSIC) (JAUNTY JAZZ MUSIC) There's no doubt that fish is a healthy food source. It's low in saturated fats, high in protein and famed for its omega-3 fatty acids. Our bodies don't produce omega-3 naturally, so if we want to benefit, we need to eat food containing them. But do I need to do all of this, or can I just pop one of these? In the US, $1 billion is spent on fish oil every year, and in New Zealand, it's among our most popular dietary supplements. And who can blame us for taking them, when omega-3 fatty acids may reduce the risk of numerous health conditions such as arthritis, Alzheimer's, heart disease and mood disorders? (JAUNTY JAZZ MUSIC CONTINUES) Fish oil supplements are often more convenient than fresh fish, but do they deliver the same goods? In 2015, the Liggins Institute made international headlines when a study lead by Dr Ben Albert revealed some startling results. So, we knew that the omega-3 fats that are found in fish oil are chemically fragile, so we went out and bought a whole range of omega-3-containing fish oils from the market and then tested them to look at how oxidised they were and also how much omega-3 fats were present. When oils oxidise, they have essentially gone off. The good omega-3 fats turn into a range of other chemicals. So, we tested 35 products, and we found that 90% of them exceeded at least one of the limits of oxidation that we tested for. No way. Are these oxidised, or 'off', products dangerous? We know that really oxidised oils given to animals in quite high doses are harmful, But in the sort of doses that people consume, we're just not sure. You also looked at the amount of omega-3 in products. Most of the products had less than the labelling says. Only three products had as much as the label said or more. And these were just off-the-shelf products? All of them were purchased either from supermarkets, pharmacies or health stores. And were they all within their best-before date? Yeah, all the products we used in this study had a best-before date at least six months from the time of purchase. So is there anything that can clue the consumer into the condition of these products? We looked at the best-before date; we looked at how much the product cost, where it was from and what sort of shop it was sold in, and unfortunately, none of those things had any impact on whether the oil was oxidised or not. So, really, as a consumer buying a fish oil product in New Zealand, you can't tell if the product has as much omega-3 as the label says, and you can't tell if it's oxidised above recommended levels or not. Keeping that in mind, perhaps it's best to go straight to the source ` but take note. Not all fish are created equal when it comes to getting these good oils. The omega-3 found in oily fish like salmon and mackerel far outweighs that found in white fish. Farmed salmon contains around 10 times more omega-3 than tarakihi. The last New Zealand diet survey showed that 28% of adults hadn't eaten seafood in the past month. It's a good idea to aim for at least 250mg to 500mg of marine-sourced omega-3 fatty acids per day. To get my fix, I'm sold on the real thing. The Heart Foundation suggests we should eat two to three servings of fish a week ` especially oily fish. A good guide to a portion size is the palm of your hand. With fish oil supplements, there's no easy way to guarantee you're getting what you're paying for. There is evidence people who eat seafood one to four times a week are less likely to die of heart disease. If fresh fish isn't in your budget, canned is a great source too. Fish is by far the best source of omega-3. But for the fish-phobic, it is also found in a variety of vege oils, walnuts and seeds. At this time, when buying fish oil supplements, it's not possible to know whether they are oxidised or contain the amount of omega-3 claimed, so I'm gonna stick with fresh or tinned fish. Not only is it a great source of omega-3, but it contains other nutritional goodies such as iodine, selenium and protein. SAMANTHA: Earwax ` it is there for a reason. If your feet are too close to the front of the belt, you'll take smaller steps and you're more prone to injury. Plans for the holidays? I'm starting my kitchen renovation. By yourself, unsupervised? I've seen the TV shows. You can do better. With a Gem personal loan you could get someone to do up your kitchen. And with our 'pay it faster' option you could save up to $1,000 in interest just by paying an extra $50 a month. Yeah, course. I just really wanna knock out a wall first. You can do better with Gem, powered by Latitude. Ask today. * SAMANTHA: Long ones, small ones, attached ones, pierced ones. There's a big array of ears out there ` and numerous ways people are cleaning them. You've probably heard that nothing smaller than your elbow should go into your ears. So what is the answer when it comes to cleaning them? What most people are trying to do is remove earwax, but it is there for a reason ` to lubricate our ear canals, which stops them drying and cracking, and to help prevent infection by trapping dirt and repelling water. Even if your ears are this big, you should never stick anything in them. Not pens, not keys, not hairclips, nor the end of your glasses. Definitely not these. They even say so on the packet. Cotton buds can actually push bacteria and wax further in and can damage the eardrum if pushed too far. Ear candles are another no-no. They're ineffective and can cause burns. The best way to clean our ears is to leave them alone. The amazing thing about ear canals is that they clean themselves. The day-to-day actions of talking, chewing, yawning and moving our jaw propels earwax and skin cells towards the ear opening and beyond. If you do get a buildup, a couple of drops of olive oil into each ear twice daily for a few days should help ease the wax out. If that doesn't work and your ears are still troubling you, see a doctor. They may have to flush or suck the wax out, and that is a job for the professionals. (LAID-BACK MUSIC) Gym bunny or pavement pounder? There's no doubt exercise is good for us, but does it matter where we do it? How does running on a treadmill compare to... running outside? Is one better than the other? Do they impact the body differently? And which gets you fitter? It's a case of horses for courses, dependent on your individual training needs and what you want to achieve. The number of calories you burn during exercise depends on the intensity of your workout and, therefore, the rate of oxygen you consume. When we run outside, we have to combat air resistance, uneven terrain and propel ourselves forward. This requires a higher rate of oxygen consumption and burns more calories than a treadmill. On a treadmill, the belt is fed to you, and air resistance isn't a factor. You can, however, combat this imbalance by setting the treadmill to a 1% gradient. Another problem is that running on the treadmill distorts our perception of speed. On average, people tend to run slower on the treadmill and aren't always getting the most out of it. Gym instructor Brandon Wong has some tips. So, the most common mistake is people hold on to the handlebars when they're running on the treadmill. Using your arms when you run will increase the intensity of your workout. But be careful not to go overboard. You don't wanna burn out too quickly. And does it make a difference where you stand on the treadmill? Yes, it does. You wanna make sure that your feet are in the centre of the belt so you can get a long stride when you're running. If your feet are too close to the front of the belt, you'll take smaller steps and you're more prone to injury. Even when using the treadmill correctly, I'm still likely to get fitter outdoors. But what's safer for our bodies? You won't trip over a kerb or slip on a wet surface while running on a treadmill. The belt also absorbs more of the runner's impact than outdoor surfaces, which means less stress on the feet and knees. However, the lack of varied terrain has the potential for repetitive strain injuries. When we run, each foot comes into contact with the ground about 180 times per minute, and that can lead to a lot of wear and tear. Running outside, especially off the pavement, each step is relatively different, due to the terrain. This helps strengthen ligaments and activates a variety of different muscles, which lessens the wear and tear. However, when it comes to hills, avoiding them on the treadmill may not be a bad thing. Running on a treadmill, you get the strength- and endurance-building benefits of uphill training without the downhill, which is often a lot harder on the body. There are pros and cons for both treadmill and outdoor training, but we also exercise for our mental health. Exercising outdoors in the fresh air has been proven to increase our mental well-being, helping us feel more energetic, positive, and it can even combat depression and anxiety. Some studies have also found exposure to nature can lower the levels of the stress hormone cortisol ` and don't forget the added bonus of a healthy dose of vitamin D. All up, running outdoors does seem to come out on top, but you're more likely to keep it up if you enjoy it, so choose whatever makes you happy. Captions by Maeve Kelly Edited by James Brown Captions were made with the support of NZ On Air.