C8 Tuesday, February 18, 2014
FITNESS & WELL-BEING HEALTH BITES
SWEET NOTHINGS
............................................ Jeanette Wang jeanette.wang@scmp.com
Artificial sugar substitutes are a favourite of the food and drink industry, but for years debate has raged about whether they pose a health risk. David Tan examines the latest studies
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n 1879, Constantin Fahlberg made a sweet discovery. A chemistry research assistant, he was working on coal tar substances when he spilled a compound he had synthesised on his hands. At dinner, he noticed its intense sweetness and called it saccharin. And so began the story of artificial sweeteners. The next major low-calorie sugar substitute to be discovered (in 1965) was aspartame, which is 200 times sweeter than sugar, followed in 1967 by acesulfame K (Ace K). Other sweeteners include cyclamate and sucralose. The food and drinks industry has been an enthusiastic proponent of these sweeteners but concerns have regularly emerged about how they may affect health, including links to cancer, premature birth, and an increased risk of developing type 2 diabetes in regular and high consumers of artificially sweetened drinks. The debate rages on, with conflicting studies and opinions. In December, the European Union’s food safety watchdog, the European Food Safety Authority (EFSA), released a risk assessment report saying that aspartame and its breakdown products poses no health risks at approved consumption levels. The report concluded that the no-calorie sweetener could be used by pregnant women and that it does not cause cancer, harm the brain or nervous system, or affect behaviour or cognitive function. The acceptable daily intake is set by the EFSA at 40 milligrams per kilogram of body weight per day. That is equivalent to 2,400mg for a person who weighs 60kg. The US Food and Drug Administration has set the limit at 50mg/kg. A can of diet soda usually contains about 180 milligrams of aspartame, according to the American Cancer Society, so a typical adult would have to drink more than 13 cans to exceed the recommended limit. A University of Adelaide study has since revealed that drinks sweetened by Ace K and sucralose had the same effect on a healthy human gut as a glass of water. The finding, published in the
Diabetes Care journal, was contrary to other studies that showed artificial sweeteners have a negative impact on the body, including the storage of fat. The study also questioned whether these sweeteners had any benefit, such as producing responses that signal fullness to the brain. “So far it appears that artificial sweeteners have limited impact in the short term, but in people in a pre-diabetic or diabetic state, who are more likely to be regularly high users of artificial sweeteners, it might be a different story altogether,” says study co-author Dr Richard Young, a senior postdoctoral researcher at the university’s Nerve Gut Research Laboratory. In Hong Kong, a number of artificial sweeteners are permitted for food use, including Ace K, aspartame, cyclamate, saccharin and sucralose. The law requires that such food additives must be listed by their functional classes and specific names or identification numbers on food labels. The EFSA was asked to fully re-evaluate aspartame after European MPs raised concerns. Aspartame is made up of two amino acids: aspartic acid and phenylalanine. When digested, aspartame is broken down into its constituents. Because of this, people with phenylketonuria (PKU), a metabolic disorder that stops the breakdown of phenylalanine, should avoid the sweetener. Phenylalanine builds up in the blood of PKU sufferers and can affect the brain and lead to seizures and other serious medical issues. But for everyone else, aspartame has been deemed by health authorities to be safe. The EFSA’s panel on food additives and nutrient sources added to foods reviewed nearly 2,000 studies and datasets from the 1960s to the present that were “produced to internationally recognised scientific standards”. In addition, it held a public consultation, receiving more than 200 comments from the public, non-governmental organisations, academics, national food safety agencies, and journalists. Two studies on aspartame published in 2010 stood out.
The chase is on It’s said that men love a chase – well, there’s a challenging new one in town. The inaugural Prodigy Running Skirt Chaser takes place in Mui Wo on March 2 and will pit men against women over an 8.5 kilometre trail run. The women will be given an eight-minute head start and the winner will be the first runner – male or female – across the line. Organised by Lantau Base Camp, the race costs HK$180 per person plus a HK$100 donation to the Hong Kong Breast Cancer Foundation. For details, go to lantaubasecamp.com. Manga message bears fruit Japanese comic art, manga, could help promote a healthier diet among children, finds a pilot study done in two New York afterschool programmes. Nearly 60 minority students of about 11 years of age were first given either a manga comic, titled “Fight for your right to fruit”, or a non-health-related newsletter to read. After The first study claimed that pregnant Danish women who consumed artificially sweetened soft drinks had an increased risk of pre-term delivery. The second study, from Italy, claimed that aspartame could cause lung and liver cancers in male mice that were fed the artificial sweetener throughout their lives. Previous complaints about aspartame included headaches, allergic reactions, behavioural changes, and cancers of the blood and brain. But the panel found that there was either no or little evidence for any of the concerns. For the 2010 study of Danish pregnant women, the ESFA found that “there is no evidence available in this study to support a causal relationship between the consumption of artificially sweetened soft drinks and pre-term delivery.” A more recent study from 2012, conducted in Norway, found a “barely discernible association” between artificially sweetened soft drinks and pre-term delivery. As for the second 2010 report claiming that aspartame caused
So far it appears that artificial sweeteners have limited impact in the short term DR RICHARD YOUNG
cancer in male mice, the ESFA concluded that “the validity of the study and its statistical approach cannot be assessed and its results cannot be interpreted”. Another conclusion was that the breakdown products of aspartame – aspartic acid, phenylalanine and methanol – exist naturally in fruit and vegetables. The exposure to these
the brain – and only arises when sugar is broken down into a form where it is usable as fuel for cells of the body to function. “According to the data, when we apply substances that interfere with a critical step of the ‘sugar-to-energy pathway’, the interest of the animals in artificial sweetener decreases significantly, along with important reductions in brain dopamine levels,” says the study’s lead researcher, Professor Ivan de Araujo. “This is verified by the fact that when hungry mice – who thus have low sugar levels – are given a choice between artificial sweeteners and sugars, they are more likely to completely switch their preferences towards sugars even if the artificial sweetener is much sweeter than the sugar solution,” de Araujo says. life@scmp.com
A little goes a long way Ace K Brand names: Sunett, Sweet One ● A combination of an organic acid and potassium, it is about 200 times sweeter than sugar. ● Used in food and drinks, and as a tabletop sweetener. ● Heat-stable and can be used in cooking. Aspartame Brand names: Equal, NutraSweet ● A molecule consisting of two amino acids – phenylalanine and aspartic acid.
Photo: Corbis
compounds from consumption of aspartame was low. “This opinion represents one of the most comprehensive risk assessments of aspartame ever undertaken,” said Alicja Mortensen, who chaired the panel. But do artificial sweeteners help to curb sugar consumption? A study by Yale University of School of Medicine published in September last year found that it is hard to fool the brain by providing it with “energy-less” sweet flavours, leading to a higher likelihood of sugar consumption later. The study, conducted on mice, identified a specific physiological brain signal that is critical for determining choice between sugars and sweeteners. This signal regulates dopamine levels – a chemical necessary for reward signalling in
● About 200 times sweeter than sugar. ● Not heat-stable and therefore not suggested for use in cooking.
Saccharin Brand names: Sweet’N Low, Sweet Twin, Necta Sweet ● Oldest low-calorie sweetener approved for food and drink use. ● About 300 times sweeter than sugar. ● Used in many diet foods and drinks; may have a bitter or metallic aftertaste.
Sucralose Brand names: Splenda ● Made from a process that begins with regular table sugar (sucrose). ● About 600 times sweeter than sugar. ● Heat-stable and therefore used almost anywhere sugar is used, including in cooking. Sources: US National Institutes of Health and International Food Information Council Foundation
reading, they were offered the choice between fruit or an energy-dense snack (such as cookies and crisps). Sixty-one per cent of children in the comic group chose the healthy snack versus 35 per cent of the control group. The study appears in the Journal of Nutrition Education and Behaviour. Doubles happiness Couples who go on a double date may draw closer to each other. New research found that high-self-disclosure interactions with other couples can increase feelings of passionate love. In two studies with about 150 couples, researchers used the “Fast Friends” activity, where couples answered basic “getto-know-you” questions, then progressed to deeper, personal topics. In one study, couples who did the activity reported higher feelings of passionate love than those assigned to non-emotional small-talk. The second study found that how responsive another couple was to personal disclosure predicted the increase in passionate love following the Fast Friends task.
FROM THE EXPERTS
When to proceed with caution with your workout ................................................ Dr Ray Ng life@scmp.com Enthusiasm for exercising is a good thing, and should be encouraged. But there are some things to consider before starting exercise, especially if you have an injury or underlying conditions. Here are a few scenarios I have come across in my practice. Scenario 1: Jenny, a 30-year-old gym enthusiast, has been experiencing pain in her left wrist for several weeks, especially when performing exercises such as push-ups. It is likely Jenny is suffering from wrist tendonitis. The first thing to do is determine the range of movement in the wrist: if she can move the left and the non-painful right wrist in all directions to similar degrees, it is unlikely there is any serious damage to the tendon. Jenny should consider consulting a doctor if the wrist pain and limited movement have resulted from a fall on the outstretched hand, as it could be a fracture. Medical attention
will also be needed if the pain does not resolve after seven days, or if the wrist starts swelling and that progressively worsens over 24 hours. I have seen patients with different types of tendonitis injuries of the wrist, shoulder and Achilles, who are surprised that the pain does not resolve, especially if they persist in the same type of exercise which continues to inflame the injury. If a part of your body is hurting while performing a certain exercise, don’t be a hero and push past the pain. Pain is telling you to rest that muscle or tendon until it has healed. Many people do not want to miss training time, but this will further damage the tendon and can delay the return to exercise. It can take a week or more for the pain to resolve. In the meantime, if you are not known to be allergic or previously suffered any adverse effects to anti-inflammatories, it may be worth using this medication to expedite your recovery. If after two weeks of resting the tendon, you still have pain on resuming exercise, it may be time to visit your doctor.
Sprained ankles need plenty of rest to recover. Photo: Corbis
Scenario 2: Alan, a 43-year-old who plays basketball, sprained his left ankle during an awkward landing. When the ankle is sprained, the foot often gets twisted inwards, which can lead to swelling of the outer part of the foot. Most
of the time, this is due to the tearing of ankle ligaments which causes inflammation. In order to reduce the swelling, Alan should remember this simple acronym: RICE, which stands for rest, ice, compress, elevate.
Rest means taking the weight off the leg. Most of the time, the injury will force this to be done intuitively. Alan could consider a pair of crutches to aid his mobility. Fill a bag with ice cubes and some cold water. Wrap a towel around the ankle, and apply the ice bag to the painful area. The cooling effect works best in the first 24 hours of injury and brings down the swelling. Compress the ankle during the first 24 hours of the injury by binding a bandage around the ankle. It shouldn’t be so tight that it causes more pain. The foot should be elevated above the heart. The best way to do this is to lie supine on the bed and place your foot on one or two cushions. This ensures that blood flows back towards the heart and doesn’t pool in the foot. If Alan is limping badly and there is a suspected fracture, he should see his doctor to determine whether an X-ray is required. Anti-inflammatories can be useful to reduce pain in this scenario, with the same caveats as the previous case.
Scenario 3: Roger, a 55-year-old time-pressured male executive with a body mass index of 28 and a waist circumference of 94cm, is keen to lose weight and wants to know about high-intensity interval training (HIIT) If Roger wants to resume physical activity after a sustained sedentary lifestyle, he should seek medical advice first. Due to the high-intensity aspect of HIIT, people who are not used to exercise can find it too demanding. For the purposes of Roger’s case, I refer to HIIT as the highintensity circuit training routine by Brett Klika and Chris Jordan of the Human Performance Institute in Orlando, Florida. Their routine consists of 12 bodyweight exercises, each done intensely for 30 seconds, and with a 10-second transition time between each exercise. The circuit lasts about seven minutes, and participants can repeat it two to three times, depending on their fitness and amount of training time. There are many sevenminute workout smartphone apps that can guide users through the circuit.
HIIT is one way of getting fit, and the advantages are you do not necessarily need a gym as you are using your body weight, and it is relatively quick. But it is not a panacea and is not suitable for everyone. Previously sedentary people will need to build up to this circuit slowly by not doing all 12 exercises initially, and perhaps doing each exercise for only 10 seconds. Those experiencing knee pain due to arthritis should avoid jumping exercises and people with high blood pressure and a history of heart disease are advised not to do exercises involving the Valsalva manoeuvre (attempting to forcibly exhale while keeping the mouth and nose closed). This can strain the heart. Swimming or brisk walking in the pool are safer alternatives for them as the water provides resistance while its buoyancy supports the knees. Ray Ng practices as a family physician in a Central clinic. He is a member of the Royal College of General Practitioners (UK). info@medicinemadeclear.com