Beck Health & Nutrition - Latest Health & Nutrition News

The following is a selection of articles from past issues of Beck Health & Nutrition's Latest Health News email updates that relate to nutrition and health during adolescence.

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Teenage athletes still look to mum and dad for nutritional guidance

A study of almost 3000 athletes in high-school and college settings throughout the United States has found that 77% of athletes ranked their parents as being their most important source of nutrition information. College athletes were also found to have significantly less nutrition knowledge than nonathletes.

Dieting and exams don't mix

Australian research now shows that dieters are more forgetful when it comes to carrying out some complex cognitive tasks as it seems that some of their memory space is taken up thoughts of food, weight and body image. Researchers from Adelaide's Flinders University divided 92 female university students into three groups: those currently on a diet, those who had dieted in the past and those who had never dieted. The students then performed a series of cognitive tasks, such as tests recalling sequences of short and long words. The researchers found that those currently dieting struggled with complex verbal tasks. "You would think that dieting doesn't have much to do with verbal type things. But our study showed that when people were doing a task and then had to say something like numbers at the same time it affected their performance,".

Interestingly, only those who were currently dieting were affected; those who had once dieted performed on par with those who had never dieted. The researchers said this indicated it was the dieting behaviour itself that contributed to the poorer performance. The researchers reported that the study findings were consistent with the idea that it was dieters' preoccupying thoughts that led to poorer memory performance. Source: http://www.abc.net.au/science/news/health/HealthRepublish_1105852.htm

The effect of starvation during adolescence the ultimate health impact starvation can cause during childhood and adolescence has been a constant unknown for people dealing with conditions such as anorexia nervosa however results from a study of childhood survivors from Leningrad in WWII may shed new light on the risks. For almost 3 years from 1941, Leningrad was under siege by Hitler’s armies. Hundreds of thousands of people died, many from starvation.

About 1500 men who lived in Leningrad during the siege were followed over 25 years from the mid 70s. As children and adolescents during the war, they would have been living on about 300 calories (1200 kilojoules) per day. People have suspected that starvation can cause heart and blood vessel problems later in life - but the results of research have been mixed.

Men who had been in the siege, especially around puberty, had higher blood pressure and more body fat. And during follow up they were significantly more likely to die of a heart attack or stroke than men who hadn’t experienced such starvation. These findings allowed for the men’s smoking, alcohol intake and other factors which might have clouded the results.

The reason may be that puberty is a vulnerable period where the stress of starvation can permanently re-set hormones and damage the heart. The question is whether the same thing occurs in people with severe anorexia nervosa - and there is some evidence that it does.

Juice claims lack substance it seems that juice bars are popping up in shopping malls and CBDs of every major city and town and the range of fruit and vegetable juices available in supermarkets continues to grow but how healthy are these juices and can they replace fruit and vegetables in the diet? Juices are a great source of nutrients however in general Australians are already not consuming enough dietary fibre so relying on juices to provide much of our fruit and vegetable requirements is reducing our dietary fibre intake further. Juice gives you all the dietary energy of a few pieces of fruit but not the fibre that fills you up. And what about the claims by many juice bars that particular juices will provide an energy boost, improve immunity or reduce stress? Such claims are normally reliant on herbal supplements such as ginseng, guarana or echinacea being added to the juices. In this instance you are relying on the quality and dosage of the herbal supplement being used. Source: Goodyer P. Juice claims lack substance. Sydney Morning Herald Thursday April 15 2004.

Are overweight kids malnourished? We tend to assume that the obese child is overfed however new thinking is pointing towards childhood obesity in fact being a form of malnutrition. The term malnutrition can be defined as ‘lack of proper nutrition resulting from deficiencies in the diet’ and a recent study of Australian school children found that many obese children were shorter than the other children by about 2 centimetres. The findings suggest that while these children are obviously consuming more than dietary energy, the types of food that they are commonly consuming do not provide enough of the vital nutrients required for growth and development. It seems as though excess calories are replacing the core food groups of meat, milk, fruit and vegetables in the diet so despite all the food the obese child is eating they may actually be missing out on vital vitamins and minerals. Source: http://www.abc.net.au/catalyst/stories/s1073786.htm

Angry teenagers should eat more fish A new US study reports that a diet rich in fish may reduce hostility in young adults. The study examined the relationship between fish intake, levels of DHA (a fatty acid found in fish) and levels of hostility among 3581 young adults. The researchers found that even after adjustment for factors such as age, sex, race, education, physical activity, body mass index, smoking and alcohol consumption dietary intake of the fatty acid DHA was significantly associated with reduced likelihood of hostility in young adults. Source: Iribarren C et al. Dietary intake on n-3, n-6 fatty acids and fish: relationship with hostility in young adults - the CARDIA study. EJCN 2004;58:24-31 cited in www.blackmores.com.au.

Teenagers who skip breakfast are more likely to smoke, not exercise, have lower education levels, drink more alcohol, have a higher body mass index (BMI) and have more behavioural problems than their breakfast-eating counterparts. The Finnish Study of more than 10000 teenagers also found that the most statistically significant factor in teenage breakfast eating was whether the teenager's parents ate breakfast regularly. Reference: A Keski-Rahkonen et al. Breakfast Skipping and Health-compromising Behaviors in Adolescents and Adults. European Journal of Clinical Nutrition (2003) 57, 842-853

Children not getting enough sleep: US Study. A new poll by the National Sleep Foundation in the U.S. has found that two-thirds of preschool aged children there are not getting enough sleep. Sleep experts over here agree saying that many Australian children's lives are so packed with activity that they're not resting enough. Dr Margot Davey, from the Melbourne Children's Sleep Unit comments that "the demands on the modern child are such that sleep is not always a priority and that has a significant impact on young lives" and Dr Arthur Teng from the Sleep Medicine Unit at Sydney Children's Hospital says that parents need to know why sleep is so important to their children "I don't think that there is enough emphasis yet because when you're looking at young children who might present with behavioural or learning problems, a lot of doctors are not even asking about sleep, and it has been shown in research studies that it is very rate that parents actually bring up the issue of sleep, even with their GPs" and its not just the children who suffer, the same U.S. poll also noted that parents are losing up to 200 hours sleep a year as a result of their children's lack of sleep (Reference: ABC Online, PM Program available at http://www.abc.net.au/pm/content/2004/s1078259.htm).

US Scientists dub soft drinks as “cigarettes of obesity”

Low-fat, low-cal, low-carb. Atkins, South Beach, The Zone. Trendy diets may be distracting attention from something more insidiously piling on kilos: beverages. One of every five calories in the American diet is liquid. The nation's single biggest "food" is soda (soft drink). Now two groups of US researchers hope to add evidence to the theory that soda and other sugar-sweetened drinks don't just go hand-in-hand with obesity, but actually cause it.

Proving this would be a scientific leap that could help make the case for higher taxes on soda, restrictions on how and where it is sold - maybe even a surgeon general's warning on labels. "We've done it with cigarettes," said one scientist advocating this, Barry Popkin at the University of North Carolina in Chapel Hill.

However, those making the case against soda include some of the nation's top obesity researchers at prestigious institutions like Harvard and Yale.

"There are many different lines of evidence, just like smoking," said Dr David Ludwig, a Harvard paediatrician who wants a "fat tax" on fast food and drinks.

Beverage companies seem worried. Some are making sodas "healthier" by adding calcium and vitamins, and pushing fortified but sugary sports drinks in schools that ban soda. This could help them duck any regulations aimed at "empty calorie" drinks, said Jennifer Follett, a USDA nutritionist at the University of California in Davis.

"Even defining 'milk' is getting tough these days," with so many flavoured varieties and sweetened liquid yoghurts, she complained. "It tastes like you're sucking on ice cream."

Proving that something causes disease is not easy. It took decades with tobacco, asbestos and other substances now known to cause cancer, and met strong industry opposition. It would be especially tough for a disease as complex as obesity.

Diet is hard to study. Most people drink at least some sweetened beverages and also get calories from other drinks like milk and orange juice, diluting the strength of any observations about excess weight from soda alone.

Children are growing and gaining weight naturally, "so we have this added complication" of trying to determine how much extra gain is due to sweet-drink consumption, said Alison Field, a nutrition expert at Harvard-affiliated Children's Hospital in Boston.

Soft drink consumption rose more than 60 per cent among adults and more than doubled in kids from 1977-97. The prevalence of obesity roughly doubled in that time. Scientists say these parallel trends are one criterion for proving cause-and-effect.

Numerous studies link sugary drink consumption with weight gain or obesity. One by Ludwig of 548 Massachusetts schoolchildren found that for each additional sweet drink consumed per day, the odds of obesity increased 60 per cent.

Another at Harvard of 51,603 nurses compared two periods,
1991-95 and 1995-99, and found that women whose soda drinking increased had bigger rises in body-mass index than those who drank less or the same.

Biologically, the calories from sugar-sweetened beverages are fundamentally different in the body than those from food.

The main sweetener in soda - high-fructose corn syrup - can increase fats in the blood called triglycerides, which raises the risk of heart problems, diabetes and other health woes.

This sweetener also doesn't spur production of insulin to make the body "process" calories, nor does it spur leptin, a substance that tamps down appetite, as other carbohydrates do, explained Dr George Bray of the Pennington Biomedical Research Centre in Baton Rouge, Louisiana.

"There's a lack of fullness or satiety. The brain just seems to add it on," said Dr Louis Aronne, a Weill-Cornell Medical College doctor who is president of the Obesity Society.

Two studies by Penn State nutritionist Barbara Rolls illustrate this. One gave 14 men lemonade, diet lemonade, water or no drink and then allowed them to eat as much as they wanted at lunch. Food intake didn't vary, no matter what they drank.

The second study gave 44 women water, diet soda, regular soda, orange juice, milk or no drink before lunch. Total intake was 104 calories greater for those given caloric beverages than those given diet soda, water or no beverage. Caloric drinks didn't help women feel any fuller either.

Then there is the "jelly bean study." Purdue University researchers gave 15 men and women 450 calories a day of either soda or jelly beans for a month, then switched them for the next month and kept track of total consumption. Candy eaters ate less food to compensate for the extra calories. Soda drinkers did not.

Sugar-sweetened beverages affect the intake of other foods, such as lowering milk consumption. Popkin contends they also may be psychological triggers of poor eating habits and cravings for fast food.

He examined dietary patterns of 9,500 American adults in a federal study from 1999-2002. Those who drank healthier beverages - water, low-fat milk, unsweetened coffee or tea - were more likely to eat vegetables and less likely to eat fast food.

Conversely, "fast-food consumption was doubled if they were high soda consumers and vegetable consumption was halved," he said.

Harvard epidemiologist Eric Rimm saw a similar effect in a different federally funded study of more than 5,000 young adults. With high soda consumption, "you see this pattern of less healthy intake across the board," he said at the obesity meeting.

Many studies of different types link sugary drinks and weight gain or obesity. Some even show a "dose-response" relationship - as consumption rises, so does weight.

Collectively, they meet many criteria for proving cause and effect, Dr William Dietz, director of nutrition at the federal Centres for Disease Control and Prevention wrote in an editorial accompanying a study in February's Journal of Paediatrics.