With the science of nutrition, medicine, and psychology rapidly unveiling new information our bodies almost daily, it’s hard to keep track on what is considered healthy. Below are fifteen things that were once celebrated as healthy, but are now decidedly unhealthy.
Posts Tagged ‘Nutrition’
Nutrition and health: Protection racket
April 8th, 2010 |
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Eating lots of fruit and vegetables may not help stave off cancer, after all
FOR snivelling children and recalcitrant carnivores, requests that they should eat five portions of fruit and vegetables every day have mostly fallen on deaf ears. But those who did comply with official advice from charities, governments and even the mighty World Health Organisation (WHO), could remind themselves, rather smugly, that the extra greens they forced down at lunchtime would greatly reduce their chances of getting cancer. Until now, that is. Because a group of researchers led by Paolo Boffetta, of the Mount Sinai School of Medicine in New York, have conducted a new study into the link between cancer and the consumption of fruit and vegetables, and found it to be far weaker than anyone had thought.
In the past, veggie-associated reductions of cancer-risk rates as high as 50% had been reported. But it appears that some of these early investigations may have been biased by the use of “case-control” studies. Such studies try to identify the factors contributing to cancer by comparing people who have the disease with those who do not, but are otherwise similar. The problem is that they can easily be biased if researchers do not adequately establish that the two groups being compared are, indeed, otherwise similar. Walter Willet, at the Harvard School of Public Health, says it appears that earlier investigations were more likely to use health-conscious people as their controls. These types of people are, unsurprisingly, more likely to agree to be interviewed about their health than slobby couch potatoes. …
Nutrition: Note to self
October 29th, 2009 |
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The best ways to get enough omega-3 oils
THE best ways to get enough “good” (ie, long-chain) omega-3 oils are either to eat lots of oily fish or to take, every day, supplements that contain at least 500mg of eicosapentaenoic acid (EPA), or docosahexaenoic acid (DHA), or both (though some studies have suggested as much as 1,100mg a day is better). Products that contain short-chain omega-3s, such as alpha-linolenic acid from plant oils like flax-seed oil, have not been linked with the strong health benefits shown by fish oils.
Having got enough long-chain oils, though, it is important to let them do their work. That means reducing consumption of omega-6 oils—those found in maize, sunflower, olive and most other seed oils. Many people have turned to these seed oils as a way of reducing their intake of saturated fats, but omega-6 fatty acids compete in the body with omega-3s, since the two have similar chemical properties. The best dietary ratio of omega-6 to omega-3 is reckoned to be less than 4:1. In Western diets, it is typically more like 10:1. The message, then, is: eat less fat and get more of it from fish. And those who buy omega-3 supplements that also contain omega-6s are probably wasting their money. …
Nutrition and health: Food, glorious food
October 29th, 2009 |
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The way health claims about food are regulated is changing
BARELY a day seems to pass without a new study reporting the benefits of omega-3 fatty acids. A high intake of omega-3s has been linked with reduced rates of depression, cardiovascular disease and homicide. In pregnant women the consumption of these wonder molecules has even been associated with an uplift of the IQ of their offspring. The food industry has responded to this bonanza of evidence by putting omega-3s into everything from baby milk to drinks to margarine in the hope of increasing sales while bringing health benefits to fat and sickly customers.
Behind the silver lining, though, looms a black cloud: not all omega-3s are created equal. The good ones (long-chain fatty acids) come from expensive sources such as fish. The far less beneficial ones (short-chain fatty acids) come from cheap plant oils like flax seed and soya, as well as from leafy green vegetables. No prizes for guessing which type of omega-3s some less-scrupulous manufacturers have chosen to put in their products in order to imply health benefits. …
Sports Nutrition at an Athlete Level
August 11th, 2009 |
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It takes a lot to become an athlete. As well as the ability to excel in your chosen area, you also need to have an enormous amount of time and dedication to devote to your cause. Whether you’re a dedicated footballer, a long distance runner or a powerful weightlifter, there’s one thing that all athletes [...]
Organic food has ‘no health benefits’
July 30th, 2009 |
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Organically produced foods are not nutritionally superior to conventionally produced foodstuffs, according to researchers.
Consumers appear willing to pay higher prices for organic foods based on their perceived health and nutrition benefits, however, the new study from London School of Hygiene & Tropical Medicine found no evidence for superior nutritional content of organic food.
During the review, [...]
The truth about sports drinks
July 28th, 2009 |
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Sam Murphy reveals how much fluid you need to drink before, during and after a workout, and whether water does the job just as well as sports drinks
Do I really need a sports drink? Won’t water do?
It depends on the intensity and duration of your workout. “Water is generally sufficient for shorter sessions, but for exercise lasting more than 60 minutes, an isotonic sports drink is recommended,” says Wendy Martinson, registered dietician and sports nutritionist.
But Nick Morgan, head of sport science at Lucozade, believes sports drinks can be useful for shorter workouts, too: “If you’ve had a good high-carbohydrate meal in the three-four hours before your workout, you probably don’t need a sports drink”, he says. “But if you haven’t eaten for ages – if, for example, you’ve just got up or have hit the gym straight after work, a sports drink will provide a little extra energy, helping you get more out of yourself and reducing your ‘perception of effort.’”
Just for the record, a study in the Journal of Applied Physiology found that consuming an isotonic sports drink increased treadmill running time to exhaustion by 27% in recreational runners.
What should I look for in a sports drink?
According to Martin Gibala, an associate professor of kinesiology at McMaster University in Canada, there are two key ingredients in a good sports drink: “Carbohydrate, which provides fuel for working muscles, and sodium, which helps to maintain fluid balance.”
But formulation is key. An isotonic drink (such as Lucozade Sport or Gatorade) contains a 6-8% carbohydrate solution, which is absorbed into the body more rapidly than water, as well as providing energy. A sports drink should also contain approximately 50mg of sodium per 100ml, along with smaller amounts of the other electrolytes, such as potassium and chloride, which are lost in sweat.
Morgan highlights another important consideration: palatability. “Studies show clearly that if you don’t like the taste of a sports drink, you won’t consume enough of it.”
Are all sports drinks isotonic?
Confusingly, no. Lucozade Sport Hydro Active, for example, is ‘hypotonic’, meaning it contains a less concentrated carbohydrate solution (1-3%). “This will promote water absorption, but provides less carbohydrate energy and fewer calories,” explains Martinson.
At the other end of the scale are ‘hypertonic’ drinks, with a carbohydrate concentration greater than 10%. “These will have a slow gastric emptying rate, thus decreasing fluid absorption,” says Martinson. Energy drinks – including Red Bull – and soft drinks – such as Coke and Pepsi – come into this category, which makes them unsuitable for use during exercise.
How much do I need to drink?
In 2007, the American College of Sports Medicine, an international authority on sport science, revised its guidelines on fluid intake during physical activity, no longer suggesting specific volumes per hour. “We now know that individual needs vary so much it is impossible to suggest a ‘one size fits all’ amount that will suit everyone”, says Morgan. “Issues surrounding the risks of dehydration on one hand and hyponatraemia (water intoxication) on the other make this dangerous ground.”
So what’s the best way forward? Martinson advises calculating your own personal ‘sweat rate’ (see below) so that you can determine how much you need to drink. “Exercise performance is impaired when there is only a 2% decrease in body weight [due to fluid loss]“, she says. “Determining your own sweat rate will enable you to drink sufficient amounts of fluid to minimise weight loss to less than 2% body weight.”
According to Joseph Verbalis, Professor of the Department of Medicine at Georgetown University Medical Center, you should also listen to your body. “Thirst is a good indicator of your body’s need for fluid,” he says.
Working out your sweat rate
• Record your nude pre-training weight (in kg)
• Record your nude post-training weight, towelling off sweat first.
• Opt for a 30- or 60-minute session, during which you don’t consume fluid. (This makes the maths easier!)
• Subtract your post-training weight from pre-training weight to work out the weight lost, and multiply by 1,000 to convert to grams. The amount you lost in grams is equal to the amount of fluid you lost during that session. If you did a 30-minute session, multiply by two to get your ml per hour figure. This is the amount you should aim to consume in subsequent sessions. For example, if you lost 500g in 30 minutes, you’d be looking to consume 1000ml per hour.
• Bear in mind that the temperature, weather conditions and the intensity of the session will influence your fluid loss – factor this in when determining how much to drink in future sessions.
Should I drink before my workout, or just during?
It’s important to start exercise well hydrated. Research suggests that the body cannot absorb ingested carbohydrate efficiently if the body is dehydrated, so even if you are guzzling sports drinks, they may be of limited benefit. The ACSM recommends drinking 5-7ml of fluid per kg of your body weight in the three-four hours before exercise. (So, if you weigh 60kg that means drinking 300-420ml.) If your urine is still dark after this, they suggest drinking a further 3-5ml/kg. Water will do just fine – but, says Martinson, consuming a sports drink helps to top up carbohydrate stores.
Does it matter if I drink sports drink and water in the same session?
Martinson believes not. “You will still benefit from the carbohydrate and electrolytes in the sports drink even if you drink some water as well,” she says.
Scientists at the Gatorade Sports Science Institute, however, disagree, stating: “Watering down a sports drink dilutes the taste, carbohydrate content and electrolyte level – any of which will diminish its performance benefits.”
What about if I mix sports drinks with gels? Am I destined for the Portaloo?
Despite a belief among many runners and triathletes that you shouldn’t mix drinks and gels, according to Morgan it shouldn’t make any difference. “The important thing is to get enough fluid and enough carbohydrate on board – whatever the source,” he says. But like any nutrition or hydration strategy, you need to test it out in training.
Once I’ve finished exercising, is there any benefit in drinking a sports drink?
“You need to think about what kind of workout you’ve done and when you’ll next be exercising to determine whether a sports drink will help you recover,” says Morgan. If you’ve swanned around the gym for 20 minutes, forget it. If, however, you’ve done a tough session and will probably be doing another one within the next 48 hours, you’ll definitely benefit from taking extra carbohydrate on board within the first hour.
“Research also supports the practice of consuming protein after exercise to promote muscle recovery,” adds Gibala. Proprietary ‘recovery’ sports drinks typically tick both the carb and protein boxes, but research from Northumbria University found chocolate milk to be highly effective in facilitating recovery.
Other recent research, published in the Journal of Applied Physiology, found that athletes who added caffeine to their recovery cocktail had 66% more glycogen in their muscles four hours after finishing an intense workout.
I have ‘tidemarks’ on my clothes after exercise – should I take extra salt on board?
Tidemarks on clothes are an indication of a ‘salty sweater’. But, says Morgan, this alone is not reason to take extra salt on board. “It needs to be considered alongside the volume you sweat: so you could be a salty sweater who doesn’t lose much sweat (so not too much sodium lost) or a non-salty sweater who sweats buckets (increased loss of sodium.) If you sweat profusely and are a salty sweater there may be need for extra salt, but you would probably be suffering from cramping or extreme fatigue if this were the case.”
How to make your own sports drink
This sports drink recipe, provided by Wendy Martinson, will produce an isotonic drink containing 6-7% carbohydrate solution, depending on the type of squash used.
Mix 250ml ordinary squash or 200ml high juice squash (not sugar-free or low calorie) with 750-800ml cold water, or mix 100-110ml standard Ribena with 900-890ml cold water. Add 1.25g salt (1/2 level tsp).
More information
lucozade.com/sport
gssiweb.com
American College of Sports Medicine on exercise and fluid replacement
Do you swear by sports drinks during exercise, or does water keep you going? Will you change what you drink after reading this article? Let us know in the comments section below.
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Healthy breakfast and lunch can guarantee kids’ academic success
July 27th, 2009 |
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Want your kids to do well academically? Well, in that case, just make sure they eat a healthy breakfast and lunch, says a team of researchers.
According to scientists, good nutrition improves mental and behavioural performance.
Mary Pat Alfaro, education coordinator in Nutrition Therapy at Cincinnati Children’s, explains multiple studies have shown that poor nutrition [...]
Science Weekly: In search of time
July 13th, 2009 |
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What it time? Is it the uniform, steady flow envisaged by Newton that helps us follow our daily routines? A spooky, purely subjective feeling? A dimension of Einstein’s space-time? Or simply the phenomenon that stops everything from happening all at once?
Science writer Dan Falk is on hand to discuss the neuroscience, the physics and the philosophy of chronology and poses the question – do we really know what time is?
James Randerson and Nell Boase join Alok for a round-up of the week’s science news including claims that vegetarians are 45% less likely to develop cancer of the blood compared with meat eaters, a monster haul of new dinosaur species discovered in the Australian outback, and the G8 nations’ battle with climate change.
We also visit the Royal Society’s Summer Exhibition to sink our teeth into some of the latest creations of science. Among the exhibits were a virtual cow, lasers that can treat cancer – and a very excitable and science-literate bunch of schoolchildren.
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Vegetarians ‘less likely to get cancer’
July 1st, 2009 |
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• Striking difference found in risk of disease in blood
• Scientists acknowledge more research still needed
For years, they have boasted of the health benefits of their leafy diets, but now vegetarians have the proof that has so far eluded them: when it comes to cancer risks, they have the edge on carnivores.
Fresh evidence from the largest study to date to investigate dietary habits and cancer has concluded that vegetarians are 45% less likely to develop cancer of the blood than meat eaters and are 12% less likely to develop cancer overall.
Scientists said that while links between stomach cancer and eating meat had already been reported, they had uncovered a “striking difference” in the risk of blood cancers including leukaemia, multiple myeloma and non-Hodgkin lymphoma between the groups. The study looked at vegetarians, fish eaters and people who ate meat.
Co-author Naomi Allen, from the Cancer Research UK epidemiology unit at Oxford University, said: “Previous research has found that processed meat may increase the risk of stomach cancer, so our findings that vegetarians and fish eaters are at lower risk is plausible. But we do not know why cancer of the blood is lower in vegetarians.”
She said the differences in cancer risks were independent of other lifestyle factors including smoking, alcohol intake and obesity.
However, Allen urged caution over the interpretation of the findings. “It is a significant difference, but we should be a bit cautious since it is the first study showing that the risk of cancer of the blood is lower in vegetarians. We need to know what aspect of a fish and vegetarian diet is protecting against cancer. Is it the higher fibre intake, higher intake of fruit and vegetables, is it just meat per se?”
The study also reported that the total cancer incidence was significantly lower among both the fish eaters and the vegetarians compared with meat eaters.
The study, published in the British Journal of Cancer, is part of a long-term international study, the European prospective investigation into cancer and nutrition (Epic).
Today’s findings were based on a study of 61,000 people who scientists followed over 12 years. During this time, 3,350 participants were diagnosed with cancer. Of those, 68% (2,204) were meat eaters, 24% (800) were vegetarians and 9.5% (300) ate fish but no meat.
They found that 180 meat eaters developed blood cancers, while 49 vegetarians developed the diseases and 28 fish eaters. They found the risk of being diagnosed with cancers of the stomach, bladder and blood was significantly lower in vegetarians than in meat eaters but, in contrast to earlier work, they found the rate of bowel cancer was slightly higher among vegetarians than meat eaters.
A spokesman for BPEX, the British pig executive, questioned the methodology of the study: “We are unable to take a view on this because there is mixed evidence based on the compounding factors to do with lifestyle that come into it.”
Richard Lowe, the chief executive of Eblex, the English beef and lamb executive, said: “We think that the link between diet and cancer is complex and as scientists themselves say, more research is needed to see how big a part diet plays.”
The Oxford research is the latest in a series of reports to discourage too much meat in the diet. Last year, Dr Rajendra Pachauri, chair of the UN Intergovernmental Panel on Climate Change – which last year earned a share of the Nobel peace prize – urged giving up meat at least once a week as a way of combating global warming. The UN’s Food and Agriculture Organisation has estimated that meat production accounts for nearly a fifth of global greenhouse gas emissions.
Two years ago, the World Cancer Research Fund found a link between red and processed meat and bowel cancer and recommended that the average amount of meat eaten should be no more than 300g a week. In Britain, the current meat intake is about 970g a week for men and about 550g a week for women.
In 2005, the Epic study, funded by the Medical Research Council, Cancer Research UK and the International Agency for Research on Cancer, concluded that eating just two portions of red meat a day – the equivalent of a bacon sandwich and a fillet steak – increased the risk of bowel cancer by 35%. It found that eating fibre, in the form of vegetables, fruit and wholegrain cereals, lessened the risk of cancer and that fish, eaten at least every other day, was also protective.
Annette Pinner, chief executive of the Vegetarian Society, said: “It is widely recognised that a third of cancers are directly related to diet and what’s interesting in this study is the findings on blood cancers. We wouldn’t claim vegetarianism is a panacea for cancer but it is a step in the right direction.”
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