This story was first published in November, 2015 in an e-book titled 50 Food Myths Busted, in The Straits Times Star E-books app. In the book, experts clear the air on widely held misconceptions and beliefs about food. They address questions on myths on the daily diet, pregnancy and babies, fuelling workouts, sickness and what we drink. The book was conceptualised and written by the team at Mind & Body, the weekly health features section in The Straits Times.
Preface by Poon Chian Hui, editor, Mind & Body
Eat this, not that. People have plenty of beliefs about food - even more so when it comes to their health.
At Mind & Body, a health features section of The Straits Times, we get questions from readers about nutrition, dietary guidelines and even warnings about certain food items.
But the answers aren't always clear-cut. Studies may contradict each other, and experts can have different opinions.
The Mind & Body team rounded up 50 confounding food myths and asked doctors and dietitians islandwide to clear the air, once and for all.
You will also find handy tips on how best to navigate each situation.
Should you always choose fresh produce over frozen food? Does eating before exercise give you cramps or stitches? And will consuming more fibre help to ease constipation?
Read on to find out - the answers may surprise you.
CHAPTER I. THE DAILY DIET
MYTH 1: Replace white sugar with brown sugar, honey or agave syrup for a healthier fix
These sugars are no better than refined white sugar, which is a simple carbohydrate that is easily utilised by the body for energy but stored as fat if it is not needed.
"Essentially, all sugars are the same, with minor differences in terms of the presence of minerals, impurities and colouring," said Ms Jenny Ng, principal dietitian at Mind Your Diet.
"Regardless of the type of sugar, it will eventually be broken down into glucose, which will enter our bloodstream and be used as energy by our cells."
Sugar should be taken in small amounts as it provides empty calories and has no nutrients.
Ms Ng said people should watch out for hidden sugars in food and drinks. Soft drinks, in particular, have a lot of sugar - one can of drink can have as much as eight teaspoons of sugar, she said. And if you add sugar to your drinks or to your food while cooking, you may be increasing your caloric intake significantly without realising it.
MYTH 2: A calorie is a calorie, so it doesn't matter what time of the day you eat, including late-night meals
It does, said Ms Sarah Sinaram, senior dietitian at Raffles Diabetes & Endocrine Centre.
An Australian study published in 2007 showed that night eating syndrome, where most food is consumed in the evening and night, was associated with a higher body mass index, she said.
Another study done in 2013 concluded that eating more of the day's total energy intake at midday is associated with a lower risk of being overweight or obese, while consuming more in the evening is associated with a higher risk.
When it comes to eating late at night and its potential for weight gain, the following points should be considered, she said.
1. Portion sizes: Delaying your mealtimes can lead to consumption of larger portion sizes.
2. Quality of food: After a long day at work or school, fast food may seem more appetising than steamed vegetables and broiled fish.
3. Mindless snacking: Snacking on fried, oily or sugary snacks while studying or watching TV may result in the consumption of excess calories.
4. Health concerns: Going consistently without food for long periods of time, only to follow it with a large meal, can negatively impact the interaction between your blood sugar and insulin and make yourself more vulnerable to type 2 diabetes.
Limiting late-night meals and snacks may be an effective weight management strategy for some people because it helps them to control their overall calorie intake.
Some people find it helpful to set a time limit each day to make sure they do not eat past a certain time. This helps them to minimise or eliminate the possibility of munching on a lot of high-calorie food at night.
MYTH 3: Radiation from microwave ovens kills more nutrients in food compared to conventional cooking.
Not true, at least, that is what current evidence shows. If properly used, cooking using microwave ovens do not affect the nutritional content of food more than conventional heating on the stove.
Rather, as the microwaves affect mainly water molecules, they "steam" food from inside out, and this helps to retain most nutrients, according to an article in Harvard Health Publications by Harvard Medical School in the United States.
It is important to note that all types of cooking tend to cause a loss of nutrients, according to dietitians and food scientists. The key to minimising it is to keep the cooking time short with the least possible amount of liquid - something that microwave ovens fare well at.
Try not to cook vegetables in water using the microwave, unless you intend to consume the water as well. This is because nutrients may leach out into the water, according to Harvard Health Publications.
You can try steaming greens in the microwave instead, by placing a container of water inside the oven.
MYTH 4: Choose margarine over butter to lower your risk of heart disease
It's not that simple.
Indeed, margarine products that are based on plant oil are mostly higher in unsaturated fat, which is known to be beneficial for our heart health. They also contain lower amounts of unhealthy saturated fat, said Ms Gina Lin, a dietitian at Singapore General Hospital.
The only exceptions, however, are those made of palm oil. Up to 50 per cent of its content can be saturated fat, she pointed out.
Also, the hydrogenation process of making margarine from plant oil high in unsaturated fats can create trans fat. This type of fat increases one's risk of heart disease as it raises the level of "bad" cholesterol and lowers the level of "good" cholesterol in the body.
The softer the margarine, the lower its trans fat content. So, soft or tub margarine made from plant oil high in unsaturated fat (such as olive, sunflower and canola oil) is better. Choose those labelled with the "trans-fat free" Healthier Choice Symbol, as this indicates that they contain no more than 0.5g of trans fat per 100g of margarine. You can also choose margarine labelled as "reduced fat" or "reduced salt to further decrease your risk of developing heart disease.
MYTH 5: Frozen yogurt is better for your health than ice cream
Frozen yogurt and ice cream are both made from dairy sources, yet frozen yogurt has been dubbed a healthier alternative to ice cream.
Indeed, yogurt is lower in fat due to the use of milk instead of cream.
But fat-free or low-fat products may not be low in calories and sugar.
Sugar makes up 15 to 20 per cent of the ingredients in frozen yogurt, which is equivalent to the sugar content in ice cream, said Ms Janie Chua, a senior dietitian at National Healthcare Group Polyclinics.
A serving, or about 90g of ice cream, provides 180kcal; 100g of frozen yogurt provides 150kcal.
A better alternative to frozen yogurt would be natural low-fat yogurt, which is lower in calories and sugar, she advised.
A serving of natural low-fat yogurt, or about 120g, has 100kcal.
Based on a 100g serving, the sugar content of ice-cream, frozen yogurt and natural low-fat yogurt would be 23g, 24g and 14g respectively.
In addition, frozen yogurt may have less probiotics than yoghurt as some live cultures may be killed during its freezing process.
If you are watching your fat and calorie intake, you may opt for frozen yogurt, but it is important to moderate your portion size and avoid toppings that are high in fat and sugar, such as assorted flavoured syrups, chocolate chips and marshmallows, said Ms Chua.
Instead, go for toppings such as fresh fruits or nuts, which are lower in calories, fat and sugar.
MYTH 6: Fresh produce is more nutritious than frozen or canned food
Not always. Fresh fruit and vegetables, if not stored properly, may lose their nutrients fairly quickly.
But if frozen quickly after harvest and stored properly, a significant amount of their nutrients can be retained for up to a year, said nutritionist Benjamin Lee and dietitian Chelsea Chang from Health Promotion Board (HPB).
Phytochemicals, antioxidants that are found in fruit and vegetables, can sometimes be more abundant in processed food. Heat applied during the canning process, for instance, can increase the levels of lycopene, which is associated with a reduced risk of prostate cancer, they said.
In general, you won't find any less phytochemicals in frozen and canned food, compared to fresh ones.
Frozen or canned products can be a good way to stock up on fruit and vegetables at home to meet your daily recommended intake (two servings of each), especially if you are too busy to buy fresh varieties regularly, said Mr Lee and Ms Chang.
Do note, however, that canned food usually contain lower amounts of heat-sensitive nutrients, such as vitamin C. Canned fruit also tend to contain sugar syrup, while canned vegetables are preserved with brine. Therefore, look for items that are lower in salt or contains light syrup or natural juice.
MYTH 7: Regular refined salt is less healthy than sea salt, other fancy salt or salt flakes
All salt comes from either the sea or salt deposits, and they all contains sodium, which can raise one's blood pressure if consumed in excess.
"Sea salt and table salt are basically the same in terms of nutritional value. By weight, they contain the same amount of sodium," said Ms Chloe Ong, a dietitian with CanHOPE Counselling & Support Services at Parkway Cancer Centre.
The difference between sea salt and table salt lies in how they are produced and their texture.
Sea salt is usually produced through the evaporation of sea water.
Depending on the water source, some trace minerals and elements, such as magnesium, may be left behind, said Ms Ong.
While table salt, sea salt or kosher salt are not much different in sodium content by weight, there is a difference by volume, as sea salt and kosher salt are usually coarser than table salt.
This means that if you keep to a recipe that calls for a teaspoon of salt, for instance, you will consume less sodium if you use the larger-grain kosher salt instead of fine-grain table salt.
MYTH 8: Skipping meals will help you lose weight
When we skip a meal, we tend to inadvertently overeat at the next meal. We will also crave snacks, said Ms Ler Yi Bin from Mount Alvernia Hospital's nutrition & dietetics services.
So, in the long run, skipping meals can lead to weight gain.
In fact, during a "fasting state", the body will push to conserve calories rather than burn them, she added. It first breaks down glycogen, which are energy stores, in the muscles and liver, before using fat for energy. The amount of energy output reduces, and lean tissue begins to shrink and grow weaker. Meanwhile, hormones will also slow down your body's metabolism.
Try not to skip any meals, especially breakfast. Our body's metabolism slows down during sleep, and delaying a meal will result in a tough time digesting the food later, said Ms Ler. A big meal after a long delay may even lead to weight gain as more calories get stored as fat. Also, don't just drink coffee for breakfast. Fluids get digested faster than solid food, so hunger pangs may strike earlier and you may end up eating too much at lunchtime.
MYTH 9: Splitting calories between six meals, compared to three square meals a day, staves off hunger and boosts weight loss efforts
When it comes to losing weight, it does not matter if you have six small meals or the usual three meals a day.
"It is really up to the individual to decide how many meals he or she is able to have in a day," said Ms Sarah Sinaram, a senior dietitian at Raffles Diabetes & Endocrine Centre.
For example, a salesman may only be able to have three meals a day due to his schedule while an office worker can choose to have up to six meals per day, she said.
Ultimately, it's the calories consumed that matters. "If both are consuming fewer calories than their caloric output, both will lose weight," said Miss Sinaram.
Reduce your overall calorie intake if you want to lose weight. If you eat more calories than what your body uses for daily activities and exercise, you will gain weight.
"Research tells us that following any diet that advises calorie restrictions can result in weight loss," said Ms Sinaram.
MYTH 10: Remove the skin on foods, like potatoes and apples, as they carry germs and are low in nutrients
Many people tend to remove edible skins from their food, such as apples and potatoes, but they contain beneficial vitamins, minerals, phytochemicals and fibre, said Ms Ler Yi Bin from Mount Alvernia Hospital's nutrition & dietetics services.
If you were to compare the flesh or pulp of the food and its skin, the skin is packed with more fibre. In addition, it usually contains insoluble fibre, which adds bulk to stools and prevent constipation, said Ms Ler.
The peel of some types of citrus fruit, such as oranges, lemons and grapefruit, also contains vitamin C, which aids in immunity.
And fruit peels of berries, guava and grapes carry higher levels of antioxidants than their flesh.
Eat edible skin whenever you can. Just make sure to wash them thoroughly to remove any dirt and soil, said Ms Ler.
CHAPTER II: PREGNANCY AND BABIES
MYTH 11: Pregnant women should eat for two
A pregnant woman should not double her normal food intake, said Dr Ann Tan, an obstetrician and gynaecologist at the Women & Fetal Centre at Paragon.
If she eats too much, she will end up putting on too much weight. This can increase her risk of gestational diabetes, backaches and high blood pressure. She may even need a caesarean birth because her baby is too big.
In the first six months of pregnancy, a woman will need an extra snack a day, containing 200 to 300 calories, said Dr Tan. This is the equivalent of a bowl of cereal with low-fat milk and a small banana, a bowl of soup or a muffin, she said.
And in the last three months of pregnancy, she will need up to 500 calories more than her normal intake per day as there is much more weight gain and growth of the baby at this stage, said Dr Tan. This can be a sandwich or a low-fat meal, she said. For those who start off being underweight or overweight, their calorie needs will be different.
For mothers carrying twins, their calorie requirements will have to be increased accordingly, said Dr Tan.
MYTH 12: Eating food that contains oestrogen boosts fertility
Too much of this female hormone will upset the normal hormonal balance in the body, and this is actually detrimental to one's fertility, said Dr Loh Seong Feei, medical director at Thomson Fertility Centre.
In fact, the effects of oestrogen-containing food is a complex matter, he added.
It depends on your body status and whether you have any medical conditions which may be worsened by the presence of oestrogen, such as endometriosis, where the lining of the uterus grows outside the womb, he said.
Men can get a fertility boost from eating foods that are high in antioxidants, as these are beneficial to the production of healthy sperm, said Dr Loh.
MYTH 13: Caffeine, like smoking, lowers your chances of getting pregnant
There is conflicting evidence on this, said Dr Loh Seong Feei, medical director of Thomson Fertility Centre.
A multi-centre European study published in 1997 found that women who consumed 500mg of caffeine or more daily took a longer time to get pregnant. The authors concluded that high levels of caffeine might delay conception, said Dr Loh.
But a review of studies from 2000 to 2009 found that caffeine consumption did not seem to affect fertility, sperm quality and success rates of in-vitro fertilisation (IVF).
What is very clear, though, is that smoking lowers your chances of getting pregnant.
"Smoking has consistently been proven to affect various aspects of human fertility, including egg reserves, sperm quality and IVF pregnancy rates," said Dr Loh.
In the light of the initial 1997 study, doctors still generally advise women who want to get pregnant to reduce their consumption of coffee to one or two cups a day, said Dr Loh.
MYTH 14: Expectant mothers must take folic acid and vitamin supplements daily throughout pregnancy
Daily folic acid and vitamin supplements throughout pregnancy are not compulsory, although they are good for expectant mothers, said Dr Ting Hua Sieng of The Obstetrics & Gynaecology Centre, a Singapore Medical Group clinic.
Folic acid is a vitamin that can help prevent neural tube defects, which involve the incomplete development of the brain and spinal cord, among other benefits.
"If the pregnant mother is already eating a healthy balanced diet, she should have all the folic acid and vitamins she needs from her diet," said the specialist in obstetrics and gynaecology.
However, expectant mothers often have poor appetites due to morning sickness and other problems.
That's when supplements become important, said Dr Ting.
The recommended dose of folic acid for pregnant women is 1mg daily, said Dr Ting. However, taking more is not an issue as it is water-soluble and gets excreted in the urine, she said. Unlike folic acid and vitamin C, vitamins A, D, E and K are not water-soluble. One should not consume too much of these as the excess cannot be easily excreted through urine, said Dr Ting.
MYTH 15: A new mum should start dieting immediately, even if she is breastfeeding, in order to quickly shed the pregnancy weight
Post-natal mothers should consume plenty of fluids and a balanced diet for nutrition, said Mrs Wong Boh Boi, a senior lactation consultant and assistant director (clinical) at Thomson ParentCraft Centre.
Ideally, they should not diet at all, because their body needs extra nutrients at this stage to produce enough milk for her baby, she said. A woman's metabolic rate usually increases by 25 per cent during this period.
Nursing mothers burn about 500 more calories per day, and would need to consume three main meals and two snacks daily. Her diet should preferably be light and include fish, chicken or pork. She should also choose whole grains, instead of starchy grains, to obtain the necessary energy required for breastfeeding, said Mrs Wong.
The amount of fluid intake depends on the mother's needs - she can take extra fluids as long as she feels thirsty. Warm water or beverages, as well as soup, can help increase vascularity and aid in lactation, said Mrs Wong.
MYTH 16: Avoid spicy food as it may trigger early labour
There is no evidence to prove that eating any food will trigger labour, said Associate Professor Tan Thiam Chye, head and senior consultant at the inpatient service division of obstetrics and gynaecology at KK Women's and Children's Hospital (KKH).
That said, eating healthily before conception and throughout pregnancy is one of the best things you can do for yourself and your baby.
Good nutrition optimises the growth and development of your baby and, at the same time, safeguards your own health, he said.
Also, a pregnant woman does not need to eat specific foods just before giving birth, said Ms Nehal Kamdar, a senior dietitian at KKH's nutrition and dietetics department.
She should continue to eat a balanced diet throughout her pregnancy.
A balanced diet means choosing foods from all the food groups in "My Healthy Plate" - a visual tool designed by Health Promotion Board, said Ms Nehal.
This means eating a variety of foods, including fruits and vegetables for folic acid, vitamin A and vitamin C; fatty fish for docosahexaenoic acid (DHA); milk and high calcium foods like cheese and yoghurt for calcium; and meat like chicken for iron.
MYTH 17: Do not eat or drink "cold" stuff after giving birth as the body is weak in qi
Based on Western medicine's perspective, there are no "cooling" or "warm" foods, said Associate Professor Tan Thiam Chye, head and senior consultant at the inpatient service division of obstetrics and gynaecology at KK Women's and Children's Hospital.
As long as the diet is balanced, the new mother can eat all kinds of food, he said.
Try not to overeat foods such as ice cream as the sugar content is high, said Prof Tan.
Drinking sufficient fluids after delivery is also advisable, especially if the mother is breastfeeding.
The kidneys will produce more urine in the next few weeks after the baby is born to remove excess fluid that has accumulated during the pregnancy.
MYTH 18: The bigger the baby, the healthier he is
Size does not determine a baby's health, said Associate Professor Tan Thiam Chye, head and senior consultant at the inpatient service division of obstetrics and gynaecology at KK Women's and Children's Hospital (KKH).
In fact, large newborns weighing more than 3.8kg face more complications than normal-sized babies, said Associate Professor Victor Samuel Rajadurai, head and senior consultant at KKH's department of neonatology.
These include birth injury, low blood sugar, low calcium levels and jaundice.
On average, the weight of full-term babies in Singapore range from 2.8kg to 3kg, said Prof Tan.
Most large babies are born to mothers with underlying diabetes or who developed diabetes during pregnancy. In general, such babies have a three-fold higher rate of birth defects involving the brain, lungs, heart, gastrointestinal tract and spine. Some can be critically ill.
A birth-weight of more than 4kg puts the baby at high risk of developing obesity and diabetes as a child and also as an adult.
Pregnant women should monitor their blood glucose in the second half of their pregnancy to detect any emergence of diabetes.
If the condition is well-controlled, most of the adverse effects can be prevented, said Prof Rajadurai.
MYTH 19: Don't drink too much water one month after giving birth as you will get water retention
Drinking sufficient fluids actually helps the body to remove excess fluid, said Associate Professor Tan Thiam Chye, head and senior consultant at the inpatient service division of obstetrics and gynaecology at KK Women's and Children's Hospital (KKH). The body starts to retain more fluids from the third trimester of pregnancy onwards.
It is also advisable to drink enough after delivery, especially if the mother is breastfeeding. The kidneys will produce more urine in the next few weeks after the baby is born to remove excess fluid that has accumulated during the course of the pregnancy, he said.
To manage water retention, women should reduce their salt intake, drink more water and avoid foods which have a dehydrating effect, such as coffee, tea and alcohol. Also, exercise regularly and elevate the legs whenever possible, suggested Prof Tan.
MYTH 20: You shouldn't follow a vegetarian diet if you are pregnant or breastfeeding
Going vegetarian during breastfeeding will not cause a drop in the mother's milk supply. Plus, the nutritional needs of breastfeeding women on vegetarian diets do not differ from that of a woman on normal diet, said Ms Nehal Kamdar, a senior dietitian at the nutrition and dietetics department at KK Women's and Children's Hospital.
Depending on the type of vegetarian diet a breastfeeding woman is following, her nutritional intake may need to be adjusted to ensure that she is getting adequate calcium, iron, vitamin B12, omega-3 fatty acids and vitamin D.
Vegetarian food sources for calcium include milk, yogurt, cheese, beancurd, broccoli, spinach, nuts, and fortified products, such as calcium-fortified soy milk.
For iron, take eggs, green vegetables, beancurd, legumes, nuts and dried fruit. Vitamin B12 is in milk, fortified soy milk, eggs and fermented soy products, such as miso or tempeh. As for omega-3 fatty acids, they are found in oil (canola, soybean), seeds (flax, chia), nuts and legumes (soybeans, lentils). For vitamin D, take eggs, fortified milk and get 10 to 15 minutes of sun exposure daily.
Chapter III: FUEL YOUR WORKOUT
MYTH 21: Water is just as good as a sports drink for hydration after exercise
Water, in general, does not contain electrolytes (for example, sodium, potassium and chloride) that people lose through sweating.
Based on this, water does not assist with fuel needs of some people, depending on the type of physical activity they are engaged in, said senior dietitian Joanna Tan from Changi General Hospital.
Sports drinks, on the other hand, contain between four and eight per cent of carbohydrates and electrolytes. They are better options for meeting fluid and carbohydrate requirements simultaneously following a long workout.
Water is more than sufficient to replenish fluid requirements for non-endurance physical activities - those that are less than 30 minutes - as well as skill-based sports with little aerobic requirements, such as shooting, bowling and archery.
People taking part in physical activities lasting beyond an hour may want to consider taking sports drinks. In addition, sports drinks may taste better than water, and this could make people more inclined to stay hydrated.
MYTH 22: Carbohydrate-loading simply means eating lots of starchy food, such as rice or pasta, the night before an endurance event
Carbohydrate-loading involves increasing the amount of carbohydrates one eats several days before a high-intensity sporting event, while scaling back on one's activity level, said senior dietitian Joanna Tan from Changi General Hospital.The goal is to stock up on carbohydrates in muscles - known as muscle glycogen - which would be depleted in the race.
That said, consuming a meal high in carbohydrates the night before an event does help to increase the storage of muscle glycogen and enhance exercise performance.
Three days before an event, most athletes should consume between 8g and 12g of carbohydrates for every kilogram of body weight each day.
If an athlete weighs 60kg, the estimated carbohydrate intake will be between 480g and 720g. If he has four pieces of white bread with one tablespoon of jam, a medium-sized banana and a 250ml cup of low-fat milk for breakfast, he would already have obtained 105g of carbs.
They are encouraged to try out this eating regimen well before important competitions to ensure that they are comfortable with the food choices and their quantities.
MYTH 23: To burn more fat, exercise on an empty stomach
This concept is flawed, said sports dietitian Kejendran Mangaikarasu of National University Hospital (NUH) and NUH Sports Centre.
Different factors, such as the type and intensity of exercise, affects our bodies' source of energy.
During low- to moderate-intensity exercise, such as walking or cycling, our body tends to use up more fat stores.
But for high-intensity activity like running or vigorous swimming, our body uses less fat and more of its carbohydrate stores.
The time of the last meal prior to the workout, and the type of food eaten, also matters, he said.
For instance, carbs would slow down the rate of fat being used to provide energy during exercise later.
Eat before you exercise, as the benefits of doing this may outweigh that of exercising on an empty stomach, said Mr Kejendran.
A pre-exercise meal can help you to get the most of your workout.
You will be able to train more vigorously over a longer period of time and experience less fatigue.
MYTH 24: Eating or drinking before exercising gives you cramps or stitches
There has yet to be concrete evidence on this.
What studies have shown is that the risk of stitches depends on the sporting activity, said sports dietitian Kejendran Mangaikarasu of National University Hospital (NUH) and NUH Sports Centre.
Such exercise-related transient abdominal pain (ETAP) is more common in swimmers and runners, compared to cyclists.
ETAP is described as a localised abdominal pain characterised by cramping or a sharp, stabbing sensation.
Other possible reasons for the discomfort include poor fitness levels, high-intensity exercise and the lack of warm-ups, he added.
Do proper warm-ups before engaging in exercise. Also, improving your fitness level can help, said Mr Kejendran.
Don't skip your pre-exercise meal as it actually helps you to finetune your carbohydrate and fluid needs. Failure to meet one's energy needs can result in an impaired sports performance, reduced immunity and fatigue.
MYTH 25: Fat burner products don't help you shed any weight
Fat burners act by raising the body's metabolism, decreasing one's appetite or blocking fat absorption, among other methods.
Many of these products can help you to lose weight, say dietitians.
But there's a catch: After you stop taking them, there is a high chance that you will regain the weight.
Sometimes, you may end up even heavier than what you started off at, especially if you have not adopted a healthy diet and exercise regimen.
It's best to avoid fat burners, as they can cause side effects, such as a rapid heart rate, constipation, an elevated blood pressure and sleeplessness, warn experts.
Some also contain ephedrine, which may cause dependence on the product.
Other ingredients like aspirin may cause bleeding.
Incorporating a balanced diet and exercise remains the safest route to take for long-term benefits.
MYTH 26: Avoid isotonic drinks if you are not exercising. Their sodium content will affect the kidneys if consumed regularly
Excessive consumption of isotonic drinks has not been known to cause kidney problems.
But these drinks contain carbohydrates in the form of sugar, which contribute to weight gain if consumed in excess, said senior dietitian Joanna Tan from Changi General Hospital.
The sodium content of most commercial sports drinks is between 10 and 25 millimoles per litre. Excess electrolytes, which include sodium, are passed out of the body through the urine.
Isotonic drinks, rather than fruit juice, are encouraged for those who have had at least 45 minutes of moderately intense physical activity.
Compared to isotonic drinks, fruit juices are higher in carbohydrates but contain negligible amounts of electrolytes. There is also a possible risk of an upset tummy if the juice is high in fructose (fruit sugar).
MYTH 27: Consuming protein supplements improves your sports performance
What protein supplements have been proven to do is to help in the repair of muscle wear-and-tear.
Research has yet to conclusively show that they can enhance sports performance, say dietitians.
Taking protein helps the body to recover from intense exercise by restoring muscle glycogen, which acts as a source of fuel.
Protein also provides a person with some energy during exercise, especially during prolonged sessions.
This is because when carbohydrate reserves are low, the body turns to protein for fuel.
Get protein from food, if possible.
For instance, half a chicken breast would have roughly the same amount of protein as that in a protein shake.
Both endurance and strength athletes can benefit from taking some protein before exercise to promote muscle repair, say experts.
MYTH 28: Protein shakes can be safely used as a weight loss tool
There is no guideline on what would be a safe amount of protein shake to take for weight loss, said Mr Chad Han, a dietitian at Alexandra Hospital.
However, recent research has shown that protein helps to make one feel full and therefore, reduce one's need for snacking.
A high protein intake is also linked to lower levels of hunger-inducing hormones.
It is therefore not wrong to say that protein shakes can be used as a weight loss tool.
But drinking too much of it may not be safe for everyone. A high protein intake increases the amount of waste products in the body which, in turn, increases the risk of dehydration. This would be indicated by dark-coloured urine.
Muscle cramps have also been reported with higher protein intakes.
Furthermore, protein shakes may not be suitable for people with pre-existing kidney problems that require protein restrictions.
The body requires a wide variety of nutrients, so consuming protein shakes alone can deprive a person of nutrients, leading to unpleasant symptoms, for instance, hair loss due to a lack of zinc.
As there are no regulatory bodies governing the nutritional content of protein shake products in the market, they can range widely from close to 100 per cent protein to mostly carbohydrates and fat with little protein.
Healthy weight loss can be achieved on a calorie-controlled diet without the use of protein shakes.
MYTH 29: Take plenty of antioxidant supplements, such as vitamin C, shortly after your workout to reduce oxidative damage in the muscles
Too many free radicals in the body may be bad, but they do play a positive role in exercise.
Large doses of antioxidants can cancel out the effects of free radicals and, in turn, reduce the benefits of your workout, said Ms Ng Puay Shi, a senior dietitian at Tan Tock Seng Hospital's nutrition and dietetics department.
Free radicals operate as signalling molecules. They appear to regulate many physiological processes and functions. Taking antioxidants, such as vitamins C and E, may hamper muscle adaptation, said Ms Ng.
Studies have even shown that such supplements decrease the production of mitochondria, which generates energy in our cells.
It is not advisable to consume antioxidants in the form of supplements as they often contain high doses, said Ms Ng.
Eat two servings of fruit and veggies daily to meet your antioxidant needs instead.
MYTH 30: Coconut water is an ideal replacement for regular sports drinks after prolonged or endurance exercise
While both beverages contain sugar, potassium and sodium, the low sodium level in coconut water may not suit the needs of athletes after a lengthy workout, said Ms Ler Yi Bin from Mount Alvernia Hospital's nutrition & dietetics services.
This is because only drinks with high levels of sodium can help to rehydrate and replenish lost electrolytes after prolonged or endurance exercise, she said.
One serving (250ml) of coconut water has only 2.5mg of sodium, which pales in comparison to the 135mg found in sports drinks.
In other words, coconut water can only help to keep the body hydrated, just as water does.
Drinks with sodium actually enhance water uptake in our body and help to maintain fluid balance.
A low sodium level in the body may give you cramps and cause exhaustion, said Ms Ler, adding that sports drinks are still the best bet after a long workout. But watch how much you drink - sports drinks do contain calories after all. As for people who do light exercise, plain water is good enough or, if you like some flavour, throw some lemon slices into the cup.
CHAPTER IV: IN TIMES OF SICKNESS
MYTH 31: Avoid eating seafood, such as prawns, after chemotherapy or surgery
Shellfish, such as prawns and crabs, have long been believed to be "toxic" to those who eat it, especially those in need of physical recovery from an illness or medical treatment.
It is believed that eating them would slow down wound healing.
But they are just sources of protein, said Ms Gina Lin, a dietitian at Singapore General Hospital.
Unfortunately, besides having a bad reputation for being "bottom feeders", shellfish are commonly responsible for triggering certain allergies.
Chemotherapy or surgery puts the body under tremendous stress and weakens the immune system.
The body thus requires more protein for recovery. Options include fish, lean meat, poultry, eggs, dairy products, prawns, crabs, beans and legumes.
Ensure that these foods are well-cooked so as not to further compromise the patients' already weakened immune systems.
MYTH 32: Putting honey on burns can soothe the pain as it has anti-bacterial and anti-inflammatory properties
This is inconclusive. While some studies have demonstrated the anti-inflammatory properties of honey on wounds, the quality of the research is low, while some studies have methodological flaws.
This is according to a review article on this topic published in 2013.
It revealed several gaps in the research of honey in modern wound care and made recommendations for further research.
When you suffer a burn, first extricate yourself from the site of injury to prevent further injuries, said Dr Chong Si Jack, an associate consultant at the department of plastics, reconstruction and aesthetics surgery at Singapore General Hospital.
Place the wound under running water until the burning sensation stops. This reduces further burn injuries to the skin.
Then, apply a topical antiseptic and put sterile dressing on the wound, said Dr Chong. This keeps the wound moist, reduces further contamination and can be easily removed without pain.
Consult your general practitioner if the wound is small and superficial.
But if the area involved is large, go to the hospital's accident & emergency department.
MYTH 33: Vitamin C can prevent colds
In most cases, vitamin C supplements won't help to prevent colds, according to a study of 20 trials with more than 11,000 people.
Taking the vitamin reduced colds by only 3 per cent, according to the study on the Mayo Clinic's website.
However, for those under high physical stress, such as marathon runners, the extra vitamin C cut their incidence of colds in half.
Taking vitamin C before the onset of cold symptoms may shorten the duration of symptoms. Meanwhile, chicken soup can speed the recovery of colds. Studies have shown that it can improve the ability of cilia, which are tiny hair-like parts of nasal passages, to protect the body from bacteria and virus, said Ms Alefia Vasanwala, principal dietitian at Mount Elizabeth Hospital.
Plus, a rich chicken broth can provide the body with protein and calcium. It also contains electrolytes, which are especially valuable when one is dehydrated.
MYTH 34: Superfoods or organic food can prevent cancer
"Superfoods" is a term used by marketers and manufacturers to describe foods with apparent special health benefits.
Some examples are blueberries, raspberries, broccoli, garlic and green tea. Besides being high in antioxidants, these foods are also claimed to have anti-tumour properties.
But studies investigating the benefits of these so-called "superfoods" have been inconclusive, said Ms Gina Lin, a dietitian at Singapore General Hospital.
In general, fruit and vegetables are known to reduce cancer risk, thanks to their antioxidant properties and high fibre content.
Organic food, on the other hand, have gained popularity as healthier alternatives to food grown by traditional techniques which includes using chemical pesticides, herbicides, hormones or antibiotics.
Some evidence has shown that exposure to pesticides may increase the risk of certain cancers.
However, the evidence again remains inconclusive, said Ms Lin.
No single food can provide us with all the nutrients our bodies need. Particularly for cancer patients, the utmost nutritional priority is to ensure they get adequate energy and protein from their diet to cope with the cancer or cancer treatment.
Eating only "superfoods" or organic food may be too restrictive and deprive the body of essential nutrients it requires. A balanced diet providing sufficient energy, protein and other nutrients is encouraged.
MYTH 35: Eating lots of fat raises cholesterol levels in the blood, leading to clogged arteries and heart disease
People tend to think that anything that contains fat is bad and avoid eating these items.
This mindset needs to be corrected, as our body needs some fat to function properly, said Dr Lim Su Lin, chief dietitian at the department of dietetics at National University Hospital.
For instance, fat helps with the absorption and transportation of fat-soluble vitamins A, D, E and K.
"Our body also requires a type of fat called essential fatty acids (such as omega-3 and omega-6) which must be obtained through food."
A moderate amount of fat in the diet, in particular unsaturated fat and omega-3 fatty acids, have been shown to be beneficial for health.
People should focus on the quality of fat consumed. Choose foods prepared with healthier oil, for instance, said Dr Lim.
Polyunsaturated fat, such as sunflower and soya bean oil; and monounsaturated fat, such as canola and olive oil, can lower the amount of bad cholesterol in the blood.
If you need to eat deep-fried food, cook them at home with healthy oil no more than once a week and discard the leftover oil, said Dr Lim.
Try to include some oily fish in your diet too, as studies suggested that eicosapentenoic acid (EPA) and docosahexaenoic acid (DHA) found in fishes, such as salmon, cod and sardines, can help to lower one's risk of cardiovascular disease.
MYTH 36: Preparing or storing food in aluminium foil and cookware can cause Alzheimer's disease, as the metal content gets deposited in the brain
The actual amount of ingested aluminium absorbed by a healthy person is minimal, as it can be naturally excreted from the body, through one's faeces and urine, said Dr Lim Yen Peng, principal dietitian at Tan Tock Seng Hospital's nutrition and dietetics department.
This controversial claim was made in the 1960s when scientists found that exposing rabbits' brains to the metal caused some brain damage similar to that seen in Alzheimer's disease. But several subsequent studies did not back this claim.
Since then, major public health agencies, including the World Health Organisation, as well as international Alzheimer's associations, have said that aluminium is not a significant risk factor for the incurable disease.
Don't worry about using aluminium cookware and foil. It is unlikely that avoiding these products can reduce your level of exposure to aluminium significantly, said Dr Lim. Aluminium is, after all, naturally present in the environment. It is also found in soil, water, air and food.
The levels of aluminium in food, medicine, cookware and foil products are generally deemed safe by regulatory agencies and do not pose threats to one's health, she added.
MYTH 37: Consuming gelatin or glucosamine supplements help to strengthen joints and repair cartilage
There is no clear evidence that these products repair one's cartilage or reverse the effects of osteoarthritis.
The hype over glucosamine supplements is largely based on small numbers of pre-clinical (animal) studies which show that glucosamine sulphate - one of two forms of glucosamine - slightly increased the amount of cartilage in the laboratory setting. But this has never been proven in clinical or human studies, said Dr Kevin Lee, an orthopaedic surgeon at Mount Elizabeth Medical Centre.
Glucosamine is a basic building block of joint cartilage. Most glucosamine products work via an anti-inflammatory pathway to provide slight pain relief in mild cases of arthritis. The effect generally wears off after six months, noted Dr Lee.
Movement stimulates our body's natural production of hyaluronic acid, the lubricant in joints. It is why joints stiffen quickly when they are not moved, for instance, when you have your knee in a plaster cast for weeks. It is best to avoid exercises that lead to high impact in those joints affected by arthritis, said Dr Lee.
For instance, if you have arthritis in the knees, then you should avoid high impact sports such as running - which puts up to six times one's body weight through each knee on every stride - and switch to low-impact sports such as swimming, brisk walking or working out on the elliptical machine, he advised.
MYTH 38: Drinking cold water after a meal can solidify oily food, raising your risk of a heart attack or cancer
Nothing remains cold or hot for a very long time in our system. The liquid will quickly reach the same temperature as the body, said Ms Alefia Vasanwala, principal dietitian at Mount Elizabeth Hospital.
In fact, water is necessary for fat digestion to take place. It does not solidify fats in the meal, nor does
it raise the risk of cancer or a heart attack.
Five different body organs secrete digestive juices in order to digest food - the salivary gland, stomach, small intestine, liver and pancreas.
By the time food leaves the stomach, digestion of carbohydrates, proteins and fats would have begun, and the process gains momentum in the small intestine.
There, the pancreas, liver and small intestine contribute additional digestive juices, which contain enzymes, bicarbonate, and bile.
The gall bladder squirts bile into the small intestine whenever fat arrives there. After the fats are emulsified, enzymes break them down
Avoid a high fat diet, as it can lead to obesity, which is indirectly related to diseases like cancer and heart attack.
MYTH 39: Eating more fibre helps to ease chronic constipation
Fibre is not the panacea to constipation. While it binds to water and softens stools, it is unlikely to work well in people whose constipation stems from a narrowing of the large intestine, pelvic floor disorders or slow colonic movements, said Dr Eric Wee, head of the division of gastroenterology at Khoo Teck Puat Hospital's department of medicine.
Soluble fibre, which are found in food items like oats, apples and nuts, reduces
pain and one's need to strain when moving his bowels, as well as improves
But there is conflicting data on the effectiveness of insoluble fibre, which passes through one's gut almost unchanged.
In general, if you are eating too little fibre to begin with, try increasing the intake gradually.
If this does not work, or cause symptoms like bloating and discomfort, try taking over-the-counter laxatives. Examples are lactulose and polyethylene glycol.
And if you still experience constipation after these measures, consult a doctor.
MYTH 40: Acidic fruit can trigger or worsen gout, which is caused by a buildup of uric acid in the blood
The natural acids found in fruit, such as citric acid, malic acid and ascorbic acid (vitamin C) are unrelated to the level of uric acid in our blood, said dietitian April Cheung from Alexandra Hospital.
Fruit are also naturally low in purines, a natural substance found in many types of food from which uric acid is produced.
Consuming seafood, offal, meat extracts, such as stock cubes and gravies, as well as yeast-containing food like beer, increases the risk of having gout because these are high in purine.
Limit your daily intake of meat, poultry and seafood to one or two servings.
A portion should contain just 60 to 90g.
Limit raw oatmeal to 2/3 cup daily, and ½ cup of vegetables such as asparagus, cauliflower, spinach, mushrooms and green peas.
Try to have more vegetable soups instead of meat-based soups.
Abstain from alcohol if you have having an acute gout attack. On other days when you are well, consume no more than one standard drink (1 can of beer, 1 glass of wine or 1 shot of hard liquor) a day.
CHAPTER V: WHAT WE DRINK
MYTH 41: Mixing alcohol with energy drinks gets you drunk faster or harder
It is more likely that energy drinks, which contain stimulants, would mask the depressant effects of alcohol, based on current studies.
While the true effects of the combination remain a controversy, it is popular among people who are seeking to increase their tolerance to alcoholic drinks, said Ms Teresa Ng, senior dietitian at Tan Tock Seng Hospital's department of nutrition and dietetics.
This way, they can engage in longer periods of social activities without getting intoxicated.
It is not advisable to consume both drinks together, as this may impact your health negatively, said Ms Ng.
A reduced sensitivity to alcohol intoxication, for instance, can lead to alcohol poisoning, poor judgement, diarrhoea, vomiting, headaches and an increased heart rate, among other problems.
Those who mix energy drinks with alcohol are also three times more likely to binge-drink, studies have shown. This habit leads to major health issues like liver cirrhosis and brain damage, said Ms Ng.
MYTH 42: Ice-cold water, or lemon water, helps you to lose weight
There is no scientific evidence to prove that drinking cold water can help speed up a person's metabolism. Eating lemons also does not help with weight loss, though its vitamin C content may have some impact on weight loss, said Ms Sarah Sinaram, senior dietitian at Raffles Diabetes & Endocrine Centre.
A study done in 2005 suggested that those who are deficient in vitamin C may find it harder to lose fat mass. It found that those who take sufficient amounts of vitamin C can increase body fat oxidation during a moderate bout of exercise compared to those who didn't.
To lose weight, your energy intake needs to be less than your output. This means that you need to either eat less or increase your physical activity, said Ms Sinaram.
There is some research that vitamin C may help to burn fat so you can include foods that are high in vitamin C, such as fruit, in your diet, she added.
MYTH 43: Eating a big meal before drinking alcohol will help to keep you sober
The presence of food in the stomach may delay a person from feeling drunk, but it will not stop it completely, said Dr Taufique Ahmed, a consultant hepatologist at Khoo Teck Puat Hospital's department of medicine.
Food in the stomach, the type of alcoholic beverage and the person's constitution influence the rate of alcohol absorption by the body.
The main mechanism for a slower absorption of alcohol is a delay in gastric emptying, or the time it takes for food to empty from the stomach and enter the small intestine.
This is observed when alcohol is ingested along with food, especially fatty or heavy, solid or protein meals.
Many studies have shown that when alcohol is ingested together with or after food, it is absorbed more slowly than when it is consumed on an empty stomach.
However, this does not mean that one can drink a greater amount of alcohol on a full stomach - you will still become intoxicated, just that it will take longer.
MYTH 44: Drinking milk before bedtime can help you get a good snooze
There is a lack of evidence that milk can promote sleep.
Milk contains an amino acid known as tryptophan, which results in the release of a neurotransmitter, serotonin, that boosts calmness and helps regulate sleep.
Tryptophan is also a precursor to melatonin, which is a hormone that helps a person fall asleep and sleep through the night.
Despite that, the tryptophan content in milk is probably too low to have any significant effect on promoting sleep, said Dr Michael Lim, a consultant at the division of paediatric pulmonary and sleep at National University Hospital.
Other amino acids in milk also compete to reach the brain, so tryptophan's effects on the brain may be dampened due to the presence of other amino acids.
To improve sleep quality, try to avoid alcohol and caffeine.
Other tips include keeping the bedroom cool, quiet and dark; keeping entertainment gadgets out of the bedroom; and establishing a routine that helps one to relax before bedtime, such as light reading or listening to soothing music.
Do not eat dinner too close to bedtime and drink enough fluids so you don't get thirsty in the middle of the night - but not so much that you have to get up to use the bathroom.
Exercise a few hours before bedtime so that the stress hormone (cortisol) generated during physical activity will drop to a level that will not affect your sleep quality.
MYTH 45: Collagen-rich drinks give you better skin
After consuming collagen supplements or collagen-enriched food, the protein is digested into amino acids - this is no different from any other proteins, said Dr Ang Por, a dermatologist from a Paragon clinic.
Though ingesting collagen is harmless, it has not been proven to directly or significantly boost skin collagen production.
Collagen is the main component of skin, connective tissue, cartilage, ligaments, tendons and bones. It breaks down over time from wear and tear and has to be replaced, said Dr Ang.
Some ways to directly stimulate skin collagen formation include using topical products called retinoids and undergoing procedures such as laser therapy, chemical peels and light treatments.
Retinoids that are available over-the-counter include retinol and retinaldehyde, while adapalene, tretinoin and isotretinoin can only be bought with a doctor's prescription.
MYTH 46: Energy drinks have more caffeine than regular coffee
Coffee is actually the stronger pick-me-up - it has about 30 per cent more caffeine than an energy drink.
One cup (250ml) has about 104mg of caffeine, compared to about 80mg in the same amount of Red Bull energy drink, said Ms Ler Yi Bin from Mount Alvernia Hospital's nutrition & dietetics services.
While energy drinks may contain other ingredients like taurine, glucuronolactone, herbal extracts and B vitamins, some studies claim that caffeine remains the core ingredient for their stimulatory effects.
Drink no more than three servings of caffeinated drinks day, said Ms Ler. This includes both coffee and energy drinks.
Caffeine stimulates the central nervous system, giving the body a sense of alertness. But it also increases one's heart rate and blood pressure and dehydrates the body.
An overdose (more than 300mg) can affect your sleep pattern, quicken your heartbeat and cause headaches and dehydration.
MYTH 47: A beer belly is not directly caused by drinking beer
You get a beer belly when you consume more calories than the amount that is burned.
The excess energy is stored as "belly" fat, said Ms Gina Lin, a dietitian at Singapore General Hospital.
As alcohol is quite energy-dense (1g packs 7 calories), and it is easy to overindulge in it, drinking can actually contribute significantly to an excessive calorie intake.
It doesn't help that foods that are commonly consu med together with alcohol are energy-dense too, such as peanuts, potato chips, fried chicken wings and pizza.
But alcohol may not have much to do with beer bellies among older adults. With age, it is easier to put on weight due to lower calorie needs. Many may also lead less active lifestyles as they get older.
There is no one magic diet that can help people lose abdominal fat more efficiently.
In general, eat fewer calories and participate in regular physical activity to burn more calories. Limit the amount of energy-dense food like alcohol, sugary drinks, pastries and deep-fried items.
MYTH 48: Going on a juice diet periodically detoxes your body
A juice cleanse replaces all meals with cold-pressed juices made from fruit and vegetables, for a period ranging from a day to a week.
Such a diet is not backed by scientific evidence, so no one can pinpoint the exact toxins that are flushed out, or prove that a prolonged juice diet is safe, said Ms Gladys Wong, chief dietitian at Khoo Teck Puat Hospital.
Healthcare professionals will not condemn a short-term juice diet, though they would not endorse it either.
While it is relatively safe for one to live only on juices for up to five days, such a diet will not meet a person's usual energy requirement, said Ms Wong.
Plus, he is likely to feel hungry even after taking the juices.
This is because the act of drinking does not exercise the jaw, unlike munching or chewing, which contributes to satiety, she added.
MYTH 49: Take soya milk or other soy-based products to get more calcium in your diet
Soy milk, made from soya beans, is generally lower in calcium than cow's milk. Therefore, it is not considered a good source of calcium, said Ms Ruth Ho, a dietitian at Alexandra Hospital.
Similarly, other soy-based products such as soy yoghurt and tofu are generally lower in calcium.
However, they can be good sources of calcium if they are fortified with the mineral.
Calcium is vital for maintaining bone health and reducing the risk of osteoporosis as one ages. The daily recommended amount of calcium for an adult below 50 is 800mg.
Adolescents and those above 50 should increase their calcium intake to 1,000mg a day.
Purchase soya milk or soy-based products that are enriched or fortified with calcium.
This means that they have had calcium in the form of calcium phosphate or calcium carbonate added into them. Look out for these ingredients on the food packaging.
Vitamin D, which is made in bodies when one is exposed to ultraviolet rays of the sun, is equally important as it helps bodies absorb calcium.
MYTH 50: Adding milk to tea alters its antioxidant activity
This has not been proven for sure, said Ms Gina Lin, dietician at Singapore General Hospital.
Tea contains flavonoids which, when consumed, act as antioxidants in bodies. These substances are believed to help counter the damage caused by free radicals, which are released when bodies use oxygen for daily processes.
But excessive amounts of free radicals can damage our body cells and tissues.
Environmental factors like cigarette smoke can also cause free radicals to form in our bodies.
When preparing tea, infusing the tea in water for a longer duration may maximise the tea's antioxidant activity. Infusions that make use of loose tea leaves, instead of tea bags, may have a higher level of antioxidant activity too.
All in all, decaffeinated, bottled tea and instant teas may have less antioxidant activity than freshly brewed versions.
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