Questions and answers
Question
"Why won't my mom let me eat a lot of sugar?" Alex, Age 5, Sherman Oaks, California
Answer
Well first of all, it is important to remember that some sugar in our diet is necessary to give us energy. We can get this energy from sugars found in bread, pasta and potatoes, even though they don’t taste sweet and also in yummy fresh fruits.
Too much sugar though, can cause several problems. First, we may start to feel nauseous or sick to our stomachs after eating too much sugar. Also, and more importantly, if we overdo the sugar too often, our body can get ‘stressed’ and produce a lot of insulin all at once and over time we may lose the ability to produce it in the right amount during every meal. Producing too much insulin makes us more likely to get diabetes, specifically Type 2 Diabetes, in the future. Although just eating too much sugar alone does not cause diabetes, together with other bad habits such as a lack of exercise, it can certainly make people more susceptible to the disease. Diabetes can be a very serious disease that over time can affect our vision, our nerves, our kidneys and our heart.
Another problem that comes from eating too much sugar is tooth cavities which can result in many trips to the dentist. To avoid these problems, it is important to listen to your mom and not eat too much sugar and also avoid sugary drinks like pop, fruit cocktails and sweetened juices.
- Dr. Amira Klip, PhD, Senior Scientist, Cell Biology
Question
"Why do kids get epilepsy?" Nellie, Age 10, Toronto, ON., August 10, 2010
Answer
There are many, many reasons that children get epilepsy. These range from abnormalities in the development of brain, infections of the brain, traumatic brain injury, birth injury to brain, and a variety of genetic causes. In addition, in many children who have epilepsy we never determine a cause. We attempt to find out the cause by a careful history of the seizures in terms of onset and what they look like, a careful family history and past medical history of the child, and a neurological examination. Laboratory tests depend on where the history leads us, but we almost always obtain a brain wave. Brain imaging such as CT scan or MRI scan of the brain is not routinely done unless the seizures or the history suggest that there might be an anatomical lesion of the brain.
- Dr. Carter Snead, MD, FRCP(C),
Division Head, Neurology, Senior Scientist, Neurosciences & Mental Health
Question
"What causes pimples and what are the best ways to remove or keep them down using natural remedies?" Dillon, Toronto, ON., July 27, 2010
Answer
Several things lead to the development of pimples or acne. Hormones, which are special chemicals in the blood that help control our body functions, change around the time of puberty. Certain hormones are increased and this causes changes in the body. One of the changes that can be caused by hormones is that the oil glands in the skin start making more oil. This oil goes from the glands, deep in the skin and comes out onto the skin though the pores, which are small openings seen on the face. This oil can get stuck in pores and contribute to “clogging” them. The old skin cells that are in the pores need to be removed each day to make room for new cells. This is called skin shedding and is a normal process. In acne, those cells can become trapped along with the oil in the pores and can also contribute to clogging. The two other factors that can lead to acne are certain bacteria that normally live on the skin and inflammation which is when the body causes redness and swelling and sometimes pus. All these factors come together to make different types of pimples: whiteheads and blackheads (called comedones), pimples and pustules.
Acne can’t be completely prevented. However, as some of the above processes start to increase in the teenage years, and sometimes into adulthood, they can be treated or controlled. Good skin hygiene including simple wash routines and eating a healthy diet may contribute in a minor way to acne management. These are both good natural ways of addressing acne. However, for more significant pimples, medical therapies might be appropriate. It is important to discuss this with your doctor. Avoid “picking” and “popping” pimples because this can lead to scarring and an infection on top of the pimples.
- Dr. Miriam Weinstein, Staff Physician and Dermatology Fellowship Director, Section of Dermatology and Project Investigator, Paediatric Medicine; and Assistant Professor, Department of Paediatrics and Faculty of Medicine, University of Toronto
Question
"Does eating carrots actually help your eye sight?" Sarah, Age 15, Tecumseh, ON., July 13, 2010
Answer
Carrots have Vitamin A in them and this vitamin is used by the retina to see. Having too little Vitamin A can cause problems with eye sight. However, this doesn’t mean that having lots of Vitamin A gives you super-vision. In fact, too much Vitamin A can be harmful in some cases. In general, carrots should be eaten in a moderate amount as part of a healthy diet.
Now that the science is out of the way, here's a little joke to tell your friends about carrots:
Why are carrots good for your eyes? Because I have never seen a rabbit wear glasses!
- Dr. Kamiar Mireskandri, MBChB, FRCSEd, FRCOphth, PhD
Staff Opthamologist and Project Investigator, Opthamology and Assistant Professor, Department of Opthamology and Visual Sciences, University of Toronto
Question
"Why are babies born with defective hearts?" Drew - Age 9, Palmerston, ON., June 29, 2010
Answer
Babies are born with defective hearts for many reasons. One of the reasons is that the genes that control how the normal heart forms are missing or defective. Think of genes as a string of millions of beads. Each bead carries a code that sends the message to form various body parts. If a bead is missing or defective, then this code or message is lost or is misread, and the organ does not form properly. In some cases, this defective gene is passed down from a parent to a child. The heart is like a pump with many screws and bolts and valves and connections and even one missing connection can make the heart pump defective. In some cases, heart defects occur because the mother was exposed during her pregnancy to smoking, alcohol, infection, some types of medicines, chemicals, and other damaging agents. Unfortunately, we still do not know all the causes of defective hearts but we are finding more and more each day.
- Dr. Seema Mital, MD, FACC, FAHA, FRCP(C)
Staff Cardiologist, Cardiology, Associate Scientist, Genetics & Genome Biology
Question
"With the numerous types of HIV mutations, would an HIV vaccine really be effective?" Tommy - Age 21, Toronto, ON., June 15, 2010
Answer
Making a vaccine to completely prevent HIV is going to be extremely difficult. There are several reasons for this. First, there are many different strains, or “clades”, of HIV. Because these clades differ genetically from one another a vaccine may work against one, but be completely ineffective against another. Second, the best potential protein targets of an HIV vaccine (preserved between clades) are hidden deep within the protein structure making it difficult for antibodies to bind to them and neutralize the virus. Third, vaccines work by helping the immune system respond to an infection, but ultimately it is the immune system that must eradicate the infection. Unfortunately, HIV is different from vaccine-preventable infections in that the immune system is not able to eradicate HIV from the body. All this said, it is important to note that as our understanding of the biology of HIV and the immune system response to it improves, it is possible that we will be able to devise new methods, not thought of previously, to develop an effective vaccine.
- Dr. Sean (Ari) Bitnun, MD, MSc, FRCPC
Staff physician & Consultant in Infectious Diseases, Infectious Diseases, Assistant Professor, Paediatrics, University of Toronto
Question
"How does cancer grow and spread?" Bond - Age 9, Toronto ON., June 1, 2010
Answer
Cancer starts when one cell somewhere in the body stops working properly and starts to divide much more quickly than it normally should. The genes in the cell that would usually program the cell to stop dividing or stop growing don't work properly. Other genes start to tell the cell to invade tissues nearby and from there to spread through the blood stream or directly to other organs of the body. Eventually, these cancer cells multiply so much (making trillions of themselves), they cause severe damage to normal body organs or use all the nutrients and oxygen that the body needs to survive. Eventually, unless it's treated, the cancer builds up to the point that the person in which it started, cannot survive. Fortunately, for children, most cancers can be cured!
- Dr. David Malkin, FCFP (C), FAAP, LMCC
Senior Staff Oncologist, Haematology/Oncology, Co-Director, Cancer Genetics Program, Senior Scientist, Genetics & Genome Biology
Question
"Does gum really stay in my stomach for 7 years?" Cameron, Age 9, Toronto, ON., May 18, 2010
Answer
If you accidently swallow a piece of gum you have been chewing, it does not stay in the stomach. As part of the normal way you digest food, it has to be moved through your digestive tract (which is like a long tube) to be digested properly and the nutrients absorbed. After you swallow the food moves from the esophagus (swallowing tube), stomach and intestines until it eventually comes out as feces (poop!). This movement of food that is getting digested is called peristalsis. Although gum isn't food and not digested the same way, it is pushed through the gastrointestinal tract and out into your poop.
- Dr. Nicola Jones, MD, PhD, FRCP(C)
Staff Gastroenterologist, Gastroenterology, Hepatology and Nutrition and Senior Scientist, Cell Biology
Question
"Does everyone see the same colours? Is it possible that my green is another person's red?" Spencer - Age 14, Tecumseh, ON., May 5, 2010
Answer
That is absolutely correct. Spencer's perception of red may look the same as another person's green. Colour vision is abnormal in about 8 per cent of males. At the back of the eye there are special receptors to light that pick up light in a red direction, a green direction and a blue direction. Some males (and very few females) have either the red or the green receptor missing. This means that a red and green light may look the same colour. However, the blue receptor is rarely missing. This means that purple (red and blue) will look different to orange (red and yellow).
- Dr. Carol Westall, PhD, BSc (Optom)
Vision Scientist, Ophthalmology and Vision Sciences and Senior Associate Scientist, Neurosciences & Mental Health
Question
"When you chomp on your food, and then it goes down the slide into your stomach what happens to the food when it goes into the intestines?" Callum - Age 4, Vancouver, BC., April 21, 2010
Answer
When you chomp your food it gets smashed and broken up in your mouth. Then it goes down the slide called the esophagus into your stomach where it sits for awhile. Juices from your stomach continue to break up the food and the stomach muscles mash it together into little balls. The balls of food then go into a large tube called the small intestine. In the small intestine, the balls of food are smashed up even more so your body can get all the important nutrients it needs including vitamins, minerals, proteins, sugars, and fats. Finally, the food balls enter an even bigger tube called the colon where your body gets all the water and some more minerals from the food before it leaves your body as poop.
- Dr. Aleixo Muise, MD, PhD, FRCPC, Gastroenterology/Hepatology/Nutrition
Question
"Why do I get light headed when I first stand up?" Gemma, Age 15, Staples, ON., April 7, 2010
Answer
Dizziness immediately after standing can result from a temporary drop in blood flow and therefore oxygen to your head. In medicine this is sometimes referred to as “postural hypotension” - postural meaning body position and hypotension meaning low blood pressure.
Standing, especially after a long period of lying down, can result in blood being pulled by gravity away from your head and chest into your lower body. This momentarily reduces the amount of blood returning to the heart, which results in lower blood pressure and less blood flow to your head, causing dizziness.
Luckily, your body will detect this and can react quickly – your heart will beat faster and your blood vessels will contract to direct more blood to your head.
- Dr. Christopher Macgowan, PhD, Scientist, Physiology & Experimental Medicine
Question
"What makes a non-cancerous tumour different from a cancerous one?" Alayna, Age 24, London, ON., March 24, 2010
Answer
Cancerous tumours are made up of cells that grow very fast and can move to places where they don't belong. In contrast, non-cancerous tumours (also called a benign tumours) do not usually grow or spread to other parts of the body. An example of a non-cancerous tumour would be a mole on your skin. The reason cancerous tumours grow without control and spread is because their cells have acquired mutations in genes that normally prevent them from growing and moving to other organs and tissues.
- Dr. Brent Derry, PhD, Scientist, Developmental & Stem Cell Biology
Question
"What is the cure for hiccups?" Alexandra, Age 15, Tecumseh, ON., March 10, 2010
Answer
Cures for hiccups date back centuries and most recommendations are based on anecdotal experience rather than controlled scientific studies. Some people believe that holding one’s breath helps stop hiccups. But does this really work? A variety of remedies that temporarily bring breathing to a halt -- such as sneezing, pulling knees up to the chest or being surprised by a sudden fright -- have been reported to be effective in stopping hiccups and indeed, there may be scientific validity to this remedy. There is a theory that a cycle of activated nerves that control movement of the diaphragm is responsible for inducing hiccups. Breath holding breaks the cycle and stops the hiccups. There are those who believe that the trigger point for hiccups is at the back of the palate near the uvula (hang ball) and that hiccups can be stopped by stimulating the back of the pharynx with a spoon or by sipping ice water. Others have recommended swallowing a teaspoon of dry granulated sugar as a successful means of interrupting the hiccup cycle.
Hiccups affect almost everyone, are difficult to avoid, have no known useful purpose and must be endured until they simply pass on their own. The use of one of the many harmless suggested remedies, such as breath holding, may help you feel that you are doing something until nature takes its usual course.
- Dr. Moshe Ipp, Paediatrician and Project Investigator, Paediatric Medicine
Question:
"How come you can’t store up your sleep? For example - Why can’t you sleep for 14 hours one night and then be rested after sleeping for only a few hours the next night?" Katie, Age 26, Midland, ON., February 24, 2010
Answer
The exact reasons for why we sleep surprisingly remain unclear to most scientists. Many believe that sleep represents a time that the brain reserves for itself to learn or rewire itself, like re-fragmenting a hard drive. Others believe sleep represents a time for the body to repair itself from the stresses of the day. While the function of sleep remains a mystery, it is well known that humans need sleep to function and sleep deprivation usually results in limited abilities to learn, remember and perform daily tasks, but it can also lead to increasing harm to the body.
The precise timing of sleep really reflects two major forces, called a circadian and homeostatic sleep drive which both serve to entrain our brain to determine what time we sleep and what time we wake up.
In the circadian sleep drive, the strongest determinant in length of sleep is exposure to light, more specifically sunlight. The eyes sense light, and a lack of light stimulates a gland in the brain, called the pineal gland, to release melatonin, a hormone that tells the brain that sleep should begin soon. Exposure to sunlight in the morning signals the brain to stop releasing melatonin and we feel awake.
The other regulator of sleep, the homeostatic sleep drive, is related to the molecule adenosine. Adenosine levels build up in the brain the longer you stay awake. At a high level, adenosine will then help the brain determine when someone has been awake for too long thereby triggering the brain to initiate sleep. Once asleep, adenosine levels fall until a level where it no longer stimulates the brain to stay asleep which allows us wake up. Interestingly, caffeine promotes wakefulness by inhibiting adenosine.
- Dr. Rakesh Bhattacharjee, Sleep and Respiratory Medicine
Question:
“I know that scientists grow cells in their labs. What do the cells eat?” Jaden, Age 5, Markham, ON., February 10, 2010
Answer:
We grow cells in a clear liquid media that looks just like “Kool-Aid”. It’s pinkish and it has all the nutrients that cells need to grow. The nutrients include sugar, amino acids and minerals like iron and magnesium. We also put a small amount of cow serum (the part of our blood without any red or white blood cells) into our media since it has specific growth factors to tell cells to grow.
We grow cells in this media and they double in number every two to three days. After that we have to change the “Kool-Aid” and dilute the cells a bit so they don’t get too concentrated in the dish. If they grow too much, and get too concentrated, they start to die off and we can’t do our experiments.
- Dr. John Brumell, PhD, Senior Scientist, Cell Biology