Friday, 21 April 2017

Reoviruses and Celiac Disease: A Possible Connection

Reoviruses infect the respiratory tract and intestine of humans. Researchers have recently made a potentially important discovery about the viruses in relation to celiac disease. The scientists have found a link between a reovirus infection and the development of celiac disease in mice that are genetically susceptible to getting the disease. The scientists have also discovered that at least in the people that they tested, people with celiac disease have an elevated level of antibodies against reoviruses compared to people without the disease.

Wheat bread contains gluten, which is harmful for people with celiac disease.
Public domain photo by Couleur

What Is Celiac Disease?


Celiac disease involves an immunological reaction to a protein complex in certain grains known as gluten. As a result of this reaction, the inner lining of the small intestine becomes inflamed and the villi (tiny folds on the lining) flatten. Villi increase the surface area for nutrient absorption. When they're flattened, the quantity of nutrients that can be absorbed is greatly reduced. The intestinal effects can lead to a host of unpleasant and sometimes dangerous symptoms that appear in the digestive system and sometimes far beyond this location. Even a small amount of gluten can trigger inflammation. The immediate effects of this inflammation are not the only problem. Untreated celiac disease produces an increased risk of intestinal cancer.

Gluten is found in wheat and all its varieties, including spelt and kamut, as well as in rye and barley. It's not completely understood why the gluten provokes an immune response and triggers inflammation, although researchers have found some possible or partial explanations.

What Are Reoviruses?


Reoviruses get their name from the term "respiratory enteric orphan viruses". They were originally referred to as orphan viruses because they were thought to have no effect on the human body. The words respiratory and enteric in the name refer to the parts of the body where the viruses are most often found. ("Enteric" refers to the intestine.)

Viruses contain DNA or RNA surrounded by a protein coat called a capsid. Many viruses have a lipid envelope outside their capsid. The DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) contain the genome or genetic instructions of the virus. Reoviruses have double-stranded RNA, a double-shelled capsid, and no lipid envelope.

People with celiac disease must avoid these products, but fortunately
gluten-free breads are available.
Public domain photo by Couleur

Avoiding Gluten 


If scientists knew that reoviruses can cause celiac disease in genetically susceptible people, it would be useful to develop a vaccine or other method to prevent an infection. The current cure for celiac disease is to stop eating gluten so that the villi grow back. This may seem like an easy step to take. There are problems with the treatment, however. 

One problem is that it's hard to avoid gluten. Though there are gluten-free grains, they may be contaminated with gluten in the field, in the storage area, in the processing area where products are made, or in the home when meals containing gluten are made. Flour containing gluten can drift through the air and land on gluten-free food. A person with celiac disease may pick up gluten from crumbs left in a toaster or particles left on countertops and cutting boards. In addition, non-food items such as toothpaste may contain gluten. Eating outside the home, such as in restaurants or at school events, is always a time for vigilance.

Despite the potential difficulties, someone with celiac disease who tries hard to avoid all sources of gluten can generally reduce their exposure to such a low level that the intestinal inflammation disappears and their villi recover. Some people find that even after avoiding gluten for as long as a year, however, their intestine doesn't heal. This condition is rare, but it's very unfortunate for the people who experience it.


Mice are often used in lab experiments that may apply to humans.
Public domain photo by auenleben


The Mouse Experiments


The scientists involved in the recent research found that one type of reovirus triggered celiac disease in genetically susceptible mice if the animals were eating gluten when they developed the viral infection. While it's true that results of mouse experiments don't always apply to humans, they often do. An interesting aspect of the research was the fact that the scientists also found that antibodies against reovirus were two to five times higher in people with celiac disease compared to the situation in people without the disease. This doesn't mean that all patients respond abnormally to the virus, but some may. 

It could be very helpful if reoviruses are proven to cause celiac disease because the discovery could lead to prevention of the disease. Biologically, though, one mystery will have been replaced by another. We don't know all the details involved in gluten's action in the body and we don't know how reoviruses trigger celiac disease in humans (if in fact they do). Many discoveries in science build on previous ones, so we may eventually have answers to the puzzles.

References


A common virus might trigger celiac disease (from NPR, or National Public Radio)
Celiac disease information (from the Mayo Clinic)

Sunday, 28 February 2016

Weight Gain and Memory Problems - A Possible Connection

A Potentially Important Discovery

Researchers at the University of Cambridge have found evidence suggesting that there is a link between being overweight and having poor memory. It's already known that being overweight or obese increases the risk of heart disease, stroke, type 2 diabetes, fatty liver disease and some types of cancer. The new research found that individuals with a higher BMI had poorer episodic memory. Episodic memory is defined as the ability to remember events in our lives.

Keeping track of body mass is important for maintaining health.
Franck Mahon, via flickr, CC BY-SA 2.0

What is BMI?

According to a press release from the University of Cambridge, the study linking weight gain to memory problems involved 50 adults aged from 18 to 35. The BMI or body mass index of each participant in the study was measured. BMI is a calculation based on a subject's height and weight. It's not a perfect indication of being overweight, since some people may be heavier than others
of the same height due to the possession of more muscle instead of more fat. BMI is a useful indicator of potential health problems for most people, though.

There are online sites that calculate a person's BMI from the data that's entered. If you do a search for the NIH BMI calculator you'll find a reliable one. NIH stands for the National Institutes of Health, which is a government organization in the United States.

In general, in an adult a BMI of less than 18.5 indicates that a person is underweight. A number between 18.5 and 24.9 indicates normal weight, a number between 25 and 29.9 indicates that a person is overweight and a number of 30 or greater indicates obesity.

Regular and moderate exercise is very useful for maintaining a healthy weight.
Photo by Ha'anala 76 via publicdomainpictures.net

The Experiment

The participants in the memory experiment were asked to "hide" items in a complex scene on a computer screen. They then had to recall which items they hid, when they hid them and where they put them. The researchers found that the people with high BMI had a poorer ability to memorize.

Previous studies have shown a link between being significantly overweight and dysfunction in two parts of the brain. One of these areas is the frontal lobe of the cerebrum, which is involved in problem solving and decision making. The other is the hippocampus, which is involved in memory. The new discovery could be related to this information.


The location of the hippocampus
Photo by OpenStax College, CC BY 3.0 License

Interpretation

There are some precautions that need to be taken when interpreting the information gained in the new experiment. First, the 50 subjects used in the Cambridge study is a small number. The research will need to be repeated with a much larger group of people. Secondly, it's unknown if the results apply to real life situations as well as the experimental one. The result of the experiment is interesting, though, and in my opinion deserves further investigation.

According to the press release from the university, about 60% of adults in the United Kingdom are overweight or obese. According to the CDC (Centers for Disease Control and Prevention), the percentage in the United States is 69%. These are shocking statistics. Being significantly overweight is a serious problem for both the individual and for society. It's a problem that we badly need to solve.

The press release describing the experiment and giving a link to the full research report is available online.

Tuesday, 17 March 2015

Caramel Colour, Soft Drinks and Cancer Risk

Caramel colour or colouring is a chemical that is added to some soft drinks to given them a rich brown colour. Some versions of the colour contain a chemical called 4-methylimidazol, or 4-MEI, which has been found to cause cancer in lab animals when a large dose is administered. A controversy has arisen about whether the chemical poses a risk to humans. According to the FDA (Food and Drug Administration), the chemical is safe in the normal amounts consumed by humans. However, a recent report by scientists at John Hopkins University claims that many people may be ingesting caramel colour on a daily basis and may be increasing their risk of cancer as a result.

Cola and root beer may contain caramel colour.
Photo by PDPics at pixabay.com
Although they are related products, caramel colour is not the same thing as caramel. The first product is used as a food colour, while the second is a sauce used in pudding, candies and chocolates.

Caramel sauce is a brown, gooey and (I think) delicious product. It's made by heating sugar to a high temperature very slowly. The sugar loses its water content and changes to a light brown colour. The sugar is said to have been "caramelized". Caramel is added to some candy bars. The production of toffee and dulce de leche also involves caramelization of sugar.

Like caramel, caramel colour or colouring is made by heating a carbohydrate. (Sugar is one type of carbohydrate.) It's a more extreme process than the caramelization used to make candies and desserts, however. An acid, alkali or salt is added to the carbohydrate as it's processed, producing a dark brown liquid.

Based on their studies, the John Hopkins researchers say that in the United States 44% to 58% of people over the age of 6 generally drink one can of soda a day. Assuming the soda contains caramel colour and that this colour contains 4-MEI, this means that the people are exposed to 4-methylimidazol on a daily basis.

It seems to me that the following questions must be answered before we can decide whether soft drinks are safe or dangerous (with respect to cancer).
  • Does the person's chosen brand of soft drink contain contain caramel colour?
  • If so, does the caramel colour contain 4-MEI?
  • How often must 4-MEI be consumed and in what quantity before it's dangerous to humans?

The FDA report and the John Hopkins report are both interesting to read. They may leave a person confused about the best plan of action. To me, it doesn't make sense to ingest a potentially dangerous chemical that has such an unimportant function as colouring a drink. We are exposed to many substances in the environment that may slightly increase our risk of cancer. It seems advisable to avoid as many of these substances as possible - including caramel colour - whenever we can. If I were a regular soda drinker I would make sure that my soft drinks either contained no caramel color or contained a form of the colour without 4-MEI.

Thursday, 12 March 2015

Inadequate Sleep, Weight Gain and Insulin Resistance

Some interesting - and scary - research about the effects of inadequate sleep have just been published. Researchers at the Weill Cornell Medical College in Qatar have found that losing as little as 30 minutes of sleep a day can cause weight gain and increase insulin resistance. Furthermore, they say that not getting enough sleep on weekdays and then catching up on sleep on the weekends isn't helpful.

Not enough sleep? Photo by GaborfromHungary
at morguefile.com
The researchers studied 522 patients who had recently been diagnosed with type 2 diabetes. The height, weight and waist measurements of the patients were measured during the study. In addition, their fasting blood sugar was recorded. The patients also had to fill out sleep diaries and calculate their weekday sleep debt.

Even at the start of the project an interesting statistic was discovered. People who had a weekday sleep debt were 72% more like to be obese than those without a sleep debt. As the study progressed, the researchers found that the longer a weekday sleep debt existed, the more serious the effects.

After six months, a weekday sleep debt was "significantly" associated with both insulin resistance and obesity. Insulin resistance is a condition in which cells no longer respond to insulin or respond to it inadequately. Insulin is a hormone that causes glucose to pass from the blood, through the cell membrane and into the cell. Glucose is the cell's energy source. Insulin binds to the cell membrane in order to trigger the entry of glucose. When cells no longer respond to insulin, the blood glucose level rises.

After the research project had lasted for 12 months, some more information was discovered. For every 30 minutes of weekday sleep debt that was reported at the start of the survey, insulin resistance was increased by 49% and the risk of obesity by 17%.

Research performed by surveys in which participants self-report data is considered to be less accurate than research involving clinical trials. It can still be valuable, though. It would be interesting to see the results of a sleep survey involving more people. 522 subjects is actually quite a small sample size for a survey. It would also be interesting to see the results of a study performed on people without diabetes.

The research suggests that lack of regular sleep causes metabolic disruption in the body. This is definitely something that I need to pay attention to. I follow the not-enough-sleep-on-weekdays and catch-up-on-sleep-on-weekends lifestyle myself. I've been thinking that I need to change this habit for some time and am pretty sure that I would feel better if I did. The new discoveries are just the prod that I need!

Thursday, 1 January 2015

Milk Thistle - An Intriguing Plant with Possible Health Benefits

Milk thistle is an interesting and intriguing plant that may have benefits for liver health, cancer treatment and type 2 diabetes. Like many other thistles, the plant has an attractive red or purple flower head. It also has shiny green leaves with spines and white veins. The seeds of milk thistle contain a substance called silymarin, which is thought to be responsible for the plant's potential health benefits. Silymarin is an antioxidant and an anti-inflammatory substance.

The milk thistle's scientific name is Silybum marianum. It's also known as the Marian thistle, the Mary thistle and the holy thistle. The plant is native to Southern Europe and Asia but has been introduced to many other parts of the world. It belongs to the family called the Asteraceae or the Compositae, which also contains daisies, sunflowers, dandelions and ragweed.


Milk thistle has had a long history as both a food and a medicine. It was once the custom to use the leaves like lettuce, once the spines had been removed. The stalks and roots were also eaten. The seeds were roasted and used like coffee. Eating the plant seems to be less popular today, but researchers do agree that the plant is either nontoxic or has very low toxicity. Since it's a member of the same family as ragweed, however, people who are allergic to ragweed may be allergic to milk thistle.

Evidence suggests that milk thistle may have health benefits, but the evidence is inconclusive at the moment.
  • It may be helpful for treating liver problems caused by toxins.
  • It may be helpful in protecting the livers of children during chemotherapy treatment.
  • Some experiments have shown that milk thistle is helpful for hepatitis (liver inflammation), alcoholic liver disease and cirrhosis of the liver. Some researchers say that these experiments were poorly designed and don't consider the results to be valid, however.
  • Milk thistle has been shown to slow the growth of some types of cancer cells in lab equipment and inside the bodies of lab animals, but its effect in humans is unproven.
  • In some experiments, milk thistle has been shown to reduce blood sugar, improve insulin resistance and improve the cholesterol profile of people with type 2 diabetes when taken with traditional medication. Once again, however, better quality experiments are needed to confirm these effects.
  • Animals studies and some human observations suggest that silymarin can help to counteract symptoms and protect the liver in cases of poisoning by the so-called death cap mushroom (Amanita phalloides). Poisoning by this mushroom is a medical emergency, however. Anybody who has eaten the mushroom must visit a doctor immediately instead of waiting to see if silymarin helps!
Milk thistle seeds are sold in a supplement form and as a tea. It's a shame that more rigorous studies haven't been performed so that consumers know whether milk thistle is likely to be helpful for their problem or whether it's a waste of money buying it. Hopefully these studies will be performed soon. The preliminary results of research definitely seem to be worth investigating.

It's important that anyone planning to take milk thistle for a medical problem checks with their doctor first. Even safe natural medicines can interact with some traditional medications. In addition, even safe supplements may be a problem when taken in a very concentrated form or in large amounts. Another consideration is that some natural medicines may not be safe for people with certain medical conditions.

Milk thistle photo by Fir0002, CC BY-SA 3.0 License

Thursday, 18 December 2014

Trans Fats and Memory Loss - A Disturbing Link

A professor from the University of California has completed a study suggesting that trans fats hinder our memory, at least in men. Trans fats are added to processed foods to reduce spoilage and increase their shelf life. On food labels, they are often listed as partially hydrogenated oils or fats. The latest discovery adds further support to the idea that we should eliminate trans fats from our diet.

Even before the new discovery it was known that trans fats are unhealthy. They not only increase the amount of LDL cholesterol in our body but also lower the amount of HDL cholesterol. A high level of LDL cholesterol can lead to the blockage of blood vessels by plaque and can also increase the risk of heart disease and strokes. This type of cholesterol is often known as the "bad" cholesterol. On the other hand, HDL cholesterol - the good cholesterol - can remove plaque from blood vessels.

Plaque in an artery
Illustration by BruceBlausen, CC BY-SA 3.0 License
Small amounts of natural trans fats exist in meat and dairy foods. These don't appear to cause health problems. Artificial trans fats are potentially dangerous, however. They're made when hydrogen is added to vegetable oil in a process called hydrogenation. This process changes the oil from a solid to a liquid. Artificial trans fats are most likely to be found in commercially baked goods, snack foods such as potato and corn chips, deep fried food and non-dairy coffee creamers.

Processed food manufacturers are reducing the amount of trans fats in their products, which sounds like good news. According to US law, however, companies can claim that their product is trans fats free if the product contains less than 0.5 grams of trans fat per serving. If someone eats a lot of processed foods, a small amount of trans fat in each serving could add up to a significant intake.

Potato chips often contain trans fats.
Photo by avantrend at pixabay.com
The University of California research project involved about 1000 men. The study examined the memories of men aged forty-five or younger. The test subjects were represented with cards that had words written on them. The men had to say whether the words were new or whether they'd seen them before in the test.

The researchers found that each gram of trans fat ingested in a day (as reported by the men) was linked to 0.76 fewer words remembered. The men who ate the most trans fat remembered 11 fewer words than those who ate no trans fats. According to Dr. Beatrice Golomb, who carried out the study, "Trans fats increase the shelf life of the food but reduce the shelf life of the person."

Surveys are helpful in medicine, although they aren't as useful as clinical tests in showing relationships. The results of the survey don't prove that the ingestion of trans fats is the cause of decreased memory. In addition, the results were announced at a medical conference instead of being published in a peer-reviewed medical journal. Still, they are interesting and thought provoking. Combined with our previous knowledge that trans fats are bad for blood vessels, it definitely seems like a good idea to avoid them.

Thursday, 27 November 2014

Another Benefit of Yogurt - Reducing the Risk of Type 2 Diabetes

Yogurt has the reputation of being a very healthy food, especially in its plain, unsweetened form. It gives us the helpful nutrients found in dairy foods and also contains bacteria known as probiotics. Some of these bacteria can survive in our intestine, where they are thought to have beneficial effects. Now researchers have found evidence suggesting that yogurt has another benefit. It seems to reduce the risk of type 2 diabetes.



Type 2 diabetes is a disorder in which the body's cells become resistant to insulin's effects or in which not enough insulin is made to satisfy the body's requirements. Insulin is a hormone made by the pancreas that triggers glucose in the blood to enter the cells and supply them with energy. Blood glucose is also known as blood sugar. The glucose comes from the digestion of food. When insulin can't do its job, blood sugar may rise to a dangerous level and cause multiple health problems. Unfortunately, the incidence of type 2 diabetes is increasing.

Researchers from the Harvard School of Public Health examined data collected from people involved in the following surveys: the Health Professionals Follow-Up Study (41,497 people), the Nurses Health Study (67,138 people) and the Nurses Health Study ll (85,884 people). There were actually additional people involved in each of the three surveys, but some weren't included in the diabetes project due to the presence of certain health problems or the fact that they didn't give any information about their dairy consumption. Still, the number of people in the study was sufficiently large to give some credence to the results.

By analyzing the data, the researchers made the following discoveries.
  • Total dairy consumption was unrelated to type 2 diabetes risk
  • There was no link between the consumption of whole milk, skim milk or cheese with diabetes.
  • People who regularly ate yogurt had a lower risk of developing diabetes.
  • After looking at the results of other published studies as well as the results of their own study, the researchers concluded that eating 28 grams of yogurt a day is linked to an eighteen percent reduction in the risk of developing type 2 diabetes.

Eating a healthy diet, getting regular exercise, using stress reduction techniques, getting adequate sleep and avoiding smoking and excessive alcohol intake give the best chance for health. However, in a busy life it can sometimes seem overwhelming to succeed in all these areas. It's nice that a simple act like eating yogurt seems to give us significant help in preventing type 2 diabetes. However, we should be aware that very unhealthy habits - such as following a diet that is extremely poor apart from yogurt consumption - may negate the beneficial effect of the yogurt.