BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: diet (Page 2 of 2)

Links Between Human and Mice Obesity

A new study of the genomes and epigenomes of mice and humans is beginning to link the two, especially in regards to obesity.

As Andrew Feinberg, MD states, “It’s well known that most common diseases like diabetes result from a combination of genetic and environmental risk factors. What we haven’t been able to do is figure out how, exactly, the two are connected,”. Therefore, Feinberg began to study epigenetic tags to further understand gene usage.

His project with his team was to study the epigenetics of identical mice that were fed either normal or high-calorie diets. He found that the difference between normal and obese mice was the presence of chemical tags, or methyl groups, that prevent the production of proteins. This is significant because as we have learned, these types of modifications of DNA can be copied and inherited, which is then passed on into the next generation. This revealed that the normal and obese mice did not have the same location sites of their tags, giving them that alteration in their DNA. This is often seen in the alterations of the Agouti gene in mice.

Pictured here is effect of epigenetics on the physical appearances of mice (Agouti gene)

This proves that epigenetic changes are related to the environment and food sources that are around us, creating patterns based on one’s diet (which can create risk if a high-calorie intake is continuous).They also found that epigenetic changes affect genes that are already both linked to diabetes as well as those who aren’t, allowing them to further conclude that genes plays more of a role in diabetes than we previously thought.

This allows hope for future to provide epigenetic tests, which can prevent diabetes in those who are on track to have it later in life.

Article  Source: http://www.sciencedaily.com/releases/2015/01/150106130510.htm

 

You Are What You Eat

Mouse

Whenever a person consumes healthier meals and therefore less calories, according to a new study on mice at the NYU Langone Medical Center, they could be lengthening their lives.

Using female mice, scientists fed one group of mice a diet of pellets containing a high amount of calories, while feeding another group of mice a diet of pellets containing 30% less calories. The hippocampus and the region surrounding it in the brains of the mice were then examined for expression of aging-genes throughout various stages of maturity. The results of the study, while not entirely applicable to humans, has shown that the mice that ate the lower calorie diets had less expression of aging genes and had less risk of chronic illnesses such as hypertension and stroke.

“The study does not mean calorie restriction is the ‘fountain of youth,’ but that it does add evidence for the role of diet in delaying the effects of aging and age-related disease.” Stated Stephen D. Ginsberg, a researcher involved with the study. The study examined more than 10,000 genes related to aging, which is a much larger amount than that previously studied by researchers. While the study was performed on mice, the results could be similar in humans, and the researched performed by Dr. Ginsberg and others should serve as a warning for our ever-indulgent world of fast food and high caloric intake.

Article:  http://www.sciencedaily.com/releases/2014/11/141117110650.htm

Diet Tip #1: Hang Out with Skinny People and Go on a Low Calorie Diet

labrat

Microbiomes are incredibly vast and mysterious; we don’t quite know how they work. However, with a few experiments, we have come to a few conclusions.

1) Microbiomes determine your weight.

Scientists extracted bacteria from the intenstines of human twins, one lean and one larger. The injected these microbiomes into twin mice. The mouse who received the large twin’s microbiome gained fat and the mouse who received the lean twin’s microbiome remained small.

2) Fat microbiomes can be influenced by a skinny microbiome.

A fat mouse placed in a cage of skinny mice lost weight.*

3) Skinny microbiomes cannot be changed.

A skinny mouse placed in a cage of fat mice remained skinny.*

4) With the correct diet, you can become skinny.

Fat mice eating healthy food made them skinny but when they ate junk food, they stayed fat. A different group of scientists replicated this experiment with overweight humans and a low calorie diet. Their microbiotic diversity was low and increased significantly, leading to weight loss.

5) Diet does not affect skinny people.

Regardless of which diet the skinny mice ate, they stayed skinny. A different group of scientists replicated this experiment with skinny people and a low calorie diet. Their microbiotic diversity was already high and did not change much.

*read the full study here

Why?

Fat microbiomes tend to be more efficient at extracting nutrients from food and storing the excess, so whenever someone with an efficient microbiome eats, he/she stores a lot of the nutrients. Skinny microbiomes, on the other hand, are not as efficient at extracting nutrients so there is less energy to store after a meal. Going on a low calorie diet if you want to lose weight could solve the problem because whatever can be extracted from the food will be used for day to day functions. Considering that skinny people already are not extremely efficient at extracting nutrients, a low calorie diet will not necessarily cause any significant changes.

This source performed a study (humans) where they discovered that obese people typically have lower genetic diversity than lean people. Obese people who went on a low calorie diet had a higher genetic diversity at the end of the experiment than those who did not go on a low calorie diet, and obese people who continued to have a low genetic diversity gained significantly more weight over nine years. Lean people who went on a low calorie diet did not have a significant increase in microbiotic diversity compared to lean people who did not go on that diet. However, this correlation does not imply causation because some obese people have a high genetic diversity. Scientists believe that a low genetic diversity is linked to metabolic disorders, which could cause obesity, but that obesity in and of itself is not always caused by low genetic diversity.

Whenever you touch, breathe, or eat something, bacteria is entering your body and interacting with the native bacteria. So, when fat mice interact with skinny mice, it’s possible that the fat mice pick up diverse bacteria from skinny mice, contributing to their increase in microbiotic diversity, and when skinny mice interact with fat mice, they can’t lose genetic diversity but also have nothing really to gain from mice with low genetic diversity.

Conclusion: If you have a metabolic disorder, it could be beneficial to surround yourself with skinny people and eat low calorie foods because you’re more likely to absorb diverse types of bacteria while also storing less energy from food.

Pull-Ups, Biology, and Our Sexist Society

Men and women are different, right? Guys have more testosterone, which leads to greater muscle mass, facial hair, deeper voice, and greater height. Women have more estrogen, which leads to the development of characteristics like wider hips, and breast development. Having less testosterone means it is harder to gain strength, but not impossible. Anyone can, with the proper training regimen  increase their strength, regardless of sex. This, however, goes against what New York Times writer Tara Parker-Pope writes in her article Why Women Can’t Do Pull-Ups. In it, she cites a study in which

 Three days a week for three months, the women focused on exercises that would strengthen the biceps and the latissimus dorsi — the large back muscle that is activated during the exercise. They lifted weights and used an incline to practice a modified pull-up, raising themselves up to a bar, over and over, in hopes of strengthening the muscles they would use to perform the real thing. They also focused on aerobic training to lower body fat.

According to the study, only four of the seventeen women were able to do one pull-up at the end of the study. I, along with several hundreds of people who have posted angry comments on this article, have several issues with this study, and with the title of the article.

First, they focused on exercises that would strengthen the biceps and latissimus dorsi. My question is, what about the deltoids and trapezius muscles, and the core muscles in the abdomen, and grip strength? All of these come into play to some extent in a pull-up.

Second, I know from personal experience that using an incline to work your way up to pull-ups, often called a supine row, does not work.  I tried this for months and still could not do a pull-up. What did work was jumping over the bar and lower myself slowly (this is called negatives), and using resistance bands to hold whatever weight I could not support while doing a full pull-up. Now, I can do pull-ups. And, when you really think about it, a supine row uses the same muscles but the movement is in no way similar, so it doesn’t make sense to see it as a “toned-down” pull-up for beginners.

Taken by Amber Karnes
http://www.flickr.com/photos/ambernussbaum/4472515271/
2010 CrossFit Games; Women did pull-ups with a 14 lb vest.

Third, how in shape were these women? This was not made clear in the article, and obviously, even after six months to a year, a morbidly obese woman may not be able to do a pull-up.  I think the issue with the study and the article comes down to two things: bad journalism and bad science.  When a 17 year old AP Biology student is able to poke a bunch of holes in your argument and find a bunch of flaws in your experimental procedure, the competence of the individuals involved comes into serious question.

So, readers, can YOU do a pull-up? Do you know any females that can do pull-ups? And, if you were to run the experiment, what would you do differently?

Comment!

Original Article:

http://well.blogs.nytimes.com/2012/10/25/why-women-cant-do-pull-ups/

 

Additional Information:

http://en.wikipedia.org/wiki/Supine_row

http://en.wikipedia.org/wiki/Pull-up_(exercise)#Muscles_used

 

Photo: http://www.flickr.com/photos/ambernussbaum/4472515271/

Spring Allergies?

Photo Credit Flickr user: spakattacks

I don’t know about you but, I tend to have very severe environmental allergies in the spring. And spring is right around the corner! These allergies are often called hay fever. I came across an article that sheds light on some things one might be doing to aggravate spring allergies.

I found it very surprising that one of the things that can aggravate your allergy suffering is “noshing of fruits and veggies.” One of my favorite snacks is strawberries, but could this cause me more suffering during my allergy season? Many people who have seasonal allergies also suffer from pollen food allergy syndrome (also known as oral allergy syndrome). About 70 percent of people with birch tree allergies and about one in five people with grass allergies suffer from this condition. (my odds are pretty high).

You  might be wondering how you can tell if you have allergies or just a common cold. Here is an article that has more information on how to determine if you are sick with a cold or have allergies.

Now that I may have to stop snacking on fruit so much, I researched meals to help fight allergies. I also researched just some foods in general that will help with spring allergies, cause I most likely won’t have time to cook all those meals. Who knows maybe these foods could actually make a difference!

The best advice is not to procrastinate and start taking medicine before your symptoms will appear. There are many over the counter allergy medicines, but your allergist or doctor could always prescribe something stronger if necessary. Some experts are predicting spring of 2012 could be one of the worst allergy seasons in ten years due to the warmer temperatures in January. This increase in temperature has caused plants to begin blooming ahead of time. So I better stock up on some yogurt and fish!

 

S U G A R !

Mmm, sugar, so yummy…

Dr. David Katz, the director at the Yale Prevention Research Center writes of the negative effects of sugar in our lives in his article “Medicine, Museums, and Spoons Full of Sugar.” It’s a fact: kids and adults are eating way too much sugar, and this excess is known to contribute to the obesity epidemic.  Obesity itself causes other complications like diabetes and other diseases.

We’ve always known that having too much sugar is a bad thing, but how does it all add up? Soda like Coke, Sprite and Fanta are regarded by some public health experts as “liquid candy.”  Soda adds tons of calories and sugar to a typical diet.  So there you have it: soda is one of the many guilty culprits in the add up of sugar.

Taken by Yasmin Kibria

That’s only part of the problem–most of the excess sugar actually comes from foods.  “A how much is too much? According to Dr. Andrew Weil, everyone has a different response to sugar.  For some it triggers modd swings, brings on a sugar rush followed by a crash, and for some, there are no noticeable effects.  Sugar tends to drive obesity, high blood pressure, and Type II diabetes in people who are genetically programmed to develop insulin resistance.

How does too much sugar lead to obesity? According to Dr. Robert Lustig, sugar causes more insulin resistance in the liver than does other foods.  The pancreas then has to release more insulin to satisfy the liver’s needs.  High insulin levels obstruct the brain from receiving signals form leptin, a hormone secreted by fat cells.

The Importance of a Teenage Balanced Diet

 

Photo Credit Flickr User: Writing Program PTW

 

We all have heard someone in our life say: “what you do and how you act now will affect you in the years to come.” The teenage years set the foundation for the rest of your life. The choices you make on a daily basis affect you in later years. One of those daily choices is what you eat, and this choice is more important in your teenage years than you think.

A recent study sheds light on the importance of specifically iron intake in your teen years. Iron has more of an influence on ones brain than most would think. Professor Paul Thompson measured levels of transferrin in adolescents and discovered the “transferrin levels were related to detectable differences in both the brain’s macro-structure and micro-structure when the adolescents reached young adulthood.” Iron and the proteins that transport iron are critical for brain function.

After reading this article one problem I found is too little iron can result in cognitive problems but too much iron promotes neurodegenerative diseases.  So what is the right amount of iron intake? This article talks about iron intake and how much you should be incorporating in your diet everyday. Since both a deficiency and an excess of iron can have a negative impact that makes the body’s regulation of iron transport even more crucial.

A shocking aspect of this research was as it states in the article about the test subjects: “we were looking at people who were young and healthy — none of them would be considered iron-deficient.” The young individuals who were part of this study were not even iron-deficient! Yet still the research showed that healthy brain wiring in adults depends on iron levels in your teenage years.

Is it too late to start incorporating iron in your diet as an adult? Ofcourse not! You may be wondering how you can incorporate more iron in your diet. Iron can be taken in as a vitamin and found in many foods. As a healthy teenager you may not be always thinking about the things you eat but another thing people always say is: “you should have a balanced diet” and they are correct!

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